I am working on a prototype of a design of something that in the future may be made out of plastic in high quantity with injection molding. A part that I need to make for it has several complex curves and angles but for now I could make it by pressing some kind of mold-able clay like epoxy against some of the parts it will be working with, and forming other sections of it by hand or with some tools, if the clay like epoxy will: 1) not sag or droop after I form it, so that when it cures it is still in the same shape even though it will be free standing without support on several sides after it is formed. 2) will harden into something similar to a piece of rigid plastic when it cures. 3) will not shrink, or expand from the time it is formed to after it is cured. It does not have to be a epoxy (2 part) product, it could be something that air drys, as long as it meets all the requirements. I looked online, and found a large number of products that might work, I am wondering which ones will actually meet all the requirements? These are what I have found: 1) Aves Apoxie Sculpt 1Lb $20.00 2) Blick art material 3) Htf epoxy putty stick 4) Rector Seal EP--200 2oz Epoxy Putty Stick 5) JB weld waterweld white epoxy putty 6) JB weld steel stick weld epoxy compound 7) Gorilla all purpose epoxy compound 4242501 at homedepo and amazon 8) PC Products 25567 PC Marine Moldable 9) Alvin 12 oz lab metal repair putty 10) Loctite 2 oz all purpose epoxy putty 11) GSI Creos Mr. Epoxy Putty Pro-L 12) Visbella Epoxy Putty Stick Moldable 13) Rockler J-B Weld Kwik Wood Epoxy 14) Milliput Silver Gray Epoxy Putty 113 g Pack 15) Por-15 49033 Epoxy Putty 1 Lb 16) Pro-Bond Epoxy Putty 17) Oatey Fix-it stick epoxy putty 18) Blue Magic Quicksteel Epoxy Putty 2 oz $6.99 @ autozone auto parts 19) Loctite 64856 Epoxy Putty all purpose 2 oz 20) Free Form Sculpt Epoxy Putty trial size $35.43 @ walmart amx3d.inc 21) Plastic Weld JB Weld 8237 plastic repair epoxy putty @ amazon 22) Loctite 1999131 All Purpose Perair Puty 2 oz @ Amazon 23) KwikWood Epoxy Putty 1 oz 24) Sugru original formula black 3 25) Mohawk epoxy stick black (20 minute) kingsport wood I am thinking numbers 1 or 20 may be the best choice for something that will not sag between the time it is formed and it hardens, but I am open to suggestions about what might work best. There may be others that I am not aware of. Based on your experiences what do you think would be the best product for this application? Please tell me what you think will work best for this application, and if you have actual experiences using the product you recommend? Thanks in advance for any information.