Finish on top of acrlyic paint

[Johnhamdun]

Hey Guys,

An artist is painting an old fender body I had laying around with acrylic paint and I had a question for you. I talked to the chemist at Laurence McFadden and he said that he was worried that because Nitro has to "bleed in" to the paint behind it and because acrylic dries harder than Nitro that the nitro might "de-laminate" if I just sprayed it on top of the acrylic. The design is to complicated to do another coat and then spray before it dries so that's out of the question.

Has ANYone done anything like this before? Should I spray polyurethane instead or is that going to suffer from the same issues?

Thanks a lot guys,
John Duncan

 

[vanhagar]

If you are going to leave the original color, I would wet sand the complete body with #400 or 600 just enough to dull the finish, then do the graphics with acrylic and re clear the body in acrylic.

 

[Johnhamdun]

If you are going to leave the original color, I would wet sand the complete body with #400 or 600 just enough to dull the finish, then do the graphics with acrylic and re clear the body in acrylic.

That's actually exactly what we did, except we can't find clear acrylic. Have you ever seen clear acrylic? If so, where would I buy it?

 

[vanhagar]

Most CarQuest and UAP dealers will have it in either a spray can or by the quart.

 

[Johnhamdun]

Most CarQuest and UAP dealers will have it in either a spray can or by the quart.

Great, thanks Vanhagar

 

[Davidh]

Ok, all well, BUT is there a particular reason why you shouldn't use PU here?

 

[Johnhamdun]

Ok, all well, BUT is there a particular reason why you shouldn't use PU here?

I was kind of thinking the same thing. So, tomorrow night I am using poly (if thats what you meant by PU) on a test piece of wood to see if itll react negatively with the paint. Assuming all goes according to plan I will let you know how it turns out. If nothing screws up then I will/should have the guitar finished by monday. I'll post an update soon.

Any input from anyone else would be really helpful!

 

[Davidh]

Cool! I'll be looking forward to your results, as I was planning to buy my paints and stuff on monday!

 

[Johnhamdun]

Cool! I'll be looking forward to your results, as I was planning to buy my paints and stuff on monday!

so far both the water based and oil based PU's are reacting fine. The water is dry and we have to wait a little whil on the oil. I think we will used water-based regardless because Acrylic is water-based. Lessen the chance of delamination?

Ill post again soon

 

[Davidh]

Allright, cool.

 

[Johnhamdun]

Update: I am applying the Poly by hand. So far so good. There are a few runs but I am letting it dry for a few days so I can sand them smooth. anyone have any advice on this?

In terms of poly on acrylic it is working perfectly so far.


any advice on what type and grade of sandpaper? micromesh?

 

[Davidh]

Aha, so you switched from the spray poly? Do you use a satin or glossy variant?

 

[chowlee]

Yesterday I had this: www.ckdoublenecks.com/bldgtr12.jpg .  Then I sprayed on acrylic clear and poof -  ten minutes later it was ruined

 

[Johnhamdun]

Yesterday I had this: www.ckdoublenecks.com/bldgtr12.jpg .  Then I sprayed on acrylic clear and poof -  ten minutes later it was ruined

wow... that sucks... sorry man. So far mine is working perfectly. I am letting it dry for a week (or more) and will disassemble the guitar to sand smooth and buff or sand smooth and add another coat depending on how I feel when it comes time. Will post pictures soon.

 

[Davidh]

Yesterday I had this: www.ckdoublenecks.com/bldgtr12.jpg .  Then I sprayed on acrylic clear and poof -  ten minutes later it was ruined

Ouch! So acryl on acryl is no guaranty either... (Fortunately I've got a cheap neck I use to practice the whole finishing process on). Good luck!

 

[Davidh]

Just had a guy from a company selling luthier products on the phone. I asked if their poly spray can was water-based or white-spirit based, since my paint is acryl and will solve in white spirit. He said a water based one in a spray can would be hard to fabricate since it would require a much higher pressure. I interpretet it as all spray cans are white spirit based and thus not useful when you used acrylic paint.
I thought this might be good to know if you're about to finish your guitar, to avoid the result Chowlee got.