Large Model Association Forum

Hi
Will some one please advise me as to whether you should use "shrinking" or "none shrinking dope when puting nylon covering onto a solid structure.In this case a planked fus.
Thanks for your time
Arthur

Seal the surface with sanding sealer, this can be made from non shrink dope, and talcum powder, rubbed down with fine garnet paper, put the nylon on wet, brush it through with shrinking dope, 50/50 thinned, 2further coats of non shrink dope, with a few drops of castor oil in, will seal the nylon, the castor oil is there to plasticise the finish, and stop paint cracking in the future,

BUT, Everyone these days would glass the surface, getting a longer lasting finish, and imparting greater strength to the structure, why nylon?

Hi Alan.Thanks for the reply.Why dope finish?.the problem is i have developed a reaction to epoxy.Years ago i built a full size boat and used 15 gallons of west epoxy with glass cloth with no problems,and have used it since again with no problems.However a month ago i glass clothed a wing and in the morning my face was red and very sore,Week to get better ,had to finish wing so had another go,same result only worse, needed a vist to the doctors,so no more epoxy for me.(there had been no skin contact)
Have tryed water based floor varnish etc but find being water based the wood warps .Any idears would be appreciated.Thanks Arthur.

Oh hell, that wont do will it? Well, can i suggest practicing on some balsa sheet first? Shrinking dope never stops shrinking, hence the castor oil drops to keep it plasticised, ive actually not done it for years, but it never leaves the mind, DONT be tempted to tissue the surface, its fragile, and punctures easily, i have a top flite corsair i bought, tissued, not being the bestvstorer of models ( shut it jonesey ) its full of dint and scrapes

Just to add to Alan's reply, nitrate dope stops shrinking once completely dry, it's butyrate dope that continues to shrink - here's an interesting article:

https://www.awm.gov.au/media/conference ... itrate.pdf.

Non-shrinking dope will shrink to some extent so if you've managed to apply the covering without wrinkles, non-shrinking dope may be all that's needed. The risk with shrinking dope is that it will warp or distort a fragile structure, or create the 'starved horse' effect on a curved, sheeted area. When doped the covering only needs to be taut enough to remove any slackness, trying to achieve a drum tight finish does not gain anything, except warps...........I know from experience!

Arthur, get someone else to do your epoxy work and then finish the model they way you normally do!
Cary

Thank you all for the advise.

Arthur

I have the same problem with epoxy but now used Bondaglass G4 for all my glass work. No mixing and no waste and very easy to apply. Search this forum for several postings on how to use it.

John