Chris Armstrong Posted January 1, 2009 Share Posted January 1, 2009 Hello, I'm building a couple of Frog Speedy free flight planes from plans and I am using the tissue/dope process as per the originals. The wings are only coated with sanding sealer. The sealer I have is quite viscous (heavy) and I would like to thin it down by at least 50 %. Will this actually save weight ? will it affect strength of the balsa, I assume the strenght gain will be less than the unthined stuff ? Regards, Chris Quote Link to comment Share on other sites More sharing options...
simon barr Posted January 2, 2009 Share Posted January 2, 2009 Hello Chris,Sanding Sealer only fills the grain so that you can produce a nice finish using tissue etc. What you need to use to strengthen the wood is Dope. This can be thinned with cellulose thinners and when applied in several thin coats, sanding between each coat, will produce a smooth toughened wing. This is the method I used to use on my sheet balsa control-line models MANY years ago.Simon. Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted January 2, 2009 Share Posted January 2, 2009 And/or put some talcum powder in your dope also Cor Memories Again All those lovely smells & no burning ones cough, cough Quote Link to comment Share on other sites More sharing options...
simon barr Posted January 2, 2009 Share Posted January 2, 2009 I don't know, Myron, my mum was always moaning about the smell of dope around the house... Quote Link to comment Share on other sites More sharing options...
Chris Channon Posted January 2, 2009 Share Posted January 2, 2009 Remember, dope goes on before sanding sealer or else the dope will pull off the sanding sealer, ok i know most people know, but perhaps some don't !HeheheChris. Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 2, 2009 Share Posted January 2, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Chris Channon Posted January 5, 2009 Share Posted January 5, 2009 Hi Eric, no i am right, ( ok i know, makes a change), if you put talcum powder in either dope or sanding sealer then apply dope on top, the dope will pull the talc out, resulting in a very lumpy finish.Apply dope first, dries very quickly, rub down, apply a second coat of dope, rub down, then apply sanding sealer to fill where you have rubbed down ( missed)Rub down then the airframe is ready for the finish ( film, tex, or tissue)RegardsChris. Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 6, 2009 Share Posted January 6, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Chris Channon Posted January 6, 2009 Share Posted January 6, 2009 Hi Eric, I wonder who is actually right?, perhaps i have been doing it wrong for so long i thought it was right?oop's.regards,Chris Quote Link to comment Share on other sites More sharing options...
Bruce Richards Posted January 6, 2009 Share Posted January 6, 2009 Maybe it doesn't really matter what order you do it in as long as you make sure it has dried properly Quote Link to comment Share on other sites More sharing options...
260 Flyer Posted January 6, 2009 Share Posted January 6, 2009 I always apply one well thinned coat of dope which raises and seals the grain followed by one or two coats of sanding sealer, sanding in between as necessary. When I am happy with the finish a final coat of dope to give a gloss finish and then flat it down with fine wet and dry. Any dings etc then show up as dark glossy spots.I have never had a problem with dope dissolving the sanding sealer, just slap it on and let it dry. Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted January 6, 2009 Share Posted January 6, 2009 Nobody has mentioned the proportions of talc to dope or thinned dope ( & it's my fault I mentioned talcum powder ).The idea is to fill the grain gaps as deep as possible .In which case the thinner the dope and the minimum amount ot talc to start with the better .so that it really penetrates the wood & gives it strength too .After that ,increase the thickness of the mixture and sand off 'til you have a perfectly smooth surface .After that - depending on what covering you chose, for instance tissue- you would just use thinners or if you want to paint the smooth surface you've created use a different paint base eg enamel /fuel proofer/ whatever /for that perfect finish - even emulsion for our non- gooey (is that how you spell it ) foamy/ electric fliers By the way Eric Solar film is supposed to be applied to bare balsa wood or suitably treated plywood etc isn't it ? Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 6, 2009 Share Posted January 6, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted January 7, 2009 Share Posted January 7, 2009 Sorry Eric It was Mr Channon who finished off by saying " ready for film tex or tissue " I read recently somewhere of someone preparing balsa with a 50 / 50 PVA water mix before Solar filming .Must try it to see if it works next time as I believe PVA is fuel proof to a certain extent SO if wood did become exposed fuel might not penetrate so far into the balsa But if it sticks better , that wouldn't be an issue would it ? only on joins . I am confusing myself now Quote Link to comment Share on other sites More sharing options...
Chris Armstrong Posted January 7, 2009 Author Share Posted January 7, 2009 Thanks chaps, I'll have an experiment with some scrap sections of balsa before I apply it to the real thing. It's been about 25 years since I last used tissue & dope so I can't remember that much about the finer points. I'll probably give the talc a miss as mass is a bit of an issue. I used slightly thicker balsa than recommanded in an attempt to improve their durability when my children get their hands on them. Quote Link to comment Share on other sites More sharing options...
Jeff Glasser Posted January 25, 2009 Share Posted January 25, 2009 Thought I'd chuck my two pennorth in, I've been building models since the early '50's, and learnt what I learnt from skilled R.A.F. airframe chappies, also modellers. Sanding sealer first, then dope. followed after rubbing down by tissue/nylon/dope. I'm only getting back into the hobby after a long break, but the old ways are still with me, even though I do have trouble remembering where I live sometimes! Jeff Quote Link to comment Share on other sites More sharing options...
Skankster Posted October 15, 2017 Share Posted October 15, 2017 Hi when using tissue covering I used to sanding sealer first 2 coats then sand smooth, wet the tissue then lay it on whatever I'm covering pulling it tight then apply cellulose thinners to the areas of framework which melts the sanding sealer and sticks it to the framework and as the tissue drys out it tightens. I used a sanding block with fine garnet paper stuck to it to remove the excess tissue by very lightly sanding around the edges. Two more coats of sanding sealer and a sand smooth gives a great finish and the I think I put a couple layers of dope to finish. This works great with sheet areas and framework Quote Link to comment Share on other sites More sharing options...
Pete Crosby Posted April 13, 2020 Share Posted April 13, 2020 so can I paint over dope, or will I need to apply tissue first ? Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted April 13, 2020 Share Posted April 13, 2020 Here is a small snippet from the Gyron instructions, Steve. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted April 13, 2020 Share Posted April 13, 2020 Posted by Pete Crosby on 13/04/2020 18:39:08: so can I paint over dope, or will I need to apply tissue first ? Over sheet balsa? Tissue helps to smooth the surface reducing the amount that the grain shows through the finish, and possibly more importantly, it helps to prevent the wood splitting along the grain. If you use coloured tissue you can either rely on that for the colour or use it as a base so you need less coats of colour paint to get a good depth to it. However you can just paint over doped balsa if you want to. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted April 14, 2020 Share Posted April 14, 2020 The finish that I used to use was as follows Dope and talc to fill the grain, THen doped on tissue folowed by coats sanding sealer to get a perfect finish which was rubbed down with fine wet and dry paper and then crocus paper followed by sprayed on paint also rubbed down with crocus paper and then burnished to a high gloss with metal polish. You get a pretty good finish that way NOTEthat you have to leave each coat to dry for a long time or eventually it will sink to reveal any blemishes Edited By Peter Miller on 14/04/2020 08:25:37 Quote Link to comment Share on other sites More sharing options...
Former Member Posted April 14, 2020 Share Posted April 14, 2020 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Mike T Posted April 14, 2020 Share Posted April 14, 2020 What I'm getting from this is that there is no 'golden rule' and that people get acceptable results from varying approaches. FWIW (I last used tissue about 30 years ago...) I tended to use Peter's sequence on larger models and Barrie's on smaller... Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted April 14, 2020 Share Posted April 14, 2020 Posted by Mike T on 14/04/2020 12:35:52: What I'm getting from this is that there is no 'golden rule' and that people get acceptable results from varying approaches. FWIW (I last used tissue about 30 years ago...) I tended to use Peter's sequence on larger models and Barrie's on smaller... I should have mentioned that my sequence is for solid sheet, not tissue covered frames. Things like fuselages and solid sheet covered wings etc. Quote Link to comment Share on other sites More sharing options...
Former Member Posted April 14, 2020 Share Posted April 14, 2020 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.