Repairs to a spraygun.

[ajlelectronics]

I have two LVLP guns with the same fault of continuously passing air, without the trigger pulled. I put them away some time ago but having had my new tenant complaining about solvent smell from my Devillbis, I could do with sorting them. The manufacturer isn't interested in helping, sadly.

It looks to me that it might be a faulty needle packing (item 6) but not certain what the air path is? That having been said, I might not even be able to buy spares!

 

[grim_d]

Id say more likely to be something in items 12-16 as that relates to the path of air, item 6 is a seal but its for the fluid in the cup. Air passes round the outside of the fluid needle assembly.

Id be surprised if you can get spares for a gun like that to be honest.

first step would be to dismantle and check for issues/debris, wouldn't take much to get jammed in the seat for it to not seal correctly, though since both are doing so it does suggest a fault, hopefully just an o-ring and a cheap fix.

 

[norsa]

I've got an Iwata AZ30 that does that. I've done everything I can think of to stop it leaking, to no avail. Still sprays well and is my go to gun for smaller non panelwork.
Nick

 

[sako243]

I had something similar with a pressure pot spray gun. Just strip it down, give it a good clean and reassemble. Pretty much guarantee there'll just be a bit of dirt stopping either the needle or trigger seating back fully.

They're not complex beasts and rely more (at least the ones I've got) of a decent machined fit between needle and 9 and the nozzle 2. Everything else is simply to set up how far the needle retracts and how much air is let through to the channel. If that needle doesn't seal against the nozzle then everything else is moot.

 

[ajlelectronics]

I've got an Iwata AZ30 that does that. I've done everything I can think of to stop it leaking, to no avail. Still sprays well and is my go to gun for smaller non panelwork.
Nick

Yes, these still work well otherwise, but I suspect that it may be a design defect.

 

[sako243]

Yes, these still work well otherwise, but I suspect that it may be a design defect.

If that's the case can you lap the needle to the nozzle like you would a valve seat?