Tony H Posted November 26, 2012 Author Share Posted November 26, 2012 All my other Foam Core wings turned out strong, maybe the melted together. It goe's on to add that 5min Epoxy should be safe to use instead of PVA. hmmmm strange Quote Link to comment Share on other sites More sharing options...
Tony H Posted November 26, 2012 Author Share Posted November 26, 2012 I have now Joined the wings using PVA white glue for the first time ever on a foam core wing, I hope it holds (doesn't have the grab of Epoxy). I added an central Aluminium tube to add strength, which I also glued with PVA glue. I will obviously be bandaging and epoxying later too. Quote Link to comment Share on other sites More sharing options...
Simon Webb Posted November 26, 2012 Share Posted November 26, 2012 I use wooden dowels, but your aluminium tube should do the trick. PVA takes a while to grab, but it does give you time to position your wings true. Once dry you will be amazed how strong the join is......plus your glass fibre bandage and epoxy will make it very stiff and strong! Well done Tony! Quote Link to comment Share on other sites More sharing options...
Hugh P Posted November 26, 2012 Share Posted November 26, 2012 I have never know 2 part epoxy to melt foam, I use the 20 min variety to join the wings and then glass fibre bandage and epoxy , never used a tube or brace unless the plan called for it. If in doubt test on some scrap foam. However NEVER use glass fibre resin (smells terrible, also 2 part) as this will just melt foam like a hot knife through butter. Also a good trick to do is before applying the bandage, dribble hot candle wax into the gap where the aileron torque rods stick out, then apply the bandage and epoxy. This will stop any epoxy resin glueing up the torque rods! You will find a hard edge to the bandage after the epoxy has cured, this is due to the weave of the bandage, simply rub down being careful not to damage the veneer then mask about 2cm away and give another coat of epoxy to fill the weave. If needed do the same again. Finally simply cut around the rod and dig out the wax and you will have a free moving torque rod again and a really strong wing join with a feathered edge to the epoxy covered bandage. Quote Link to comment Share on other sites More sharing options...
Simon Webb Posted November 26, 2012 Share Posted November 26, 2012 I think we may be getting our wires crossed with ambiguous writings..... Epoxy resin melts foam......ie the 2 part stuff you use for glass fibre bandages Epoxy doesn't melt foam.....ie the 20 minute stuff you get in 2 tubes. I was questioning myself reading some of this but no...I stand by my comment here! Quote Link to comment Share on other sites More sharing options...
Hugh P Posted November 27, 2012 Share Posted November 27, 2012 Hi Simon. I must admit I have never used epoxy resin, just the stuff you mix in equal amounts, I thought they were one and the same thing. Fibre glass resin is a definate NO NO. Just test it first if unsure. I'll shut up now and just get on with balsa bashing and keep away from these threads. Quote Link to comment Share on other sites More sharing options...
Tony H Posted November 27, 2012 Author Share Posted November 27, 2012 Thanks guys, I think normal 2 part epoxy glue is okay to use. The epoxy resin for fibre glass I think is the same as the 2 part epoxy glue only thinned with a cellulose based thinners and it's that which melts the foam.Edited By Tony H on 27/11/2012 21:48:49 Quote Link to comment Share on other sites More sharing options...
Lee Smalley Posted November 28, 2012 Share Posted November 28, 2012 epoxy resin does not melt foam, i use laminating resin all the time on foam with fiberglass skinning and it never melts foam, it is not thinned with thinners, polyester resin will melt foam, epoxy based resins (non that i have ever used) melts foam, i have used the flair wing joining pack, west systems fibertech and GB sytems epoxy skinning systems and it has never melted foam Quote Link to comment Share on other sites More sharing options...
Lee Smalley Posted November 28, 2012 Share Posted November 28, 2012 **LINK** Quote Link to comment Share on other sites More sharing options...
Simon Webb Posted November 28, 2012 Share Posted November 28, 2012 When I said epoxy resin I meant epoxy based resin. Quote Link to comment Share on other sites More sharing options...
Trevor Crook Posted November 28, 2012 Share Posted November 28, 2012 Keep us posted on the weight when it's finished, Tony. My electrified one weighs exactly 4lb with 3000 3s lipo on board. My fuselage mod may help knife-edge performance and my torsion bar mod avoids bent u/c Quote Link to comment Share on other sites More sharing options...
Lee Smalley Posted November 28, 2012 Share Posted November 28, 2012 Not sure what you are going on about mate but on the whole epoxy based resins are safe to use on foam from.the stuff you get for applying fiberglass bandage to the 5 min stuff you get from delux materials and most epoxy based laminating resins, you should always test new epoxy on some scrap foam as you can never be sure what they have put inthe stuff, if you buy cheap crap epoxy then use at your on risk, join foam wings with Bob smith industries 15min epoxy let set then bandage with 24 hr epoxy warmed if required, just to reiterate i have never had epoxy resin (based or otherwise) eat foam, polyester yes epoxy no. I am sure there are some out there that do but i have yet to find one Quote Link to comment Share on other sites More sharing options...
Les Littleton Posted November 28, 2012 Share Posted November 28, 2012 Bought my magician second hand from Whitchurch models about 4 years ago. Originaly fitted with an OS 40fp it flew fine but i have changed the engine a couple of times just for the sake of change, once to an OS 52 fourstroke and now flying on an Irvine 46 wich makes the model very fast indeed . I dont know who owned the model originally but heres a pic in case someone recognises the finish , Quote Link to comment Share on other sites More sharing options...
Simon Webb Posted November 28, 2012 Share Posted November 28, 2012 I am seriously confused by this Lee. What are all the instructions in kits going on about when they say do not let epoxy based resins come into contact with foam on about? Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted November 28, 2012 Share Posted November 28, 2012 Keep up the good work Tony, and keep her light! CS Quote Link to comment Share on other sites More sharing options...
Lee Smalley Posted November 29, 2012 Share Posted November 29, 2012 I have no idea simon i have read that a few times and wondered what they are using, i guess there are some crap epoxy that melts foam but i have yet to come across any and i have been building for 20 years, i stick (pardon the pun) to quality makes, devcon, BSI, and ,delux materials, for joining and glass bandages, never had a problem, mybe some cheap aldi stuff does bit i dont use that rubbish, if i am glassing a wing i use buck composites or the west systems stuff, the lads use the west systems stuff with carbon cloth directly onto the foam underneath the veneer when vac bagging wings Quote Link to comment Share on other sites More sharing options...
Tony H Posted November 29, 2012 Author Share Posted November 29, 2012 Damn! I wish I had used my BSi epoxy now as it would have made a stronger joint than White PVA, although it feels fairly tough. hopefully the allumimium tube and epoxy bandage will keep it plenty strong enough. I have built the Fin, Rudder and Stabilizer now with lightning holes, i'm just sorting out the epoxy bandage and Alierons for the main wing. Once thats all finished I will make a start on the Fuselage ( looks pretty straight forward). Trevor - Did you do anything to lighten your Magician? and if you did what did you do? Also do you have anymore pics or your build? I might consider doing your undercage design, is that just a block or hard wood the wire is in? Les - I like the livery on your Magician it's like the Super Chipmunk one of my favourite planes in those colours. Edited By Tony H on 29/11/2012 14:21:45 Quote Link to comment Share on other sites More sharing options...
Simon Webb Posted November 29, 2012 Share Posted November 29, 2012 Tony it will be absolutely fine trust me! Once you have the bandage on.......it will be as strong as an Ox. My models do all the manouvres in the book at maximum G forces. The wings have yet to fold on me and I have been doing it for 20+ years! Quote Link to comment Share on other sites More sharing options...
Tony H Posted November 29, 2012 Author Share Posted November 29, 2012 Thanks Simon that at least has reassured me. Here are a couple of photo's of some extra lightening, it may be a little anal but every little helps. I have added some thin CA glue to help with strength Lite Ply Formers before making up the fuselage Quote Link to comment Share on other sites More sharing options...
Trevor Crook Posted November 29, 2012 Share Posted November 29, 2012 Tony I didn't take any steps to reduce weight, as modern electric power trains are light and if chosen wisely give at least as much power as ic. Sorry I didn't take any build photos. The u/c clamps you can see are screwed into a ply section epoxied to the bottom of the fus. The wire legs go up though the ply into hardwood blocks (about 25mm) which are glued to the fus sides. Good luck with the rest of the build - they fly really well. Quote Link to comment Share on other sites More sharing options...
Lee Smalley Posted November 29, 2012 Share Posted November 29, 2012 it will be loads strong enough the only advantage for using epoxy over PVA is speed Quote Link to comment Share on other sites More sharing options...
Tony H Posted November 29, 2012 Author Share Posted November 29, 2012 Cool Thanks Lee, feeling much better now. It might even be a slightly lighter joint Quote Link to comment Share on other sites More sharing options...
Andy Gates Posted November 29, 2012 Share Posted November 29, 2012 Want to loose weight, don't use the lite ply formers! If the strength is needed use propper ply, if not use balsa only. I would make new formers from framed up balsa, much stronger and way lighter. I have built a WOT Trainer-a-like machine with thinner wood sections and framed formers. Only places for propper plywood was for F1, the undercarriage mount and for the first ribs on each wing panel. My plane has lost over 20% of the weight of the origional with no structural strength loss. Only other thing I would do if you go lighter with the fuselage is to plan to use rubber mounts for the F1 to motor mount fixing which avoids the vibration being transfered to the fusealge and makes the plane quieter. Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted November 29, 2012 Share Posted November 29, 2012 Looks very nice! My Domino has built up balsa formers like so... which are very light and strong, espcially when glued in. The Magician formers have a more complex shape but a bit of good quality balsa cut correctly would be lovely. Keep up the good work! CS Quote Link to comment Share on other sites More sharing options...
Tony H Posted November 30, 2012 Author Share Posted November 30, 2012 I think maybe you are right most of the Wizard was made with balsa formers and that well strong enough. I will cut new formers from balsa. Any thoughts on the thickness they should be? The lite ply ones are 1/8th thick or 3mm, I was thinking maybe 5mm balsa? Quote Link to comment Share on other sites More sharing options...
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