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That T.P.A. Paint sticker

By: David Elsberry and Jim TenCate (USA)

INTRODUCTION

TPA Paint? “That Pissy Awful” paint is what one Jaguar owner calls it in a forum you might wander into if you’re looking for information on this paint. If you’ve got a 1979 or newer wedge, you may be wondering what that TPA Paint sticker on your strut tower is all about. Actually, you may or may not have a sticker on your strut tower, they didn’t stay on very well. Don’t worry, Triumph also put the sticker on the sides of the headlight pods, though you will have to remove them to find it (see the photo). It could also be that you’ve had your car stripped to bare metal and repainted and it’s quite certain the body shop would not have used TPA paint for the repair. What's the fuss all about anyway? Is TPA paint the reason so many of the 1980 and 81 metallic paints look so dull? What can you do about it? Can it be easily repaired? How should you treat it?

TPA, or Thermoplastic Acrylic paint, was a single stage acrylic lacquer resin paint mixed with a heat-setting plasticisers used by British Leyland starting in calendar year 1979, and used into 1987. Not unique to Triumph, this paint technology was also used on other BL cars, as well as some Fiats and even some Ferraris. Coincidentally, production of the Jaguar Series III at the Castle Bromwich plant began in 1979 also, and TPA paint was introduced on the all-new Series III Jaguar with less than stellar results. On Triumph cars, it seems that the change to TPA paint coincided with the move from Speke to the Canley facility, and continued to be used through the end of production at Solihull. What is not clear however is exactly when in 1979 TPA paint went into use. It is reasonable to assume however that around 15,000 cars were produced by Triumph with TPA paint, although arguably that is at best an estimate. It’s also worth noting that some colors may be found in both an early non-TPA version and a newer TPA version (Carmine and Vermilion are two examples we know about).

TPA paint was applied by spraying and then subsequently baking the body shell to flow the paint out to a deep gloss. By baking the paint, the lacquer was dried, and the plastic in the paint softened and flowed into a smooth top coat of paint. When initially applied, the paint was beautiful, especially considering that during the early to mid 1970s the paint in use on the majority of cars was acrylic enamel, which was known for its tough surface and ability to withstand abuse. Compared to enamel paints and their inherent tendency to develop an orange peel texture, these new acrylic lacquers were beautiful and glossy, with a depth not seen since nitrocellulose lacquer fell out of use. They have a unique depth of gloss not seen with the newer base coat / clear coat technology, which looks more like “paint under glass”.

UH OH...

It would seem that this new formulation of paint that gave the beauty of nitrocellulose lacquer, addressed many of the environmental concerns of the solvents commonly used in lacquer (i.e., high volatiles or VOCs), and used plasticisers to provide both flexibility and toughness like enamel, would have a lot going for it. Unfortunately, the plasticisers in the paint did not lose the ability to soften when heated, which became the inherent problem with the paint. There were numerous problems with the paint post production, perhaps seen worst on the new Jaguar cars, and many of the new Jaguar Series III cars were repainted under warranty, sometimes even before the cars could be sold at the dealership. The paint was easy to stain (see the photo for an example), was easily damaged by solvents, and far too flexible, at times literally cracking off the primer substrate. The paint over time would alligator and exhibit symptoms of “lacquer check”. This was due to the lacquer being baked into a hard surface, while the plastic binders in the paint continued to be flexible. This was particularly noticeable with the metallic paints. I remember that in 1987 my 1980 Poseidon green TR7 had these finish problems - but only when it was cold. When you parked the car in the summer sun in Georgia, the plastic within the paint would expand, and the finish looked perfect! Jim took a closeup of the paint on a recently found TPA Platinum metallic car (see photo) which shows just how ugly the paint can get.

WHAT TO DO

If you still have TPA paint however, don’t assume the worst. All is not lost, it’s just that you need to think about how to take care of it compared to more traditional paints in use today. TPA paint has no clear coat to protect it, so whatever you do to it, you’re doing it directly to the base paint. It is very solvent sensitive, and odds are pretty good that if you have ever had a clutch master cylinder leak, or just simply had a “fluid pouring incident” trying to put fluid in the brake or clutch master cylinder, you are already aware of the solvent sensitivity. Jim’s car has a (probably permanent) stain coming from the gas filler cap. Traditional thinners will wipe the paint away. When buffing the paint with a buffer, it is critical that you know exactly what you’re doing, because too much pressure with a buffer can create heat that will cause the paint to soften and can very quickly remove the paint, particularly on sharp edges. Another concern is that the paint seems to thin over the years as it deteriorates, and usually the places that the paint looks the worst are in fact also the thinnest, and almost without exception are the horizontal surfaces. With all these things in mind, your choices for polishing the paint are limited. The best choice for paint care we think is cleaning with a clay bar, followed by a very gentle polish to clean off the dirt embedded in the paint and an acrylic sealer—and inside storage! Any good clay bar and its associated lubricant will work to remove surface contaminates. Klasse (All-In-One Cleaner/Polish and Sealant Glaze) is a very good gentle cleaner and sealant that works extremely well on TPA paint, however there are other manufacturers products that should work comparably. Both of us have had extremely good results with Klasse on TPA paint though.

If your paint is beyond help, your options are somewhat limited based on the technology used in the original paint. Even if you don’t ever plan on personally repainting your car, you should be aware of what steps may be needed in the event of a partial or total repaint. If any individual areas need to be resprayed, an acrylic lacquer paint would be your best choice to match the paint gloss, if this paint technology is still available in your area of the world. Note that this is not nitrocellulose lacquer that is rather difficult to obtain (and an inferior paint technology by today’s standards too). Your second choice should be a single stage polyurethane, which will have somewhat dissimilar depth of gloss, but depending on the color you are spraying may or may not be as obvious. Clear-over-base is not a good choice, and if necessary, should be used only for a complete respray. The paint will not match well due to the depth of gloss in the clear coat, or the “paint under glass” effect. A base coat / clear coat paint simply won’t match the milky depth of TPA paint.

Regardless of what paint you choose, and whether you are spraying a single panel, or the whole car, you cannot spray over a cracked or crazed surface. If you have a surface that shows the typical cracking of TPA paint, you will have to remove the paint to the base metal and start over. Areas that have not been damaged can be sealed with an epoxy-based primer, however underneath the epoxy will always be a paint technology that may eventually fail and will require complete removal. If you have areas where the paint is chipped or scratched, watch out for rust, as the primer is very porous and will absorb moisture. In the process of preparing my car to be repainted, every spot that I found a paint chip, I found surface rust on the base metal. Removal of the paint is best done with a combination of media blasting for seams, and chemical strippers or use of a heat gun and a paint scraper. Sanding the paint off is possible, however due to the nature of the paint and its heat sensitivity, it will quickly melt and clog sanding discs and stripping wheels.

Jim’s second TPA (Platinum Metallic) TR8 was stored in a garage in Reno, Nevada for 8 years but still started out looking very much like it was done in flat grey camouflage and he was sure the car needed to be stripped and repainted---much like his first original platinum car was repainted 20 years ago. However, with repeated applications of Klasse All-In-One polish and lots of clean rags being used up to extract the dirt from the paint, he finally got it to where the color and the shine were acceptable. Numerous coats of the Klasse Sealant/Glaze really brought out the depth and luster too. Yes, the hood/bonnet is still stained and the gasoline spill on the rear is still visible but it’s original paint and looks very different from the clear over base on his first wedge. Jim likes it enough to live with it even with the stains. However, his daughter commented the other day that she liked the clear over base paint on his first TR8 better. Why? The TPA Platinum metallic “looks like snot” and the original car (clear over base) is shinier and looks like glass. Guess there’s no accounting for taste with kids these days!

DISCLAIMER

All of the information here is what we’ve learned from perusing and searching and scouring the internet and reading lots of forums and talking with knowledgeable paint guys over the past year or so. If you know something we don’t or we somehow got something wrong or you have a tip to share, please write us or the newsletter editor and let us all know! Thanks.