acrylic lacquer problem: solutions?

[Cat MacKinnon]

Valspar is listing acetone and isobutyl acetate on the msds. From what you're saying, it isn't nitro.

Seems to be working fine, though.

Those are common solvents and used in both acrylic and nitro lacquers (and other paints.) But if it doesn't list nitrocellulose/cellulose acetate or butyl cellosolve (or one of the dozen other names its called), then is most likely not nitro. An MSDS needs to list every hazardous component of a particular product, and nitrocellulose certainly falls into that because it's highly flammable. On the other hand the acrylic resins used are fairly inert and harmless, so they're not always going to be on an MSDS unless the manufacturer decides to list them. Nitro is also dangerous to manufacture, so when you combine that with the lower toxicity of acrylic lacquer, it's no wonder most manufacturers aren't bothering to make nitro lacquer for consumers anymore. Of course there are still plenty of manufacturers on the pro/commercial side, it's just less convenient for us because it's no longer a matter of just hitting up the hardware store.

On a related note, I did discover that SprayMax's 1k clear is actually an acrylic lacquer (I assumed it was an enamel.) Considering the quality of their other products, it might be really good stuff and at $9 a can the price is right. If someone was interested in trying out various acrylic lacquers, I think it'd be a good one to check out. In fact, if I had the cash (or if someone wanted to donate materials), I'd be willing to buy several of the readily-available aerosol acrylic lacquers to test them. Maybe I should setup a crowdfunding thingy to make that happen .

 

[DrASATele]

While we're on the subject, I just like to remind everyone that 2k poly(urethane or -ester) is absolutely not the same thing as the poly you get at a hardware or woodworking store. Hardware store poly like Minwax and General Finishes is simply just another oil varnish that happens to have polyurethane resins added for durability; 2k (catalysed) poly is a completely different type of finish that just happens to share a couple similar resins with the hardware store stuff. Otherwise they're not related at all. Water-based "polyurethanes" (like Polycrylic) are a third different type of finish, although they're marketed as waterbased "counterparts" to regular wipe-on poly; in reality, most waterbased finishes are kinda their own thing, but that gets into chemistry that is confusing to the average consumer so it's easier for them to just say it's the waterbased version of the oil-based stuff.

At any rate, hardware store poly and 2k poly aren't really compatible in the sense that they won't chemically bond to each other; they are not lacquer (lacquer is a specific family of paint, not a generic term.) The Minwax stuff might adhere to 2k poly finishes with scuff-sanding first, but usually they just peel off so they're not considered compatible (although there are very few chemicals that will actually damage 2k poly; even MEK and acetone won't touch it!) Lacquer will stick to 2k poly a little better, but again the 2k is really slick and most other types of finishes just don't stick to it very well. Lacquer on a headstock to bury a decal isn't too bad though since it's not a "high wear" area, although don't be too surprised if the lacquer scrapes or chips off fairly easily (but it may not either, it just depends. Plenty of people have sprayed lacquer over 2k to bury headstock decals with no problems, so it certainly works.)

I only bring this up to help others who may come across this thread in the future. Lately I've been a lot of posts online where people assume Minwax Poly and 2k poly are the same thing, when they're not. I figured it was a good time to toss a reminder up, at least for the benefit of future DIY'ers.

Thanks Cat, this was what my inadequate post was trying to get at in terms of what they might use in the factory setting.
I hope no one got confused I wasn't suggesting the GF was a 2K, it just a better store bought version of the waterbased minwax stuff.

 

[Vizcaster]

Minwax Polycrylic isn't lacquer, it's polyurethane. Fresh layers of it do not burn into previous layers like lacquer does, and thick applications of it stay plastic forever.

What you're looking for is nitrocellulose lacquer. If I'm using spray cans I use Watco or Valspar. Valspar has several clear coatings, look for the one the specifically says lacquer.

You can still go waterborne and get burn-in from one coat to the next, so nitrocellulose lacquer is not the only option. Target Coatings EM6000 will completely burn in to prior layers - no witness lines when sanding, and no reveal when drop-filling. But you can't get it in spray-bombs. Quite frankly, if you invest in a cheap HVLP kit it will pay for itself because spray cans are a really expensive way to buy finish.

 

[dsutton24]

You can still go waterborne and get burn-in from one coat to the next, so nitrocellulose lacquer is not the only option. Target Coatings EM6000 will completely burn in to prior layers - no witness lines when sanding, and no reveal when drop-filling. But you can't get it in spray-bombs. Quite frankly, if you invest in a cheap HVLP kit it will pay for itself because spray cans are a really expensive way to buy finish.

Minwax Polycrylic is nothing like Target EM6000.

 

[Vizcaster]

Minwax Polycrylic is nothing like Target EM6000.

I agree. I found Polycrylic to be hazy, blue, and easily scratched. And the name itself invites confusion about the resin component and the general classification of finish. Target Coatings industrial products are in a different league and I continue to use them.

 

[kingoflimbs]

lacquer over poly. never poly over lacquer.

 

[Rano Bass]

On a related note, I did discover that SprayMax's 1k clear is actually an acrylic lacquer (I assumed it was an enamel.) Considering the quality of their other products, it might be really good stuff and at $9 a can the price is right. If someone was interested in trying out various acrylic lacquers, I think it'd be a good one to check out. In fact, if I had the cash (or if someone wanted to donate materials), I'd be willing to buy several of the readily-available aerosol acrylic lacquers to test them. Maybe I should setup a crowdfunding thingy to make that happen .

It is acrylic lacquer but it's nor really good for guitars......I used it and it is like the Duplicolor clear, it never fully hardens.
Those kinds of automotive acrylic lacquers are designed mostly for bumper repair and since most bumpers in modern cars are made of flexible plastic those lacquers are somewhat flexible too.
Acrylic lacquers designed for wood (Rustoleum, Valspar, etc) dry harder IMO.

 

[Cat MacKinnon]

It is acrylic lacquer but it's nor really good for guitars......I used it and it is like the Duplicolor clear, it never fully hardens.
Those kinds of automotive acrylic lacquers are designed mostly for bumper repair and since most bumpers in modern cars are made of flexible plastic those lacquers are somewhat flexible too.
Acrylic lacquers designed for wood (Rustoleum, Valspar, etc) dry harder IMO.

That's good to know regarding the SM 1k. I'd actually like to try Mohawk's CAB-acrylic, I feel like that might be a good option for guitars if it's anything like some of the other CAB-acrylics people are using.

 

[Rano Bass]

I'd actually like to try Mohawk's CAB-acrylic, I feel like that might be a good option for guitars if it's anything like some of the other CAB-acrylics people are using.

That should be a good lacquer.

I have used Sherwin Williams CAB acrylic lacquer with very good results.

 

[Cat MacKinnon]

That should be a good lacquer. View attachment 390164 View attachment 390165
I have used Sherwin Williams CAB acrylic lacquer with very good results.

Is CAB-acrylic as forgiving as nitro, or does it have the rather strict thickness limits of pre-cat?

 

[Rano Bass]

Is CAB-acrylic as forgiving as nitro, or does it have the rather strict thickness limits of pre-cat?

It works just like nitro but does not yellow overtime. It's water clear in the can.

 

[Cat MacKinnon]

It works just like nitro but does not yellow overtime. It's water clear in the can.

Excellent! That's what I hoping to hear. I don't like the yellowing of certain colors (whites, pastels), so I really need to give some CAB-acrylic lacquer a try. The Mohawk comes in aerosol, so I'll have to order a can to play with (it's only about $7.)