GF white poly streaking

I'm getting some streaking using General Finishes white poly. I'm using a 2.5 tip and over lapping by 1/2 or better. Was wondering if anyone has used their extender to increase the flow properties.

I added 3% Extender the last time I sprayed Enduro White Poly. It really improves how well the product flows out.

John

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Originally Posted by Mark Bachler

I'm getting some streaking using General Finishes white poly. I'm using a 2.5 tip and over lapping by 1/2 or better. Was wondering if anyone has used their extender to increase the flow properties.

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What sort of gun are you using?

General Finishes recommends a 1.3-1.5 mm tip with HVLP for Enduro White Poly, and says that up to 10% dilution with water or extender is allowed "if desired". I'd try shooting it straight with a smaller N/N if you can, and only dilute it if that doesn't work. My guess is that you're simply using too large of a tip for the available airflow, and it isn't atomizing sufficiently.

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Originally Posted by Patrick Chase

What sort of gun are you using?

General Finishes recommends a 1.3-1.5 mm tip with HVLP for Enduro White Poly, and says that up to 10% dilution with water or extender is allowed "if desired". I'd try shooting it straight with a smaller N/N if you can, and only dilute it if that doesn't work. My guess is that you're simply using too large of a tip for the available airflow, and it isn't atomizing sufficiently.

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Its a qualspray LVLP from Homestead Finishing. It just seems I have to have the valves way open with the smaller tips to get any width in my pattern. A day of experimenting I guess.

Keep in mind GF's recommendations are based on an air assisted HVLP gun. Enduro White Poly isn't going to go through a gravity gun with a 1.3 - 1.5 mm N/N. It has a viscosity of about 100 seconds #4 Ford cup. It does spray great through my air assisted Qualspray HVLP gun with a 1.3 mm N/N set, better with 3% extender, but still good even w/o. If the OP is using a gravity gun, he needs that large N/N or something close.

John

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Originally Posted by John TenEyck

Keep in mind GF's recommendations are based on an air assisted HVLP gun. Enduro White Poly isn't going to go through a gravity gun with a 1.3 - 1.5 mm N/N. It has a viscosity of about 100 seconds #4 Ford cup. It does spray great through my air assisted Qualspray HVLP gun with a 1.3 mm N/N set, better with 3% extender, but still good even w/o. If the OP is using a gravity gun, he needs that large N/N or something close.

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You're right, obviously. Like you I'm spoiled by the fact that all of my setups have at least the option of pressure feed, and I wouldn't attempt to spray a heavy finish without it. If you already use PPS (as we both do) then it's an easy retrofit to add pressure feed to any conversion gun.

As you allude, the big advantage to pressure feed is that you can "squeeze" a heavy finish through a small nozzle, and get good atomization even with a lower-airflow LVLP rig.