How much overspray do you experience? At what PSI?
I’ve sprayed automotive paint and primer before and was wondering what to expect.
I’m out…as I only use the dump guns.:o
The lower the pressure the better but has to be thinned out resin.
Not quite gelcoat but Duratec sprayed at between 2.5 & 3 bar, on smallish parts zero overspray, on large parts just minimal. And one of my cheap HVLP guns is almost 3 years old now, WOW thinking of having a party for it, almost lost it once. I have a sealed tub full of Acetone that after each spraying session i strip the gun down and leave the parts in.
Baz
So that’s 30psi or so I guess. I’ll be giving it a try in a week or so.
I’m also wondering what kind of spray pattern is good, I’ll look up some old specs on spraying high build primer, should be pretty similar.
Baz, interesting that you soak your gun like that. I thought that most guns contain rubber or plastic seals that will degrade with soaking.
Owen
I have been “trying” to spray gel coat and it just didnt work out. i used a 1.4 tipped drilled. so i then bought a 2.0 tip and yet to spray. i also thought about it, why the HELL do i leave the filter in the gun!? so this time around, im going to use 2.0 tip, and no filter. ill post soon.
Yes, take that filter out, it’s useless. Also get some cup gun liners, makes cleanup a lot easier. Plastic sandwhich bags will work sometimes.
Might want to try “percolating” too. After you’re done, dump out whatever’s left in the cup, run some acetone through the gun (spray into a rag or something).
Then turn down the air pressure, unscrew the cap on the front and squeeze the trigger. you can do this with the cup lid off like I do, just make sure the pressure is low and don’t shove your face into the cup while doing this:rolleyes:
What this does is back-feed air into the gun and you’ll get bubbles in the cup, releasing whatever is trapped in the spray gun’s body. I usually do this a couple of times after spraying.
good info and good thread
the sandwich bag trick is a great idea!!! I find thats the worst, cleaning the cup. The small parts are easy to clean that dang cup though lol
I use a 2.0 tip and spray with 50psi showing at the gun without the trigger pulled.
Spray pattern is about 4-6 inches at 6-8 inches away. I cover my last pass with a 50% overlap.
Rez, no not the whole gun just the metal parts.
Baz
Thanks, I read here that someone does a dust coat first and then subsequent thicker layers.
I guess this will give me the opportunity to try out my new mil thickness gauge. I have the barrel shaped one, I’m supposed to lay it in lengthwise right?
What mil thickness tooling coat do you guys lay down?
Baz,
Thanks, I get it now. I do the same thing.
Rez…just because you saw your Plastics ROP teacher do it in the classroom:rolleyes:…but those are the cheap HVLP guns…
I shoot gelcoat out of a HVLP with a 2.2mm tip. Overspray isn’t much of an issue because the gun really doesn’t atomize the gelcoat. I put on about 25-30 mils. Some manufacturers recommend 40 mils put on in two 20 mil sessions.
That wasn’t me…I never saw any spraying going on except for the clear on the clipboards once. Did I miss something???
youre firt coat cant go on thick…it should look like crap from being waxed and will want to sag if you make full coverage the first pass…
I dust it…count off a minute or so for flash time and then start working it.
It takes me about 10 passes to get the coverage…I dont use a mil gauge…I just keep going till it looks bad and I know Im probably still a little light.
I can’t wait to try this!
Just a note, I tried a bag liner in the cup. Seemed to hinder flow of the thick gelcoat.