Can you use plaster to make a mold for a fiberglass bumper?
05-20-2008, 04:57 PM
#1
Melting Slicks
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Can you use plaster to make a mold for a fiberglass bumper?
Can you use plaster to make a mold for a fiberglass bumper? What else needs to be done to make sure the plaster will not stick to the original bumper or the new fiberglass?
05-21-2008, 08:15 AM
#2
Le Mans Master
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i think your hardest problems will be to design a mold frame that will separate into two pieces (top and bottom) due to undercut sections, and also be strong enough to support the weight of the plaster.
jeff
jeff
05-21-2008, 04:07 PM
#4
Melting Slicks
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St. Jude Donor '12
go to fiberglass forums and they will have the answers you are looking for. i have been told that you can put a release agent on your bumper and make a fiberglass mold of it. i think there are threads that cover mold making there. the guy that is helping me with my car has done them in the past with interior parts. i can ask how he did it and what he used.
05-21-2008, 09:13 PM
#5
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the bumper has many complex curves that will prevent the original bumper to be removed from the hardened plaster. that's what i ment buy "undercuts". the weight of the amount of plaster you are going to need will be more that the tensile strength of the unsupported plaster. i wouldn't be surprised if the total weight of the "die" is several hundred pounds. you are making a mould of a large object. remember that the water that is added to the plaster does not evaporate, it chemically combines with the dry gypsum and increases the weight.
jeff
jeff
05-26-2008, 03:09 PM
#6
I think it would be easier to make a mold out of styrofoam blocks. There was a good show on Spike "Powerblock" where they did this to make molds for 'glas fender flares for a Mustang. It was very labor intensive, and required some specialized materials, but I'm sure it could be done by a talented shadetree mechanic.
Temvette72
Temvette72
