Finish Moving After Final Buff?

[Daniel Sorbera]

After finishing in 2k poly and letting it dry for around 5 days. I sanded/buffed the finish and it looked amazing. But a week after that the finish has started to shrink some and it looks like orange peel because the finish has sunk into the pores a little bit. I re-leveled and re-bffed and it looks great again and I've not had any more problems with it. Is this normal that the finish would still shrink after it's been cured, sanded, and buffed?

Edited November 2, 2006 by Godin SD

[Drak]

Sorry Godin, since I don't shoot poly I can't help you there, I just wanted to comment that I think the term orange peel is THE most overused and abused term out there in finishing land. People use this term for basically anything that doesn't look like a perfect gloss from what I've read.

Everything from normal spray wave to a dry mix to debris getting into the mix and more all get attributed as orange peel.

How a finish that has sunken into the pores could possible look like orange peel is far beyond me, it just looks like a finish that has sunken into the pores is all, I see it happen all the time, to every single finish I shoot, that's why I wait several months so it will happen before I final level, it's quite normal really to get depressions in the pores, but it doesn't look anything like real orange peel.

Just razzin' ya pilgrim.

[rhoads56]

It wasnt cured before you buffed. Get a spray booth with a heat/UV/IR source, or wait a LOT longer.

[Setch]

In short: yes, it's normal

Even chemically cured finishes shrink, though not as much as evaporative ones, so it's always worth waiting a while to buff, unless you have a very good curing booth or UV cure system.

[Southpa]

Everything shrinks back to some degree. I can remember my first guitar, an all mahogany custom job that I didn't grain fill beforehand. I shot tons of poly into that guitar until I reached a buffable finish. It looked like the top of the bar at your local drinking establishment. Now, 4 years later I can see the grain showing through. Its not a big deal, one day I'll just give it a good scuffing and reshoot. From now on all my mahogany will get an epoxy filling. Its much quicker, easier and more thorough to pack it in by screeing with a knife or plastic card than it is to just shoot repetitive coats.

[PaintIt]

This is typically reffered to as die back. This is when the finish shrinks during the curing. In some cases it is the primers that are still shrinking if they were top coated while still wet or not fully cured. I like to spray my filler primer and let it sit a day before sanding. I do spray my basecoat over the sealer as soon as the sealer has flashed in order to get a good chemical adhesion. Clear can be sprayed as soon as the basecoat has flashed to get the best adhesion also. If the base coat is left open out of window then it needs to be sanded to get a good mechanical adhesion. As we know sanding the basecaot is not an option on metallic color so it is best to clear in window or use a intercoat clear over the base to allow for scuffing.

Depending on the temp 2k clear is curing for about a month and can sie back after buffing. I like to cut and buff twice. Once within 24 hours of clearing( the clear is easier to sand ) The second cut and buff about 1 week later. You also need to be carefull of the heat from buffing as this can cause the wood to swell and contract. hope this helps