reproducing castings ?

[Mike Mullins]

Reading on another thread, I am wondering if anyone here has ever looked into reproducing the right side cover for the Super Hawks, and what it would entail/cost. I have a friend who was making Pope bullet molds and had a run of the castings made. The cost was actually pretty reasonable I thought (he did his own pattern making, though.) Has anyone here looked into this ? Or does anyone here have any experience in this field ? Just a thought ( of the wild hair variety.)
Mikeyrx

[cyclon36]

I'm sure the guys in Taiwan are thinking about this right now :-)

Not sure what costs would be but if you just search for aluminum casting, tons of sites pull up that offer quotes. You might even be able to get it on the cheap if you solicit services from this forum: http://www.backyardmetalcasting.com/

[Snakeoil]

I would think that cost associated with that type of work is driven by the intricacy of the part and then the number of parts to be produced. So market for the parts will determine if it is economically feasible to produce the cover and make money doing it. So the answer to your question is what is the demand for that cover? Are there enough Superhawk people out there to give you a market size to support your idea?

I don't know how big the VJ market is. I do know that the vintage Harley and Indian markets are big enough to support repro castings. But these are all sand casting and no die castings so I would suspect that the patterns might not be as expensive to make. And I would think you could take your patterns to any small foundry to have them make cast iron or alum sand casts.

My guess is the cost of the the die molds would be pretty high.

A relatively new technology is the use of lasers and resins to produce very precision patters for investment casting. I believe in the case of that process, the pattern is actually a softward program that tells the machine how to make the pattern. So the cost then becomes the cost to develop and debug the program until you get a perfect part and then the cost to have a small foundry investment cast your parts. Again a guess, but I would think this would be the most economical way to reproduce the side covers.

I've always wondered about things like this for other things like antique boats and such. The catch to Japanese bikes is their parts are relatively high tech. So the parts are a bit harder to reproduce. The really antique stuff was pretty crude. There was a boat builder named Snyder who made wood sail boats up until the mid to late 60's on City Island in NY. He made everything in his boatyard. He had a foundry that cast all the bronze fittings, turnbuckes, etc.. The only thing he did not make was the wood the screws and the nails he used to build his boats.

regards,
Rob

[G-Man]

One way of getting low volume cast parts is investment casting. Although you will see shrinkage (normal patterns are larger than the part they produce) you can use the original part (repaired if necessary) to create a master mold into which you can cast a wax 'pattern'. You then repeatedly 'invest' the wax into a slurry of plaster and bake it. Once the mold is finished you melt out the wax.

The method is used extensively for high precision castings as the mold is very stable. The method has been around since the Egyptian times.

See http://en.wikipedia.org/wiki/Investment_casting

You can also use modern rapid prototyping techniques to create the master, as Rob says.

I have a friend who uses the process with plastic construction kits (such as Tamiya or Revell) as the master. He 'invests' the plastic parts in Plaster of Paris, melts out the plastic, then casts silver in its place. Very impressive compared with the original plastic model.

If you can get hold of the book / movie about John Britten you can see him casting his own engine parts at home. He was using the water from his swimming pool to quench the aluminum castings. Amazing....

http://en.wikipedia.org/wiki/John_Britten
http://www.advrider.com/forums/showthread.php?t=62090

I'm hoping to try casting a new piston for my old Matchless using the investment method.

G

[Mike Mullins]

Hmmm. Might be a good retirement project ? (Like I'm going to get to retire anytime soon.)
Thanks for the info. I think I'll look into this.
Mikeyrx