The Stovebolt Site Forums The Shop Area Paint and Body Shop Automotive paint vs equipment enamel

I may get a lot of backlash for this question but here goes: I am struglging to find anyone that is interested in working with me to paint my truck. Body shops are not interested in such a project. The option to paint it myself is a potential but I would need to buy a good/better paint gun (apparently the one I have is not considered up to the task), source the paint, and set up some sort of booth. Temperature control in the "booth" would be a concern depending on the time of year I actually get to the actual painting.

The other option is to use a readily available equipment enamel. While I should probably still construct a booth it seems that all of the other underside painting that I have done with this type of paint has been okay without it. One of the benefits of this approach is being less temperature senative and I perceive more readily available touch up paint availability.

I have great expectations of getting the painting done this year before winter sets in but on-going body work is making that seem less and less likely. I would really like to use the winter months to assemble all of the painted parts and start working on all of the after paint assembly required. I do have a heated work space but I do not believe I can use it to effectively control temperature during painting due to the nature of the heating system (propane fired buner haning from the ceiling).

Automotive finishes will give you a more level surface if everything else is equal. The equipment enamel is a heavier based material and won't lay as flat due to the higher viscosity so you will most likely see some "texture" or very light orange peel. One advantage of any enamel is that the final coat is normally a self glossing finish, no rubbing needed. I have used the PPG line of acrylic urethane and am very pleased with the ease of applying it. Temperature AND humidity will play a big part of any material. If I were going through all of the prep work, I would use automotive finishes, I don't care for the "thick" appearance of heavy enamels and over-applied repaints.

FWIW, I used paint I got from Jim Carter (PPG ALK-200 - an acrylic enamel) and shot everything except the bed (which I painted outside) in a tent I set up in front of my garage. As long as the outside temp was going to be above 50F, I painted parts. I got varying degrees of success, mostly because I was learning as I went. Some of the first parts (cab, fenders, etc.) had some orange peel (appropriate because of the color ), while other parts (hood, running board aprons, and the passenger door) came out nice and smooth with very few defects. The paint is easy to color sand and buff out to remove the few dust nibs and minor orange peel. The gun I used was a pretty inexpensive PPG Accuspray gun with disposable tips and cups. For the amateur painter, the cleanup is very easy. You also need a good compressor with water removal filters ( I used a final filter right at the gun.)

The PPG Acrylic Urethane (I think it's AUE-300) that 78buckshot mentioned would also be a good option.

I think it's worth a try for you.

Thank you both for your insight. Being able to paint down to 50 degrees would be a big help. I do have an unheated portion of my garage that I think I can set up for a paint booth without too much construction required. It would be warmer than an outdoor tent so that may help the timeframe somewhat. Kevin, if understand correctly your paint choice was an enamel, just not the hardware store variety. Not sure of the uethane option has the same temperature range.

I will look into the PPG Accuspray gun, clean up with the HVLP gun I have is a pain. I thnk my compressor is up to the task but I will need to add a regulator and filters to the air outlet area that is in the unheated protion of the garage.

I don’t recall the mixing on the ALK line from Carter ( IIRC it is premixed) but if you go to a proper automotive paint store you can get the paint, hardener, and a reducer specifically for low medium or high temperature.
The correct reducer will help control flash time and reduce the chances of sagging/runs. Temperature is both the ambient AND the part…
My local shop had the PPG Delfleet line of truck fleet paint, a single stage system that worked well for me. Layed down shiny and can be color sanded if necessary.
50 degrees is like the very lowest temp to shoot, even 5 degrees warmer is certainly better….

Chuck

The ALK-200 that Carter sells is sprayable right out of the can. But it can also use ALK-201 hardener and can be thinned up to 10% if needed with Xylene. I found some 1/2 pint cans of hardener (which is enough for a gallon of paint at 15:1 ratio) and used that. I also found that thinning just a touch gave better flow-out.

I found a Tech Sheet for the AUE-300 urethane and it looked way more involved than the ALK-200. It required hardener (rather than optional with the ALK-200) at a higher mix ratio.

Here's the Tech Sheet for ALK-200. I was on PPG's website and it's listed under their Versolon line, but was unable to download a current Tech sheet for it (or any others for that matter.)

The Accuspray gun I bought is for the older PPS system, and supplies are getting a bit more scarce. If I were to buy a new one I would go with the newer system, just for the availability of supplies. The gun with 4 different size nozzles, a cup and I think 4 lids and liners goes for about $300 on Amazon now. You can get various size cups and liners (I used a number of the "mini" (6 oz) size cups for smaller jobs.) Cleanup involves filling the cup adapter on the nozzle with solvent and spraying it thru a couple of times, using just a few ounces of solvent. The liner and integral filter in the lid get tossed.

One small word of caution if you're in a "drive it while you work on the body" situation. It's tempting to spray a light coat of primer over sheet metal repairs over weeks or months, and then do an overall paint job when the metalwork is finished. One problem- - - - - -primer soaks up moisture like a sponge, and if you do your overall paint job without sanding off all the temporary primer, you run the risk of creating a rust layer under your expensive new paint job. Ditto for body filler if it stays exposed to the weather for any length of time. When I co-owned a body shop, we would refuse to paint a vehicle if the owner insisted we apply finish paint over primer that had been exposed to the weather, even for a few days. It's OK to spot prime as you go, but always sand it ALL off and reprime before applying the final finish.
Jerry

Jerry's caution is a good one, but epoxy primer (in most instances) will seal out moisture, so you don't have to worry about sanding it off. But any one-component primer, and even some 2-part primers (urethane) are not moisture resistant.

Propane fire burner + flammable chemicals and off-gassing paint = bad stuff. Plus the increased chances of swirling dust and things.

Thank you for all the additional input.

While I am not in a "drive it while work on the body" situation per say, and I have been priming (using various epoxy primers) as I work on various panels and they have been exposed to the air and related humidity in my garage. For some parts it could be months. I am hoping that the epoxy primer will be viable such that I do not need to remove all of it to reprime prior to painting.

MNSmith, I agree and that is why I do not plan to paint in the heated portion of my garage resultig in the potential temperature delima as fall is upon us.

A little more info for you to think on. With all of the different materials I have sprayed, I use a 50 year old Binks Model 7 and a 50 year old Binks model 37, both of these guns are traditional siphon feed, they can spray lacquer, alkyd enamel, acrylic enamel, acrylic urethane, and probably whatever comes down the road next. I also used a Harbor Freight air brush for some close, tight work using the acrylic urethane. My point is, you don't have to use the latest and greatest equipment, find a decent gun, choose a product line and stay with it, practice, then practice some more, and then practice a little more until you are comfortable with the results.

I remember back in the mid 70's a high school buddy had a Road Runnder. He grandpa and dad were mechanics and owned a garage. They painted the car with white appliance enamel. I remember that because I thought it was strange to use appliance enamel but he said it was a very hard finish. As far as the apperance, it was a great looking car.

I've probably mentioned this before, but for the "non-professional" painters out there, you should be extremely cautious around enamel paint "hardeners". Most of them are some variety or another of "cyano-acrylate" compounds. "Cyano"- - - - -yep, CYANIDE! It's a contact poison, which means it can be absorbed through skin exposure. Even if you wear a really good activated charcoal respirator, you should wear a plastic lined disposable paper "shoot suit", gloves, and booties. Use a masking tape wrap to seal sleeves to gloves. No exposed skin whatsoever. Some of my friends who painted with hardener in acrylic enamel for years now have nerve damage that makes them feel like they have bugs crawling under their skin 24/7! Hardeners are great, but their chemical compound demands extreme safety measures while using them! Oldtime gunsmiths got similar nerve damage from hot salts gun bluing procedures that also used chemicals containing cyanide compounds.
Jerry

The urethane hardener is good stuff, I thought I was supposed to wash my hands with it, just like we did with carbon tetrachloride, leaded gasoline, etc. Mercury, and the spit balls we made from the asbestos insulation on the steam pipes in grade school were also part of our fun. I'm pretty sure all of those great materials are the reason I'M so well preserved. Now that I think about it, it must have been the sodium nitrite, sodium nitrate, and whatever else I inhaled, ingested, and absorbed while in the meat industry producing ham, bacon, hot dogs, cold cuts. All kidding aside though, take every precaution to protect yourself from the chemicals in the painting process.

Jerry's point is well taken and rasies the question; "why use a hardner"?

While not related we know that hardened steel is typically more brittle than mild steel (unless alloyed to prevent it) so would hardened paint be more likely to chip?

Thank you one and all for your input on this topic. You have given me a lot to think about without all the negative feedback I was fearing.

The acrylic enamel can be sprayed without a catalyst, the hardener with help with gloss retention, paint durability, and negates the re-coat time if you have to re-spray a spot. As far as I know, the acrylic urethane has to have the hardener in order for the finish to cure. If I'm spraying either one of those, I use the hardener.

DuPont "IMRON" was the original acrylic urethane paint, which was eventually copied by other manufacturers once the patent expired. I remember a "gallon" of IMRON being 3 quarts of color, and a quart of activator. There were a few proprietary colors- - - -DuPont made no effort to match any OEM shades. One of the first uses of the stuff was on crop duster airplanes, where the chemicals they sprayed would eat normal paint like popcorn. Once mixed, there was about a 12 hour pot life before the paint became solid, regardless of the thickness of the coat. A friend ruined a very expensive paint gun by leaving activated IMRON in it overnight. The next morning he found that all the paint in the cup, and in every passage in the gun had gotten rock solid! At that time, back in the early 1970s, there was no stripper or solvent known that would remove IMRON- - - -it had to be sanded off.
Jerry