Are competition mustangs finished in poly?

[RoséBear]

I’m just wondering- there’s a lot of hype behind these guitars- mostly because of Kurt. But did the original comp stangs use nitro or poly? From my understanding this was after CBS acquired Fender and switched to poly?

[Rob]

I’m just wondering- there’s a lot of hype behind these guitars- mostly because of Kurt. But did the original comp stangs use nitro or poly? From my understanding this was after CBS acquired Fender and switched to poly?

Poly.

[Highnumbers]

All Fenders after 1968 (even toward the end of that year) used catalyzed polyurethane paint, and the factory stopped using nitrocellulose lacquer except for sealing decals on the headstock.

The term “poly” is misleading because polyurethane is not the same as polyester. The former was used from ‘69 to ‘73(?) and replaced by the much thicker polyester finish.

Both are two-part catalyzed finishes which were more efficient in production, curing hard in a matter of hours instead of weeks, and far more durable than lacquer finishes. Customers at the time complained about how quickly nitrocellulose lacquer wore through on the body and fretboard, so the switch to polyurethane completely solved that issue.


IIRC, the first use of polyurethane finishes on Fender guitars was for the Paisley & Flower Telecasters because lacquer couldn’t build thick enough to fully bury the printed contact paper that covers the bodies on these guitars. I believe that’s where Fender discovered polyurethane, though they still bursted the edges with nitrocellulose lacquer. Nearly all of those Teles were built in 1968.

[copacetic]

Most Fender finishes post 1967-68 or so are polyurethane, (Technically it was called Aliphatic Urethane Coating) but i have seen quite a few Competition Mustangs and other examples of the era with nitro finishes. It seems Fender werent always consistent with their clear coat usage around the late 60's when they switched. Perhaps there was a period where they were using up all their leftover nitro. Documentation from any direct sources regarding this is scarce as far as i know so we can only speculate

Nitro finished original 69 compstang:



Urethane is indeed different from modern day "Poly" finishes Fender uses which are actually Polyester, a much harder, more durable plastic-like finish. This is why you often see vintage fender "poly" finishes still age/yellow over time and pick up a nice worn look. "Transitional" Poly(urethane) finishes from Fender arent overly thick and it seems they sprayed them much like their nitro finishes, but by the early/mid 70s or so, the finishes get thicker and thicker until the eventual switch to polyester sometime in the mid-late 70s IIRC. Modern Polyester is basically designed to stay as close as possible to factory looking for as long as possible. Id wager that in 40-50 years our Classic Vibes and MIM Fenders probably wont have near as much yellowing or "mojo" going on with the finish, which may be desirable depending on who you ask

[JSett]

Weirdly, I've had two early 70s Fenders that were nitro (tested with acetone), both sunbursts, so those must have still got it for a while past '68.

One was a 72 JM, the other a 73 Mustang.

All the colours and natural finishes I've seen post 68 have been poly.

[RoséBear]

Very interesting! So it seems modern reissues of these guitars are more accurate than I thought!

[Highnumbers]

Very interesting! So it seems modern reissues of these guitars are more accurate than I thought!

Not really, if you read our posts above. The reissues today are painted in polyester — the one finish type (out of the three) that was never used on original Compstangs in 1968-1973.

[Gavanti]

Weirdly, I've had two early 70s Fenders that were nitro (tested with acetone), both sunbursts, so those must have still got it for a while past '68.

One was a 72 JM, the other a 73 Mustang.

All the colours and natural finishes I've seen post 68 have been poly.

Ditto on nitro on my '72 Jag and a '73 JM, both sunburst. I'm pretty certain the headstocks are also finished in nitro, but the necks are poly. I read somewhere that this was typical of early 70s sunbursts. A 69 Mustang I had for a bit was definitely the highly reactive poly Fender used.

[Matthias]

Yeah, I’ve seen other people on forums reporting their sunburst or black Fenders appear to be nitro. Fender were using plastic sealers from about 63… I’ve not seen anything to contradict that the necks were poly from about ‘68. Except, decals responded better to a nitro top coat, so Fender oversprayed the headstocks with nitro right into the late CBS years.

Metallics and Olympic White were never nitro as far as I recall reading, not in the 60s and 70s… They were acrylic lacquer and I think I also read Fender didn’t change those when they moved to poly for other finishes. But then, the competition models were unique finishes weren’t they?

[Highnumbers]

Metallics and Olympic White were never nitro as far as I recall reading, not in the 60s and 70s… They were acrylic lacquer and I think I also read Fender didn’t change those when they moved to poly for other finishes.

While many of the colors were acrylic lacquer (lucite, specifically for most of the metallics), the operative word is lacquer.

Regardless of the formulation, lacquer is a solvent-based finish system. It requires no catalyst and dries hard when the solvents in that paint evaporate over weeks. That’s why you can easily wipe away lacquer finish with paint thinner or acetone decades after it’s sprayed, the finish will liquify again after you add a solvent back to it.

It doesn’t matter if it’s a “nitrocellulose” or acrylic, the only thing that matters is that it’s a lacquer system.

By 1969, Fender had replaced all lacquer finishes with catalyzed polyurethane. A catalyzed finish requires mixing a hardener liquid into the base color, which makes it spray on thicker and cure very quickly (in a matter of hours).

Fender absolutely switched from lacquer based paints to catalyzed polyurethane in 1969 and then again to catalyzed polyester in the early 70s - this includes all colors such as the Olympic White you mention above.

Sounds like a few people are saying they kept sunburst as a lacquer finish into the early 70s (maybe for spraying the burst?) but that has not been my experience with the guitars I’ve handled from that era. They were polyurethane or polyester.

[JSett]

Sounds like a few people are saying they kept sunburst as a lacquer finish into the early 70s (maybe for spraying the burst?) but that has not been my experience with the guitars I’ve handled from that era. They were polyurethane or polyester.

The acetone on the end of my Q-tip and the back of a SB '73 Mustang begs to differ...



I did the same test under the guard of my SB '72 JM and had the same result, black and clearcoat...

[MattK]

I'm not 100% sure but I believe acetone can dissolve polyurethane. I have a black 78 Musicmaster I tried to clean with methylated spirits (ethanol/methanol mix) and the finish instantly softened and ran. I don't think 70s Fender finishes play by any rules.

[Matthias]

Metallics and Olympic White were never nitro as far as I recall reading, not in the 60s and 70s… They were acrylic lacquer and I think I also read Fender didn’t change those when they moved to poly for other finishes.

While many of the colors were acrylic lacquer (lucite, specifically for most of the metallics), the operative word is lacquer.

Regardless of the formulation, lacquer is a solvent-based finish system. It requires no catalyst and dries hard when the solvents in that paint evaporate over weeks. That’s why you can easily wipe away lacquer finish with paint thinner or acetone decades after it’s sprayed, the finish will liquify again after you add a solvent back to it.

It doesn’t matter if it’s a “nitrocellulose” or acrylic, the only thing that matters is that it’s a lacquer system.

By 1969, Fender had replaced all lacquer finishes with catalyzed polyurethane. A catalyzed finish requires mixing a hardener liquid into the base color, which makes it spray on thicker and cure very quickly (in a matter of hours).

Fender absolutely switched from lacquer based paints to catalyzed polyurethane in 1969 and then again to catalyzed polyester in the early 70s - this includes all colors such as the Olympic White you mention above.

Sounds like a few people are saying they kept sunburst as a lacquer finish into the early 70s (maybe for spraying the burst?) but that has not been my experience with the guitars I’ve handled from that era. They were polyurethane or polyester.

I checked guitarHQ and it would seem some of the info around this phased cut-off might be circulating from that…http://www.guitarhq.com/fenderc.html No idea if this is 100% accurate but it at least would explain why we find people who are confident their early 70s bursts and *some* black guitars lacquer (as logically and if true, Fender would have black nitro around). The most interesting claim there is shooting the aliphatic urethane clear over lacquer coats…

Fender sort of confirm that here, although ambiguously, by suggesting aliphatic urethane was brought in initially to replace nitro clear coats… And then came polyester in the 70s. But I’ve seen Fender get specs wrong on their site before so not sure how reliable this necessarily is either https://www.fender.com/articles/behind- ... f-finishes

Intriguing, for sure… I’m open-minded on this, just interested there are a few angles on this doing the rounds.

I'm not 100% sure but I believe acetone can dissolve polyurethane. I have a black 78 Musicmaster I tried to clean with methylated spirits (ethanol/methanol mix) and the finish instantly softened and ran. I don't think 70s Fender finishes play by any rules.

I’ve wondered how reliable the acetone test for lacquer is. I know the stuff can attack various plastics.