Tinting a poly finish

[Jakester]

So, say someone has just acquired something that had been professionally finished in a polyurethane clear coat which didn't match something else which has aged due to a nitrocellulose clear coat. 

 

Short of stripping off the poly in its entirety, tinting and then refinishing (either in poly or nitro) is there any way of 'tinting' the poly finish?

 

For example, is it possible to shoot a tinted poly clear coat on top? (I know poly coats stay separate when cured, unlike nitro ones which 'blend' into one another). Does such a product exist?

 

I know you can get tinted nitro clear coat for 'aging' guitars - is there a poly equivalent? Could I just spray tinted nitro on top of the poly (taking all necessary safety precautions of course)?

 

Could I just wipe on something like a tinted Osmo oil? Would that cure on top of poly?

[honza992]

Others with more knowledge of Poly/nitro will I'm sure offer more help, but Osmo definitely won't work.  It bonds to the wood itself and isn't a film forming finish.  There are film-forming oil finishes, eg Truoil, but I've got doubts it would bond to poly....

[Jakester]

Thanks - I only ask about the Osmo as I have some knocking around that would give the perfect tint. Sounds like you’ve prevented a very messy mistake though, thank you!

[Manton Customs]

Unless you have dedicated spray room and equipment, you probably won’t find a suitable Poly. This would be done with a 2k clear with tint added to it.
 

You should be able to spray Nitro over the top of the existing finish, but it depends what type of Poly it was sprayed with in the first place. People use the word for a lot of different finishes. If it was a catalysed 2k finish as is used on mass produced guitars then you should be fine. You can spray tinted nitro over it after first sanding it with 600 grit to give the finish a key. Also make sure you throughly wipe down and degrease the surface first. Then once your tint is sprayed, follow up with clear nitro to protect the tint. You’ll need enough clear to be able to completely level sand and buff afterwards without breaking through into your tinted coats… So it’s not a 5 minute job!

 

Nitro over the type of Poly(ester) you usually find on bodies works well and is what the majority of the new Fender nitro finishes are.

 

If you do go ahead…spraying a tinted finish takes practice to get it even. So maybe do some practice goes on card first.

[Jakester]

Thanks.

 

Worth knowing a dedicated spray place could add a tinted poly. 

 

I suspect it's a 2K as the previous owner told me it was clear coated by a car spray place.

 

Some good advice there, thanks v much.