UMP Black Primer

[bilbo]

I've recently bought some UMP black primer, and when I try to use it in my air brush, it sprays fine for about 30 seconds, and then just stops. If I do a full strip down and clean it then works for 30 seconds until it completely blocks again until another full strip and clean.

I'm spraying at 25 psi, and have the 0.4 needle in my airbrush, and i believe I'm keeping at clean as possible, but will try a deep clean tonight.

Does anyone else use UMP primer and have any advice? should I thin it? if so what ration would be advised?

Thanks,
Dom.

[Guest]

Dom could be you have bits in the paint. If it performs at full throttle for 30 secs then stops that would be one pointer.
0.4 needle/nozzle is quite large.

Whan deep cleaning I use the needle & carefully thread into the nozzle to push any grotty stuff out. I then Look thought the nozzle against a white & lit back ground. This will show if the nozzle is nice & clean. also just check the needle does not have any burrs.

Try thinning of a improve flow liquid.

Laurie

[Tim Marlow]

Sounds like tip drying. Try dropping the air pressure to 15psi. Also remember when operating an airbrush it’s air on, paint on, paint off, air off. The air in a double action brush should always be passing through the brush when you trigger the paint.

[bilbo]

Laurie, Tim thanks for your replies I’ll try them, Tim I didn’t know about air on paint on and paint off air off will have to remember that.

[Tim Marlow]

No probs Dom. It minimises the residual paint left on the tip after each pass, so reduces build up. I didn’t know about it for years either :smiling2:

[Guest]

Sounds like tip drying. Try dropping the air pressure to 15psi. Also remember when operating an airbrush it’s air on, paint on, paint off, air off. The air in a double action brush should always be passing through the brush when you trigger the paint.

Very interesting analysis Tim & very helpful. Following on if I have left a brushfilled with paint I always give a good long squirt on a pad I have in the oaint booth. Plus after filling a cup I also give a good squirt mainly to ensure any residue of cleaner is removed.

Laurie