Gravity Feed Gun Question...

[Happyfunballs]

Geez, how long are you waiting between coats? It shouldn't thicken up that much. I do one of two things if I anticipate a long period between coats. Put the gun in the fridge, yes it sounds funny but the lower temps don't promote catalyzation as quickly. Secondly, as a last resort, I'll thin it a bit more.

[Johnjan]

Typically 10-15 mins between coats. I've tried putting the paint in the fridge but not the entire gun. The Omni MP-182 primer surfacer is the worst. That stuff dries on the inside of the cup within 15 minutes with an ambient temp of 80 degrees or so.

I'll try the backfeed trick, I can always turn the regulator down a bit so as not to blow the top off.

[68protouring454]

as tyhe guys have said it should not thicken between coats unless its 100 degrees outside or in shop, most urethane primers are 4-1-1, some say for thicker applications or more mil coverage to mix 4-1, i always thin my urethane primer, it builds more than enough thinned out.
do you have mixing cups?? how are you mixing it?? i would bet it is getting to much hardner, also what size tip are you using for the primer?? i would not go below a 1.6 or so, i personally like a 1.8 to 2.0, but now and then i will use a 1.6 for a finish coat of primer before final wetblock sanding, let us know
jake

[Johnjan]

The Omni MP182 I'm using mixes 5 - 1 with hardener and I'm spraying with a 1.8 tip. The first coats sprays awesome, the second OK, and thie third is a waste of time. Ambient temp 80 - 90 degrees.