[Resolved] Tormach Coolant smells rotten

Not sure what is causing it but the Tormachs coolant smells absolutely putrid. To the point where it is stinking up the workshop with a rotten egg smell.

Just talked to David and he told me the automatic oiler was setting off a low oil alarm lately and it was filled back up. i wonder if it is over oiling now? A brief google search shows issues of coolant and oil causing a breeding ground for bacteria that smells like rotten eggs.

I am not sure what the next steps here would be. Can the coolant be salvaged or should we drain and replace it? If so, what is the procedure for that and where does the waste coolant go? Also, if we drain it how will we know this won’t happen immediately again if there is an issue with the automatic oiler.

I cannot stress enough how absolutely horrid this smell is. :nauseated_face:

The only real way to prevent coolant going bad is to use it all the time. But yes, it needs to be drained and fresh mixed.

I heard using an aquarium bubbler can help with machines that are used intermittently like this one.

Bigger concern at the moment is what to do with the 3-7 gallons of nasty coolant that needs to be disposed of properly.

Repeating what I said on Slack for non-stewards to see: Put the waste into empty distilled water bottles. Take the label off and mark it clearly as WASTE, then leave it by the compressor. James has offered to handle our waste; he can take bottles from there at his convenience. We should have a few extra empty bottles on the same table as the full distilled water bottles.


Did this issue get resolved? I see the Tormach is available again in Skedda.

Yes. Coolant has been replaced and the system has been flushed and cleaned. The machine is ready for use.

Just a note if you plan on using it. Please check the coolant with the refractometer. It was at 5% Brix when i mixed it. If its higher than that then some distilled water needs to be added to bring the brix to or under 5%.


Seth did a ton of nasty work here; many thanks to him!


Awesome, thanks Seth!

Happy to check with the refractometer, although I haven’t used that before. I’m planning to be in tomorrow. Could you give me a pointer to the manual and where it’s stored?

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If the coolant is too concentrated down the road, don’t add DI water directly. Instead, mix a small amount of coolant (1-2% is fine) with DI, then add to the machine. Adding DI water directly can potentially break the emulsion.

Likewise, add the measured coolant concentrate to water when mixing it up, not the other way around.


The refractometer is in a blue case in the machine shop cabinet, generally the second shelf. I don’t know if we have a manual, but I’m sure there are videos and such explaining it. It really is quite simple: put liquid on the slide, put the cover on it, peer in the end.

Yep, super easy to use. We are right at 5%.

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