Large Model Association Forum

Hello all

I am looking for a suitable covering material for my latest project,i normally use solartex but it is not wide enough for my wings.

The chord of my wings are 36" so something 1 mtr wide would be ideal,nylon would do the trick but as yet i havn't managed to

find any suitable.Any sugestions woul be appreciated.

Many thanks,Dave.

Dave, try DIATEX as used on the full size. It comes 60" wide and in various weights. It is also heatshrink. I get mine from a company in Lincolnshire but for the life of me I don't have the details to hand. Just Google Diatex and it will come up. Cheers, Stuart.

Stuart/David.
The Lincolnshire company is probably Skycraft Ltd, near Spalding. http://www.sky-craft.co.uk 01406 371779
Use the lightest weight material they sell, alternatively use Sig Koverall available from Pegasus Models, this is 48" wide and up to 5yds long. For either material you will need: fabric cement, fabric cement reducer, non-tautening dope and its reducer, all available from Skycraft. Don't try to substitute cellulose thinners to thin the fabric cement or the dope although thinners can be used for brush cleaning.
Once you've tried this, you'll not go back to Solartex or nylon!
Regards

Thanks Stuart/John

I have been on the site you suggested superb,especially the dope.

Many thanks,Dave.

David,
If you use Diatex or Koverall, use the recommended fabric cement to stick down the edges, it can be done with full strength dope but is much more difficult as the dope doesn't dry as quickly and tries to turn over the edges. Also cut the material with pinking shears, both fray easily and will leave an untidy edge if trying to trim with a knife, this is especially so if using dope as the adhesive - the edges have to be 'worked' which only leads to more fraying. Pinking shears and fabric cement will lead to satisfaction, not angst!

All

I have been using Diatex for years. The grade you require is Diatex 1000. I do not use the fabric cement any more preferring to use balsalock instead as it allows the covering to be ironed on and seems to avoid the frayed edge problem. Obviously after ironing on the bottom covering more balsalock needs to be applied to the edge of the bottom covering to allow the top covering to overlap and stick but this is simply done. I apply the balsalock with a small sponge to avoid brush marks which can show through the covering. After applying the top covering I brush dope all round the edges to seal and firmly fix them down before heat shrinking. Be careful with the shrinking as it shrinks more than Solartex and can warp the structure, you only need to shrink it enough to make it go tight.

John

Hi John,
thanks for the info on Diatex. I am looking at using this on my Spacewalker. After you have attached the Diatex and finished shrinking what else do you then do before painting?...such as applying dope/thinners etc.
Regards
Andy

Andy,
Not sure which John you are requesting imformation from, however after shrinking (just enough heat to remove the wrinkles, don't make the covering drum tight) apply 4 or 5 coats of thinned non taughtening dope. I normally thin about 2 parts dope to 1 part thinners and brush it on). What you're trying to do is fill the weave with the dope. DIatex has quite an open weave (and no adhesive behind it like Solartex) so don't stipple the first coat untherwise it may pool on the reverse side. If this happens just brush the area with neat thinners and the dope will dissolve.
Once doped, apply primer and cut back between coats until you get the base you want. Do this carefully as primer is soft and its easy to go straight through the primer and dope and fray the covering. Any low spots or pin holes will be visible after a couple of coats of primer, these can be fixed with filler or more primer. After that its ready for top coating in whatever is your favourite paint.

Question to John Rickett. If you are using Balsaloc to attach Sig Koverall do you need to apply 2 coats of nitrate dope to the framework before you apply the Balsaloc or do you use some other form of sealer ? Thanks in anticipation.

Peter,
My preference is to use fabric cement. I find it easier to work with. Balsaloc, though cheaper, leaves a residue which is not dissolved by dope and won't sand, also I find it difficult to 'stretch' the covering during application whereas fabric cement can be softened and effectively reactivated by using thinners, or more cement.
I do not seal the surface prior to applying fabric cement, just apply two coats (it dries almost instantly, so there is no waiting) then lay the covering over the structure and paint through the fabric with more cement.
Another benefit - the grip with cement is far more tenacious than Balsaloc so making the covering of concave areas easier (great for wing fillets). It can also be used just as effectively on balsa, ply, fibreglass and metal surfaces.
I imagine each of us develops our own preferences and ways of doing things, for me fabric cement wins every time - apart from the cost!

Thanks John for the in depth info. I'll do some test patches and then apply the treatment to my Sky 120 when I've built it. First time I've looked forward to covering anything!

I have just bought Ceconite light from lasaero, it comes in 60 inch widths and at £4.50 a yard is very good value. It looks and feels very much like solartex, not had chance to try it out as yet.

David bell

Lasaero number is 01837 658081