Hello,
My company is developing a custom Gasket for a pressure vessel. The gasket groove is a fabricated groove with a welded ring that makes up the out side wall.
I would like to be able to make a cast impression of this groove to be able to share with the gasket company. Any suggestions on the type of material to use to make this type of impression?

Thank you,
Phil

http://www.flexbar.com/IM_replica-proofing.htm

Reporubber is good, but you might want to pound the alloys into it. The rubber can break. Also the mix up stuff can make a harder cast, which is brittle.

You can also just use plaster. But be aware you can get growth and shrinkage.

I am not afillated with any of them.

I've always had great luck with dental impression wax. Get the kind that softens around 120-130F, get it good and soft, almost to the point of melting, and take your impression. Unlike Reprorubber, it's ready to measure in about a minute, and for regular shop use it can be used over and over.

Regards- John

I wonder what the coe is for dental wax for a 62° temp change?

Also how much cheaper is it? Can you scribe lines?

Right now where I am at, we use plaster. Maybe dental wax can replace it.

Thanks for the replies. This may sound obvoius, where do you get the dental wax, your local dentist?

Phil

I've always used Reprorubber and never had an issue. They offer both the normal paste thickness as well as the liquid thin pour depending on your needs. If you need a hard casting, Flexbar sells 'Facsimile', which will harden (and heat while doing so!) to a very hard casting that you can later finish if necessary.

Reprorubber is relatively inexpensive(~$140 for 520 ml), and very helpful to have around. If you don't see yourself using it very often they offer a smaller trial size for ~$60.

I'm siding with the Reprorubber. We swear by it and use it ALL day EVERY day. It does tend to crack with time (we are usually done with it by then) but it works very well for us!