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Troubleshooting & Tips for Leather Filler Application

Troubleshoot application issues with leather filler like peeling, curing, bubbles or shrinkage.

Why is Soft Filler is peeling up?

There are three possible reasons:

  1. Sanding where the filler is thinly feathered on the perimeter of the repair area has peeled it up.

    Soft Filler adheres best to worn areas where suede or fabric (like a subpatch) are exposed. Where the filler overlaps and is thinly blended on finished or undamaged areas, it has less to grab, and care should be taken not to over-sand these areas.

The Solution: Be minimalist to avoid removing the resin completely and starting again (though this is okay too). Trim away any bulky peeling sections with nail scissors. Blend any peeling edges with rubbing or denatured alcohol. Allow to completely dry. Apply more filler, minimally, as needed. Avoid sanding and do a final texturizing coat to avoid a smooth, patched appearance.

2. The repair area has residue from other conditioners, furniture polish, or body oil.

The Solution: Perform the tape test near the repair area. If the tape doesn’t stick, neither will the filler. Clean thoroughly with denatured alcohol (or acetone as a last resort) to resolve the adhesion problem. Then re-repair using the suggestions for #1.

3. Filler was applied to thickly or is not fully cured.

Water in the filler evaporates in the curing process. The surface will skim over, giving the illusion that it’s dry. Applying more can then peel up the skimmed surface.

The Solution: Apply thinner layers. Ensure the filler is completely dry before applying more. Use an incandescent bulb or direct sunlight as a heat source to accelerate cure time. Hair dryers are not recommended, because they push moisture inward.

Why is Soft Filler not curing?

There are three possible reasons:

  1. Filler was applied too thickly and/or its water content has not sufficiently evaporated.

The Solution: Apply thinner layers. Ensure the filler is completely dry before applying more. Use an incandescent bulb or direct sunlight as a heat source to accelerate cure time. Hair dryers are not recommended, because they push moisture inward.

2. Adhesives used to subpatch any hole may may contain a solvent that is preventing the filler from curing.

The Solution: Ensure any glue from subpatching a hole has completely cured.

3. The repaired area was not sufficiently cleaned prior to application.

The Solution: Make sure to clean the surface with denatured or rubbing alcohol prior to application of Soft Filler.

Why did Soft Filler dry with bubbles?

Bubbles in the cured resin are caused by too much heat. If you’re using an incandescent bulb, move it farther away from the repair area.

The Solution: Use a needle to poke a tiny hole in each bubble to allow it to deflate.

If the bubble lays down smoothly, apply a tiny bead of filler in the hole and smooth with your finger to seal it.

If the bubble did not lay down smoothly, try blending any peeling edges with denatured or rubbing alcohol. Acetone can also be used, but it will dramatically etch the filler, so be conservative. Allow to completely dry. Apply more filler, minimally, as needed. Avoid sanding and do a final texturizing coat to avoid a smooth, patched appearance.

Why did Soft Filler shrink after drying?

Shrinkage during the curing process is caused by applying the filler too thickly in any single layer and/or use of a hair dryer, which pushes moisture inward, rather than allowing it to evaporate with a radiant heat source (like sunshine or a light bulb).

The Solution: Apply thin layers of filler. Ensure it is completely cured before applying more. Use an incandescent bulb or sunlight to speed curing.

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