Hey guys, the last 2 bows I've done had some spots show up in the finish. I have to sand them completely out and respray them multiple times. It's like it's oily spots or something because the finish will not lay over those specks. I've never had his happen before. I use buffalo hide from Big Jim. I do 3-4 coats of gloss and 2 coats of satin. It only seams to be in the gloss. It's not old so I don't think that is the issue. Any one experienced this?      

Your air isn't putting oil in it is it?

Or water?

Yupper, air or water spots.

That's what I was thinking. Oil, or maybe water... maybe even solvent from cleaning the gun? What type of filter do you have between the compressor and gun.

If you clean the gun with laquer thinner between gloss and satin applications, make sure you run the gun with nothing but air going through it for a bit to rid it of solvent, and then when the finish canister is put on the gun, spray some finish out into the air for several seconds to further purge the gun of any solvents. Then lay finish down on the bow.

I have an oil and water separator on the gun. I can't remember the brand but I bet it was cheep! Lol. I use the buffalo hide thinner to clean the gun and have been leaving a little in the gun between uses to keep it from gumming up.  I always empty the gun and spray air through it for several seconds before adding any sealer to the gun. I bet I'm not getting all of the thinner out of the gun like Jeff said.

Ps.. I never used to leave and thinner in the gun between uses. Not sure why I even started doing it. But I won't from now on and see if that helps

I live in a high humidity area.  When I set my spray system up I put 2 inline water/oil separators about 10 feet before the gun. So far no problems with moisture. My compressor is oil less. I use Krystal from Big Jim and I leave thinner in the gun too. When I set up to use it I run air thru it like you, so far no problems.. So maybe it a moisture problem? how are you cleaning the bow before spraying?

would you call those spots "fish eyes" or is that "solvent pop"?

There is a drain on the bottom of the air compressor.

my 2 cent's

Over the years I've done a fair amount of airbrushing. Contamination of air is disastrous in this case. My compressor has filter and moisture traps in and out. It doesn't have the capacity to use for finishing but I know the air is clean.

Fish-eyes are usually associated with oils/wax but what you have looks different - fish eyes are kind of saucer shaped rather than sharp like what you are seeing.

I think air contamination of some kind is the culprit here.

Robert, I think it's more of a solvent pop. I clean the bow with denatured alcohol and give it plenty of time before I set up to spray. Then I spray the bow off with air from my gun right before I spray it. Never had this happen till I started leaving thinner in the gun.  My filter is at the gun itself and I spray the moisture out of the filter with the valve every so often.  I won't have a chance to spray again till Monday or Tuesday. I emptied the gun of any solvent and cleaned it up real good before I left town.  I'll let y'all know how it goes . Maybe it'll save someone else from making the same mistake.

I got one of these from Harbor Freight for $35. I also bought a "Speedaire" 40 micron filter. Both are on line 10 feet before the gun. I use 2 filters because I was paranoid about moisture in the Florida air. I have never seen a single drop of water in the second filter.  I would think any small amount of thinner in the gun would either mix with the Buffalo Hyde or spray out when you adjust the gun. I'm still using a Finex 1000 HVLP mini spray gun.    

Probable bad glass....?

Still voting water.  It  looks like water drops sat and displaced the finish and then evaporated leaving that acne behind.

Stick to yer trilams roy boy!  

How often should you replace your filter? Hmmmmm...

I bought 4 filters for the Speedaire. I have only sprayed 20-25 bows since buying it.. still using the original filter. The only thing I use the oil less compressor for is spraying bows so it does not get a lot of run time.

We had that problem..

This fixed it for us..

http://www.eastwood.com/dessicant-snake.html

Heck yea, that looks like it will be worth trying! Thx Conner!

I was gonna make an iron pipe water trap..but never got around to it. The dessicant snake looks like it should work nicely.