Pulsing spray gun

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PostPosted: Sun Jul 25, 2021 1:21 am
So yesterday,

Grabbed out my full size / cleaned Star 1.4 nozzle spray gun and cleared a coat of thinners through it first.

Loaded up the paint and started spraying and it was pulsing the fluid out, stripped the gun down, extra cleaned it payjng attention to every orifice and air gallery, checked the packing washer on the needle etc.

Filled the gun with thinners and again sprayed it out, sprayed just fine with thinners, addded some nitrocellulose paint, thinned down and filtered and it started pulsing again.

Something obvious is alluding me but I cannot guess what it is, recommendations, my next thing to do is put a new seal kit through the gun.

My thoughts are, the thicker fluid (well thicker than just thnners) is making the gun draw air from some void, i just cannot spot thatarea of leak

Steve

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PostPosted: Sun Jul 25, 2021 5:17 am
Did you clean the hole in the cap in the lid?
Chris



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PostPosted: Sun Jul 25, 2021 6:43 am
Sure did, i scrubbed it spotless

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PostPosted: Sun Jul 25, 2021 8:27 am
Make sure the tip is tightly threaded into the gun.
I normally snug it with the wrench and then give it that little extra just to be sure.
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PostPosted: Sun Jul 25, 2021 2:07 pm
Seal under fluid tip not sealing, IF its similar gun to a Devilbiss.
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PostPosted: Sun Jul 25, 2021 9:05 pm
Doright wrote:Seal under fluid tip not sealing,


It's a Star - no seal there. It's one of their claims to fame, that their engineering and machining is so good that they don't need seals. Largely true. Design is more like an Iwata than a Devilbiss.

Simso, not much goes wrong with these. Make sure fluid tip and aircap are properly seated and tight. Remove needle and clean, ensuring no paint stuck to it (can't see but can feel) and make sure seal is seated and tightened, but not too much.

Also check the connections between gun and pot - I've had the rare occasion of those coming loose.

Also remove, check and lubricate the main air flow valve operated by the trigger. These can dry out and get a bit sticky.
Chris



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PostPosted: Sun Jul 25, 2021 10:30 pm
Thanks guys,

Yeh its a pretty good gun, just started pulsing, I also have a star 1.8 so might swap out the needle/cap assembly and see if problem transfers over to new gun

Steve

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PostPosted: Mon Jul 26, 2021 6:50 am
your fluid nozzle is loose.
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