Painting - How much Spray Pressure?

YamaPilot · 07-10-2008, 07:33 PM

Painting our track bikes again in a week and I completely forgot what pressure I should be spraying at. We're using a PPG base coat and PPG Speed Clear coat.

Also, anyone ever use those rattle can adhesion promotors? I've gotten a lot better over the years, but every now and then, I'll get a run or two during the first coat.

BigGSXR600 · 07-10-2008, 07:44 PM

between 30-40 psi depends on ur spray speed and liking. Bulldog is a great adhesion promoter if you can get your hands on it

kevinwilly · 07-10-2008, 07:53 PM

about 30-38psi if you're using HVLP. If you're using a conventional gun, it'll be a lot higher.

I have never needed an adhesion promoter. I use an epoxy primer/sealer, and it works really great.

MNRF900R · 07-10-2008, 09:36 PM

40 is the highest Ive gone on a paint gun. Use hvlp for best results.

YamaPilot · 07-10-2008, 10:54 PM

Yep, I have a HVLP gun.

Stupid question, but I can't use the adhesion promotor with the clearcoat, can I?

kevinwilly · 07-10-2008, 11:28 PM

Quote:

Originally Posted by YamaPilot

Yep, I have a HVLP gun.

Stupid question, but I can't use the adhesion promotor with the clearcoat, can I?

the adhesion promoter can only be used under your first layer, normally.

You may check the spec sheet for the clear you are using, though.... many of the PPG products have adhesion additives that you mix in with the clear.

But if it's a standalone adhesion promoter, I'd only put it under my primer. But with a nice primer, you don't even need it.

What exactly are you having problems with?

BigGSXR600 · 07-11-2008, 12:58 AM

yea man I'd spend a extra $20-$40 and buy a sealer and just spray your sealer over the bike then paint and clear you dont have to let the sealer set over nite you can just go right at it. Wont have any adhesion problems as long as you preped right.

BigGSXR600 · 07-11-2008, 12:58 AM

And yes if you use bulldog you can use it in between every coat I work at a custom shop and you can tho not needed or recommended

Grashopr · 07-11-2008, 01:54 AM

I dont know, I always let my sealer set up for at least 16 hours or so (overnight) before spraying anything on it, as typically you've got a 72 hour window before you have to sand it, and with 16 hours of dry time, you can see any shrinkage that occurs so it wont come back in a pearl or metallic and bite ya. But that's just me.

BigGSXR600 · 07-11-2008, 03:00 AM

yea it all depends on product we were using HOK paints for a while and we let a sealer set over nite and then sprayed base the next day and everything flaked off. I'v had good luck at using a expoxy primer and over reducing and using that as my sealer.

Grashopr · 07-11-2008, 03:25 PM

I've been getting more and more frustrated with HOK lately because of things like that. I tried switching to their urethane striping kit, but the stuff was so runny, it was absolutely useless for pinstriping. Their clears have always been super wet also. Their sealers you have to 'dust' them on to keep from getting a super-glossy finish on them, regardless of your overcoat time, as the finish on the sealer can actually be TOO smooth for the next coat to bite into. I prefer to make sure I've got a physical bite as well as a chemical bite on the sealer, so after the sealer flashes, I like to lightly scuff it with some red scotchbrite, especially in problem areas, then let it sit long enough to make sure that the scratches from the scotchbrite aren't going to cause any chemical interactions with the next coat by gassing out.

BigGSXR600 · 07-11-2008, 03:57 PM

yea a clear I'v been using latly and really impressed with is PPG Deltron 4000. Thats really good for a car but Deltron 3000 is faster drying clear that would be nice for the bike.

YamaPilot · 07-12-2008, 12:27 AM

Would it be ok to use extra hardener in the clearcoat?

serpentracer · 07-12-2008, 07:07 AM

the best paint I've used so far is DuPont Chroma Base and Nasson clears.
they have been the easiest to work with. and the clear came out way nicer than any PPG clear I've tried so far.(no orange peel or runs) which includes the Deltron and omni. (I don't paint for a living and but have painted 2 other bikes and mine several times and a few bumbers for cars)