Thinking of paint dipping my lower control arms in Resto Rick's cosmoline look paint, which is single stage urethane. I have read of dipping car parts in oil based paints that float on water. Would urethane paint mixed with reducer work for this?

Not sure if anyone has tried this before so I may be the first one???

Urethane paint contains isocyanate of some type. That isocyanate reacts with either water (humidity in the air - single component urethane) or a polyol (2-components paint part A/part B).

You can dilute down a urethane paint (either type) with reducer, but make SURE the reducer doesn't have any alcohol in it (any chemical that ends in "ol"). Toluene or xylene should work for you. Go ahead and give it a shot.

Thanks for the advice.

Still have not done it yet. I was going to use a Home Depot bucket, but they aren't deep enough by a couple inches. Still hunting for a slightly deeper container....

I found some hydrodipping videos on youtube and it appears they use a urethane base of some type and then cleat coat over the top afterwards.

Gotcha.... urethanes aren't cheap so I suspect you'll spend several hundred dollars for a bucket full. The single-component (no Part B/moisture cure) urethanes will "crust over" just from humidity in the air & you'll need to filter than out somehow every time you use it or open it up to the air.

"maybe" you can find some type of tube so you need less paint? Maybe a piece of metal pipe with a cap on one end???

The cans Ricks sells of his control arm paint in are pints. Already thinking one can might be enough to do just a single control arm.

If I can't find the right size container I may have to build one out of wood and then put a trash bag in it to hold the water + paint.

Use a trash can, not a trash bag.

Either clean up an existing one or buy a new one that's tall and skinny.

(If using a trash bag, it needs to be extra thick, like 6 mils.)

Just tried a little bit of leftover PPG DCC and DT 885 reducer in a preval glass jar and it mixes in with the water right away and doesn't appear to float on top like I hoped it would. I dipped a metal rod in it and it came out with very thin coverage with water bubbles all over it like you would get pulling a straw out of a chocolate milk.

Going to need to try another type of reducer or scrap this idea???