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Body part copying
Hi guys
Need a bit of advice on copying a sill/door jamb. It’s approximately 2 feet long section X 3.5 inches wide. Issue is the car is in a different location from my workshop. Quite a few miles. So basically I was thinking of getting a “3D print” of this section but not an electronic print more like using modelling clay. Not sure on how much shrinkage will come from modelling clay when dry though. Bondo would be better with little or no shrinkage but means I would have to put some release agent on the part and more costly. Any advice would be great! Thanks Bart
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Bart Risuccia |
#2
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Hi Bart,
Just thinking out loud here, but maybe you could use a plaster or fiberglass cast like used for broken bones? Lay it up on your part andremove it after it has cured.
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Steve ærugo nunquam dormit |
#3
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If you do use a plaster cast, a thin film of Vaseline will provide the mold release.
Plaster of Paris and cheese cloth does a pretty good job of mold making. Burlap is a bit harder to saturate, but builds bulk quickly. A supply house that supplies the brick and concrete trade should have Plaster of Paris at reasonable rates. CZ
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Jerry Roy |
#4
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Understand that plaster or any comparable gypsum product will generate heat and express water vapor as it catalyzes, creating & trapping condensation between the cured gypsum and the positive being copied. Then, when it's iron/steel being copied, it's about rust... Really a drag to pull your plaster mold only to see a sea of new rust that is now prone to keep bleeding through porous paint.
Burlap can be saturated just fine. It doesn't happen instantly, but that's all I use for my plaster mothers. I never use gauze. I rarely use plain plaster, unless I want a weak product for a waste mold. I bought 150lbs of hydrocal -much stronger than plain molding plaster but still not as strong as something like dental stone- this afternoon for the current projects in studio. Hydrocal is not much different in price than plain plaster. Either can be purchased at better contractor supply houses. Dental stone needs to be mail ordered, but is well worth the cost and effort. Plain paste wax- car wax, Johnsons floor wax, whatever- works well. So does Vaseline, soap (naphtha laundry soap, scraped/shaved & dissolved in water is one of my favorites. So is joy dish detergent) and some other products are effective release agents. What I use varies on the positive media. Wax helps seal paint better. Just plan your mold properly. Any draft, not just obvious overhang & undercuts, will cause that mold to lock onto your positive original part. Even if you get it off, a cast made in that drafted mold may not come out in one piece if not made strong enough. it may be necessary to produce a multi-piece mold. Not sure if you're thinking of casting a complete part to use as a sort of hammerform or simply to use it as a buck to check your progress. Dental stone is immensely more durable than any other gypsum product. Concrete products are another durable option, just like bondo, plasti paste, etc.. You may be able to make simple template patterns from chipboard, sheet metal or plastic to use to make a regular station buck that should be easily reversed to make a complementing piece for the other side. There are many options , all with their good points and bad points.
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AC Button II http://CarolinaSculptureStudio.com https://www.youtube.com/channel/UCzSYaYdis55gE-vqifzjA6A Carolina Sculpture Studio Channel |
#5
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Don't know what it's like getting medical supplies where you are but the pre impregnated cloth(glass?) that they use to set broken legs usually has a use by date and can be sourced quite cheap once past it...doesn't have the problems associated with conventional plaster. I have seen people use it as a form for carbonfibre work.
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Paul |
#6
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This is what i'm thinking https://www.amazon.com/gp/product/B0...KZ44CJMXVBT2FS
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Paul |
#7
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Quote:
I have used Durham's Rockite (hardware store) for that. Adding fibers or fiberglas cloth is helpful for keeping it together on long forms. Thin dowel or aluminum helps keep stiffness on skinny parts. Masking tape on orig, and tape dams to hold the goo until it sets up....
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. |
#8
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Wow you guys are great!
So yes its really going to be a buck, a "quick buck" as its not in my workshop where i can take time to make one from MDF etc. You got me thinking now. Even a few sticks of these may be enough. http://www.ebay.com/itm/CARGO-QUIKST...-/170699425913
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Bart Risuccia |
#9
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Bart Risuccia Last edited by Bart; 08-11-2017 at 01:16 AM. |
#10
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pic not working
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Bart Risuccia |
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