Quote:
Originally Posted by Karl Wescott
A perhaps more accurate statement would be "The use of the investment casting process would faithfully reproduce whatever detail was faithfully duplicated in the wax* model".
* Wax is the traditional medium for investment casting, when the ceramic shell is heated and fired most melts out for reclaiming and the remainder burns out with little residue. Some other plastics, whether machined, molded, or 3D printed will also burn out well (but are seldom reclaimed).
Regardless, OTTOMH, the costs with investment casting would result in a part with a 350.00-750.00 retail price. Average Joe Restorer is going to go with the 75.00-150.00 "inferior" repro.
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Wax ( I use Freeman Flakes Carvable Purple WAX-300.80) is of course part of the investment casting process I described. I have experienced no loss of detail during burnout. I like to alloy German brass (60-40 copper/zinc) Hence the claim can be made that whatever is in the original part will be duplicated in the reproduction. I have reproduced parts in this fashion for years and have noted that light stampings such as on a dime come through with no loss of detail. I have never attempted to use any 3D generated patterns.
You need not go the expense of a ceramic mold either. I use G-400 aluminum casting investment produced by Kerr Labs (
www.kerlab.com) which has a metal casting temperature rating of 2000 DegF which is suitable for brass,bronze, and like copper alloys. No problems encountered with it and breakout is pleasantly easy. I purchased a 100 pound tub that lasted for years. This product is specifically marketed to the dental industry for use in the making of dentures to give some indication to the quality of part reproduction. It is mixed with water and carefully poured into the molding box, then vacuum chambered to remove all entrained air, much like silicone mold making.
Anyway that tub was about $150.00, I suppose it would be higher now, and they may have substituted this product line for another, but dentist still make dentures. That said the new product if that be the case it probably better than the old.
Never want to count the "average Joe" out of anything. Using this process would give him the first class part he is looking for for a couple of dollars, albeit much time and effort. I suppose it come down to how hard he wants the part.....