Air brush issues

S

simso

Young Tutorling
hey folks,

I'm not fully up to date on using air brushes, but have an issue with one, and want to confirm its what I think is the problem

I have two airbrushes, a gravity fed devilbiss .35mm and a suction fed devilbiss .50mm

When I tried to spray using the gravity fed one today, paint came out the nozzle, but it also started spraying or exploding paint out of the gravity gun cup, with my normal spray guns, this means it's got a blockage and needs to be cleaned, but I stripped this airbrush apart and could not fault it

I ran the same paint in the suction fed unit and it was perfect, but there is a tip size difference

Any ideas would be greatly appreciated

Steve
 
If you are getting air into the paint cup, you have a bad seal at the nozzle. Could be at the base of the nozzle or some paint clogging the hole in the air cap, allowing air to get in through the tip.
 
Wouldn't clogged nozzle also be issue since the paint went thru .5 needle fine but not the .35 could be to thick paint?
 
Normally the bubbles in the cup is a blockage in the nozzle rather than a leak, that is how you back flush is by blocking the nozzle. Take the 0.35 off and check it's clear, tit won't take much to clog...
 
markjthomson said:
Normally the bubbles in the cup is a blockage in the nozzle rather than a leak, that is how you back flush is by blocking the nozzle. Take the 0.35 off and check it's clear, tit won't take much to clog...
Click to expand...
Backflushing is pinching your fingers over the opening of the nozzle and pulling back the trigger. There is nowhere for the air to go but through the opening of the nozzle and into the cup. If the nozzle were clogged, the air wouldn't be able to get and no ability to backflush. Bubbles in the cup are generally cause by a bad seal where the nozzle meets the airbrush body, or if the nozzle is cracked.
 
Sorry for the late reply.

I have a paint booth and spray guns, so understand re how important cleaning guns are.

I have cleaned this airbrush miticulously, its a dagr .35 tip and never had issues before, I am painting water base pigmented paints. The paints spray just fine, but whilst spraying, the cup starts to overpressurise and bubble its contents out the top. Running about 30psi, which I have been doing for a long time, my other dagr spray gun which is a .5 suction feed works prefectly with all the same settings

I have taken photos, the red bubbles out the top, came from the small amount of red airbrushing i did in the other photo, cup is half filled.

To me Im getting air into the cup, which i do not understand how, unless it is a blockage, but I have super duper cleaned it.

Steve
 

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If I understand this right , the brush starts out just fine , but starts acting up after while ? you mention water based pigmented paints : is that the automotive water base paint or is it airbrush paint ?
if you use the automotive paints the pigments are not fine enough and will block your nozzle
 
Actually no.

Using guitar water base lacquer and have been using it for two years with no problems. Nothing different, it sprays just fine, but it instantly starts to pressurise the cup.

I swapped out the nozzles and needles between the two guns today, and the housing of the gravity fed one is still playing up, even with the larger needle and nozzle.

So I'm guessing I have a cracked housing or need a new oring kit fitted, I'm going to order a new set of orings and see what happens next.

Steve
 
Looks like it has a self centering nozzle. Is there any signs of damage or wear on the inside of the body where the nozzle seats? Have you tried putting some beeswax in the to assure that it is sealed?
d9ddd9a36361aa9684726a023f97bd90.jpg
 
That's the setup all right

So maybe if there is some wear at one point of the nozzle or damage at that location or corresponding on the air brush, then potentially it will back feed air into the cup,

Makes sense, I'll have a good look tomorrow.

I doubt it's he nozzle because I swapped it with another gun, but there may be some damage in the body section

Steve
 
simso said:
I doubt it's he nozzle because I swapped it with another gun, but there may be some damage in the body section

Steve
Click to expand...

That's what I was thinking. Look for wear or damage where the nozzle seats in the body.
 
So solution is the seal showing at arrow no 5 above appears to have swoolen a fraction, I do the front cap up by hand, when i use a spanner to tighten it, no problems,

the seal appears thicker than the other airbrush so it may have swollen from solvents, this stops the cap going on tight and allows air to backfeed up pass the nozzle.

One seal kit ordered

Thanks

Steve
 
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