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BROCHURE ERMINE Basic Finishing Rules for Avoiding Common Wood Finishing Problems Coating Coverage Brochure Common FInishing Problem Spraying Cause and Remidies

Brochure Ermine

Basic Finishing Rules for Avoiding Common Wood Finishing Problems

  • Make sure all finishing personnel are familiar with application of the products. Refer to Product Data Pages as well as consult Sales/Service Representative for proper handling.
  • Have complete system pre-tested and documented detailing each operation from white wood sanding to final inspection. Follow written procedures daily.
  • Inspect all application equipment on a daily basis – ensure it is clean and in working order.
  • The curing schedule should be routinely monitored. Oven temperatures as well as plant environmental conditions should be noted. Variations may require solvent additions. Refer to Product Data Pages.
  • Always thoroughly mix materials before application.
  • Reduce finishing materials in accordance with Product Data Page.
  • Use good housekeeping measures – a clean finishing area produces clean work, reduces loss time caused by rejects, accidents, fire, etc.
  • Check stock rotation. Note batch date (Julian calendar) and rex number when material is received. Use oldest date first.
  • Finish standards should be utilized at each finishing operation to ensure consistent quality and color.
  • In refilling leftover material, strain into clean containers, fill containers to the top, and close tightly so that there will be no air leakage into the package. Label and date. Refer to Product Data Page for proper handling of catalyzed materials.

Coating Coverage Brochure

PURPOSE

This section provides information on the key factors effecting coating coverage and costs. Consideration is also given to “stretching” a coating with thinner, and comparing costs per litre.

INTRODUCTION

The purchaser of protective coatings is responsible for selecting the most economic coating available which is suitable to achieve the required protection. The coatings field is complex and knowledge of coating calculation techniques and interpretation of data is required in order to make the appropriate choice.

VOLUME SOLIDS

Most liquid coatings contain a solids portion and a volatile portion. The solids portion consists of the binder, normally oil or resin, together with colorings and functional pigments, extenders and additives. The volatile portion is the solvent or thinner that merely liquefies the solids sufficiently to carry them onto the surface being coated. The solvent then evaporates, leaving behind the dried film of solids, which provides protection and decoration. The coating user is most concerned with this remaining film volume or thickness because it is this, which provides the desired hiding, gloss, weather resistance, colour etc.
When selecting a coating the key is how much area will the solids cover per litre after the volatiles have evaporated?

SOLIDS CONTENT BY VOLUME OF SURFACE COATINGS

Solids content is a theoretical calculation based on certain assumptions concerning the densities of the raw materials used in paints. In practice, the solids content obtained can vary greatly from its theoretical value because of change in the following:

  • Densities.
  • Temperature effects.
  • Small differences in the physical condition of the paint.
  • The methods and conditions of application.

    • In addition, film contraction, solvent-retention and volatility of low molecular weight polymers can all contribute error. The determination of volume solids by ASTM, is difficult to calculate and large variations have been observed in practice. For these reasons the volume solids values given in this manual are determined by a method which corresponds to ASTM method DZ697 and ISO 3233 with a slight modification for use at practical film thickness and with usual curing and hardening requirements.
    The calculations obtained are generally higher than the theoretical calculated volume solids, but the method approximates the spreading rates obtained under ideal conditions. Volume solids should not be used to gauge practical spreading rate as so many other variables have to be taken into account. For this purpose please use the data provided later in this section.

    “STRETCHING” A COATING WITH THINNER IS A MYTH :

    Adding solvent or thinner to the liquid coating adds nothing to the hiding or spreading rate of the coating solids as the extra solvent evaporates. Instead, extra solvent merely increases the coating cost by the price of the thinner and increases application costs by the additional labor time required to mix the thinner into the coating. In the case of baking systems, the cost is increased by the greater amount of oven heating required to remove the thinner. Adequate volume solids, not thinners, are the key to proper coverage by a coating.

    COMPARING LITRE COSTS :

    Often buyers tend to select a coating strictly on a cost per liter basis without considering the volume solids of the paint. The user of a coating should be interested in the cost of finishing a given unit area and not the price per liter.
    In the long run the coating user receives value only from that portion of the liter that remains as dried coating film after the volatile solvent or thinner has been released. Volume solids are the key factor in determining coating economies and not weight solids.

    THEORETICAL SPREADING RATE

    The theoretical spreading rate is a calculation of the amount of coating on average applied to a surface, assuming no losses or penetration into the substrate. It can be calculated as follows:

    Theoretical Spreading Rate (m2/L) = Volume Solids (%) x 10 / Dry Film Thickness (In microns)

    Example (i): A Paint has a volume solids of 55% and needs to be applied at a dry film thickness of 75 microns. What is the theoretical spreading rate?

    Theoretical Spreading Rate (m2/L) = 55 x 10/ 75 = 7.33 m2 L

    Example (ii): If 10% thinner was required to thin the coating to application viscosity and a dry film thickness of 75 microns is still required. The calculation would be as follows:

    Theoretical Spreading Rate (m2/L) =55 x 10 / 75 x (100%) / ( 100% +10%) = 6.67 m2 L

    PRACTICAL SPREADING RATE

    Except under closely controlled conditions, Theoretical Spreading Rates are hardly ever achieved, therefore in estimating coating requirements and costs, allowance must be made for losses which occur during application due to such factors as surface roughness, application method and application conditions. An empirical relationship which may be used to calculate Practical Spreading Rate as follows:
    Practical Spreading Rate = Theoretical Spreading Rate X Coverage Efficiency The BELOW (table) below shows the approximate coverage efficiencies expected for various surfaces and application conditions.

    Application Method

    Surface Coating Efficiency
    Brush/Roller Airless Spray/Interior Airless Spray/Exterior Airless Spray/Windy Conditions
    New Smooth Steel 0.87 0.78 0.68 0.49
    Blast Cleaned Steel 0.83 0.74 0.65 0.46
    Power Tool Cleaned Steel 0.79 0.70 0.61 0.44
    Blasted Steel – lightly pitted 0.79 0.70 0.61 0.44
    Blasted Steel – heavily pitted 0.74 0.70 0.58 0.41
    Rough Concrete or Masonry 0.61 0.66 0.47 0.34

    Example (i) : An application had a coating with a theoretical spreading rate pf 4.0m2/L and intended to airless spray lightly pitted steel, with only light winds. Calculate the practical spreading rate:

    Practical Spreading Rate(m2/L) = 4.0 X 0.61 = 2.44 m2 /L

    CONVERSION OF SPREADING RATES TO USAGE RATES It is sometime necessary to convert from spreading rates expressed in m2/L to a usage rate in L/m2. This is gives the amount of paint required to coat a square meter of surface:

    Usage Rate (L/m2) = 1 / Spreading Rate (m2/L)

    Example:A coating has a spreading rate of 2.5m2/L. What is the usage rate in L/m2?

    Usage Rate (L/m2) = 1/2.5 = 0.4 L/m2

    DRY AND WET FILM THICKNESS It is often necessary to convert between a wet film thickness and a dry film thickness. This calculation assumes that a perfect film is laid and that after evaporation of the solvents there is no air or solvent trapped in the film. This calculation is not accurate for inorganic zincs that have a porous silicate matrix.

    Dry Film Thickness (microns) = Wet Film Thickness X Volume Solids (%) / 100

    Example (i): A coating has a wet film thickness of 100 microns and volume solids of 60%. What would you expect the dry film thickness to be?

    Dry Film Thickness (microns) = 100 x 60 / 100 = 60Micron Dft
    Similarly,
    Wet Film Thickness (microns) = Dry Film Thickness X 100 / Volume Solids(%)

    Example (ii): A coating has a dry film thickness of 100 microns and volume solids of 80%. What would you expect the wet film thickness to be?

    Wet Film Thickness (microns) = 100 x 100 / 80 = 125 microns(WFT)

    ESTIMATING PAINT QUANTITIES FOR BOATS:

    The following table outlines the calculations for paint quantities for boats, an example is provided.

    Boat Area & Quantity Calculation

    Spars & Masts length X mean circumference = square meters

    Deck Areas length overall X beam X 0.75 = square meters

    Topsides(length overall + beam) X 2 X average freeboard = square meters

    Underwater Areas length at waterline X (beam + draught) = square meters

    Example: Calculation of required paint quantity for a boat hull.

    An underwater area of a steel vessel 15 meters long at the waterline, draught of 1.5 meters and beam of 4 meters.
    The coating to be applied has a theoretical spreading rate of 7m2/Liter and the following application conditions apply:

    • Application method = Spray
    • Substrate = Blasted steel – lightly pitted
    • Area to be coated = length at waterline X (beam + draught) = 15 X (4 + 15)= 82.5 m2
    • Practical Spreading Rate = Theoretical Spreading Rate X Coverage Efficiency = 7 X (0.61) = 4.27m2/Liter
    • Paint quantity reqd. for underwater area = 82.5m2/4.27m2 /Liter = 19.32 Liters
    • Practical quantity = 20 Liters

    Common FInishing Problem

    Wood – surface preparation:

    Moisture contentAll lumber should be stored on the premises in dry warm rooms to prevent absorption of moisture. The amount of moisture contained in a piece of wood is referred to as “moisture content” and is expressed as a percentage indicating the relative weight of the water in the wood compared to its own dry weight.Wood expands as it absorbs moisture and shrinks when it loses it. The moisture content of wood changes with the level of moisture or humidity in the air. The moisture content of wood at the time it is coated should be approximately 5-8%. This may be checked by testing with one of many meters on the market designed for this purpose.

    Sanding:All surfaces should be sanded smooth. Each subsequent sanding should use a finer grit paper than the previous. A typical system would involve using 100 grit followed by 150, 180 and touch up with 220. The spread between grit sizes should be close enough so as not to leave sand scratches from the first sanding that cannot be removed by the next.All sanding dust must be removed by using either a tack rag or a blast of clean air from a spray gun. If any dirt or greases attaches to the surface before actual finishing, it must be removed by solvent wiping

    Medium density fiberboard :

    Medium Density Fiberboard (MDF) is widely used as a wood substrate in the furniture, cabinetry and novelty markets. MDF offers:surface smoothness, surface stability and resistance to cracking because joints are eliminated. Edge phenomena :

    The porosity of edges and routed surfaces of MDF presents some unique finishing problems with pigmented systems.Loss of adhesion, racking or peeling of the finishing system may occur in the routed areas or edges. This failure is more prone to occur with catalyzed finishes such as : Primer, Surfacer and Pigmented Conversion Varnish, but may occur with other highly pigmented systems. This phenomena occurs only in the routed areas and edges and does not occur on the smooth MDF face.When the first coat of primer or primer surfacer is applied to these porous routed areas, the resin tends to soak into the wood leaving behind a very highly pigmented surfacer layer. The stress from subsequent topcoats can cause adhesion loss and peeling in these areas over time.

    finishing MDF with pigmented coatings, we recommend the edges and routed areas be sprayed with a coat of:Wood Vinyl/acrylic Sealer before applying pigmented primers or primer surfacers:

  • Reduce the sealer from 50 to 100% with lacquer thinner, depending on the porosity of the MDF. This is a penetrating application rather than a build coat. This treatment controls penetration of subsequent coats into the wood. It functions much like a washcoat when used with a wood filler. If the subsequent primers and topcoats are catalyzed, the Vinyl Sealers would be catalyzed too.

    • Preparing MDF for painting:

    Routed areas and edges of MDF panels would be cut with sharp, high quality cutting tools. Ceramic, carbide or diamond coated cutting tools is recommended. The quality of initial cutting and machining has a significant impact on the amount of labor necessary for subsequent finishing operations. Worn or dull tools pull wood fibers from the board leaving a course surface with many voids. Routing and cutting also creates fiber raising.To minimize this fiber raising, the routed and cut areas, as well as the unmilled flat surfaces, should be sanded with 240-320 grit no-fil sandpaper. Do not use worn belts or paper or very fine grades of sandpaper which will polish and decrease adhesion.

    Common Finishing Problems:

    Sr.No PROBLEM CAUSE REMEDY
    1 BENARD CELL
    • A. Excessive/draft air movement.
    • B. Improper solvent.
    • A. Minimize air movement by eliminating the source of the draft.
    • B. Use correct solvent blend. Refer to Data Page.
    2 BLEEDING
    • A. Organic red pigments or various dyes under stain or undercoats that have not been sealed properly.
    • A. Best remedy is to avoid use of bleeding colors i.e., red. Pre-test catalyzed systems to ensure they do not cause undo color change.
    3 BLISTERING
    • A. Sometimes strong solvents tend to react with preceding coat.
    • B. Temperature too high entering oven.
    • A. Be sure that the under-coats are thoroughly dry. Use primer recommended. Use thinner with lowest solvent strength which will still act as steady diluent. Allow for more flash-off time. Refer to Product Data Page.
    • B. Lower temperature entering oven, gradually increasing temperature.
    4 BLUSHING
    • A. Separation of nitrocellulose due to:
      • 1. Humid weather.
      • 2. Drafts.
      • 3. Poor thinner.
      • 4. Lacquer sprayed when cold.
      • 5. Damp spray rooms (generally concrete floors at ground level).
      • 6. Moisture in spray equipment.
    • A. A combination of factors tend to cause blushing, and likewise, a combination of factors may be used to remedy the difficulty.
      • 1. Close windows.
      • 2. Add retarder to thinner or use a better quality thinner.
      • 3. Bring the lacquer to room temperature.
      • 4. Blushing caused by condensation of water and subsequent evaporation from cold spray rooms can be avoided by warming up the room.
    5 BREAK IN FAN OR CURTAIN(curtain coater/fan coater)
    • A. Too much air movement in the application area.
    • B. Curtain break in coating.
    • A. Eliminate draft and put draft shield next to curtain coater/fan coater.
    • B. Adjust solvent blend to increase surface tension.
    6 BRITTLENESS
    • A. It is often difficult to differentiate between "lack of adhesion" and brittleness, in evaluating some film failures. Other than inherent brittleness or lack of adhesion in a finish, the cause for either difficulty will be the same.
    • A. See #33, "Lack of Adhesion."
    7 BROWN SPOTS
    • A. Oil coming through separator of spray line.
    • A. Bleed the line at least once every shift, or every eight hours.
    8 BUBBLES APPEAR IN OPEN GRAIN WHEN APPLYING SEALER/TOPCOAT
    • A. Excessive moisture content.
    • A. Reduce moisture content to 6 to 8%.
    • B. Utilize slower evaporating solvent blend or flow additive to reduce surface tension.
    9 BUBBLING OF COATING (latex)
    • A. Temperature of material (coating) too high for application.
    • B. Air not releasing from coating.
    • C. Drying temperature too high.
    • D. Board temperature too high.
    • A. Turn temperature down. Refer to Product Data Page.
    • B. Check agitation/fluid handling equipment for air leaks.
    • C. Reduce curing temperature.
    • D. Cool down substrate.
    10 COLD CHECKING (usually takes the form of parallel lines more or less right angles in the direction of the grain)
    • A. Excessive film thickness.
    • B. Excessive moisture content.
    • C. Excessive catalyst or improper catalyst ratio.
    • D. Insufficient drying period and improper storage conditions. Repeated or sudden variations in temperature.
    • E. Wrong product used for application.
    • A. Reduce film thickness. Refer to Product Data Page.
    • B. Moisture content – range 6 to 8%.
    • C. Refer to Product Data Page.
    • D. Refer to Product Data Page.
    • E. Refer to Product Data Page.
    11 COLOR DOES NOT MATCH STANDARD
    • A. Color system was not followed.
    • A. Check wet retain for color as well as verify approved step panel color standard.
    • B. Standard should be same as substrate.
    • C. Check sanding procedure.
    • D. Check solvent blend.
    • E. Check application of stain as well as method of flash-off time.
    • F. Topcoat. Make sure same product is used for gloss and clarity.
    12 CRACKING OF FILM
    • A. Application of too-heavy a coat.
    • B. Material applied that went beyond pot life cycle.
    • C. Higher temperature will accelerate cross-linking process.
    • D. Excessive catalyst or improper catalyst ratio.
    • A. Apply only sufficient material to accomplish full covering.
    • B. See Product Data Page. Use new batch.
    • C. Lower temperature in pressure pot or application area.
    • D. Refer to Product Data Page.
    13 CRATERING
    • A. Silicone contamination.
    • B. Oil contamination.
    • C. Excessive moisture in coating.

    NOTE: Post list of possible contaminates not allowed in plant.
    • A. Locate source of contamination and eliminate it. Check wipers, belt dressings, lubricating greases and oils, hand creams, metal and wood polishes, etc., as possible sources. Check air supply for source of contamination
    • B. Check air supply for possible source of contamination as well as rubbing lubricants.
    • C. Check container for moisture. Store inside and check air supply.
    14 CRAZING OF FILM
    • A. Insufficient drying of system. Packaging of parts too soon after finishing.
    • A. Allow for complete drying and/or check oven temperature or reduce amount of slow solvent in the reducer.
    15 CRITICAL RECOAT PROBLEM
    • A. Not catalyzing sealer.
    • B. Using slow drying resin type stains.
    • C. Not using recommended system and exceeding recommended film thickness.
    • D. Stain or sealer not completely flashed off.
    • A. Catalyze both sealer and topcoat in catalyzed system.
    • B. Use only recommended stains. Refer to Product Data Page.
    • C. Refer to Product Data Page.
    • D. Allow for longer dry time. Check oven temperature and dwell time.
    16 DIRTY OR SEEDY FINISH
    • A. Unclean conditions of application
      • 1. Dust in paint room.
      • 2. Dirt in air or paint lines of spray apparatus.
    • B. Improper solvent which tends to throw resin out of solution.
    • C. Material has been subjected to extreme hot or cold temperatures which tends to throw some particles out of solution.
    • A. Cleanliness. Rearrange equipment so that any spray dust from booths does not reach drying chambers.
    • B. Use the recommended thinner.
    • C. Strain material. Allow material to reach room temperature before applying. If seediness is still present, replace batch.
    17 DISCOLORATION
    • A. Presence of foreign vapors.
    • B. Waterborne coatings will rust steel parts in application equipment and can contaminate coatings.
    • C. Improper drum liner.
    • D. Inadequate cleanup at changeover.
    • E. Tannin bleed.
    • A. Investigate the nature of any vapors which might be present. It will then be necessary to shield off the vapors from contact with the finish.
    • B. Change to stainless or plastic pots.
    • C. Make certain correct liner is being used.
    • D. Flush lines completely. Clean up pumps, hoses, filters, reservoirs.
    • E. On red oak, for example, check waterborne systems for tannin bleed as well as acid-cured systems. Avoid self sealing – use sealer.
    18 END GRAIN DARKER WHEN STAINED
    • A. End grain more absorbent than top grain.
    • A. Wash coat before staining.
    • B. Use faster solvent blend.
    19 EXCESSIVE BODY
    • A. Any material which will dry in the presence of air at normal temperatures will tend to take on body by virtue of the oxidation which takes place.
    • B. Even an alkyd type enamel will tend to take on additional body due to evaporation of solvents.
    • C. Change in pH.
    • D. In the more advanced stages of oxidation, a livering action often occurs which is aggravated by the too-swift an addition of extra thinner. It should be remembered that thinner should always be added slowly and the mixture stirred at the same time.
    • E. Use of improper solvent.
    • F. Freezing (latex).
    • G. Beyond shelf life.

    GENERAL: The primary cause of excessive bodying is, in most cases, improper handling of dip tank or other storage facilities. A method for keeping all storage tanks tightly sealed should be arrived at and carefully adhered to.
    • A. If bodying of the material has not proceeded to the point where there is livering action, it is often possible to bring the thickened product back into solution by addition of a stronger solvent of the same general type or class.
    • B. Add power solvent to bring liquid to proper viscosity and body.
    • C. Make necessary adjustments to pH. Refer to Product Data Page.
    • D. If a definite livering has occurred, a sample should be obtained for evaluation.
    • E. Use recommended reducer.
    • F. Store inside or above 32ºF. If material has freeze/thaw stability, do not agitate material when frozen. Allow it to return to room temperature undisturbed (65ºF - 72ºF).
    • G. Check Product Data Page for shelf life information.
    20 EXCESSIVE CHALKING
    • A. Finish coat applied over porous surface which absorbs the binder and leaves unprotected pigment at surface.
    • A. Seal porous surface thoroughly before application of finish coat.
    21 EXCESSIVE MARRING
    • A. Film not completely dried.
    • B. Too low of film thickness.
    • A. Allow for complete drying and/or check oven temperature.
    • B. Apply recommended film thickness.
    22 EXCESSIVE MATERIAL
    • A. Not triggering the gun at each stroke.
    • B. Gun held at wrong angle to surface.
    • C. Gun held too far from surface.
    • D. Wrong air cap or fluid tip.
    • E. Depositing material film of irregular thickness.
    • F. Air pressure too high.
    • G. Fluid pressure too high.
    • A. It should be a habit to release trigger after every stroke.
    • B. Hold gun at right angle to surface.
    • C. Work gun 6 to 10 inches from surface.
    • D. Use correct combination.
    • E. Learn to calculate depth of finish of wet film with wet film gauge.
    • F. Use least amount of air necessary.
    • G. Reduce pressure.
    23 EXCESSIVE PRINT/BLOCKING2
    • A. Insufficient drying time.
    • B. Too heavy a coat.
    • C. Slow drying due to poor air drying conditions.
    • D. Selection of improper quality.
    • E. Incorrect catalyst ratio.
    • F. Substrate too warm.
    • A. Allow for longer air drying and/or check oven temperature and dwell time.
    • B. Apply lighter coats.
    • C. Increase air movement and/or room temperature.
    • D. Check customer requirements for proper product submittal.
    • E. Check Product Data Page for recommendations.
    • F. Cool substrate before stacking.
    24 EXCESSIVE SETTLING
    • A. Over-reduction or improper thinner.
    • B. Too rapid thinning.
    • A. Refer to Product Data Page.
    • B. Add thinner gradually, stirring constantly.
    25 EXCESSIVE SPRAY FOG2
    • A. Wrong solvent blend.
    • B. Atomizing air pressure too high.
    • C. Over-reduction of material.
    • D. Gun held too far from surface.
    • E. Spraying past surface of the product.
    • F. Wrong air cap or fluid tip.
    • G. Fluid pressure too low.
    • A. Usual remedy is to choose a slower evaporating thinner.
    • B. Use least amount of compressed air necessary. Refer to Product Data Page.
    • C. Use less reduction. Add fresh material to that which has already been over reduced.
    • D. Hold gun at proper distance from work (usually 6 to 10 in.).
    • E. Release trigger when gun passes target.
    • F. Ascertain and use correct combination.
    • G. Increase fluid pressure.
    26 FLAT SPOTS
    • A. An absorbent-type putty has not been sealed in and accordingly, causes top coat to strike in.
    • B. Oily or dirty surfaces.
    • A. Seal the putty.
    • B. Provide clean painting surface.
    27 FOAMING WATER-BORNE COATINGS
    • A. Agitation too rapid.
    • B. Air leak in system.
    • A. Reduce the amount of agitation.
    • B. Add recommended defoamer.
    • C. Check pumping apparatus. Change pump, if necessary, to diaphragm pump.
    28 GLOSS DOES NOT MATCH STANDARD
    • A. Overspray.
    • B. Moisture.
    • A. Insufficient agitation.
    • A. Correct spray pattern. Use slower solvent blend.
    • B. Check air supply for moisture contamination.
    • C. Make sure material is properly agitated before removing from con-tainer. Use agitation on line for low gloss materials.
    29 GRAY PORE
    • A. Filler not completely dry.
    • B. Sanding dust left in pore.
    • A. Allow more dry time, check oven temperature and dwell time and adjust to faster evaporating solvent.
    • B. Remove sanding dust with air nozzle.
    30 GUM BLUSH OR HAZE
    • A. Incorrect thinner.

    NOTE: Both blushing and gum blush can almost always be removed from finished articles by spraying reflow thinner over the affected parts.
    • A. Use the correct thinner as recommended by Product Data Page.
    31 GUN SPUTTERS CONSTANTLY
    • A. Fluid tip not tightened to spray gun.
    • B. Leaky connection on fluid tube or fluid needle packing (suction gun).
    • C. Lack of sufficient material in container.
    • D. Tipping container at an acute angle.
    • E. Obstructed fluid passageway.
    • F. Material too heavy (suction feed).
    • G. Clogged air vent in cup lid (suction feed).
    • H. Dirty or damaged coupling nut on cup lid (suction feed).
    • I. Fluid pipe not tightened to pressure tank lid or pressure cup cover.
    • A. Tighten securely, using a good gasket.
    • B. Tighten connections; lubricate packing
    • C. Refill container with material.
    • D. If container must be tipped, change position of fluid tube and keep container full of material.
    • E. Remove fluid tip, needle, and fluid tube and clean.
    • F. Thin material.
    • G. Clean.
    • H. Clean or replace.
    • I. Tighten; check for defective threads.
    32 HAND MARKS/FINGER PRINTS ON FINISH COAT
    • 32 HAND MARKS/FINGER PRINTS ON FINISH COAT
    • A. Employees should clean hands thoroughly or gloves should be worn during the sanding process.
    33 LACK OF ADHESION
    • A. Unclean surface.
    • B. Sometimes the finish coat and the primer used are not meant to be used together, and the solvent in the finish coat practically lifts the primer from the surface. Even though film will dry and have good appearance, primary adhesion has been ruined.
    • C. Over catalyzation or incorrect catalyst.
    • D. Oversanding can cause polishing of the wood when fine grits are used.
    • A. Clean carefully with volatile solvent.
    • B. Make sure that recommended primer and finish coats are used together.
    • C. See Product Data Page for recommendation.
    • D. Use coarser grit. Refer to manufacturer’s guide.
    34 LACK OF ADHESION BETWEEN COATS
    • A. Sealer and topcoat not recommended for use together.
    • B. Primer surfacer may have picked up contamination.
    • C. Lack of chemical and/or mechanical bond.
    • A. Use properly recommended system. (Always recommend total system.)
    • B. Protect from contami-nants. Apply quicker.
    • C. Use recommended sanding procedure between coats. See Product Data Page.
    35 LACK OF FLOW
    • A. Insufficient reduction.
    • B. Use of solvent with too fast an evaporation rate.
    • C. Improper atomization of coating.
    • D. Application of too thin a film.
    • E. Roughness of substrate or underline coat and variations in porosity.
    • F. Draft condition.
    • G. Temperature of material.
    • A. Reduce according to instructions. Refer to Product Data Page.
    • B. If fast evaporation is due to local weather conditions, choose a slower evaporating solvent than originally recommended.
    • C. Adjust spray equipment.
    • D. Apply more material to surface.
    • E. May require a primer surfacer with filling properties versus a sealer.
    • F. Find reducing solvent or blend to provide proper flow in a draft OR eliminate the draft.
    • G. Material should be applied at temperature recommended on Product Data Page.
    36 LACK OF HIDING
    • A. Over-reduction.
    • B. Application on very hot, smooth surface which tends to cause film to flow off.
    • C. Pigment not properly stirred into suspension.
    • D. Too-slow evaporating solvent, causing too much flow.
    • E. Improper atomization.
    • F. Low film thickness.
    • A. Add fresh, unreduced material to the reduced material.
    • B. Use a faster evaporating solvent or cool down part.
    • C. Stir thoroughly to properly distribute pigment.
    • D. Use faster evaporating solvent.
    • E. Adjust spray equipment.
    • F. Apply more paint via more passes with spray gun, high solids (less reduction) faster reducer.
    37 MATERIAL LEAKS FROM FLUID NEEDLE PACKING NUT
    • A. Loose packing nut.
    • B. Dry fluid needle packing.
    • A. Tighten packing nut.
    • B. Remove and soften packing with a few drops of light oil.
    38 MATERIAL LEAKS FROM SPRAY GUN
    • A. Fluid needle packing tight.
    • B. Fluid needle packing dry.
    • C. Foreign particle blocking fluid tip.
    • D. Damaged fluid tip or fluid needle.
    • E. Broken fluid needle spring.
    • A. Tighten nut; lubricate packing.
    • B. Lubricate needle and packing frequently.
    • C. Remove tip and clean.
    • D. Replace fluid needle with correct size for fluid tip being used.
    • E. Remove and replace.
    39 MATERIAL WON’T COME FROM PRESSURE TANK OR POT
    • A. Lack of proper air pressure in pressure tank or cup.
    • B. Air intake opening inside pressure tank or cup lid clogged by dried up paint.
    • C. Leaking gasket on tank cover or pressure cup lid.
    • D. Leaky connections on fluid tube, air cap, or fluid tip.
    • A. Check for air leaks or lack of air entry; adjust air pressure for sufficient flow.
    • B. Clean opening periodically.
    • C. Replace gasket.
    • D. Check for leaks under water and repair.
    40 MATERIAL WON’T COME FROM SPRAY GUN
    • A. Out of paint.
    • B. Grit, dirt, paint skin, etc., blocking air cap, fluid tip, fluid needle, or strainer.
    • A. Add paint.
    • B. Clean spray gun thoroughly and strain paint; always strain paint before using.
    41 METAMERISM
    • A. Light source different than what color was matched under.
    • A. Use a color formula containing no more than four pigments/dyes.
    42 MUDCRACKING (Water Reducible)
    • A. Excessive film thickness.
    • B. Draft.
    • C. Too fast of drying.
    • D. Cold application (latex).
    • E. Incorrect catalyst or ratio used.
    • A. Reduce amount of film thickness. Refer to Product Data Page.
    • B. Eliminate draft.
    • C. Add additional co-solvent.
    • D. Most latex coatings will not coalesce below 50º-60ºF. Film that has not coalesced properly will be powdery or exhibit very poor film integrity.
    • E. Refer to Product Data Page.
    43 ODOR (Latex Coatings)
    • A. Bacteria growth.
    • A. Keep lids tightly sealed
    • B. Avoid extreme high temperature changes.
    • C. To correct problem, add small amounts of formaldehyde.
    44 OIL BLOOM
    • A. Rubbing down with oil before lacquer is thoroughly dry. Absorbed oil floats to the surface later.
    • A. Allow a longer dry time. Bloom can sometimes be removed by washing with Hi Flash Naphtha or spraying thin coat of clear. Allow to dry and rub again.
    45 ORANGE PEEL
    • A. Material not thinned out sufficiently.
    • B. Not depositing a wet coat.
    • C. Gun stroke too rapid.
    • D. Insufficient air pressure.
    • E. Using wrong air cap.
    • F. Gun stroked too far from surface.
    • G. Overspray striking a previously sprayed surface.
    • H. Poor thinner.
    • I. Gun too close to surface.
    • J. Material not thoroughly mixed.
    • K. Drafts (synthetics and lacquers).
    • L. Humidity too low.
    • A. Add the correct amount of solvent by measure.
    • B. Check solvent; use correct spread and overlap of stroke.
    • C. Take deliberate, slow strokes.
    • D. Increase atomizing pressure or reduce fluid pressure.
    • E. Select correct air cap for the material and feed.
    • F. Stroke the gun 6 to 10 inches from surface.
    • G. Spray detail parts first; end with wet coat.
    • H. Use better grade of thinner for strength.
    • I. Gun should be worked 6 to 10 inches from surface.
    • J. Mix material thoroughly.
    • K. Eliminate excessive drafts.
    • L. Raise humidity of room.
    46 PEELING/ CRACKING OF MEDIUM DENSITY FIBERBOARD EDGES
    • A. Dull cutting tool or router.
    • A. Replace cutting tool or coat edge with catalyzed clear vinyl sealer or replace substrate.
    47 PINHOLES OR BUBBLING
    • A. Drafts which cause surface drying and force the solvent to break through that surface film in order to evaporate.
    • B. Fine drops of moisture coming through separator in spray apparatus.
    • C. Either the solid wood or the veneer may be improperly kiln dried, or may have absorbed excessive moisture.
    • D. Gun too close to surface.
    • E. Fluid pressure too high.
    • F. Use of too heavy material.
    • G. Thinner evaporates too fast.
    • H. Porous surfacer or fillers.
    • I. Incomplete drying of filler. Strong solvent in finishing coat tends to react with undried filler.
    • J. Spots of grease on surface.
    • K. Material applied while frothy, following violent agitation.
    • L. Lack of wetting of the surface by the enamel.
    • M. Too low moisture in substrate.
    • A. Avoid drafts.
    • B. Clean spray equipment.
    • C. Only solution is to cure or dry wood properly.
    • D. Work gun 6 to 10 inches from the surface.
    • E. Reduce pressure.
    • F. Check temperature and viscosity of material. Refer to Product Data Page.
    • F. Check temperature and viscosity of material. Refer to Product Data Page.
    • G. Use slow evaporating solvent.
    • H. Use uniform surfacer or seal it before applying finish coat.
    • I. Use a faster drying filler or allow greater drying time or arrange to dry at elevated temperatures.
    • J. Clean surface carefully.
    • K. Allow froth to subside before applying.
    • L. Wipe surface to be sprayed with a solvent-saturated cloth before application of the next coat.
    • M. Moisture content should be 6 to 8% level.
    48 POOR/ INADEQUATE ADHESION OVER DARK COLOR STAINS
    • A. Excessive stain pigment not penetrating.
    • A. A cleaner wipe.
    • B. Multi-step system: dye stain, then wipe stain.
    49 PUMP FREEZE-UP (Latex)
    • A. Heat build-up in pump causes latex to coalesce.
    • A. Switch to diaphragm pump.
    50 ROUGHNESS OF FINISH
    • A. Surface not correctly sanded.
    • B. Flash-off area exposed.
    • C. Overspray.
    • A. Properly sand materials before applying finish coat and remove sanding dust.
    • B. Shield off flash-off area from airborne contaminants.
    • C. Change spray pattern. Use slower evaporating solvent blend.
    51 SAGGING OF FILM
    • A. Sagging is caused by either over-reduction or by using too slow drying solvent.
    • B. Application of too heavy a coat.
    • C. Draft condition.
    • D. Strong sunlight causing top drying and consequent later slippage of film on vertical surfaces.
    • E. Jerky operation of mechanical equipment for withdrawal from dip tank.
    • F. Subjected to unusual conditions of heat or cold.
    • G. Dirty air cap and fluid tip.
    • H. Gun held too close to surface.
    • I. Not releasing trigger at end of stroke (when stroke does not go beyond object.)
    • J. Gun held at wrong angle to surface.
    • K. Fluid pressure too high.
    • L. Operation too slow.
    • M. Improper atomization.
    • N. Reducer added too fast without sufficient stirring.
    • O. Natural oxidation of the material if allowed to remain open to the air over a period of time.
    • A. Use the proper solvent for the product, consistent with the general nature and temperature of the surface to be coated. Refer to Product Data Page.
    • B. Do not apply so much material to the surface.
    • C. Eliminate draft.
    • D. Avoid application in strong sunlight.
    • E. Repair or redesign equipment.
    • F. Keep material at a temperature 70ºF. If break occurs because of extreme heat or cold, repair or redesign equipment.
    • G. Remove cap and fluid tip and clean or replace, if necessary.
    • H. Hold the gun 6 to 10 inches from surface.
    • I. Release trigger after every stroke.
    • J. Work gun at right angles to surface.
    • K. Reduce fluid pressure.
    • L. Speed up movement of gun across surface.
    • M. Use larger air cap (internal mix); increase volume of air through horns (external mix). Check line and tank settings.
    • N. Add reducer slowly, stirring constantly.
    • O. Addition of proper amounts of solvent, plus infusion of fresh material will put batch into con-dition if oxidation has not proceeded too far.
    52 SKINNING OF LIQUID2
    • A. While it is possible to minimize skinning, it is something which will occur to a varied degree whenever any air-drying material is exposed to air.

      • NOTE: If the break is too pronounced, it may not be possible to put the material back into condition satisfactorily for use. Prepare new batch for use

    • B. Oil-type materials.
    • C. Synthetic type.
    • D. Waterborne.
    • A. Make sure that containers in which the material is stored are air tight. Dipping tanks should preferably have an oil or water-sealer cover, and cover should be in place whenever tank is not in use.
    • B. Cover remaining contents of partially filled container with small amount of appropriate solvent before sealing.
    • C. Cover remaining contents of partially filled container with small amount of synthetic reducer before sealing.
    • D. Float water and appropriate co-solvent blend. Cover remaining before sealing.
    53 SOFTENING OF FILM
    • A. Not properly catalyzed.
    • B. In contact with vinyl causing "plasticizer migration."
    • C. Incorrect solvent.
    • A. Refer to Product Data Page.
    • B. Utilize catalyzed material for maximum protection. Refer to Product Data Page.
    • C. Some retarders stay in the film for long periods of time causing film to stay soft. Refer to Pro-duct Data Page for sol-vent recommendations.
    54 SPLOTCHY STAIN APPEARANCE
    • A. Variation of density of wood.
    • B. Glue residue on surface.
    • A. Check sanding procedure or washcoat.
    • B. Remove glue residue with solvent wipe or by sanding.
    55 SPOTTY DRYING
    • A. Unclean surface.
    • A. Clean carefully with solvent.
    • B. Check sanding procedures.
    56 SPRAY PATTERN BOTTOM HEAVY
    • A. Horn holes partially clogged (external mix).
    • B. Obstruction on bottom side of fluid tip.
    • C. Dirt on air cap seat or fluid tip seat.
    • A. Remove air cap and clean.
    • B. Remove and clean tip.
    • C. Remove and clean seat.
    57 SPRAY PATTERN HEAVY AT CENTER
    • A. Spreader adjustment valve set too low.
    • B. Atomizing pressure too low.
    • C. Material of too great viscosity.
    • D. Fluid pressure too high for air cap’s normal capacity, pressure feed.
    • E. Fluid tip too large for material used.
    • A. Increase volume of air by opening spreader adjustment valve.
    • B. Increase pressure.
    • C. Thin material with suitable thinner.
    • D. Reduce fluid pressure.
    • E. Use smaller fluid tip.
    58 SPRAY PATTERN HEAVY TO LEFT
    • A. Left side of air holes partially clogged.
    • B. Dirt on left side of fluid tip.
    • A. Remove air cap and clean air holes.
    • B. Remove fluid tip and clean.
    59 SPRAY PATTERN HEAVY TO RIGHT
    • A. Right side of air holes partially clogged.
    • B. Dirt on right side of fluid tip.
    • A. Remove air cap and clean air holes.
    • B. Remove fluid tip and clean.
    60 SPRAY PATTERN SPLIT
    • A. Air and fluid not balanced.
    • B. Air cap or fluid tip dirty.
    • A. Reduce width of spray pattern.
    • B. Remove and clean.
    61 SPRAY PATTERN TOP-HEAVY
    • A. Horn holes partially plugged (external mix).
    • B. Obstruction on top side of fluid tip.
    • C. Dirt on air cap seat or fluid tip seat.
    • A. Remove air cap and clean.
    • B. Remove and clean.
    • C. Remove and clean seat.
    62 STAIN BLEED OUT OF PORE NORMALLY OAK OR ASH
    • A. Excessive use of Gilsonite.
    • B. Excessive stain vehicle.
    • A. Reduce amount of Gilsonite and/or add more stain vehicle 10-15%.
    • B. Adjust the stain formula.
    63 STREAKS
    • A. Dirty air cap and fluid tip
    • B. Not overlapping strokes correctly or sufficiently.
    • C. Gun moved too fast across surface.
    • D. Gun held at wrong angle to surface.
    • F. Air pressure too high.
    • G. Split spray.
    • H. Tipping gun.
    • I. Streaks telegraphing through from primer coat or under coat.
    • J. Variation in porosity of substrate such as fiberboard or particleboard due to manufacturing process or uneven belt sanding.
    • A. Remove cap and fluid tip and clean or replace, if necessary.
    • B. Follow previous stroke.
    • C. Take deliberate, slow strokes.
    • D. Work gun at right angles to surface.
    • E. Hold gun 6 to 10 inches from surface.
    • F. Use least air pressure necessary. Refer to Product Data Page.
    • G. Reduce air adjustment or change air cap.
    • H. Spray pattern should strike surface at right angles.
    • I. Make certain primer coat or underline coat is properly, evenly applied and uniformly sanded.
    • J. May require double filling of primer application to remedy problem. Substrate supplier should be made aware of the problem. New batch of substrate may be required.
    64 VENEER CHECKING (normally expressed in longitudinal cracks in the veneer)
    • A. Veneer quality.
    • B. Veneer moisture content.
    • C. Panel components and construction.
    • D. Processing conditions.
    • E. Gluing procedures.
    • F. Sanding.
    • G. Warehouse conditioning.
    • A. Select well-cut, tight veneers since excessive knife checks are a source of trouble. Use extra care in processing oak, walnut, and highly figured veneers. These are more sensitive to checking.
    • B. Control veneer moisture content to below 6%.
    • C. Control lumber and plywood core moisture content to 5-8% to minimize warping and telegraphing. Control particle board core moisture content to 4-10% to avoid telegraphing.
    • D. Use hot press operation wherever possible but avoid excessive drying. Keep closed assembly time to a minimum.
    • E. Apply glues uniformly and avoid excess. Use hot press operation whenever possible but avoid excessive drying.
    • F. Adjust depth of sanding according to the side of the face veneer which is exposed.
    • G. Condition and maintain moisture of the pressed panel to 5-8%.
    65 VENEER GLUE LINES SHOWING
    • A. Excessive glue used.
    • B. Excessive pressure.
    • A. Reduce the amount of glue and use colored glue to match veneer.
    • B. Reduce pressure.
    66 WASHING OF FILM
    • A. In some dip operations, faulty ventilation in the hood above the dip tank allows a concentrated collection of solvent vapors. This reduces the film on the object which has just been withdrawn from the dip tank, thereby causing the film to wash or flow off the finishing surface.
    • B. Wash caused by cleaning solvents remaining in crevices.
    • C. Greasy, waxy, or otherwise unclean paint surface.
    • D. Failure to stir all pigmented finishes into proper suspension before application. Failure to stir properly unbalances formula of applied material and often will cause poor drying.
    • E. Improper ventilation.
    • A. Provide proper ventilation over dip tank.
    • B. Be sure surface is clean, as well as all crevices. Change angle of drain.
    • C. Clean surface carefully with volatile solvents.
    • D. Stir the material thoroughly so that liquids and pigment will be evenly dispersed.
    • E. Provide ventilation.
    67 WHITE SPOTS
    • A. Water mixing with the lacquer either through the separator or by not having the surface dry.
    • A. Clean air line and separator. Be sure surface to be finished is dry. Bleed the line at least once every shift, or every eight hours.
    68 WRINKLING OF A SMOOTH ENAMEL
    • A. Too heavy a coat.
    • B. First coat not completely dry.
    • C. Sand through.
    • A. Apply light coat.
    • B. Allow more dry time.
    • C. Allow more dry time on the sealer.

    DO’S AND DON’T:

    Dried material in side port “A” restricts passage of air through port on one side. Results in full pressure of air from clean side of port in fan pattern in direction of clogged side.

    Dissolve material inside port with thinner. Do not use metal devices to probe into air nozzle openings.

    Dried material around the outside of the fluid nozzle tip at position “B” restricts the passage of atomizing air at one point through the center ring opening of the air nozzle. This faulty pattern can also be caused by loose air nozzle or a bent fluid nozzle or needle tip.

    If dried material is causing the trouble remove air nozzle and wipe off fluid tip using rag saturated with thinner.

  • Tighten air nozzle.
  • Replace fluid nozzle or needle if bent.
    • A split spray pattern (heavy on each end of a fan pattern and weak in the middle) is usually caused by:
    • 1. atomizing air pressure too high
    • 2. attempting to get too wide a spray with this material
    • 3. not enough material available.
    • 1. Reduce air pressure.
    • 2. Open material control “D” to full position by turning to left. At the same time turn spray width adjustment “C” to right. This reduces width of spray but will correct split spray pattern.
  • Air entering the fluid supply
  • Dried packing or missing packing around the material needle valve which permits air to get into fluid passageway.
  • Dirt between the fluid nozzle seat and body or a loosely installed fluid nozzle.
  • A loose or defective swivel nut, siphon cup or material hose.
  • Be sure all fittings and connections are tight.
  • Back up knurled ring “E”. Place two drops of machine oil on packing. Replace nut and finger tighten. In aggravated cases replace packing.
  • Remove air and fluid nozzles “F” and clean back of fluid nozzle and needle seat in the gun body using a rag saturated with thinner.
  • Replace and tighten fluid nozzle using wrench supplied with gun.
  • Replace air nozzle.
  • Tighten or replace swivel nut “G”.
    • A fan spray pattern that is heavy in the middle or a pattern that has an unatomized “salt and pepper” effect indicates that the atomizing air pressure is not sufficiently high or there is too much material being fed to gun.
  • Increase pressure from air supply.
  • Correct air pressures as discussed elsewhere