Coolant Staining Parts

[AMCTony]

I am having an issue with coolant staining parts. The parts are aluminum and the coolant is Castrol Syntilo 9954. It is leaving a yellowish stain on the parts. Has anyone run into this problem before? Any solutions?

[clutzed]

we always use just plain old every day kerosene for aluminium , never had any heat or staining problems

[jetpig1]

Look at the stats:

http://www.castrol.com/liveassets/bp...ntilo_9954.pdf

Says 8.0 - 8.8 ph at 5%. Fairly base. Like seawater. If you are mixing at 5%, no problem I would think. higher concentration means more base, towards the Drano side of the ph scale. You might just try immediate rinse of parts in a tub to lower ph.

[rhrubin]

We had a similar-sounding problem with staining.
The problem only occurred with one machine.
Turned out it had nothing to do with coolant, concentrations, Ph, etc.... but had everything to do with grounding.
The parts were being anodized as they were being machined.
The ground rod for the machine with the this staining problem was in middle of the shop. Here in the desert, the soil had dried to such an extent that the ground rod would not conduct.
We slowly poured a few cups of water alongside the ground rod, allowing it to seep in through the hole in the concrete floor.
Solved our problem.

[ilbebach]

We had stains on the aluminium parts if the coolant was allowed to dry on the parts

We keep a tub of Demineralised water into which the parts are dipped immediately after removing from the machine.

solved the stain problem....
( we use castrol 'COOLEDGE SL ')

[Triv]

Sometimes, it is a combination of factors.
1) Your coolant does not inhibit electrolysis as well as it should... Shop around for a better coolant.
2) You have fines suspended in your coolant from machining other materials. Mixing copper, steel, zinc and aluminum on one machine can create both black and fuzzy white stains.
a) Clean out the sump thoroughly.
b) Install a filtration system. It does not need to be too elaborate, but I would suggest a 2-stage system with both coarse and fine filters.

Good Luck!

Triv

[bglad]

I've been using Hangsterfers NeoSol 300 for a couple years, best stuff I've ever used, not cheap, but quality never is.

[apache405]

Originally Posted by rhrubin We had a similar-sounding problem with staining. The problem only occurred with one machine. Turned out it had nothing to do with coolant, concentrations, Ph, etc.... but had everything to do with grounding. The parts were being anodized as they were being machined. The ground rod for the machine with the this staining problem was in middle of the shop. Here in the desert, the soil had dried to such an extent that the ground rod would not conduct. We slowly poured a few cups of water alongside the ground rod, allowing it to seep in through the hole in the concrete floor. Solved our problem.

That's and interesting, because the grounding system should be totally bonded together-- the neutral and ground lines are both bonded at the service entrance (at least in single phase systems, not 100% sure about the grounding in a three phase set up). That means there might be a larger grounding issue in the whole wiring system of your building.

[AMCTony]

I changed out the coolant and checked the machine ground. Still getting stains. The fixture to hold the part is 1018 steel. Could that be causing the problem? The staining is worst where the part contacts the fixture.

[apache405]

Possibly a reaction due to dissimilar metal junction? Can you warp the contact points in some thing sheet aluminum?

[AMCTony]

Changed to an aluminum fixture. Problem is still there. Ready to find a tall building and jump off. First I think that I will try installing a new ground rod and run new wire. If that does not work then I am totally lost.

[scadvice]

…think of something that is coating the surface. Can you wash it off with soap and water? (A water based stain) Or do you have to use something like alcohol? (A petroleum based stain). If neither, then can you rub it off with #000 steel wool? Or does it take something more aggressive?
Electrolysis whether anode or cathode side will be leaving (depositing) or taking away material (pitting). So, if that is what may have happened, you should be able to see and feel it. Check the stain with microscope, if you can. Also the clamping fixture will also display the same problem.
What kind of Aluminum alloy are you cutting? Is it all the same lot of material?

BTW - The electrolysis marks I have seen are mostly gray.

Steve