Had a couple hours to myself so I thought I'd bite the bullet and try painting the pan. Kind of a disaster. There are so many variables and I so many of them are still weak links. First, the compressor. Its an Ingersoll Rand SS3L3. It does ok. 10.3 CFM, and as I mentioned earlier it barely keeps up with a media blaster. But for spraying, it does pretty well. Moisture is a fairly important issue with compressed air and painting. When a compressor pulls air into itself, it pulls water vapor in along with it. When pushes air out of the pump through a copper line into the tank, it expands and cools. This cooling condenses that water vapor. This condensation is now stuck in the system. It collects in the bottom of the tank, and compressors typically have a drain at the base to let this water out. Some have automatic drains. (I don't). Other systems use a compressor air dryer- basically a closed A/C dehumidifier the removes the water vapor before it even enters the system. They are expensive. I'd assume that a professional body shop would always have this and they'd be crazy to not have it. I don't have one. I'm thinking of maybe getting this budget Harbor Freight unit that is used on Craigslist right now.
Aside from pre-drying the air, or draining the moisture from the bottom of the compressor, you can also add dryers and filters after the compressor. I have a filter/dryer.
This is a cheap unit ($59.99) from Harbor Freight that holds desiccant granules. This thing is actually doing something in my case, but if the compressor runs a lot, it overwhelms the dryer and you can see the moisture making it out to the end of the lines when you're doing something like, say, sandblasting. There are also little inline filters that you can put right under the paint gun as a last ditch effort to remove water.
This cleaning up and drying of the supplied air is something I don't see much discussion about when you watch experts reviewing paint guns in the YouTube videos, but it seems to be as critical a part of the system as gun choice, pressure adjustment, mixing the paint or cleaning and prepping the surface.
Over the years I've gone through several paint guns...
- A classic Binks-style siphon-feed gun I bought 20 years ago. When it was new, it actually wasn't bad. I think my fried Roman primed another '67 bug pan for me all those years ago in a garage in Point Richmond using this gun.
Devilbiss Finishline FLG-2 HVLP from the mid-2000s. This was the first higher quality gun I ever bought and the first time I ever saw a disposable cup system which I bought at the same time. Years later, I still have all the functioning pieces of and I use it. I think it's a 3M PPS system and it works quite well. This Finishline gun was wonderful for a good while.
I painted the first bug pan with it, as well as a BSA motorcycle frame with great results. Lately though, some clogging developed internally that makes it spray asymmetrically- so bad that it sprays against the side of its own fluid tip and splattered everywhere. I threw it out a few days ago in frustration.- Sata Minijet 3. This is a spot repair gun that I used once years ago then never used again until just this weekend. It's like a little European sports car and oozes quality.
- Neiko 31216A gun with a 2.0mm tip for spraying primer. This was 40 bucks from Amazon. This is a cheap primer gun and probably a copy of some other brand name piece.
It's heavy and has a kind of cool black chrome finish, so when you pick it up it feels like high quality... at first. It comes with a multiple size wrench tool which fits exactly zero of the fittings. If you remove the air cap and try to unscrew the fluid tip it take tremendous force. This is common complaint of ultra-cheap Harbor Freight guns. When you finally get it off, it appears that the tip is glued in place. This appears to be a way to seal the gun but obviously it makes it near impossible to clean. When you inspect the machining of the internals surfaces, they are rough and unfinished. So far I have not had much luck with but it's not over yet... - Devilbiss Finishline 4 FLG670. This is the successor to the FLG2, obviously. Has not arrived yet but I have high hopes.
The bug pan has been an uphill battle with it comes to paint. Trying to spray prime on the front axle beam, then later on the pan, the primer was so thick that it was like a textured finish. Almost like orange peel on steroids. I sanded this out.
On the bottom, which was rusting so fast I could almost sit there and watch it, was painted with a very expensive etching primer from PPG. This is intended to go over bare metal, and have a very light film thickness. It's called PPG SX1071 OneChoice Etching Primer. If it builds up too much, it won't dry. It will stay tacky and sticky for hours. It's a weird one and I don't think I'll use it again.
Last weekend I decided to just go for it and spray the single-stage gloss black. This did NOT go well. First of all, the paint is a single stage urethane. It's a PPG product. It's called DelFleet Essentials Single Stage Enamel or ESSS (acronym doesn't quite make sense, I know). It's not a basecoat intended to be covered with a clear coat. It's intended for repainting truck fleets, forklifts, trailers, that sort of thing. It's basically a simple gloss black paint with the durability and toughness of proper 2K car paint, so it appears to have a following with car restorers because that single stage enamel is how cars were painted 40-60 years ago. When I finally got the area set up and the paint mixed, my old Devilbiss FLG2 gun was clogging immediately. I busted out the old siphon gun. That wasn't much better, spraying in uneven spurts but I made the best of it. I still had half a pint of black mixed up and I was super bummed. I remembered I have one more spray gun! I pulled out the Sata Minijet and filled it up. That at least put down a proper coat, but the orange peel texture is some of the worst I've seen. So, lots to learn here. it's drying out too fast before it hits the surface.
Looking at guidance for how to paint properly, I had seen many references to reducers but I never understood what the deal was. Slow reducers, medium or fast. To me this was paint thinner, essentially. So why would I want to thin out such expensive, high quality paints? At Stevenson's in Carson, I asked about the thick milkshake of grey primer I was using on the pan and the results I was getting. He said, "It will spray on kind of like stucco if you don't add reducer to it." Ah-HA! So I wasn't crazy. That's exactly how it sprayed. Not like how I remembered PPG's DPLF primer to be, which was so smooth. In the fine print about mixing ratios, this other primer specifies the option of adding reducers, up to 15%. So now I know one more detail. This is a paint that has to be reduced to flow out properly. So that is my next project: figuring out what effect exactly the reducers have on either primers or the single stage black that I am painting the chassis with.
All in all, I am NOT happy with this. At a distance it looks ok, and yes, it will be covered with carpets and seats and it's not really a visible part of the car. But this is my test bed for getting this right. If you look closely at the frame head on the lower left, you can see how excessive the orange peel is, and the coverage is so uneven. The lesson I think is that I have to spray closer and heavier, and I need a proper gun. I'm also not crazy at all about the glossiness. I'm going to stop using the Delfleet paint and switch to something I found at Stevenson's. I think it's a Valspar product. Also a single stage 2K urethane, but it comes in gloss black, semi gloss or flat black. I looked at the sample card in their store in it was very close to the stock paint that's still present around the stick shift area.
Note: I inquired about a semi-gloss version of the Delfleet paint at the store that supplied the gloss version to me. I They said it doesn't exist... but it does.... this could be the semi gloss single stage I am looking for.
The other supplier for paint which is designed for restoring black running gear is Eastwood's chassis black. For some reason I haven't ever ordered anything from these guys. Maybe the exact paint is staring me in the face and I'm not paying attention.