Modeling in General
General discussions about modeling topics.
Airbrush question - paint stopping/starting.
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New Zealand
Member Since: May 13, 2013
entire network: 165 Posts
KitMaker Network: 30 Posts
Posted: Monday, August 06, 2018 - 10:51 AM UTC
Hi guys. I was hoping someone could help with an issue that pops up from time to time with my airbrush especially while using varnishes.

I'm currently using some Mig Lucky Matt varnish, undiluted. The problem is it will periodically stop while I'm spraying, as if its blocked. I pull the trigger further and further back until it suddenly comes out all at once. This makes careful, light application very difficult.

I have an Iwata HP-C Plus double action. My compressor doesn't have a gauge so I can't tell what my pressure is set to. The instructions on the bottle call for 17psi. I would think using a low pressure would just make it worse but I will try it.

Is there anything else I can try?

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Queensland, Australia
Member Since: September 04, 2015
entire network: 1,517 Posts
KitMaker Network: 309 Posts
Posted: Monday, August 06, 2018 - 12:42 PM UTC
Either you have not mixed it well or have dry-tip, if it dries on the tip of the needle try to lower the pressure a bit and maybe dilute it a bit with thinner or even better with Flow-improver or retarder, check also that the AB is nice and clean there could be some gunk in the nozzle.

Above all Matt must be mixed really well because the agent tends to settle.

Anyway go to Bunnings or any other Hardware store,also on eBay ,Aliexpress or Amazon etc ... and buy a water-trap with pressure control and gauge,are cheap and easy to install,and make life easier .
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Ontario, Canada
Member Since: March 06, 2011
entire network: 3,971 Posts
KitMaker Network: 568 Posts
Posted: Monday, August 06, 2018 - 01:05 PM UTC
Had you used any lacquer based paints and cleaner recently in your airbrush? I used to have the problem using Vallejo Air or Ammo by Mig Acrylics. What I found out is lacquer can turn both to gel, and if there are ANY tiny bit inside your airbrush, it can cause that issue.

I have since reserved one airbrush to acrylics only, and have not had the problem since with that airbrush.

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Santa Cruz de Tenerife, Spain / Espaņa
Member Since: July 04, 2013
entire network: 1,288 Posts
KitMaker Network: 337 Posts
Posted: Monday, August 06, 2018 - 07:53 PM UTC
Seems to me that the tip is clogging as Vicious suggest, which may be aggravated by old residues from previous sessions.

Apart from a thorough disassemble and clean and what is said above, you can also clean the tip with solvent if it clogs again while spraying