Transcribed from Steve Styer’s educational minute at the October 27, 2016 member meeting.
I came upon something just within the past couple of months that I never realized. I thought I’d pass it on to you folks tonight. I’ve been painting cars since 1948, which maybe precedes the birth of some of you. That was an experience. I painted my dad’s 12 year old Buick with a $4.95 car paint kit that I bought at the Western Auto Store. The car had a lacquer paint job and after a few years of cleaner, the paint was gone and we were down to the primer. So I said to my dad, when I think I was 14, “How about if I paint your car?” Dad said, “Well alright.” So I went down to the Western Auto, got a quart of enamel in a can about this big around. And inside was a coil spring and then a little tray about a ¼” deep. With the kit, you got a mitt with a fuzzy end on it. The way you painted the car was to take this mit and dip it into that tray. The paint would get on the mitt and you would smear the paint on the car. Each time you dip it, then, of course, the paint would disappear from the tray. But with the spring, you could push it down farther into the paint until you finally got to the bottom. Well, I want to tell you, we had that car until 1953. That paint job was still on the car. Not a paint job I would be proud of today.
Since 1970, I’ve been painting cars legitimately. (Pulls paint gun from box) Traditionally, this is what we call a syphon gun. Hole in the canister. Paint down here. Tube in. It works on the same principle as a straw, a carburetor. The air is blown by an orifice and it sucks the paint out of the container, mixes with the air and spreads the paint.
That was fine. That topic tonight though is how to paint with a spray gun upside down. Now, I have not painted upside down. Well, obviously the siphon gun isn’t going to work because paint is going to run out of the hole. The tube is not going to get in the paint. It doesn’t work. So forget that. (Pulls different paint gun from box)
The new technology on the HVLP, High Volume-Low Pressure. Much more popular now is the gravity feed. That is, the paint is not sucked out of the canister, but the weight of the gravity feeds the paint down from the canister, into the orifice and then the trigger regulates how much paint is allowed to go into the air stream. That’s simple.
However, it still doesn’t work upside down. Because now the paint runs back down out of the canister. If you’re under the car and you do have paint equipment, how do you paint upside down? Typically, you hit at an angle, but that doesn’t work as well. So, now, what’s the answer?
Here’s the system. The way it works: It’s in the bag. You get these paint proof plastic bags with a special inserter and a ferrule at the end. This tool puts the ferrule in. You pull it out. Instead of putting the paint directly in the canister, you put the bag in the canister and then fill the bag with paint. That then allows the paint in the bag to run into the orifice to paint. So, what makes it an upside down gun?
The bag seals, just like any other seal, tight. You can seal the bag. Once you seal the bag, there’s air in there. The way it becomes an upside down gun, is you invert it. Now the paint runs back, but it doesn’t get out of the bag. It’s still in the bag. You pull the trigger and again, the air passing the orifice is drawing .. it’s a vacuum, negative pressure. It’s actually trying to blow paint, but there isn’t any paint. So what it does, it blows the air out of the bag. The atmospheric pressure collapses the bag. As you hold it upside down, the air compresses the bag and finally the paint comes out because there isn’t anymore air in the bag. Nowin the third , for the rest of the painting, you can use it is a standard paint gun or you can turn it upside down and it won’t come out, but atmospheric pressure still puts it up. On the Studebaker, for instance, on the door sills, to paint up or underneath the door, you can turn it completely upside down.
If you ever have occasion to need to paint actually with the proper equipment, you can paint directly upside down. I came upon it accidentally.