will any sanding sealer work as a undercote for wbpoly or what is the best can't seem to find the deft brand in buffalo ny thanks , useing minwax water base poly

I have experimented with the wbpoly in the past... I have found to use only wbpoly the entire process, even as a sanding sealer. The reason I say this is that you may try a particular sealer and to find that there is bonding issues with the wbpoly. If you look around here on RCU there is a thread dedicated to this practice that includes very helpful tips.

the minwax sanding sealer should work as well of course it doesnt hurt try a sample first, but I cant imagine minwax sanding sealer not working with minwax poly.

Where I live you cant get sanding sealer, I ended up using a spray can of transparent varnish that is used generally over outdoor furniture and such. It work great.

air-madness how do you use the wbpoly to seal the grain without warping the wood? I have heard of doing that but it made me a little nervous.. if that sheeting warps you are in a heap of trouble!

I used MinWax sanding sealer to seal the balsa before I glassed my Stuka with MinWax PollyCryllic. There were no compatibility problems encountered.

Both were purchased at Home Depot.