I got a roll of Doculam foil from the Oregon Laminations Company (www.oregonlam.com
). The material is identified as 1C01.5G12x500, has 1.5 mil. thickness and is fully covered on one side with the heat activated glue. One side of the foil is glossy, the other dull. The dull side is covered with glue.
I have ironed the 12" long piece of Doculam to the medium density 1/4" thick 4" wide balsa plank using the maximum heat from my Hangar9 iron (280-290 deg.F). I had to use such high heat as, according to the Oregon Laminations Company, the glue activation temperature is~270 deg.F.
Material covered the unprepared balsa surface well, is smooth and there are no wrinkles. Peel test showed that the adherence is satisfactory but weaker than that for Ultracote that I normally use for wings.
Material shrinks very little, though, and the ironing must be careful and gradual in order not to leave larger wrinkles.
Then, I run the shrink test. I made a rectangular 5x6" cutout in larger piece of paper-foam-paper board (PFP, 1/5" thick foam board bought in Dollar Store) and attached the piece of Doculam to the edges of this cutout. I purposely created small (~1/32" high) diagonal wrinkles while attaching Doculam to check if they disappear when heated. They did disappear but slowly and only after six iron passes. The temperature of the iron was again ~280-290 deg.F.
The Doculam "window" created is drum tight and looks good but the foam core of the PFP was partially melted by heat so the PFP surface is sort of wavy.
I was told that, after roughing up the Doculam exposed surface with #200 sand paper, this surface can be primed and then painted with "everything". I do not know, though, what primer has to be used to avoid peeling, cracking etc.
I would be grateful for more information about Doculam use on balsa, covering the open cells and painting.
1. Can the heat gun be used on Doculam to achieve higher shrinkage and better "accidental wrinkles removal"?
2. Will Doculam stay safely attached to the unprepared balsa after, say, two years? Some say the glue dries with time and Doculam will start peeling.
3. How to paint it and with what?
I am considering to use Doculam on the full size (62" total span) wing with six open cells per side. Cells size: ~5"x~3".
I will not even try to cover the hollowed soft balsa wing tips with Doculam as I do not think this material will cover properly the surface with 3D curvature.
Or maybe there is some neat trick to do it?