DaveyP Posted January 28, 2018 Share Posted January 28, 2018 Hi all, I'm currently building a trainer which has a veneered polystyrene wing, a first for me. The veneer covers the top, bottom and leading edge of the wing and I need to glue the balsa TE and wing tips to the exposed polystyrene. The instructions say to epoxy the two wing halves together but should I use epoxy for the trailing edge and tips ? or is there another glue I could use ? I usually use Aliphatic for wood joining. Tia Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 28, 2018 Share Posted January 28, 2018 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
DaveyP Posted January 28, 2018 Author Share Posted January 28, 2018 Thanks Percy very useful info Quote Link to comment Share on other sites More sharing options...
Levanter Posted January 28, 2018 Share Posted January 28, 2018 DaveyP for aliphatic and I like Percy's idea about the diamond shape. I have just put together a set of wings the same as yours with the veneer wrapped around the leading edge only requiring the trailing edge to be glued. I used elastic bands as this keeps the joint nicely compressed while the glue dries. I buy bags of bands from stationers as they always come in useful. The small ones I had would not stretch far enough and the large ones were a bit loose so I simply tied a knot to get the right tension. Aliphatic is much easier to sand than epoxy and the one thing you don't want to do on this type of wing is sand through the veneer. There is not much rom for error. Levanter Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 28, 2018 Share Posted January 28, 2018 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Mike Etheridge 1 Posted January 28, 2018 Share Posted January 28, 2018 I have never heard of Aliphatic glue but I always use PACER Z-POXY FINISHING RESIN to join veneered foam wings with fibre mats top and bottom. The finishing resin takes a long while to dry so I coat one side of the wing first and leave it to dry overnight and then coat the remaining side. The resin drys with a clear glass finish which without rubbing down may not take covering material too well. However I have used paints that match covering material quite successfully. I should mention that the Epoxy Resin comes in two plastic bottles 'Resin' and 'Hardener'. The Hardener may fluctuate in colour without causing problems and the Resin may solidify if kept in cold storage. However the resin bottle may be heated in hot water to return the Resin to a liquid state, something I have done with the Z POXY 5 minute glue. After repair Before repair Edited By Mike Etheridge 1 on 28/01/2018 21:47:03 Edited By Mike Etheridge 1 on 28/01/2018 22:00:31 Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 28, 2018 Share Posted January 28, 2018 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Nigel R Posted January 29, 2018 Share Posted January 29, 2018 In your position, I would use: PVA (or aliphatic) to attach the TE. The masking tape trick is good to help avoid going through veneer when shaping. PVA or aliphatic, join panels with correct dihedral, using tips to set the alignment. PVA or aliphatic and glass tissue (not cloth or bandage) to reinforce the joint. Glass tissue is quite thin and several layers are needed, I would do one wide and one thin layer. If your trainer is 60" (ish) then I'd go for a 10" wide first layer and a 5" wide second layer. Old credit card to spread the PVA and press it into the glass. This method doesn't need any filling / sanding around the edge of the cloth like the thick cloth + epoxy method. I would use two layers on anything up to around an 8lb model. Just add another layer after that. I'm not anti epoxy - it's just that PVA is cheap as chips and perfectly effective for all these jobs. As is the glass tissue. Quote Link to comment Share on other sites More sharing options...
DaveyP Posted January 29, 2018 Author Share Posted January 29, 2018 I have now used aliphatic ( Titebond ) to fix the TE and tips I do like the trick of using masking tape when shaping to prevent damage to the veneer I've never heard of glass tissue ? there is some glass cloth supplied with the kit buy it is very thick and I think it will look unsightly. Any recommendations of where to get glass tissue ? Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted January 29, 2018 Share Posted January 29, 2018 Tissue on ebay Edited By Denis Watkins on 29/01/2018 11:33:19 Quote Link to comment Share on other sites More sharing options...
Nigel R Posted January 29, 2018 Share Posted January 29, 2018 "I've never heard of glass tissue ? " It's simply very light cloth with no regular weave. As Denis hints, on ebay it goes for a couple of quid, for enough tissue to go around a good few wing joins. I'm not a fan of the heavy cloths that are usually supplied for exactly the reason you state, you will need to dress the edge somehow. And a sharp edge at the end of the cloth is a stress riser which is always a Bad Thing to have. Quote Link to comment Share on other sites More sharing options...
David Foley Posted January 29, 2018 Share Posted January 29, 2018 Cloth can now be got as light as .5 ozs. and is much stronger than tissue. Tissue is just a light version of chopstrand mat. All glass supplied in kits is what's known as "fibre glass tape", will do the job but a little over kill. Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 29, 2018 Share Posted January 29, 2018 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
FilmBuff Posted January 29, 2018 Share Posted January 29, 2018 Doh! Should have read the OP properly... But anyway... Back in the day - we used to use Copydex for veneering as it was a contact glue that did not have lots of moisture to get rid of. Edited By FilmBuff on 29/01/2018 18:50:37 Quote Link to comment Share on other sites More sharing options...
DaveyP Posted January 29, 2018 Author Share Posted January 29, 2018 I've ordered some glass tissue and some 24g/sqm glass cloth to see which I prefer, they are both cheap Again another great idea Percy, i'll certainly try that, this is all very new to me. My previous models have all been tissue and dope with one exception which I covered in Solarspan. Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 29, 2018 Share Posted January 29, 2018 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
PatMc Posted January 29, 2018 Share Posted January 29, 2018 Glass tissue adds very little strength but soaks up a lot of resin so in terms of weight against strength is heavier than cloth. Ordinary bandage from a pharmacist used with aliphatic instead of epoxy resin would be better. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted January 29, 2018 Share Posted January 29, 2018 I used to use the 2 or 3" wide thick wing bandages for joining but it is a bit OTT. 25-50 gm/sq m is fine at a 2" width. Works with built up wings as well. Epoxy resin is still by far the best thing to use. Put a strip of Sellotape down each side of it on the veneer to get a clean edge. A light sand and iron on covering should stick OK. Regarding the TE, I agree that Tite Bond is the stuff to use. Some products I have tried which are sold as Aliphatic are little more than PVA, which does not set hard enough to sand down. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted January 29, 2018 Share Posted January 29, 2018 Slightly off topic but cyanoacrylate applied to glass tissue can be very useful for small local strengthening fillets. It sets very quickly & gets hot too...also don't breathe in the fumes...nasty. Try a small test patch & you'll see what I mean.....I use it to strengthen fixing points on FG Cowls..... Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted January 29, 2018 Share Posted January 29, 2018 But ca does not actually adhere to epoxy unless you use a catalyst like polyolefin primer, surely? Great idea for wooden parts though. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted January 29, 2018 Share Posted January 29, 2018 I'd not heard that before Martin...you may be right & it may be that the cowls I've used are polyester rather than epoxy resin. It certainly sticks though I can tell you.....I usually drill the mounting hole, then place an M3 washer over the hole....small square of glass tissue & spot of CA....smoke, fumes & the job is done... I say again though keep well away from the fumes..... Quote Link to comment Share on other sites More sharing options...
Nigel R Posted January 31, 2018 Share Posted January 31, 2018 "Cloth can now be got as light as .5 ozs. and is much stronger than tissue." Didn't know that. If cloth is now to be had at the same weight as tissue I won't be buying tissue next time I need wing joining supplies. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted January 31, 2018 Share Posted January 31, 2018 Left to my own devices I use three layers of 20gm cloth applied with epoxy, layered as per Percy in different width diamonds. I lay the weave at 45 degrees so that both weft and weave cross the wing join. With the weave at 90 degrees only one set of threads is contributing to the strength. Saying that, for the Lavocking that I'm building at the moment I just used the supplied 3" tape with a good coat of laminating epoxy. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted January 31, 2018 Share Posted January 31, 2018 I think that most of us overdo the wing joining. One layer of the lightest cloth should do in most cases. The wing will fail at the fus. line long before the centre joint. Try snapping a defunct wing joined like this to see what I mean. Nothing to do with the OP of course, but these discussions do tend to wander a bit. Edited By Martin McIntosh on 31/01/2018 19:45:42 Quote Link to comment Share on other sites More sharing options...
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