stunthanger.com
Building Tips and technical articles. => Paint and finishing => Topic started by: kevin king on July 17, 2023, 08:48:24 AM
-
I was under the impression you brush a coat of dope on the structure just prior to laying down the dampened silkspan. Ive also seen applying the silkspan on an already dried dope surface. Which method is better?
-
My method,since 1954, is to apply 3 or 4 coats of clear to the wood, sanding each lightly, then applying damp silk span to the wing, using thinned dope to adhere the silk span to the structure, rubbing the dope in with my fingers.. Pulling the silk span gently to remove wrinkles. Do the top then the bottom on one wing, then do the other wing. Let the silk span dry, I like to leave it over night, then apply one coat of thinned tautening dope, followed by 3 or 4 thinned coats of non tautening dope. Exact same way I apply silk..
Polyspan goes on dry, as it is a plastic, SHINY SIDE UP, heat shrink very carefully, apply tautening clear, then follow on with non tautening. Has worked for me every time. H^^
At times, just before laying down the silk span, I have applied a quick wet coat of dope to the root area of the wing, but not the rest, This was to make sure the silk span stayed in place as I pulled it
tight along the wing. D>K
Your method will come from experience, not from others, as a lot depends on the dope, silk span, size of the structure, type of structure,etc. In other words, what works for you. H^^
-
Nominally, 3 unthinned coats of dope applied, lightly sanded in between. Should have a very slight sheen to the surface at that point.
Brush on 1 more coat thinned 50/50 to 60/40 (thinner/dope) to prepare for silkspanning.
Mist the silkspan with water (some use windex) on a towel (to absorb the extra). Carefully lay the silkspan on the still wet doped surface. Brush on more of the thinned dope and rub it into thebsilkspan and surface below, thoroughly attaching it in the process.
Try to get as many wrinkles out as you can, but in some cases, wrinkles will remain. Don't stress, as after more coats of dope and sanding, most wrinkles simply disappear.
Important tip - try not to cut the silkspan with an xacto or scissors. Try carefully ripping it where it is needed to not cause a possible stress riser and to better hide the seam. Also, if needed, leave the silkspan long, and after a few coats of dope, you can simply sand it off, using the sandpaper to cut it (much like with fiberglass and epoxy).
After trimming, another 2-3 coats of thinned dope should work to firstly fill the silkspan and give a slight sheen. Be sure to carefully sand with high grit sandpaper (320 or higher) in between, and use a block to keep the surface level.
At this point, you're ready for primer/silver.
Hope this helps.
Steve
*info above shamelessly stolen from Windy finishing videos.
Sent from my SM-N986U using Tapatalk
-
Thanks.