If you browse the this part of the forum you will find I use a product called "MODPODGE" from the arts and crafts store.   They have several version and the one I use is the matte finish.   You bruh it on the perimeter of what you are covering and let it dry.  Brush it as thin as you can.  Cut poly-span to size and used a monokote type iron to adhere the material.   Don't slide the iron across the material.   Then from there on the finish is up to you.  For me I then iron on a mylar covering similar to SLC from the Corehouse.   If you want the poly-span type finish with dope put the Mylar/SLC on first.  But you have to buff the mylar/SLC to s dull finish before the poly-span goes on.  Even if you use another type finish than dope it will take less material.  Double covering like this makes for a very durable covering.  Remember it takes practice, patience and time.

I agree with Doc on the use of Mod-Podge. I've used it for years on both RC and UC planes. It's water soluble and very user friendly. I found through trial and error that I only need to apply one coat to the balsa surface. It soaks in and makes you think it is not going to work, but the heat from the iron will activate it and the material will stick well. I've used it to attach Polyspan, Monocote, Ultracoat and various other coverings, but have never tried silkspan.

Paul

Is the Mod-Podge better than Balsarite?  My main question was what OTC stuff to use to stick down polyspan but I should expand to building up the coverage.  Can you use lacquer's or polyurethane then finish with enamel?  My wife is quite allergic to dope so I have avoided it at all costs.  MonoKote and electric motors have probably saved our marriage but I want a real finish on my PA ship for next year.

Ken
 

Mod-Podge does not stick better than Balsarite, but is much easier to use since it is water based. I have always had trouble keeping Balsarite soluble in the can for any length of time so I quit using it. After ironing down the covering, I use Minn-Wax lacquer to seal the Polyspan and build up with Dupli-Color filler/primer. The lacquer does not dissolve the Mod-Podge. I have also used Minn-Wax lacquer with talcum powder with good success, but applying with a brush is a pain. I tested a sample piece using the lacquer to stick the Polyspan, but it required heating with an iron. It did not dissolve when brushed through the covering like dope does.  It did not stick nearly as well as Mod-Podge. Have never tried  polyurethane for covering. I have used Rustoleum over Minn-Wax lacquer/Dupli-Color primer many times with excellent results. Hope this helps.

Paul

Thanks a bunch.  I have some Min Wax lacquer and I was hoping it was comparable with Rustoleum.  Sad, but I just can't use dope.

Ken

Its called Sand paper and lots of dope.   I quit trying fo 20 point finishes years ago when a Nobler of mine I hid behind the bush at VSC one year still got me a 12 point appearance,  As Larry says the SLC over poly-span makes for a durable finish.   If you browse this forum you will see some of my finishes

I like your method and I think I will try it.  One question, I gather that SLC is not a product.  I have searched it here but nowhere can I find a posting that doesn't assume that I know what it is!  I found out you can iron it on, sand it and paint it but I still am clueless as to what "it" is and where "it" can be acquired other than "phil c" had it back in 2012.

Please forgive my ignorance - Ken

SLC film is sold by Phil Cartier.  .75mil polyester film.  Low temp, iron on film.  Not the same as lamination film. 

https://stunthanger.com/smf/profile/?u=238

http://home.earthlink.net/~philcartier/webcat/pricelist.html