Aussie Dave Posted April 2, 2008 Share Posted April 2, 2008 hey guys,does any one have any info/links on making a hot wire foam cutter for wings / fuse.cheers. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted April 2, 2008 Share Posted April 2, 2008 I do. I have one here at home which I made up a few yers ago. I will dig out some pictures and info for you......... after breakfast Quote Link to comment Share on other sites More sharing options...
Andy Green Posted April 2, 2008 Share Posted April 2, 2008 HiI've just done a Google search on 'hot wire cutting bow' and get a load up, the Charles Rivers site is worth a look.I've just had my breakfastAndy Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted April 2, 2008 Share Posted April 2, 2008 Just finished mine.... Right then...( good site that Andy ) here's mine. General construction, templates for root and tip chord cut from litho-plate, ( could use ply ) and first quickie test results. I used an aluminium square section "U" tube for the main brace....feeding one of my battery connections along it and down to the wire end. Accurate slop free bearings /pivots at one end are needed, to ensure a rigid slop free structure. I used hardwood strip to form the vertical arms....anyway you get the gist of it I am sure from the photos .Theres lots of info on that site, and others ,about how to make /use.They range from very very simple to very overcomplicated . I think mine falls somewhere between the 2. I powered it from an old converted UPSU, but latterly I just use a 12V leisure /car battery. Important things...1) Use a tensioner like the spring idea - the wire DOES stretch as it heats up2) Some folks say dont use nichrome wire - I did and its fine....not broke one yet !3) The guide templates ( and a competent partner ) are the key to a successful cut - Practice first ! Make a template for root and tip chord shapes, and mark on them "timing numbers" equally spaced across the face of the template to ensure that you both travel at the same speed and distance as it were over the whole cut. Dont go too fast or it will drag and be rough, - too slow and it will melt grooves. VITAL!! - make absolutely certain that there is not even the slightest hint of roughness on the template edges, as this will cause the wire to catch /stick as it passes over them, this will result in an uneven burn, deeper grooves and poor results, apart from increased risk of wire breakage. 4) Ensure your PSU can deliver the required current - hot is good, but too hot is bad. Experiment.5) Unhook the tensioning spring when finished to remove all tension on the wire for storage.For small non fussy jobs, it can be used single handed, but for a wing panel or similar, 2 peeps are needed. Quote Link to comment Share on other sites More sharing options...
Andy Green Posted April 2, 2008 Share Posted April 2, 2008 Just to add to Timbos excellent introduction, don't be tempted to use metal templates (Litho is probably ok) it will suck the heat from the wire and could make the wire too cold locally.Paxolin / formica are excellent, fiberglass sheet and ply are also very good.If you finally give up (it can take a while to get the knack) just send Barry your requirements and have him make them.AndyPS - just found thesehttp://www.compufoil.com/fc_tutorial.htmlhttp://webpages.charter.net/rcfu/ConstGuide/FoamWing.html Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted April 2, 2008 Share Posted April 2, 2008 Or make me a reasonable offer on mine... I never use it these days Quote Link to comment Share on other sites More sharing options...
Aussie Dave Posted April 2, 2008 Author Share Posted April 2, 2008 Thanks boys for the info.i'll have a look at the other sites and have a crack at making one.Thanks and see you later from the Aussies. Quote Link to comment Share on other sites More sharing options...
PAT Posted April 2, 2008 Share Posted April 2, 2008 Likewise, many thanks for a great feature and the useful links. Quote Link to comment Share on other sites More sharing options...
Cpt Biggles Posted April 3, 2008 Share Posted April 3, 2008 Hi allback in the 80's I made a cutter bow using 1" by 1/2" timber from a diy store using two pieces for the cross member and one piece each end. with the end sandwiched between the two center cross pieces it made a very strong bow. Tension with nylon washing line. I also used MIG welding wire for the hot wire and a car battery charger for the power with a domestic light dimmer switch to control the heat. cheap as chips and it worked very well must have cut over thirty wings with no sign of it wearing out (there is nothing to wear out except the wire) but you must use good tight fitting bolts at the joints I have not got it now as i gave it away when we moved house. when I need another one I will knock another one up.there is a knack to cutting foam accurately but keep at it and you will get there. use ply well sanded and keep the wire on the move so you do not burn the template.have fun and be creative regards to all Quote Link to comment Share on other sites More sharing options...
Andy Green Posted April 3, 2008 Share Posted April 3, 2008 You could buy one, I keep looking at the Feather cut system might buy one one day.Andy Quote Link to comment Share on other sites More sharing options...
Former Member Posted April 3, 2008 Share Posted April 3, 2008 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted April 3, 2008 Share Posted April 3, 2008 I did know a couple of guys way back who had actually practiced together so much that they could actually cut some quite severely tapered chord wings. They had it off to a fine art, with numbers marked on each template - one called out the numbers at precise intervals as he progressed across the chord, and the other was able to match the transition speed at 'tother end perfectly ! Quote Link to comment Share on other sites More sharing options...
Cpt Biggles Posted April 4, 2008 Share Posted April 4, 2008 I have cut extreme tapers and deltas on my own by plotting the taper to a point and then tethering the end of a long bow to the pivot point, after the cut trim off the blank to the right size Quote Link to comment Share on other sites More sharing options...
Andy Green Posted April 4, 2008 Share Posted April 4, 2008 I've also cut large tapers for delta's the secret is to make the tip rib a bit bigger, as the melt back (Kurf I think they call it) is bigger the slower you go, with some trial and error you can get the right tip size.Andy Quote Link to comment Share on other sites More sharing options...
Former Member Posted April 4, 2008 Share Posted April 4, 2008 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Cpt Biggles Posted April 4, 2008 Share Posted April 4, 2008 boots need plenty of salt and pepper and a dash of brown sauce Quote Link to comment Share on other sites More sharing options...
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