Trouble with siphon paint gun.

[Alan Reynolds]

Hi, I normally frequent the Brew Room as I’m a master of nothing special.
My amateurish spraying equipment consists of an old pressure gun, a gravity gun and a siphon gun which I’m using because it has the biggest pot.
The paint I’m using is a primer with a very high material content which is abrasive. It’s used on electricity pylons.
The manufacturer recommended 10% white spirit for the vinyl paint but it separates.
Celluloid thinners works but I have to thin at over 50% to get the paint to siphon.
I’m also having to use 40psi to get any paint up to the nozzle.
When it does work, the spray pulses, just as though I’m pressing the trigger and the high pressure causes the paint to dry almost before it hits the target.
This hasn’t been too much of a problem because I’ve been spraying metal drawers, so the area is small..
However, I now have to spray the large flat parts of the cabinet and I won’t be able to maintain a wet edge.
Would I be better off using the gravity gun? Not sure if the nozzle is big enough for the media. The siphon gun ‘s nozzle is 1.5
Any advice or pointers would be most welcome.
Sorry about the long post.

 

[mr haynes]

1.8 typical auto primer size so would suggest need bigger from your paint description

 

[Dcal]

What is the "pressure gun"?
If you have a "pressure pot", that would give better results for the same size fluid tip.

 

[Alan Reynolds]

1.8 typical auto primer size so would suggest need bigger from your paint description

You’re probably correct. Next question. If it’s a Chinesium gun, is it possible to get bigger nozzles and does it need a different needle? Thanks.

 

[Alan Reynolds]

What is the "pressure gun"?
If you have a "pressure pot", that would give better results for the same size fluid tip.

I did wonder about that. The pressure one frightens me slightly as the last time I used it I accidentally put full pressure through it and had to beat the bottom back into shape as it bulged right out.

 

[graffian]

Needle gland nut wants tightening.

 

[mike os]

Airless ?

 

[steveo3002]

can also try spraying neat thinners to see if the thick paint is causing a problem

sounds like you need a bigger gun and find out more about reducing the paint if white spirit separates when they recommend it

 

[Alan Reynolds]

Yes, it was too thick and must have been dropping back down the siphon tube.
I’d almost finished everything then the compressor blew a fuse and the pressure valve just kept leaking air.
I had to make a new unloaded valve out of an old car bumper rubber!
I’ll post a picture once I reassemble it all.
It’s the hardest paint finish I’ve ever used. No wonder they use it on electricity pylons.

 

[brightspark]

Yes, it was too thick and must have been dropping back down the siphon tube.
I’d almost finished everything then the compressor blew a fuse and the pressure valve just kept leaking air.
I had to make a new unloaded valve out of an old car bumper rubber!
I’ll post a picture once I reassemble it all.
It’s the hardest paint finish I’ve ever used. No wonder they use it on electricity pylons.

micaceus iron oxide

 

[hermetic]

use a roller!

 

[Alan Reynolds]

micaceus iron oxide

Thanks for that. It explains the wear on the needle and the fact that it really scratches anything that’s brass.
I’ve got 5ltrs of Buff primer if anyone has a use for it. I’m in Broxbourne Herts.