favorite polyurethane ??

[curtiss]

Is there a trick to storing this stuff ?

I have been using a Minwax version but often toss that last half of the can as it jells up. I try to seal up the can properly.

Any other favorites out there ?

[Gary Campbell]

Curtis...
Polyurethanes cure using moisture in the air. Once opened..... you know! I prefer the automotive types that use a catalyst, but they are more expensive. What is your application?

[srwtlc]

Could try something like this.

http://www.bloxygen.com/

[curtiss]

Re: What is your application?

Mostly just a final finish on signs, hardwoods.

A small amount that could be mixed as needed might be a good idea.

[ssflyer]

I've been using Varathane's water-based Spar Urethane with great results. Goes on really well, dries clear and fast, and holds up extremely well.

I even made a sign out of MDF, as a test. I sprayed 4 coats on and it is still perfect after being out in the weather for over a year!

[bleeth]

For storage (which was the question) an old trick is to exhale into the can before you close it (carbon dioxide) and then store the can upside down. Store in a cool dark place. That being said, once open, none of them have an indefinite shelf life.

As far as what to use (the other question) it depends on the application. indoor, outdoor, signage, furniture, ???
I use a lot of different products depending on material and what the final product is as well as where it's going.

[michael_schwartz]

If your having trouble using up a quart of finish before it goes bad I would sugest looking for a comparable product that is available in a rattle can. I try not to buy anything unless I know I will use it up within 6 months. If I don't use most of it up by then, odds are it will sit around for the remainder of its shelf life.

I have worked with the Minwax polyurethane's and their only advantage is that they are readily available. I prefer to reduce them quite a bit and apply VERY thin coats. These seem to be formulated for your average homeowner, or painting contractor with the assumption that they are going to be applied out of the can rather thick with the wrong kind of brush. I prefer the general finishes Arm-R-Seal over the minwax.

Lately my preference has been to work with waterborne coatings.

The difference in the chemistry of waterborne, and solvent products are night and day. Kind of like the difference between latex, and oil based paint. I know guys who still swear your supposed to thin latex paint with paint thinner, and they will look at you like your crazy when you tell them to use water :eek:

I would imagine there are guys trying to mix waterborne coatings with solvent products creating all sorts of nightmares.

[dlcw]

I use Arm-R-Seal, unless I'm using conversion varnish or lacquer.

[bruce_taylor]

I use some saran wrap and place right on top of the material and it helps a lot. They sell products that put a gas on top to seal out he air but the wrap works good for me

[beacon14]

If it's a half-full gallon can, Pick up some empty quart cans and decant the remaining liquid into them, being sure to fill them all the way and seal tightly. You can get clear marbles or glass pebbles (ask your florist - they use them to hold flowers in place in the vase) to use as inert filler to make sure there is as little air left in the can as possible before sealing it.

[ghostcreek]

I have been using Sikkens Cetol srd 250 for any exterior signs made of wood. I had a test piece out in my HOT summers and wet winters for over 3 years. Great finish, no peeling or other finish problems. Hope this helps.