During my first time painting with a pearl white tri-color, I started off with a white sealer with a hardener, then a basecoat and the pearl coat. After the sealer dried, I applied the basecoat, but after about a minute it all wrinkled, so I tried again. The first time, I let the sealer dry for about 30 minutes, but the second time I let the sealer dry for one hour. The second time, when I applied the basecoat, it was okay, but when I applied the pearl it wrinkled again. What am I doing wrong?
Question answered by Bill Warner, technical manager for Pro-Spray Automotive Finishes.
Many products have what is called "recoat windows." This is the timeframe when a product may be recoated generally without an issue. If you recoat outside of the recoat window, you have problems like lifting or wrinkling. In your case, the lifting or wrinkling happened when the product, in this case sealer, was in a semi-solid stage and solvents in the basecoat and pearl coat basically tried to rewet or dissolve the sealer. The sealer cannot go back into a liquid state, and it lifted or looked like alligator skin.
Why did this happen? There are many variables that could cause the problem:
1. Was the sealer part of a brand system? Was the sealer compatible with the type and brand of paint used?
2. Film thickness can also be a factor. Too thin does not make a good enough barrier. Too much could skin over the top and leave a semi-soft film underneath. At least 1 mil of sealer is needed so solvents don’t penetrate the dry film.
3. Temperature and proper reducer and hardener selection. Was the correct hardener used for the temperature in order for the sealer to crosslink correctly?
4. The proper amount of hardener is necessary for crosslinking. Measuring when mixing product becomes extremely important.
5. Old hardener or product could also be an issue. If the hardener is opened and not used in awhile, it could lose its reactivity.
6. Make sure the temperature of the car and environment is up and not cold. Too hot a temperature will narrow the recoat window.
Since we have many potential variables, a fix could be to apply two coats of sealer and allow to dry overnight. Scuff sand and then apply color. That should fix the problem. Check with manufacturers’ technical sheets for complete information. The bad news is, the lifted sealer must be removed first and recoated.