Paul Jarvis 1 Posted November 3, 2009 Share Posted November 3, 2009 Hi, I am building the Tony N spitfire 62", and it is my first build other than an aftf. Could someone give me guidance, I have googled a LOT but am still not sure on the curved balsa bits... I stuck the 18mm triangle soft balsa to the lower rear fuselage with the fuselage flat on the building board. I then realised the fuselage is curved towards the tail and with the triangular balsa ofcourse the tail cannot be bent without huge tension... is the standard method to pre bend the triangle balsa by soaking ? OR to glue it in place with the fuselage curved to produce the curved fuselage tail section. Similarly with the built up wing, I am about to apply the 6mm balsa leading edge to the ribbed wing,but I noticed the tip curve produces quite a bit of tension, which I guess will distort the wing. Is it standard procedure to pre bend balsa sections such as this to get the desired curve, if so how ?, soak in water, oven steam, just apply water to rear surface ? Sorry for the lengthy question but its basically just one question. Thanks Paul Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted November 3, 2009 Share Posted November 3, 2009 paul-if it's any help - i think that you can e-mail tony direct with a query like this.......there will be some one on here who will post and let you know.... ken anderson.... just had a luck-there is a thread-dedicated to tony n builders-on the forum front page of threads...........Edited By ken anderson. on 03/11/2009 19:41:50 Quote Link to comment Share on other sites More sharing options...
Paul Jarvis 1 Posted November 3, 2009 Author Share Posted November 3, 2009 Hi Ken, Thanks for your reply. I have read several of the Tony N builders threads. Its not really a question for Tony as I am just asking generally what the procedure is for building fuse / wings when adding the "curved" bits, as I assume the process is fairly standard. I am soaking and bending the wing LE balsa and seeing how it goes, I guess I should do the same with the fuselage stips.... Regards Paul Quote Link to comment Share on other sites More sharing options...
001 Posted November 3, 2009 Share Posted November 3, 2009 Paul, use a spray window cleaner, such as Mr. Muscle, spray it on, wait a few minutes and the balsa will bend a reasonable amount without breaking. Years ago builders used to use a water/ammonia mix, but this is more readily available. Quote Link to comment Share on other sites More sharing options...
andy watson Posted November 3, 2009 Share Posted November 3, 2009 Water works fine, but if you can get hold of an ammonia based cleaner then that works much better. I have tried a number of window cleaners looking for one that contained ammonia, but to be fair I have never had a result significantly better than water. I have been looking at the budget end of the market though- think smart price rather than Mr Muscle! If the strips are thick you will get a lot of compression on the inside of the curve, and a lot of stretching on the outside. This can cause cracking, and cutting slots in the strip on the insode of the curved area can reduce this. Be careful though- this will weaken the wood, so don't use it where the wood gives structural strength. Quote Link to comment Share on other sites More sharing options...
Ken Lighten Posted November 4, 2009 Share Posted November 4, 2009 Paul, for the leading edge (both inner and outer on this plan), steam over a kettle or similar whilst holding the bend in the wood and hold the bend till it cools, the bend will be retained sufficiently, for the triangular section on the fuselage, use a hack saw and cut partway through along the length of it where the bend is going to be, once the sides are joined, rub a sandable wood glue into the cuts. As these strips are really only there to allow the shape of the fuselage to carved it will not affect the structural integrity of it. Once the fuselage is shaped use a lightweight filler to fill any cuts that show through. Quote Link to comment Share on other sites More sharing options...
Paul Jarvis 1 Posted November 4, 2009 Author Share Posted November 4, 2009 Fantastic ! ! thanks very much everyone for taking time to post the advice... I am now cracking on confident that I m doing the right thing. Really enjoying my first build.... Best regards Paul Quote Link to comment Share on other sites More sharing options...
Erfolg Posted November 4, 2009 Share Posted November 4, 2009 If I feel the need to bend any sheet, mostly thicker sections. My first of two methods is a) run about circa 25-35mm of very hot water into the bath. b) place the sheet into the bath and weight down. c) leave for circa 20-30 min d) remove from water and wipe down. e) I then wrap the sheet around a tube which approximates to the curve required. f) hold in situ with elastic bands, I have occasionally put a protective plastic sheet over the balsa to protect it from the restraints. g) I then put it in a place to dry, which is typically over night. The second method, which I have not used for a number of years. This was used on strip wood.. a) Find a tube large enough to put strip into. b) attach this tube by Heath Robinson methods to an old kettle. An old kettle is required as these did not have a shut off when boiling. c) Place strip in tube from open end, d) Place the open end of tube over sink, with the open end slightly down hill. e) Fill kettle with water and turn on. f) After 10-15 minutes, the kettle can be switched of, the wood removed. h) Bend the strip into the shape required. It may be necessary to restrict the outlet from the tube to hold up the steam in the tube. Both these methods produce a permanent set to the wood, when removed from restraints and make fixing much easier. Erfolg Quote Link to comment Share on other sites More sharing options...
Andy Green Posted November 4, 2009 Share Posted November 4, 2009 I use steam, but after many years of burnt fingers from kettles, I now use a handheld steam cleaner. It also works great for cleaning things, nows there a gift idea for her indoors. Andy Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted November 4, 2009 Share Posted November 4, 2009 If you need continuous steam from most modern kettles just leave the lid up/off. The sensor is usually at the top of the handle just under the lid... Quote Link to comment Share on other sites More sharing options...
fly boy3 Posted December 28, 2009 Share Posted December 28, 2009 Hi all, as the strip of balsa I need to bend has a another peice of thinner balsa pva glued to it, should I not use steam or hot water. Fly boy3 Quote Link to comment Share on other sites More sharing options...
Bob Merrett Posted March 7, 2013 Share Posted March 7, 2013 After seeing this clip on You Tube a while back **LINK** I was suitably impressed and tried sourcing some. I trawled the local supermarkets to no avail, the product is not available in the UK, perhaps it’s something Health and Safety. I looked at the active ingredient in my anti-bacterial suface spray, Benzalkonium Chloride, and googled it. I’m no scientist, but saw it had a link to the Ammonia family and gave it a go. I have successfully bent 1/16th sheet and strip balsa (have yet to try 1/8th) using the same method as in the video. I have attached some photos of pre-bent panels and strip, ready for final trimming and fitting. Benefits;- You can manipulate the strip/planks almost immediately Dries/evaporates relatively quickly(think of when you wipe down your kitchen surfaces etc.) Better than soaking in water Saves on keep boiling the kettle Wont stink the place out, (It’s kitchen spray!) Can easily put in a 90 degree twist if you wanted to! Quote Link to comment Share on other sites More sharing options...
Ruprect Spode Posted March 7, 2013 Share Posted March 7, 2013 Nothing beats a long cold soak overnight. Using heat/steam and chemicals only serve to break down the fibres and natural resins within the wood and when it dries it becomes brittle. OK they are only models and I suppose speed of construction is an issue. Quote Link to comment Share on other sites More sharing options...
J.N. Posted February 10, 2014 Share Posted February 10, 2014 Posted by Ruprect Spode on 07/03/2013 11:37:14: Nothing beats a long cold soak overnight. Using heat/steam and chemicals only serve to break down the fibres and natural resins within the wood and when it dries it becomes brittle. OK they are only models and I suppose speed of construction is an issue. Yes it can be done. This is as per the bath. The balsa sheet is 3.25mm thick soft to medium grade and was slowly tightened around a former over a period of 2 days and then left to dry. . Edited By J.N. on 10/02/2014 10:53:47 Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted February 10, 2014 Share Posted February 10, 2014 Hi JN, I did a fairly exyensive build blog on Tony's 72" Spit. Those triangular sections are beasts to bend! I cut slots with a razor saw and then wicked zap into the cuts after it was all bent to shape. Cheers Danny Quote Link to comment Share on other sites More sharing options...
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