Originally Posted by
kregan
Portland flyer, first let me thank you for the wonderful thread. I have had this printed out since last year and just started working on a set of wings using your guidance but I just noticed this reply above... Are you saying you no longer use the poly at all?
I just applied the silkspan with poly not more than an hour ago, LOL. It sounds like you are laying the the silkspan in a clear lacquer directly on the balsa with no sealer applied first?
Can you briefly outline the steps you now use?
You will be fine with the Poly. What was happening is I was getting some warping of the wings and surfaces due to it being water based.. Because I use Ultacote on the bottoms, I wasn't coating both side, which caused some warping. The lacquer will reduce the warping, but I have found an issue with it. The lacquer doesn't seem to bond as well as the Poly and I have had a few small bubbles on the surface show up, which is no big deal structurally, it just didn't give the long term smooth finish.
If you get some warping of the wings and surfaces, I just put some weight on the opposite side and they are fine a few days. If you are silk spanning both sides of the wings and control surfaces it will even out the stress and limit the warping.
One other bedding material that works well is non taunting dope like a lot of used years ago. I did a wing with it, and it worked fine, but the stuff will kill you from the smell without a respirator. After working with this stuff for several years, the Poly has been the best for longevity.
Good luck. Anything else, let me know. BTW, I'm in Colorado now, so I guess I need to change my online name!