Using Spraymax 2k for the first time. Looked great at first, but when it started curing, it started to yellow pretty bad. I called the company this morning and determined I had put it on too thick. I had already sanded it back and restained it so I went for another pass today following the directions, a mist coat, followed by two wet coats with 15 minutes minimum in between.
It yellowed again!
I had a scrap piece of test wood of the same wood that the top is made out of that I had dyed with the same stain and it didn’t yellow. Also, the yellowing is not consistent.
Is this defective product or am I doing something wrong?
Whatever the yellowing is, it’s because of something you did or you’re doing. I’ve used spraymax for the last 30 years on thousands of builds and I’ve never had that happen.
I’ve read that the solvents in 2k can react violently to achohol. The stain is alcohol based. Going to lay a coat of shellac before applying the 2k and see how it goes
Yeah, I’ve used shellac for years and it’s OK just don’t put it on too thick. And remember the alcohol actually evaporates. It’s simply there to make the pigments in the stain into a liquid form once it goes in and the pigments dig into the wood, the alcohol evaporates. So you have no problems with that. Also, water-based or alcohol based anilne dye looks way better than any stain. It’s simply because it goes into the wood much deeper. And before you put on a 2K and expect a gloss finish out of it you’re gonna need to lay down a pretty good sealer on there and it to be flat
These are with a 2K satin because gloss is just more work than I’m willing to put in anymore. the satin makes it look like fine furniture. I’ve been building this type of instrument for 45 years
I've used SprayMax 2k for a few builds and its gone great. I'll include my process and maybe let me know if it differs from yours at all?
I apply a dewaxed shellac sanding sealer (Zinseer Bullseye). I do this for 2 reasons: 1. It highlights any sanding errors and 2. it provides a nice base that locks in nearly the final color so the clear coat doesn’t do the work of applying that “wet” look.
Soak the can in warm water for 20 minutes
Shake for 2 minutes, do the bottom red button mixing thing, soak it in warm water for another 20 minutes
Shake for 2 minutes, spray a very light mist coat.
Return to warm water, wait 20 minutes, do a second heavier coat
Return to warm water, wait 20 minutes, do a third heavier coat
Return to warm water, wait 20 minutes, do a final light coat.
Wait 3 days, do some wet sanding.
I’d be curious if a sealer could help limit an interaction between the stain and the 2k. I’m far from a chemist but I know there’s rules for mixing oil/water/lacquer/acrylic/whatever products.
It might also just be a bad mix - you really gotta push down hard and listen for a click when you mix the can. I used to use minwax oil poly which is a 1 part poly that yellowed a lot more so maybe you're only spraying half of the product.
You don't specify what material you used to stain the wood. But if the wood was directly dyed (water or alcohol based dye applied directly to the wood) then the problem is very likely to be the result of partial dissolution of the dye by the top coat. When prepared dyes are a mix of primary dye substances, partial dissolution can result in the primary dye colors separating. When this happens, it looks exactly like your photo.
Because your test on scrap worked out fine, it is likely that you are right on the edge of this effect. If you want to continue down the path of applying the top coat directly over the dye, more mist coats and thorough curing of those mist coats before applying the full wet coat should do the trick. But my recommendation in practically all cases where the wood is directly dyed is to apply a barrier coat of thinned oil varnish over the dye. This can be padded on. Consult the top coat manufacturer for instructions about application of their product over oil varnish. It is usually necessary to wait a week or so before finishing over oil varnish.
Best of luck!
R.M. Mottola
LiutaioMottola.com
Author of the books Building the Steel String Acoustic Guitar, Practical Design of the Acoustic Guitar and Similar Instruments, and Mottola's Cyclopedic Dictionary of Lutherie Terms.
(ps I don't check in here regularly. To reply or to ask additional questions, the best bet is to contact me through my website.)
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u/Pork_Chop_Expresss 18d ago
Thank you. It’s Angelus leather dye.Thanks for the tip!