I have been spraying a urethane primer and cleaning my gun with lacquer thinner, it seems OK, but I have a flier from a local body supply that has a cleaner for urethane products. Should I be using something other than lacquer thinner? I notice in between coats I need to mix up more primer and my gun pathern is poor until I hold my finger over the nozzle and backflush it- then it starts to return to normal. I'm using a binks#7 thats NOT set up with a primer needle. THANKS FOR YOUR THOUGHTS!!!

"Wash" grade lacquer thinner does just about the same job as the special gun cleaner at a cheaper price.

A Binks #7 with a standard needle and air cap should handle any kind of properly mixed primer. From your description of having to "back flush", I'm gonna guess you may not be completely mixing the primer and the heavier solids are getting into the pickup tube first. By back flushing, you are just blowing the heavier stuff back out and doing a little extra mixing in the cup at the same time. Another possibility is that you are partially plugging the vent hole especially if you are using a dripless cup. The back flushing will blow much of the clog out of the vent hole/tube.

I have to say that urethane reducer WILL cut partially cured urethane paint/clear where lacquer thinner will start looseing it's "power" the more it cures.

There are cheap urethane reducers like OMNI or NASON that are worth having around for the harder clean up jobs.

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1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
"Fan of most anything that moves human beings"

MartinSr, I'd have to agree with you if we are talking about "partially" cured. I suppose we've all forgotten to clean our gun right away and ended up with jelly in the cup. In those cases, we use whatever it takes to clean it out.

Once upon a time, I noticed a dramatic increase in the amount of reducer being used in the shop. I discovered the painters were using it for a routine quick wash of their guns when changing colors or from color to clear. At $27. a gallon compared to about $5. for wash grade lacquer thinner was a bit hard for me to justify. Even the cheaper reducers run in the $10-12 range.

I've forgotten what the MSDS says about the special gun cleaning solvents, but my recollection is that they are basically lacquer thinner perhaps with a bit more MEK.

Thanks for the advice, I will try cleaning real good with the reducer every so often and keep with the lacquer thinner.. THANKS FOR THE ADVICE!!!!!!!!!

Acetone I have found works a whole lot better than lacquer thinnner ever did! Run it through the gun twice and it's clean.