Thinning down SW exterior paint for HVLP

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Established Member
26 Oct 2019
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Lexington, KY
Just got myself a gravity feed 1000ml cup HVLP spray gun and I'm preparing to shoot some exterior bright white semi-gloss on some cedar sticks that'll be part of a garden trellis. Although the finish doesn't have to be anywhere close to perfect I'd like to see it go on as best it can, if for no other reason than to improve my skills for more demanding paint projects. I called SW for the spec sheet and they helped me translate what mm size number 3 and 4 needle size translated to, so that's fitted on the gun, 1.7mm I think. What I was surprised to see is that the sheet advises applying as is, no dilution. Although I have very little experience using HVLP I was almost certain most all paint needed to be thinned down to be applied this way, especially thick stuff like what I have.

Any recommendations on how to go about this paint application? What to dilute with and how much? Like saying, I'm new to this so all advice is appreciated.

PS When I was first asking about what to dilute with he reviewed his literature which explained 'it behaves like water' insofar as clean up is concerned, but also has alkyl properties. I suppose that has something to do with why they charge a hundred bucks a gallon for it. And to answer your question/ was the customer's request actually. I'll be switching to a much less expensive grade for my own projects.

sw paint sheet.jpg
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I’d start off following the material advice, if it doesn’t work, then and only then start to tinker. I would also get a viscosity cup (whatever the gun manufacture use to spec the viscosity of each needle / cap eg Ford no 4) to determine what the actual viscosity of the paint is and compare it the specs of the gun / setup I had.
I'm not familiar with your particular paint but thinning paint beyond the manufacturer's recommendation usually reduces its durability, so I would check with them.

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