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Fyrquel oil

Posted: Sat Nov 02, 2013 1:37 am
by Rex Allers
This is a question about an odd pump oil.

I just picked up a Precision Scientific D150. This is similar to a Welch 1402. Richard Hull has posted that he uses one.

It looked pretty clean, but had a hose coupling where the sight glass usually is. When I got it home I noticed a label that says,
"CAUTION: This pump has been specially assembled to use FYREQUEL [sic] 150 refill only with this lubricant."
Drat! I don't want to mess with special oil that is probably expensive, hard to get, and maybe not as good for vacuum.

My thought is to try to clean it out and use a normal vacuum oil.

Mostly, the pump is empty but still has a little of the oil in it. I drained a little of that out and found it doesn't mix with with some pump oil I have that is like Inland 19. Arrgh, looks like it needs to be cleaned rather than just try replacing with a couple flushes.

Here are a few links to information about Fyrquel and specifically Fyrquel 150 (spelled correctly):

Main page:


Fyrquel 150 specs:

From my experiments with a few drops of the remaining oil, it seems to mix with generic denatured alcohol and paint thinner, but the D-19 oil I have doesn't seem to mix well with alcohol but does mix with the paint thinner.

I don't have any of the cleaning oils on hand, like this:

Maybe I should try some of that, but I doubt it will mix with the Fyrquel 150 better than the 19 oil does.

So, I am wondering if anyone has experience with Fyrquel or has any thoughts about trying to convert this pump to a normal oil? My current thought is to try using paint thinner for a first-pass solvent, but don't know if this will be hard to get rid of to get a good vacuum later.

I am guessing this pump is probably the same as a standard D150 except for maybe gasket and O-ring materials, but I don't know that for a fact.

Incidentally, there was a black O-ring (buna?) in the input port fitting. While I was moving the pump around, I guess I got a little of the Fyrquell oil on the O-ring. It expanded quite a bit so that its diameter is now too big to fit in the input port groove. I'm guessing someone replaced an original O-ring with this one that is not compatible. Go figure.

Here's a link to three pictures of the pump...

Re: Fyrquel oil

Posted: Sun Nov 03, 2013 3:04 am
by Rich Feldman
Fyrquel is completely new to me. Your results in miscibility experiments remind me of brake fluid.

My humble guess is that you called it right. The "special assembly" means they used Fyrquel-compatible material for the seals etc. Can you get an overhaul kit with regular seals, or try soaking the existing seals in regular oil?

If it were my pump I'd try cleaning out the remaing Fyrquel with paper towels, etc., then whatever solvent works (alcohol, acetone, MEK?).
A heat gun (or even a compressed air blowgun) could be handy to clear out the solvent before introducing regular oil.
Steel parts can rust surprisingly fast after solvent cleaning & before re-oiling.