Cheap Fluorinert

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Cheap Fluorinert

Post by jrbpyro101 » Sun Dec 12, 2010 8:29 am

Hey everyone,

I found what seems to be a supplier of cheap FC-43 Fluorinert and did a little research regarding the use of fluorinert as a coolant in fusors.

After going through the forums and some websites it looks like some people have and want to use fluorinert to help cool their grids and to prevent thermionic emission. It looks like there are about 8 different kinds of fluorinert with the majority of them having various applications, but when it comes to cooling grids Ive seen FC-40 used and FC-77 possibly recommended.

Now Im mainly going to focus of the comparison of FC-40 and FC-43 because of the fact that FC-40 is currently being employed in at least one fusor that I know of and the company that I found sells FC-43. I couldn't really find any info on the 3M website about FC-77 (possibly out of production), but the FC-40 has a boiling point of 155 degrees Celsius whereas FC-43 has an even higher boiling point at 174 degrees Celsius which seems like it would function better for cooling grids. It looks FC-40 has a high dielectric as opposed to FC-43 which is non-conductive according to the 3M site. I do believe being non-conductive and being dielectric is different but do correct me if Im wrong, with that said it doesn't seem like having something that is dielectric or non-conductive would effect the cooling or prevention of thermionic emission in a grid, so the use of FC-40 and FC-43 shouldn't really make much of a difference from what I can tell.

After looking around quite a bit, FC-40 ranges from 100 to 300 bucks for 100 ml and about the same price range for FC-43 and so on. The website that is listed at the end sells FC-43 for 30 dollars for 100 ml which sounds like quite a deal from what Ive seen elsewhere. The site seems to be legitimate but to calm your nerves if you are considering an order, you can pay through paypal so they can not see your credit card info.

I am certainly NO expert in the fluorinert field or even the cooling of grids so everything is just based on my opinion and research. The main point of this post is to give you guys a cheap and easy source of fluorinert for grids so you can hopefully have a more efficient fusor. If I am wrong about any of this please correct me.

Fluorinert Info:

FC-43 source:

Hope this was helpful!


Chris Trent
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Re: Cheap Fluorinert

Post by Chris Trent » Sun Dec 12, 2010 5:45 pm

FC40 has a lower viscosity and would be slightly easier to circulate through small tubing, but it's nothing that would keep you from using FC43 if necessary.

One thing to keep in mind is that at high voltage there's really no such thing as completely non-conductive, regardless of what marketing materials may say. The real question is what the resistance and breakdown strength really is.

I checked the spec sheet and both FC40 and FC43 have equivalent electrical and thermal properties new. The only concern I would have is what level of impurities is tolerated in the reclamation process and do they have the same electrical properties once reclaimed? I'd presume that it's close enough for our purposes.

I've been around these forums for a while, and I've seldom seen a more talented group of scavengers. I've no doubt that they are already well aware of reclaimed sources, probably many more than we know about, but it's probably still good to have some of these sources documented here.


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Re: Cheap Fluorinert

Post by lutzhoffman » Tue Dec 14, 2010 1:25 am

Check out the Galden line of inert fluorine containing fluids, these are at least equal to fluorinert in most respects, and superior in many others like almost complete UV resistance etc. The secret is that it is already a totally oxidized fluid, with no non bound carbons in the chain to break.

The Galden fluid numbers are more easy to remember, the fluid number basically represents the boiling point in deg. C . Here is the Kurt J Lesker link on them. I got a gallon of HT110 on ebay for $75 a while back, the "Normal" price on ebay is about $100 - 300 / Gal. It makes terrific liquid insulation, they use it in industrial x-ray machines, and neutron sources for HV insulation, so that the machines can go by air, by avoiding pressurized SF-6 hazard. Here is the link: ... cfm?pgid=0

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