Edge Mapping,Solvent Penetration

Also known as: Sandscratch swelling, tramlining, lining up, flattingmarks,sanding marks, scratch swelling

Description: Enlarged sandscratches caused by swelling action of topcoat solvents, appearing at the area of the repair where it was sanded through to the substrate.


    » Improper surface cleaning or
    preparation. Use of too coarse
    sandpaper or omitting a sealer in panel repairs greatly exaggerates swelling caused by thinner penetration
    » Improper thinner or reducer, especially a slow-dry thinner or reducer when sealer has been omitted

    » Under-reduced or wrong thinner (too fast) used in primer-surfacer causes“bridging” of scratches
    » Primer not well dried before application of color
    » Application of undercoat too heavy
    » Application of color when the original finish is too sensitive to paint solvents use


    » Use appropriate grits of sanding material for the topcoats you are using
    » Avoid sanding through to soft or sensitive substrates
    » Seal to eliminate sandscratch swelling.Select thinner or reducer suitable for existing shop conditions
    » Use proper thinner and reducer for primer-surfacer
    » Do not apply coats of primer too heavily
    » Use compatible paint systems.


    » Thoroughly dry affected area
    » Sand smooth, isolate with appropriate sealer, and refinish

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