Doug, I used Styrofoam covered in aluminum foil for the BT-7 turret. I still have the form. It was constructed from layers of Styrofoam. Hard templates were used for guiding a bread knife to cut the conical shape. I used a positive mold method. The form was made a bit smaller than the finished product and served only to provide a general shape. Layers of fiberglass cloth and mat were then applied to the outside surface. Any imperfections can be sanded and refilled. This is the cheapest method that I could think of for an irregularly shaped turret. A "lost foam" method might work well for a post WWII American tank like the M-26 Pershing with an irregular, rounded shape and prominent overhang. In this method you would build your fiberglass shell over your foam core, then melt it out in an oven. Of course this would be a one off mold, but how many turrets of the same type would you want?
Paul H. ----- Original Message ----- From: Doug Conn To: rctankcombat@googlegroups.com Sent: Friday, January 09, 2009 6:36 PM Subject: [TANKS] Re: turret molding question Oh ! I see now. Ron, is this what you were describing, too ? Sorry, I misunderstood. I guess it would be like this, then, where I sand away the blue areas What material is a good choice ? I don't think foam would work for vacuforming. Even I use fiberglass, I'd like a mold that survives more than one use. Thanks for the help. - Doug -----Original Message----- From: rctankcombat@googlegroups.com [mailto:rctankcom...@googlegroups.com] On Behalf Of Frank Pittelli Sent: Friday, January 09, 2009 6:22 PM To: rctankcombat@googlegroups.com Subject: [TANKS] Re: turret molding question Doug Conn wrote: > I created patterns for the MDF layers by taking horizontal slices of the > tank turret from a 3d model. I was hoping that by having those slices the > right shape, there would be a lot less I'd need to eyeball when sanding. You can use the "bread and butter" approach: 1) Create each horizontal slab using the "maximum" dimension for each slab. In other words, each slab will extend "outside" the desired surface. 2) Create a paper template for each slab using the "minimum" dimension for each slab. The paper will represent the desired surface. 3) Sandwich the paper between the slabs and glue everything together. 4) Sand away the exposed edges of all slabs until you hit paper, making a smooth transition from one slab to the next. No artistic skill needed, just a long rasp or file used with long strokes and patience. Frank P. --~--~---------~--~----~------------~-------~--~----~ You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to rctankcombat@googlegroups.com To unsubscribe, send email to rctankcombat-unsubscr...@googlegroups.com Visit the group at http://groups.google.com/group/rctankcombat -~----------~----~----~----~------~----~------~--~---
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