Polyurethane???

[caseyboy]

I dipped a couple of boolits in semigloss polyurethane last night. They air dried over nigth and have a nice clear coat over them. Could not scratch or flake of with my thumb nail. I also smacked them with a hammer and the coat stayed put.
Anyone try polyurethane? The brand I used is by Minwax.

[TES]

I have used poly for a long time on wood floors. It might take months of curing for it to be able to "hold up". Try baking on a very low temp to cure it. It will most likely fail as it is soft plastic and probably wont hold up to temps and friction when being fired. I would be interested in seeing a poly resin like Fiberglass boat coat to see how that works.

[bangerjim]

Even though they seem to be "dry", urethane will stay mechanically soft for a long time. The volatiles take a long time to evaporate totally. And urethane wood finishes are designed to be flexable to allow the wood to breathe. Not something we want on lead!

It is nice to explore alternatives, but I would stick with the proven coatings we work with on here.

bangerjim

[felix]

On the otherhand, they might work well enough. Try a few rounds and see if they are satisfactory for the application contemplated. There are two basic types of polyurethane. Air cured and moisture cured. The moisture cured is used for industrial applications because it tougher all around. ... felix

Try one of these:

http://www.harcocoatings.com/clears/moisture-cure-polyurethanes.html

[felix]

Fiberglass "paint" material might work, but only if mixed for softer application. Stuff dries like glass normally and would shatter when shot! ... felix

[felix]

Always be prepared to clean gun IMMEDIATELY after use, making sure correct solvents as advised by the manufacturer of the poly type are used to do so. Then oil the gun down severely afterwards, just as a serious precaution. ... felix

[popper]

caseyboy - I used the minwax product, it was good. As noted, it does take a loong time to cure. I dipped it, unthinned, uncooked. No leading. I didn't tumble it so it was coated thick. Just ended up as messy the way I tried. Keep experimenting.
Note I only tried it in 40SW.

[caseyboy]

I will give it a go. I am fascinated with the "coatings". I have an old workhorse SMLE 303 that I will use as the test bed. I have shot thousands of 314299 GC boolits through it so I know what it can do. I am thinking that some baking time at a lower temp. for the polyurethane will hopefully shorten the curing time.