Warbird Information Exchange

Years ago I decided to craft a P-39 Airacobra out of wax with the idea that I would have it cast in aluminum or bronze. I wanted it to be accurate in every detail and large...the fuselage length ended up being 24 inches and when complete I sent it to a foundry in Montana but they had some trouble casting the wings and in the end the project withered on the vine and I stuck it in a big plywood box. I dragged it out the other day and it was in pretty sad shape but it can be restored. My question to other modellers is: has anyone attempted to cast models using the "lost wax" technique or some other method with the end product being made of bronze or aluminum? I'm thinking of reviving this project and any help would be appreciated.

Link to picture of this P-39:

http://www.flickr.com/photos/23057174@N02/4167783093/

Thanks,
Blake

I talked to some folks about lost wax casting back when I was doing prototypes.

Most likely didn't learn enough to help you and no longer know anybody that does it, but, places that deal in resin casting, also have metal casting supplies and books on the subject. I don't think the place I linked has hot casting materials, but it was the only link I could remember.

I can see where the foundry would have problems with the wings. Did they have any complaints with the tail? Or its size?

Were you wanting to have it cast as a single piece?

The kind model making you are wanting has changed so much in the last 20 years there may be all kinds of alternatives, it all depends on what you want the final product to be and how you want to get there.

This place may give you some ideas:
http://www.smooth-on.com/

The foundry said that the issue with casting the wings was that they couldn't get them to hold their precise angle of dihedral and realized that they would probably destroy the wax model and not be able to assure success in the end result. I'm not sure if the tail also would have presented problems but one would think that would be a more complex part to cast/pour. It may turn out that it will be necessary to cast the P-39 in several parts, probably wings, tail and fuselage then braze them together.

Thanks for the link to the casting site...there may be useful information there for me to get this project moving forward.

Thanks,
Blake

G'day Blake.

I presume you are aware that the lost wax process depends on melting out the wax master, so it *has* to be destroyed as part of the process?

I live close to a sculptor and in our chats (while dog walking!) he has mentioned he uses the lost wax process with bronze for his sculptures of various sizes. My impression is that there are foundries out there that do thins kind of work - for sculptors, which is what your excellent Airacobra is. Might be worth asking at your local art schools if foundries aren't easy to find?

Good luck, let us know how you go.

I was prepared to loose the wax P-39 using the "lost wax" method if success was assured by the foundary. The cost is rather high to have workers at a foundary do all the work so maybe I can make small plaster molds off this wax model and try casting them myself...then fit the pieces together.
Thanks for the comment,
Blake Smith

looks almost as good as a cellulose acetate silhouette i.d. model!!