Question for James Meyette....

[MetalFlake]

I just recieved the Babbit putty that I ordered after reading your reply to a question I had on vacuum fixtures.

 

http://www.emastercam.com/cgi-bin/ultimate...ic;f=1;t=009411

 

I'm a bit stumped on how this stuff is used for such applications. I was expecting something more along the lines of Bondo but without the problems of being effected by coolant like double back tape is.

 

Isn't this stuff just for sealing the vacuum and not for doing any holding like tape or heat activated glues?

 

MF

[Guest CNC Apps Guy 1]

Actually it's really for supporting thin floor stuff in vacuum fixtures where the part does not get sucked onto the fixture completly by the pump due to part topology, etc... It also cuts down vibration on turned thinwall parts though it's only effective for that under certain curcumstances.

 

HTH

[MetalFlake]

Hmmm, rats! Won't be able to use it for this job.

 

I'm still needing to come up with something that will substitute for Bondo but not be porus and soak up coolant. I need it to fill in pockets from other parts that were machined with the vac fixture so I can do this part.

 

Somebody mentioned something called "Tooling Stone" but I can't seem to find it online.

 

Any ideas?

 

Thanks!!

 

MF

[Scott Sizemore]

Do a search for Pig Putty. It works pretty well.

[randy]

we use a product called rigidx we do alot of gears and for odd teeth we fill in the tooth spaces with rigidx so we can grind part then check over a solid surface its just like a hard plastic like wax you just heat it up with a tourch and drip into your cavity to remove add a little heat and it comes right out

[Guest CNC Apps Guy 1]

There is some other stuff that a shop where I worked at used. It was glass epoxy. Looked like peanut butter. You mix it up, put glass in it and heat it with a heat gun for "a while". It'll hold. They you use a rubber mallet to break it apart. Maybe this is too destructive a method.... hmmmmm.

[Jim at Gentex]

MetalFlake,

We use several different urethane compounds to patch up our vacuum fixtures. Here is the link to the BCC product specs sheet. http://www.liquidplasticsolutions.com/pdf/...nes_epoxies.pdf

 

Check out their 8010 (Metal-Kast)or their 8163 rigid urethane compound. It sounds like either one may work for you. They are both 2 part A/B resins that you mix 1:1, so they're easy to use. One trick we have learned is to augment the Metal-Kast by adding clean aluminum chips to the mix for a bit of extra toughness in large volume pours, but it sounds like you can probably use it straight up. We usually dam up the area we want to pour with modeling clay, then fill the area with a bit more urethane than we need. After it hardens, we machine away the excess and are left with a clean, smooth surface that is ready for the next operation.

 

I have used them on both aluminum and model board vacuum fixtures to fill in voids and gasket grooves left from previous operations, which sounds like what you are trying to do. I usually run them w/o coolant, but I think the 8163 stuff is moisture resistant.

 

Hope this helps!