I reduced some epoxy today 20% with SPI urethane reducer. I am getting pinholing like crazy! It doesn't happen when I use it unreduced. This happened before when I first got my new gun and thought it was contaminant in the gun, cleaned it and remixed unreduced epoxy and it shot fine so I chalked it up to new uncleaned gun. This time I used 50-50 mixture of fast and regular spi reducer and added it to the activated epoxy(20%). Stirred for a full minute (more like 2) then let it set for about a half hour. I restirred, strained it into my gun. Panels were cleaned with waterborne spi W&G remover allowed to dry half hour or more, then tacked. Even pinholes on my test paper. Can't retest with unreduced epoxy as this was my last of it. Fast reducer is dated 10/07 and slow is dated 2/08. Never used them much for anything else as the base I have shot is ful-base(maybe some clear last summer). Any ideas? Don't think it's a water problem as I have shot 2k primer without this problem recently and I am anal about draining my tank and wall lines.

If you had the same problem before you cleaned out your gun with unreduced epoxy, I'm willing to bet your pressure is too low when your shooting it reduced.

Crank it up and see if that works!

Nah, I understood. What I meant was, if cleaning your gun helped stop the pinholes when it was unreduced, chances are you cleaned up some clogs which free'd up air flow.

Anyways, 20lbs on the lph is def. wayy too low! I crank it up to about 27-28 psi 2.5-3 turns out.

Hope this helps, I feel your pain on running out of epoxy! I'm waiting for mine too!

Dead on with the air pressure. Barry rec's for 30lbs and 3 turns on the LPH400. I think it's a little high but 27-28 lbs works for me. You need the break that epoxy up and blow some of the solvents out before it hits the panel or you'll end up with wicked fish eye/ pin holes etc.

I experienced the same thing. i just started shooting after a LONG break I purchased the IWATA and like how I am able to shoot at such low pressure. I wanted to try to use the epoxy as a seal coat,I gave the higher air pressure a try. Looks like it helped.
4,4,1
6,6,1 same results

I think I'll shoot unreduced and just sand before the base.


Do the different colors of epoxy spray differently? I would think not...Enjoyed the black, using the white, in reduced form... never tried it with the black.

If this is the case quite different results with such a small amount of reducer.

I read in a post to reduce 50-70% as sealer, maybe it is just not reduced enough?


-Ed

Assuming you are shooting the epoxy out of a 1.3 or a 1.4 tip, the right size for a sealer coat, it is pure air pressure, we could be talking 3-5 lbs is all.
White is more tricky then Black or gray epoxy.

Just adding to the previously started thread
I am shooting with a 1.4 tip (iwata) The white definitely is different than the black when shooting. Today... I used it unreduced and still had problems, it appears to me that it is much thinner than the black. I'll keep experimenting with air. I guess I should not have said "seal coat", I need to cover the black epoxy, for the base mabe I expect to cover the black to much with a first coat. However, when thin it appears to create the pin holes.
I know there are no contaniments on the panel and it is not wax and grease remover.

All panels are off, I am shooting a panel at a time, I'll end up sanding it up and try a little different settings on the next panel. Mainly it is my lack of experience. I have the panels all blocked in black (Which I had no problems with) and I need to cover them white before spraying the SS red.

-Ed

Just a guess here, but shooting the epoxy too wet will cause a funky looking problem that resembles fisheyes. You may want to try and spray just a bit less on the panel and see what happens, not dry spray of course but maybe just back off a bit and increase travel speed a touch...

The white is heavier then the black.

If that is the LPH400, then here is how you lay it to look like a powder coat job.

Fan all the way open and then turn in one-half turn.
Fluid turn in then back out two exact turns.
Air pressure at wall should be 100lbs or more.
Air at gun with trigger pulled 28-30lbs.

Hold the gun 4" from panel and lay it like a clear coat, give a 30 minute flash time and lay a second coat.

If pressure's right it WILL NOT fish-eye or pop, if it does up the air pressure.

i set up like i would for clear since the epoxy is a little thick. i did up my pressure some . i hosed it every coat and got a nice slick shiny coat each time. i did notice that it does not flow. like some clears you have to shoot for effect . i have noticed last winter that epoxy is real touchy about surface temp. not a problem now at 104

It is the LPH 400, So I'll set as mentioned... I'll be spraying some more white tomorrow.

I am surprised to hear that the white is actually thicker.

I'll let you all know how it goes with the new settings!

Thank you for the advice,


-Ed

.

That is the one nice thing about epoxy, 99% humidity and 104 degrees,
don't really bother it but it sure gets finicky at 60 degrees.


Edit,
I think JimC uses white epoxy and wonder if he has seen a difference with the white using the 2.1 voc activator??

Just crossed my mind, it may and I will do some test when I get back in a week.

you know barry, i think every time i tested the low voc activator i was using black but its been awhile and i dont rememebr for sure. i'm still trying to kill off my stock of the regular activator before i goto stocking the low voc stuff.

chew, the white is definately thicker. for all the years i have been shooting the spi epoxy it has always been that way. the key to getting the epoxy to lay right is wet coats but at the same time thin coats so dont use a primer gun, use a 1.4 clear or base gun and also add 10-20% reducer to the mix and let sit for 20 minutes before you spray. you can also bump up the air pressure as barry said. combined this will take care of anything that looks like surface contamination, but isn't. also spray evenly. avoid areas with heavy overlap where the epoxy might build up thick. thin wet coats is the key with this stuff.

Thin and wet is easier said than done, but yeah, I guess that is it. I feel I am always riding the line, often I will get a bit of strange texture where the epoxy goes on a bit too heavy...