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Up Topic Welding Industry / Inspection & Qualification / I need to make a measurement.
- - By Mikeqc1 (****) Date 10-02-2008 15:47
I know this is not welding related, but does any1 know of an epoxy (that wont shrink)that I can use to make a mold of something I need to measure? I cannot section the piece and I need a good idea of what the feature measures. I know that there is something I can use but don't know what its called.
MDK
Parent - - By CHGuilford (****) Date 10-02-2008 16:20
There is a product that gunsmiths use that I think is called "Cerrosafe".   Don't quote me on the actuals here.  Gunsmiths stop up the barrel just ahead of the chamber, and the compound is melted and poured in.  I think the temp is 175F.  When this stuff cools, it first shrinks - allowing the casting to be removed, then it expands back to actual size.  That allows measurements to be made.
Apparently the shrinkage and expansion is predictable and measurable and I believe it is reusable.

Possible something like that might work for you?  You can get more info through Brownell's.
Parent - By CWI555 (*****) Date 10-02-2008 16:39
http://4-dproducts.com/submenu/Cerosafe.htm Your correct. There are other forms of it though. Cerrosafe is a trademarked version of brownells.
Parent - - By hogan (****) Date 10-02-2008 16:39
I have used expanding spray foam. I just line the item with plastic, like a bag or sheet, and spray the foam inside. I have also used a cooking spray instead of plastic.
Parent - - By flamin (**) Date 10-02-2008 18:30
We have been using a product called Polyjel. I think it's the same stuff dentists use for dental impressions. It comes in a tube like toothpaste. When this stuff cures after a few  minutes, is has a rubbery texturel to it. It reamins flexable to it is easy to get out of tight spots, and doesn't stick. But stays in tact so you can get accurate measurements. It's is real easy to cut too, so cross sectioning is easy. Before we started using the Polyjel, we used plaster, which was messy, and brittle, so keeping a casting in tact was difficult.

Jason
Parent - - By 803056 (*****) Date 10-05-2008 03:50
You can purchase the "stuff" the dentist uses to make impressions from most dentists if you tell them what you need it for. It does a pretty good job and it isn't toxic. Basically, it is a silicon based material. It isn't cheap, but it readily available if there is a dentist in town.

Best regards - Al
Parent - By Mikeqc1 (****) Date 10-06-2008 17:53
Thank you for the repiles i found a Putty called "Reprorubber" going to give it a try.
thx again 2 all
MDK
Parent - - By Ringo (***) Date 10-07-2008 16:50
Repro-rubber
Parent - By Mikeqc1 (****) Date 10-07-2008 16:58
RIGHT....Reprorubber
MDK
Up Topic Welding Industry / Inspection & Qualification / I need to make a measurement.

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