[S10xGN]

Hi All,

I've been spraying some SPI 2k high build primer with a Devilbiss Finishline 3 HVLP gun with 2.2 tip and getting some dry spray. I've got the gun set to 13 PSI, if I'm setting it right (I hold the trigger full open and set the regulator to 13#). When shooting, I try to remember to half-pull the trigger for air only until the initial "surge" of air is gone and I'm getting my 13#. What else should I be looking at?

Thanks!

Russ

[302 Z28]

An HVLP with 13 psi suppl with the trigger pulled is way too low. HVLP guns meter the air so it is 10psi at the air cap, that does not mean 10psi supply. Also the 2.2mm tip is a little too big IMO. Most high build primers will spray good with a 1.7mm. Try about 30-35psi supply with the trigger pulled.

Vince

[S10xGN]

It acts like it's pushing too much air. Anyways, the 2.2 tip will lay some paint!

How do you measure air pressure at the cap? My thinking is when you have the trigger pulled full open with air only, the pressure you see on the regulator (small one at the gun) will be showing the "cap" pressure, since this should be where the most resistance (largest pressure drop) is. Is this wrong?

Russ

[302 Z28]

You don't need to measure pressure at the cap, it is set internally that is the design of an HVLP gun. If your setting the supply pressure at 13psi with the trigger pulled I do not see how you think it's moving too much air.

Vince

[S10xGN]

Hmm, I always thought dry spray was a result of too much air...

Are you saying I don't need to regulate the air? I have 3/8" HVLP fittings and 150# supply air. I also have the fluid valve full open.

I'm open to any suggestions!

Russ

[302 Z28]

Go to the SPI web site and read Barryk's method to adjust a spray gun, it is excellent.

Vince

[hotrodpreacher]

You are using the right pressure, so try on another piece of metal,to go a little slower,and stay about 12 to 14 inches from what you are spraying.If you still have a problem give me a shout,and we`ll talk again Hotrod Preacher

[302 Z28]

Try Barry's method and if it does not work for you shoot me a PM. I am right next door and will come over tomorrow and see if I can help you out.

Vince

[S10xGN]

I've read Barry's procedure, but it doesn't really address primers (any dummy should be able to shoot primer, right? ). Maybe because it's a frame with tubing (gawd, I hate painting tubing) that I'm having trouble. I'm gonna sand out some (flow puttied) spots tomorrow and see how it goes. It's almost ready for a topcoat of epoxy (now that sprays good with a 1.7 tip).

[302 Z28]

I hate painting tubing on frames also. I have used the SPI primer and I like it a whole lot. I'm serious about my offer if you choose to take me up on it.

Vince

[hotrodpreacher]

I must have missed something...frame? It still shouldnt make any difference, but if your still having problems,Id go next door...Good luck.Hotrod Preacher

[S10xGN]

Vince, 'preciate the offer, but I prolly won't get to spray again until mid week next (I'm slooow). You can tell by the date on the pic how slow I've been...

Hotrod, spraying a bunch of 1 3/4" tubes is quite a bit different than spraying flat panels, I'm sure you know that. I manage OK on the rails, but how do you get full coverage without bumping the gun into already sprayed parts?

Russ

[jcclark]

A Finishline 3 needs 23 PSI at the inlet (trigger pulled) to
obtain the right PSI at the cap (according to the mfg)
That's the minimum you should supply.
Most HVLP and LVLP guns do better by bumping that pressure
up 3 to 5 PSI.

If you're getting to dry of spray, use a slower reducer and
a little more of it. I over reduce primers all the time by a little,
it's not a problem as long as you allow extra cureing time.
And it'll lay a lot better.

[jcclark]

Originally Posted by S10xGN

but how do you get full coverage without bumping the gun into already sprayed parts?
Russ

The best way is to use a pressure pot for your paint,
that way you have no cup in the way.
But that's a lot of trouble (clean-up) for small jobs.

[cyclopsblown34]

Originally Posted by 302 Z28

Go to the SPI web site and read Barryk's method to adjust a spray gun, it is excellent.

Vince

BarryK's method for adjusting a spray gun helped me immensely.