Reducer for 2-part urethane clear

Re-post in correct category---

I picked up a Preval kit and a quart of urethane clear and a little can of catalyst. What I don't have is some reducer. A pint would likely be more than enough, but I'd be willing to pop for a quart if necessary. A quick trip around the internet suggests that there is none close at hand, save for gallon, 5 gallon and bigger. I looked at several SDS sheets online and it seems that most of the urethane reducers contain acetone toluene and often a little n-Butyl ether of some sort.
And now we are in for a rainy period, so a slow reducer seems like a good choice. Is it possible to reduce the urethane clear with acetone alone?

What brand of Clear are you using? I'm no paint master. I just finished my second bike, but I asked a lot of questions. I specifically asked my paint supplier about mixing brands and they said in most cases it's not a problem. However, if things go bad, you're on your own. If you have problems using all the same brand, the manufacturers rep might be able to help diagnose the issue and offer some credit for replacement.

Reducer is relatively cheap, so a quart is typically the smallest size you'll find. Call or check your clear manufacturer's website for the nearest stocking dealer in your area. Wait and get the right stuff. Clear is the final and critical step. If it goes bad, everything you've done will be wasted.

Here's the Clear on my 80 Z1R I just finished. I used all House of Kolor.

I picked up some MasterPro clear and catalyst. It seems to be O'Rielley's house brand. The only reducer they list is 1, 5, or 50 gallon containers. They have a quart reducer for their black urethane paint, and the sales blurb says it is acetone.

I want to clear some polished aluminum parts, so if it all goes sideways, it will not be the same level of disaster that a botched painted part would be.

You might have adhesion problems on polished aluminum. Most Clears recommend a 600 grit scuff surface prep for bite. Scuffing you nice polished parts kind of defeats the purpose.

The only Clear coat I've found that say it can be applied directly to polished metal is POR-15 Glisten PC. I've used it with mixed results. I brushed it on some polished hubs and it held up well. It's really thick and self leveling. You've got to keep moving the piece so it doesn't all settle as a thick blob at the lowest point. I also tried spraying some fork lowers using Xylene as recommended for a thinner. It looked good for a week or two, but then developed a white flaky surface. My guess is I didn't allow enough flash time between coats and the solvent started venting.


Polished Aluminum is going to be tricky to get a good Clear flow out without having it run. You're shooting small pieces, so you may want a faster reducer. I'd try 1-2 light tack coats and then a final heavier flow coat. Good luck and let us know how it turns out.

Will do, thanks.

Any "urethane grade" reducer should work. Must say urethane grade! Small parts go with fast dry, slow is for paint booths that let clear flow out slowly. In the booth no dust or dirt nibs will stick.
Years ago I had a fly get stuck in my clear as I was spraying, ran in the house to get some tweezers to puck him out!
I always did paint in crappy old dirty garages. Nothing some wet sand and buff won't fix.
I always use super fast drying clear. Can sand and buff within 8 hours in warm weather

Not sure about MasterPro ...but some catalyzed clears do not use reducers.

z1kzonly wrote: Any "urethane grade" reducer should work. Must say urethane grade! Small parts go with fast dry, slow is for paint booths that let clear flow out slowly. In the booth no dust or dirt nibs will stick.
Years ago I had a fly get stuck in my clear as I was spraying, ran in the house to get some tweezers to puck him out!

A painter guy friend gave me this nifty little tool for emergency usage when a chunk of shit or a bug hits the paint. It has a thin metal toothpick length shank with small barbs on the end. You gotta work fast while the paint is wet and flowing but the tool gives you a fighting chance to get rid of those pesky critters that can wreck your day.

Neat tool. I would have been tempted to use a .45 Auto. :woohoo:

Nessism wrote:

z1kzonly wrote: Any "urethane grade" reducer should work. Must say urethane grade! Small parts go with fast dry, slow is for paint booths that let clear flow out slowly. In the booth no dust or dirt nibs will stick.
Years ago I had a fly get stuck in my clear as I was spraying, ran in the house to get some tweezers to puck him out!

A painter guy friend gave me this nifty little tool for emergency usage when a chunk of shit or a bug hits the paint. It has a thin metal toothpick length shank with small barbs on the end. You gotta work fast while the paint is wet and flowing but the tool gives you a fighting chance to get rid of those pesky critters that can wreck your day.

I just tried posting the results with comments, and my pics ere too big. :pinch:

Will try again.

Ok. Second attempt with cropped pics.
Welp, considering that this is my first attempt to spray urethane, and my first time to use the Preval system, and there was torrential rain every day, and the pieces are oddly shaped, it turned out better than it might have.
My concerns about the reducer were unfounded. The clear and catalyst were thin enough for the Preval to spray as is. Acetone made clean up a breeze.
I carefully polished each part and degreased them with chlorinated brake cleaner. I shot three coats, allowing 15-20 minutes flash time between each and then 15 or 16 hours to dry. Most of the pieces had a little orange peel. A couple of them had a small run, and the muffler hanger had a sag on the most obvious part. I (almost) carefully wet sanded each with 1500 grit, and applied three more coats as before.

Here are the parts after the first three coats and drying---






Here is the piece with the most obvious run--







After the second coats had dried, I wet sanded again and buffed and polished by hand. Here is the part above after that process---






What I did not notice until I was spraying the final coats was that I had sanded all the way through the first coats in two small spots on the muffler hanger. :pinch: I decided to go ahead and finish the piece and see how they looked. I suspect that most folks will never see them, but I know they are there taunting me.
Overall, I think it went pretty well. If I had paid a shop a handful of cash to do this, I'd be much pickier. At any rate, the parts look MUCH better than they did before and I have a bunch of clear left over to practice on. Perhaps a heavy coat would keep the dog from shedding :whistle:
The Preval system worked as advertised, though like most spray cans the pattern is not as well defined as with a real spray gun. With a bit of practice, I think the results could be even better.. It was certainly worth the $4.97 I paid for it.