Balsa formers?

Discussion in 'Extended Mediums' started by garyj36, Mar 31, 2005.

  1. garyj36

    garyj36 Member

    Any opinions on using thin paper laminated to balsa for formers? Seems like a good foundation as there are already products available to make balsa more moisture resistant. "doping"?
  2. bfam4t6

    bfam4t6 Member

    The only problem I could see with that is the brittleness of the wood. Whenever I build a balsa model I always accidentally break the sections off between the slots for the stringers. I'm sure it would work, but people like me would have to be more careful when inserting a former so as not to snap it in half :lol:
  3. Darwin

    Darwin Member

    I have had success using basswood for formers. A bit more pricey than balsa, but lot's more durable, and easier to work with than plastic sheet. BTW, the splitting problem with balsa formers can be minimized by cross-grain laminating a couple of pieces of 1/32 sheet, or more simply by gluing a couple of 1/16 square sticks on the former (again, cross-grain) to give the former some bend-resistance.
  4. Gil

    Gil Active Member


    I think Dustin is right, balsa is light but fragile. The photograph below shows some trial bulkheads made out of cereal boxe cardstock and strips of 67# cardstock slathered in acylic modeling paste. The strips are covered with the modeling paste and wrapped firmly around the cutout formers. A moist paintbrush is then used to smooth out the paste. The parts are set aside to dry. The constructs are extremely robust and have potential use in all sorts of card modeling applications.


  5. Bowdenja

    Bowdenja Active Member

    Well for what it's worth..........

    On my first attempt at Nobi's C-130 I thought I would be smart and use balsa wood for the wing spars........... being the genius that I am.... I thought the cardstock from cereal boxes just would not support that long of wing without drooping. WRONG! half way though the wing build I broke the balsa in many different places with these mitts I call hands. When I started over, I laminated some cardstock and......guess what.........your right no wing droop. Now if I could just figure out how to make the landing gear wells look right.........

    Anyway that's my balsa story and I'm sticking to it.
  6. I have to agree, there is no right way only what works. In the past I have tried Bass wood and thin modeling plywood for formers and frames. Have also used Masonite turned on a lathe for formers for large cylinders. The Masonite's cheap enough, its the lathe thats pricey :wink: :wink: :wink:
  7. shrike

    shrike Guest

    I'm suddenly reminded of a forum I attented at Oshkosh 20 yrs ago (that long?!? Oy!) led by Molt Taylor (Imp, Mini-imp and Aerocar Taylor) about using cardboard for aircraft structure. He used plain old chipboard with a layer of glass-cloth and resin on both sides as a direct substitute for aircraft grade plywood of the same thickness. As I recall he had built and entire flyable airplane that way to prove it could be done.
    Strikes me as funny that we're trying to de-invent the wheel here<G>
  8. Gil

    Gil Active Member

    Acutally he used a mixture of 50% styrene monmers mixed with 50% polyester + activator to insure complete soaking of the brown kraft paper with a light fibeglass cloth cover. I've made items from this formula and they end up incredibly strong but also very light. Jack Lambie covers it in his book on the subject.

    And Shrike, how do you deinvent?

  9. shrike

    shrike Guest

    Perhaps I got in on the early experimental phase of the process, because I recall that he was just using over the counter polyester cheapie resin at the time. That was one of the express benefits. But then I did allow as to the two decade time lapse.

    De-inventing requires a Mk III* Genie-Stuffer, a suitably large bottle with secure cork and an extensive network of assassins.

    Re-inventing just requires a little research into the obscure, a crooked patent lawyer and a good PR firm.
  10. Gil

    Gil Active Member

    Styrene monomers are cheaper than polyester resin...,

  11. While I did mention the Masonite formers for cylindrical models they really need a lathe to make them right. Picked up my first one today. I plan on picking up a small engine or bench lathe to go along with this one as well as a small surface grinder and milling machine. One of my other interests is metal working specifically scale I/C radial engines
  12. Gil

    Gil Active Member


    Nice, very nice! NC adaption in the future? Real working IC engines?

  13. That's what the plan is Gil. I am currently working on the plans for my own design in 9/18 cylinders. Am also thinking about sending for the plans from Ageless Engines for either one of their 9/18s or the Bently. But this is a little much Basically the idea is to be able to keep my hand in with doing precision maching work in retirement
  14. Gil

    Gil Active Member

  15. J.L.

    J.L. Member

    Formers and Templates

    I have had good success using MDF (medium density fiberboard) instead of balsa for thin reinforcing material. It is soft, cuts like a dream with fine-toothed saws, has no grain and is very stable. It holds an edge very well.
  16. Leif Oh

    Leif Oh Member

    J.L. - please explain, what is MDF, and where would one go with a reasonably good chance of obtaining it? I wonder what it would be called in other languages... - Leif
  17. J.L.

    J.L. Member

    Hello Leif,
    MDF is now heavily used in North America in the furniture and construction industry. All my model bases are 1/4" MDF surrounded by wood trim. It is a material that is composed of very fine wood fibers compressed with glue under very high temperatures. You might think I am referring to particleboard or untempered hardboard. No, MDF is quite different. Because it can be so easily shaped in factories, it is quickly replacing trim molding (in paint grade) for such things as casings, baseboards and decorative moldings - even door skins. But in its flat form, it's smooth and so easy to work. We can get it over here in stock sizes from 1/4" to over an 1". It is a tan brown colour and very smooth.

    My table saw has a fine toothed blade protruding through a zero clearance table insert. Strips can be easily ripped from 1/4" material. I must tell you that it becomes unstable when sliced very thin. It's soft and not strong when that thin. Then, you'd be better off with laminated ply or solid wood strips.
    I describe the use of 1/4" MDF as vertical strip girders under thick card stock in Tips and Techniques for large flat areas such as courtyards.(article: Solid Support) Beats the zig-zag system of paper formers the French use in architectural models.

    It would be interesting to hear if your do-it-yourself home renovating store carries this product in Sweden.

    Hope this helps.

  18. Leif Oh

    Leif Oh Member

    Thanks, John. I'll keep looking for something that matches the description...

  19. cadwal

    cadwal Member


    MDF is available in almost any do-it-yourself store (Silvan, K-rauta etc.), just ask for it by that name. They can even cut it in pieces the way you want for a small extra charge.

    As John says it is a better, more modern version of "spånskiva" (fibreboard) that is easier to work with and achieve good results without using lots of filling.


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