Skippers Walker Posted November 26, 2021 Share Posted November 26, 2021 Hi I'm building a 2.8m glider wing from a German kit (my knowledge of German is very limited!). Most of the construction requires just common sense and care but I'm faced with threading and fixing balsa ribs onto a carbon spar and would like to know which glue would be the best glue for this task please? Cheers SW Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted November 26, 2021 Share Posted November 26, 2021 Not my area of expertise SW, they a good fit ? If so i would think medium/thick cyano would do it. 1 Quote Link to comment Share on other sites More sharing options...
Philip Lewis 3 Posted November 26, 2021 Share Posted November 26, 2021 Cyno will glue to any wood in a flash and you will never be able to break the glue joint so make sure it's definitely in the right place because a second later you won't move it, if you are gluing in say a dowel to take a screw into a carbon tube you need to get it into the tuber real quick and in one smoot motion, the bond is so strong I wouldn't even consider using anything else, if you can glue a couple of spare bits together first and you will see what I mean. 1 Quote Link to comment Share on other sites More sharing options...
Don Fry Posted November 26, 2021 Share Posted November 26, 2021 (edited) That would do it, Mick Reeves recommends this to stick his epoxy glass skins. And once stuck, you can use them as a wood chopper. The thin cyano would also be good if well fitted. A tight hole, cuts deeper than removed material, would do the job. as in position it, wick the glue in. Phillip is right, get it in position, glue it. Not the other way round. Edited November 26, 2021 by Don Fry 1 Quote Link to comment Share on other sites More sharing options...
Skippers Walker Posted November 27, 2021 Author Share Posted November 27, 2021 Many thanks guys. Cyno it is then, especially as the laser ribs are very tight fitting along the carbon spar. I note the need to carefully align before applying the cyno, the German plan is very well printed so building over it is a breeze. SW Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted November 27, 2021 Share Posted November 27, 2021 If the spar and ribs are a snug fit (and in my experience most of the engineered German kits are very precise), then slide everything in place, pin everything down over the (plastic-covered) plan in their exact positions, then zap each joint in turn with thin CA, which will wick right through. A mistake with CA can always be rectified later with CA de-bonder, but this won't be likely if you follow the above sequence. I almost never use medium CA these days, and only use epoxy for high-strength areas (e.g. wing-root joiner tubes or ballast tubes) where gap-filling extra strength is needed. PS - just seen your reply as I was typing mine - go for it! What's the model by the way? 1 Quote Link to comment Share on other sites More sharing options...
Skippers Walker Posted November 27, 2021 Author Share Posted November 27, 2021 Hi Jonathan thanks for your response. The model is an Andreas F5J 'Introduction' kit from Hoellein, Germany. Very well cut and the plan is excellent too. Cheers Chris Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted November 27, 2021 Share Posted November 27, 2021 (edited) Chris, that looks ideal for the job! There is in fact a downloadable English version of the instructions from their website: http://hoellein.com/Anleitung/gruener-cnc/Introduction-E.pdf I've got a slightly smaller 2.54m FXj bought second-hand. It has barely been flown, but I need to recover it (the builder used Oratex which is unnecessarily heavy for a thermal model!) and convert to electric-launch with a Hacker A10-7L. Enjoy the build! Jon Edited November 27, 2021 by Jonathan M Quote Link to comment Share on other sites More sharing options...
Skippers Walker Posted November 27, 2021 Author Share Posted November 27, 2021 Thanks for the building info, I've now found the English instructions. I purchased the kit 'second hand' from a fellow modeller and I never thought to check online! I have built a 2m Andreas Elektro RES a while ago powered by a an A10-7L. The "Introduction" may well get the same Hacker unit too. Cheers Chris Quote Link to comment Share on other sites More sharing options...
PatMc Posted November 27, 2021 Share Posted November 27, 2021 I have an Introduction kit that I hope to have ready for next spring/summer & have been following a couple of build threads in RCG. One piece of advice that seems a good idea to me is to cyano several turns of kevlar thread around the spars close to each last rib to reinforce the tube ends against splitting. Quote Link to comment Share on other sites More sharing options...
Skippers Walker Posted November 27, 2021 Author Share Posted November 27, 2021 Thanks for the tip regarding the spar ends. This is my first venture into carbon spar construction after many years of using balsa, spruce and other traditional materials. It's a nice kit and generally look pretty straightforward to assemble carefully Best wishes Chris Quote Link to comment Share on other sites More sharing options...
John Minchell Posted November 27, 2021 Share Posted November 27, 2021 To be really proper about it, you need to degrease the carbon spar tube as well, or wear vinyl gloves when handling it, as that ensures the cyano bonds well to the surface of the carbon. Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted November 27, 2021 Share Posted November 27, 2021 Good point John. The servo tray in the nose of my Auri DLG came loose early on after a particularly hard landing because I'd omitted to degrease that area inside the carbon fuselage. With the old CA cleaned off and the whole area roughened slightly, and an extra shoulder of epoxy after CA'ing the tray back in place, it is now fit for... future pilot-error! BUT I wouldn't worry overly about your spar/rib joints. Yes degrease the carbon tube before sliding it in, but that'll be more than enough. Quote Link to comment Share on other sites More sharing options...
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