Coolant wrecking Lexan on machines ??

[50BMG DUDE]

Hi guys,

Anyone use synthetic coolant? We switched due to our senior guy getting contact dermititis from what we think was semi synthetic, also could have been the shop cat shitting in the tumbler...not sure on that one

Now we are finding all of the Lexan cracking on our 3 Milltronics machines and our Doosan MV3016. The Milltronics are straight lexan panels so it's no big deal to change, just a PITA. The Doosan is glass/lexan and has 6 panels and our Milltronics ML15 toolroom lathe (2 panels) is glass/lexan (and curved) I'm guessing those are going to be a bit more $$$ to change. My two Hurco mills and My DMU 50 seem to be fine. Talked to a rep and he swears he's never seen it before.

 

[???]

How old are the machines. Not sure if they still put it in the machine tool manuals but they used to specify a time frame for replacement. Get the MSDS for the coolant and cross check it against the chemical resistance chart. Lexan has quite a few chemicals that it will have a severe reaction with.

I made the molds for paintball magazine adapters, the shooters would spray WD40 into the mag to increase velocity and the adapters would crack around the screw holes.

 

[dangerboy]

Lexan is attacked by many newer coolants. I use Oemeta 900 and went through two chuck guards in short order. The supplier now puts a warning on the product page.

 

[boslab]

It’s funny when you state what is happening and the manufacturers say “ we’ve not had any complaints “
Your the only one to complain ( take note of drug companies usual response, though may cause anal bleeding on a coolant drum would be very scary!)
Mix coolant, cut test tokens, stick them in and wait take some photos btw.
If a reaction occurs, send Qualchem a claim, see if that shakes the tree!
Mark

 

[DavidScott]

Are you sure it's Lexan and not some other polycarbonate?

 

[Cyclotronguy]

Ammonia compounds kill polycarbonate quick as a wink. One swipe and it's a spiderweb of micro fractures. Ditto for some of the anaerobic sealants

 

[rklopp]

It’s funny when you state what is happening and the manufacturers say “ we’ve not had any complaints “
Your the only one to complain ( take note of drug companies usual response, though may cause anal bleeding on a coolant drum would be very scary!)
Mix coolant, cut test tokens, stick them in and wait take some photos btw.
If a reaction occurs, send Qualchem a claim, see if that shakes the tree!
Mark

Even better, tap a hole with a taper pipe thread and lightly screw in a pipe plug to introduce some stress. Environmental stress cracking requires three things: a susceptible material, an environmental chemical, and stress.

 

[Houdini]

That's not even the same type of coolant, 251C is semi-synthetic(has oil) 363 is full-synthetic(non-oil based).
I have seen other full synthetics say not to run them in older machines with rubber seals, that it will degrade the seals and the paint.
That statement was even by the coolant manufacturer.
So full synthetic is hard on machines polymer parts, and less corrosion control.

We had a guy have skin irritation to new coolant, turns out he was wearing long sleeve shirts and getting them wet.

I use "invisible glove" before doing anything nasty, keeps grease and chemicals out of the skin, go back to 251C and by some of any of the wax based hand protectants.

 

[50BMG DUDE]

Ya got me on the "Lexan" - I call all acetel "Delrin" too, even though I know there are subtle differences. I have no Idea what's in the Doosan or the ML15 Lathe, But I know the mills are 1/4" Polycarb of some kind 'cuz I replaced all of them about 4-5 years ago as the facemill ops had shredded the old stuff.

 

[cnctoolcat]

If you make your own windows, use safety glass on the inside with Lexan sandwiched to it.
I use the 3M windshield urethane adhesive for the sandwich, and to secure to the machine. This stuff grabs so good, no bolts or nuts are required to hold the windows in place if you prep well. Always secure windows on the inside of the sheet metal opening, to have a solid mechanical stop around the edges for the glass/Lexan sandwich.

ToolCat

 

[DavidScott]

Polycabonate is notoriosly prone to chemical attack, right down to skin oil. Some grades are less so with Lexan being one of those grades, which is why I asked.

 

[Houdini]

I know they are not the same type of coolant. Most of what we cut is either 4140PH or P20 or H13 mold steels. No need originally for "super coolant" but my Q Chem guy said that the 363 would likely solve the guys derm problems (chlorine caused I guess?) and provide better lubricity and tool life. Did see some tool life improvement, but not enough to justify the higher cost of coolant (It's triple the price IIRC) And it's definately much more concentration sensitive and machines seem to be much more prone to rust if concentrations are off as little a 1%. Will be going back to 251C for now and exploring other brands like Rustlick 5050 or Fuchs. I ran Valcool for years and years and loved it, but it's no longer available.

The Oemeta Novamet 910 I found was similar to Qualchem 250/251C I believe it has no chlorine, and is highly skin compatible, encase your interested. semi-synth(oil)