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What glue to use and Dope alternative

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    What glue to use and Dope alternative

    Hi, this is the first time I have written in a forum so I may be writing it in the wrong place.
    I have just started to contemplate making model aircraft after a 50 year hiatus, so there is a lot to learn in a short time (as there is not a lot of time left!). I live in Australia for 6 months and Nepal the rest of the year, and the problems we have in Nepal are that we cannot find balsa or basswood, we don't have good glues and no chance of dope. As far as the wood is concerned I will have to bring it from Australia and the glues too, but not the flammable type. So two questions:
    1. Glue. Polyurethane glues can fly with us in luggage as they are water based, as can titebond (which I use to make my guitars) but are these the best glues to use? I have researched poly glue and the consensus is that it is good for end to end grain gluing, but no better than titebond for side grain gluing. I remember from my youth that there was a volatile wood glue that I used but can't remember the name.
    2. Dope. I read on the net that a viable alternative to shrink tissue paper and coat balsa wood is hairspray. Any thoughts on that? I can get thinners in Nepal but not Nitro cellulose lacquer which I am told is what "dope" is. Hairspray on the other hand is easy to get.
    Looking forward to spending time on this site and hopefully one day making a contribution!
    mauricepaul
    PS, sorry that the photos are guitars but I have no planes to show (yet)
    One of our mango guitars that we make here in Nepal The soundboard is spruce that we bring from Australia. There is nothing suitable in Nepal

    #2
    Hi Maruricepaul,

    I understand the difficulty in getting some of the material suitable for our model purposes,
    I live in the other side too, the only plus thing here is, balsa grows at our area, getting them is not hard, but getting good ones are difficult, as they are being exported to USA or Europe.


    how the model will be powered ? If its electric, you can survive with mostly CA glue.
    If you are using engine, then you can use CA at certain place but mostly epoxy, wood glue, or polyurethane at strategic places.
    You can use polyurethane thru out the build, its just a little hard to control the mess since it expands, you can tack the parts with CA glue and let the polyurethane to do the work,
    If it expands too much, better remove it after it dries, if you do it while it still expands, it will be messier and might weaken the join as there will be voids.
    I am sure regular wood glue is available mostly anywhere, it can be used as well, just make sure you have enough flat surface for the glue to hold on too, for example you can reinforce the formers to body join with triangle stock tack with CA (there is one good triangle stock cutter design available using 3D printer parts, I am sure you can get it printed while in Australia).
    https://www.thingiverse.com/thing:2016991
    i would be happy to print one for you for free, however, the shipping would be too expensive anyway.

    For a dope, try automotive clear coat, thin it with its own thinner, many of them are nitrocellulose based.
    Or if you can buy acetone in Nepal, you can melt pingpong balls with acetone. Other material that can be used is male comb, as long as its the transparent one.

    for the spar material, again, if its light enough hard balsa will be good enough, just use local ply for the wing joiner.
    A friend build twin engine super sportster with 1.5m wing span, so far so good with hard balsa spar.
    I build the same model with pine wood I bought from furniture maker.
    If its more aerobatic models, any harder wood will do.

    or you can get carbon fiber tubes/flat strip.
    You can get them cheap at aliexpress and I am sure they will send to nepal.
    For the wing spar, you can use OD5mm x ID 3mm tube
    or id you prefer the flat strip, I used 3 layers of 1mm thick x 6mm width strips. Glued them together.
    The spar with stronger material is only needed up to 2/3 length of each panel, the tip panel you can use hard balsa, and just splice join them with the carbon fiber/hardwood spar and use fishing line to strengthen the join.

    For the covering, its a lot easier and less work with the regular monokote like covering, unless you need to cover it for looks.
    You can also get it rather cheaply from hobbyking or aliexpress.





    hope that helps.
    Irwan

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