Myth Busters on the Discussion Board

[Michael H.]

How many of us have spent serious dollars in the past for "factory pack" paint for our cars, thinking we were getting the exact same stuff that was used on the assy line? I have to admit, I have. That is until about 1990 when I started to get deeply involved in OE paint formulas.

The original factory applied coating on your 50's, 60's and 70's Corvette was almost nothing like the coating that was applied at the assy plant. To begin, the basic material that was used was totally different. The binder that is the base of the material used for "service" is called a buffing/polishing formula and the material for "OE" (assembly line) is called a reflow formul. The reflow formula is designed to do just that, reflow at a pre determined temperature. That's why you can see areas on original paint cars that are shinny but still rough. Even though the finish in a door jamb may look rough and textured, it still reflowed and became shinny. Service paint will haze as it dries and generally won't shine until it's buffed.

The other major problem with "service" lacquer paint was the color. Again, most of us thought that because we were buying "factory pack" paint, we were getting the exact same material in the exact same color. In reality, "service" paint is mixed using several different mixing colors to achive the best match to original color. OE assembly line paint is made using a "single pigment" formula. That one or two year only pigment is generally not ever available to the public so that color has to be matched in the field using colors, plural.

The true meaning or description of "factory pack" paint is paint that is mixed at one of the major paint mfg's to match the OE color. It's likely the exact same color could be hit dead center by your local paint store but typically, they couldn't measure the add amounts as the mfg's did.

There are a FEW very rare exceptions to this as a few colors did come from Dupont and I think Ditzler (if I remember correctly) that actually were the real thing. Unfortunately, I don't have a list of these.

Michael

[Duke W.]

Re: Myth Busters on the Discussion Board

The only "factory pack" acrylic lacquer I am aware of is PPG DDL 9300 (and I suppose the other paint OEMs have a similar product), and I've always understood that "factory pack" means it's blended and packaged at the paint manufacturer's plant, not in the field at the paint dealer like other colors. As a result, you can order it from paint dealers even if they no longer have lacquer mixing equipment. That's all it means!

IIRC there may also be a "GM white" "factory pack" because, like black, it too was used for many, many years.

Service acrylic lacquers have always had different chemistry than OE acrylic lacquers used at the plant (because in the field the paint is buffed instead of "reflowed' in an oven), but I don't think this is widely known, understood (or remembered).

I suppose the reason that DDL 9300 is available this way is because as far as I can tell, the GM black acrylic lacquer service code did not change from 1958 to the end of acrylic lacquer use about 1980, but the actual component formula may have changed over the years.

I bought a quart or two over the years because it is the service paint for my black '76 Cosworth Vega, and it's also the service paint for 1963 Corvette Tuxedo Black.

Everyone should view "factory pack" paint with the same jaundiced eye as a "numbers matching" car. The actual meaning has become so distorted by hype that the words not longer have any meaning.

Duke

[Michael H.]

Re: Myth Busters on the Discussion Board

I just remembered the term for the additive in OE binder/base. It was called "fluidizer". This was the ingredient that allowed the paint to reflow at a certain temperature during the baking/reflow process.

The reasons for the two different types of paint would become clear when you think about the process involved for each. In production, there wasn't time to hand polish areas that couldn't be buffed so reflow paint was used to make these areas gloss. At the completion of reflow, the paint required only minor buffing on the horizontal surfaces. In service, however, it would have been totally impractical to try to bake a car at the high temperatures that were required for reflow.

Years ago, an engineer from Dupont told me that "you can walk out to the parking lot right now and reflow the paint on any car out there with original paint". I tried it on a 1971 Oldsmobile and it worked. I used a heat gun and very carefully reflowed a small area on the fender. Amazingly, the paint suddenly glossed over in the area I was working.

My next question was obvious. When can you send some of that OE binder to me? The answer was not at all what I wanted to hear. They would only be willing to discuss amounts in railroad tamk car size.

[lyndon Sharpton]

Re: Myth Busters on the Discussion Board

In the OCT/NOV 1970 issue of Corvette News, there is a article on 71 production. And it talk about a new vapor reflow gun. it puts out 360 of heat with vaporized lacquer thinner. the paint people were so excited, by the way this gun works that they're planning to use the guns to go over the entire body of every 71 corvette. well that's what the article says.Anyone know if they did?

[Steven S.]

Re: Myth Busters on the Discussion Board

All lacquer paints are thermo plastics, not thermo set. What this means is that the lacquer drys by the solvents leaving the film. In thermo set applications, a catalyst or crosslinker is added or is in the formula that causes a chemical reaction that is not reversable. Any thermo plastic will flow with heat. GM had reflow ovens to correct mistakes, runs sags etc. Light sanding and a trip to the reflow oven would correct many on line sins. Furniture companies use the same process to make fine wood furniture yet today. The only real difference in today's lacquer and yesterday's lacquer is the solvent blends allowed by EPA to meet HAP's emissions and VOC emissions. Also the pigments used are all lead free, which makes color matching more difficult. Factory paint was made in drums and totes (300 gallon) or possibly truck loads, All paint manufactures are limited by batch size to the quantities they can make at a time and ship. Most make only 4000 gallons at a time at the most. This would be a batch. They would never mix different batches in a rail car and ship. The pigments used and the solvent blends used in "factory paint" would very possibly be different that what would be used in a refinish product.

[Terry F.]

Re: Myth Busters on the Discussion Board

In my youth I had a neighbor friend that was restoring a 58 corvette. I recall him using black laqure from a shaker spray can on the dash pieces. He primered the peices then painted them black from a spray can. After it dried he would wet sand it and then wash the dust off. Then, he would place the parts under a infra red heat lamp at about 18". Slowly dull sanded areas under the lamp would turn nice and glossy. He would move the lamp around untill the process was completed. I thought it was the coolest thing to see because he made it look so simple.

A couple of times I tried to duplicate the process when I got older (without success). Now I know what was going on. Interesting. I wish this stuff was still available in a shaker can. I bet he was buying stuff off the shelf at Chevrolet that was maybe used for touch ups, etc. Terry

[Michael H.]

Re: Myth Busters on the Discussion Board

Lyndon,

I don't think that this system was ever used for the entire body but if I remember correctly, something similar was used in the "paint repair area" and also it was something other than lacquer thinner. May have been toluene?

I'm just starting to go through my records and notes on the paint system and if/when I find some info on this, I'll post it.

Michael

[Michael H.]

Re: Myth Busters on the Discussion Board

Terry,

Interesting that you should mention this because I've actually "reflowed" paint that was not reflow paint also. It worked just about the same as production paint but a higher temp was required to actually start the process. I've used a high temp heat gun to reflow paint on metal parts such as headlight doors and air intake grilles and it worked very well. The finished part looks exactly like original factory applied paint. I've also used this method on fiberglass and have been very successful, so far, but that's very dangerous. I think the reflow temp point of conventional paint is probably close to the melting point of resin so I wouldn't recommend it be done on a nice car without practice on a few old body panels first. I've been able to exactly reproduce the correct look in door jambs and louver panels where the texture of the unsanded glass is supposed to be visible in the finished painted surface. One of my favorite areas is just above the rocker molding, an area that was just raw unsanded glass that showed all of it's glass fiber strands. Restoration to another level!

Michael

[Terry F.]

Re: Myth Busters on the Discussion Board

Based on some of the things I have read. I bet that there were times when a new vet would show up at the dealers and they would just reshoot the car. Laqure being as easy to repair and touch up and all. Sounds like they could have lightly sanded the car and shot it with some laqure and buffed it out. Even if they did a quicky on it, I am sure it would have looked better in many cases. Just my thoughts.

I would like to find some paint in a can that would reflow. I will have to experiement with it again.

Thanks, Terry