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Discussion Starter · #1 ·
New to whole cha cha , but i was wondering can i make a device i mean to spray an elsto roof can i just use a cheap chemical sprayer and roll it out and thro away wen done , im sure this is a dumb girl question , why does sprayers have to i mean y cant i use my 4000 psi pressure washer with a tip connected to hose to bucket ?

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Licensed General Contractor, Painting Contractor
2,347 Posts
I know it's a silly question, but one of my favorite things to do is building little spray carts attached to hand-trucks for spraying stain on long runs of fences and such. Working on a build now using a Harbor Freight welding cart actually,12 volt pump, battery, & accumulator tank. Anyways, in theory, you could apply paint with a pressure washer, but you'll have to consider:

-Most direct drives have problems with pulling from a tank without being force-fed with positive pressure, so elevating the supply tank and an oversized intake hose would be a must. Belt or gear drive would be better, ($750 upgrade).
-Unless you run a bypass line from your unloader back to the tank, you'll pretty much have to always be spraying or you'll burn up the pump. You'll have to move fast if you're spraying 3-4 gallons per minute!
-Pressure-trapped unloaders release a huge burst of liquid before being able to equalize pressure in the pump, so stand back from the surface about 15' or you'll be wearing the paint. Or just spend $100 more for a flow-actuated unloader to eliminate the kickback when first pulling the trigger.
-Most paints are way too viscous to run through pumps, so there's that. Plan on reducing elastomeric 85% and applying 6-8 coats. If the customer brings up the subject of warranties, quickly divert their attention with compliments or expelling gas in rapid succession.
-Starving the pump of continuous liquid will cause cavitation, so get one more rig just to be safe. 3 would be better, but hey, it's a budget build!
-Most pressure washing pumps will die a quick death with elastomeric of any viscosity pumped through them, so better make a few of these setups so you don't get in the middle of a project and stranded with no rig. Dispose of said rigs upon completion of project, (if one is still kickin, that is).

Estimated Build Cost: $450 per unit, (and you'll want to have at least 2), = $900
Estimated Build Time Per Unit: 4 hrs, (x 2 @ whatever your hourly rate is...let's just say $75/hr) = $600
Estimated Time Procuring Parts: 6hrs = $300
Estimated Total For Jackwagon Jimmriggin: $1,800

An even sillier option...I and know this it out there, but maybe consider renting a sprayer that's actually capable of pushing elastomeric. It'll run you anywhere from $125/day or $600 for the entire week. Sometimes the most expensive thing we can do is use cheap tools & materials. Please keep us updated and post pics of the build, should you consider to pursue this endeavor. Good luck, and Godspeed.
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