High Vacuum Modelling Clay

Every fusor and fusion system seems to need a vacuum. This area is for detailed discussion of vacuum systems, materials, gauging, etc. related to fusor or fusion research.
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ian_krase
Posts: 636
Joined: Mon Nov 28, 2016 2:48 am
Real name: Ian Krase

High Vacuum Modelling Clay

Post by ian_krase »

All experienced amateur vacuum people know the virtues of Hysol 1C Epoxi-Patch for fixing leaks, turning bad interconnects into OK ones, assembling stalk shrouds, and making DIY feedthroughs.

I had read about a procedure for making your own "epoxy clay" and it occurred to me to try it with Epoxi-Patch. The procedure I had seen involved mixing epoxy resin with Plaster of Paris as a thickener. I instead used a powder which is apparently rather like what Plaster of Paris would be if it were somewhat less brittle, made of zircon-magnesia, and capable of surviving a temperature of 2800 F.

(I am worried about hydroscopicity. Probably a better material would be magnesia powder or fumed silica. Guess what I don't have on hand? I intend to dampen and then dry them before use.)

My test pieces are curing. If this works, it may provide an economical alternative to glass blobs and 3D-printed Ultem.
ian_krase
Posts: 636
Joined: Mon Nov 28, 2016 2:48 am
Real name: Ian Krase

Re: High Vacuum Modelling Clay

Post by ian_krase »

IMG_20171015_020359.jpg
Multipin feedthrough with screw terminal assembly for development of ion sources and the like. Screw terminals are the smallest size of euro style terminal blocks freed from there plastic casing, and the screws replaced with M2.5x4mm grub screws. Insulator structure is the aforementioned Hysol Clay. This will fit through a KF25 centering ring, barely, though it will not fit inside most KF25 nipples as was the design goal. A tungsten thermionic filament is attached.

Have not yet tested in vacuum. This has been under construction for a very long time. Assuming it works, the only part remaining for my next experiments will be a KF40 tee.
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