Silkspan Adhesion

[Phil Coopy]

When I was stripping the silkspan covering off the fuselage of my recently crashed Vector 40 I noticed that in some small places that the silkspan didn't adhere very well.  I normally give the bare wood  a couple of coats of nitrate before applying damp silkspan to a wet coat of butyrate and then priming, filling, and sanding...lots...and finally color and clear.  Something I'm doing wrong here?

Phil

[Bill Little]

Something along the things Ty said. 

A real good base of dope, and pretty thin dope to attach, or just thinner to attach. 

Why quit on the nitrate before you attached it?  It sticks better.   (of course I only use butyrate after EVERYTHING has the covering attached with the tinted non-tautening nitrate.......)  I wouldn't build up the base with nitrate and then switch to butyrate to stick it down.  Just go with the butyrate if you like.  it will do almost as good a job. 

Big Bear

[Neville Legg]

I'm having problems with butyrate dope coming off nitrate dope! I normally cover with silk put on wet. I brush 2-3 coats of sanding sealer on the airframe first, sanding lightly as you go, then lay the silk on wet and brush thinner through the silk, it sticks and shrinks fine and tight, so far so good. I then brush on 2 thin coats of nitrate shrinking dope, when they are dry, I sand it very lightly, and put another 2-3 coats of non-shrinking butyrate. Now!... when I mask up, even with low tack tape, the tape will pull the butyrate off the nitrate in places, very annoying    If I use nitrate all the way it doesn't happen, but nitrate cracks after a while. Any ideas?

Cheers

[Bill Little]

I'm having problems with butyrate dope coming off nitrate dope! I normally cover with silk put on wet. I brush 2-3 coats of sanding sealer on the airframe first, sanding lightly as you go, then lay the silk on wet and brush thinner through the silk, it sticks and shrinks fine and tight, so far so good. I then brush on 2 thin coats of nitrate shrinking dope, when they are dry, I sand it very lightly, and put another 2-3 coats of non-shrinking butyrate. Now!... when I mask up, even with low tack tape, the tape will pull the butyrate off the nitrate in places, very annoying    If I use nitrate all the way it doesn't happen, but nitrate cracks after a while. Any ideas?

Cheers

I put a touch of "plasticizer" in all my dope products..........

Haven't had an adhesion problem unless I use too hot a thinner, or too much retarder.

Bill

[Leester]

Recently I was watching Windy's profile Cardinal dvd's again and when he was putting on the dope before the silkspan he stressed that it should be around 70% thinner and 30% dope. He stated this way it soaks in the wood better and allows for better adhesion of the silk span.

[Neville Legg]

Bill, what plasticiser do you use? to my knowledge, no model dealer or model shops sell it over here! I tried a few drops of caster oil, but that didn't work. I prefer to use nitrate, but the cracking, and the fact that its not fuel proof, except for diesel fuel, is a bit of a nuisance, well, a big nuisance to be honest!

Cheers

[Jim Thomerson]

In the USA we can get non tautening nitrate and butyrate from aircraft supply places.  On wood, I prepare it shiny with dope.  On the fuselage, I put the silkspan on dry, stuck down around the edges with thinner with a little dope in it.  Then I water shrink.  When it is dry, then I stick it all down with thinner.  This gives a very smooth finish, smoother than if you stick it down all at once.