spay poly

I always sand between coats. The solvent in polyurethane (mineral spirits) doesn't partially dissolve or melt into the already applied coat like a second coat of lacquer does, so it supposedly helps to make small sanding scratches for it to bond to. Whether that is true, or really necessary, I'm not sure as I've recently read that it is just a myth and the second coat will bond just fine without the scratches. What I do know, is no matter how carefully I apply the coat of finish, there is usually something that isn't quite smooth, whether it's dust, bubbles, bugs or something else and in a slow drying finish like polyurethane, there is always something. I sand to smooth out all those imperfections between coats. I have used several spray/rattle cans of poly.

what DaleM said,
I have only tried it once, but I sanded between coats. I was happy with the results.

thanks guys, going to try it on my current project.

The rattle can poly is the lazy man's finish. It is expensive because of the many coats and the finish is not good unless sanded. I now use Minwax poly in the quart can. I thin with about 4 parts to one of paint thinner and apply with a soft cloth. No brush marks and no pimply finish from the can.

As old wrangler said the "rattle can" poly spray is the lazy way to go. It leaves a horrible finish that requires sanding.

I've recently been spraying min wax polycrylic with my hvlp gun with fantastic results. I do not dilute it at all. It's water based and is thin enough to spray as is. If you set your spray gun up correctly you can spray without sanding in between coats.

I take a brown paper grocery bag cut it up and sand/polish the final finish coat.

Paul

I use it all the time and it's not a lazy man's way. Usually I will brush a couple of coats of thinned poly on to get a good base coat. Then I put a light coat of spray on. If it seems to be thick enough to sand I will give it a light sanding and put a final coat or two on. I only sand prior to last coat unless I have some blemishes between the other coats. You can get a real smooth finish with the rattle can if you do it right.
Throwing some thinned poly on will help save you some spray can expense. I only use spray poly on odd shape pieces or hard to brush. Don't think it is easy to get a good finish with spray on poly it does take some trial and error.

EDIT: I only use Min-Wax do not know much about other brands..I tried Rust-Oleum and had good results but only used it once.

Good luck with your project,
Bill

Bill,

For arguments sake, have you used another method of "spraying" other than the tin can?

Paul

Paul.
Short answer, No, I have wanted to get a HVLP system just haven't put forth the effort and not sure if I have the correct space for it. I use the rattle can because I can get good results.
I know there is better ways to finish then rattle can but really as far as I am concerned as long as the result is good then the method isn't important. I have never used it for an entire project just where I feel it fits the need.
I have used many techniques for finishing and always learning more.

Bill