Newbie- AMAZING - Water on steel, really?

[jewells]

I would have never guessed that coolant would be mostly water!

Is it okay to let it sit on the CNC table, vise, and tooling overnight? How about for a week? Nothing will rust?

Do I need to get a drill driven paint stirrer out when I mix it up, or is a mixing stick good enough for a few minutes?

I'm using Hangsterfers S500, which came with the machine, and I trust the guy who owned it before knew what he was doing with the brand. Unfortunately he died so I can't ask him these questions.

So, what is the best mix ratio for 6061 and plastic machining? Right now I am at 15:1, but I left it 10 gallons short so I can easily change that if I need to.

Thanks!

[beege]

There are rust inhibitors in the coolant additive that address the rusting issue, and usually non-foaming agents that keep the stuff from - obviously - foaming. There are levels at which there isn't enough additive to be effective, and too much isn't helpful either. Call Hangsterfer's to get the right ratios for your purposes, and keep an eye on it, because water evaporates.

[roninB4]

Coolant is different between the brands and my knowledge is easily 15 years old. Now that I've posted that disclaimer....
Coolant can cause rust to form under the vise or on any other surface if left standing, it's always best to use compressed air at the end of the day. For some reason rust seems to like to form on internal surfaces (under SHCS, vise jaws, in C'bores, toolholders, etc.) you don't find until a week later. Coolant is supposed to have rust inhibitors but it can still leave a tacky film that traps chips, dirt, etc. on surfaces and that can interfere with your fixturing, blow the stuff off all your tooling at the end of the operation/shift/day. Old coolant can develop bacteria/mold that will produce a nasty smell that can cling to the workpiece (the customer will be impressed) and cause any minor cuts it finds to blossom with an ugly infection. Coolant tanks need to be monitored for said growth BEFORE it gets away from you. The mix proportions will be unique to your brand so you should contact the maker of that coolant for advice, they know more about it and should be glad to help you with their product.

[beege]

Originally Posted by roninB4 it's always best to use compressed air at the end of the day.

Never use compressed air to dry or clean a machine. It has a tendency to force dirt and chips to where they will do the most damage to the machine. Use other means of prevention.

[roninB4]

Well you're supposed to use some common sense along with the compressed air. If you avoid blowing INTO the way wipers, leadscrews, spindle, etc. you can use compressed air with no problems. Never is an absolute that seldom stands for long.

[Geof]

Originally Posted by jewells ....Do I need to get a drill driven paint stirrer out when I mix it up, or is a mixing stick good enough for a few minutes?.... Thanks!

I have used water mixed coolant for a few decades and have learnt to even ignore the manufacturers suggestions sometimes.

If your water is cold when you mix in the coolant sometimes a paint stirrer is helpful.

If your water is 'hard', i.e., a high mineral content you may find the coolant will not mix well and during use may form a scum. The only solution to this is to use better water; using a water softener may or may not help. I have never had to solve this problem but one way it could be done is to get the large bottles of water for use on water coolers, just make sure the mineral content is very low.

Your 15 : 1 ratio sounds about what most coolant manufactures suggest; that is between 5 and 10%. My experience with aluminum is that going up to between 10 and 15% can sometimes give better results especially if you are running fast with deep cuts and high feeds. If you are doing a lot of tapping even higher sometimes helps but then the residue left after the water evaporates gets to be too much of a nuisance.

You will very likely get a rust forming if you have the concentration around 5%; the film of coolant that is left behind is simply to thin to prevent rust.

It is practically impossible to prevent some corrosion between the contacting surfaces of equipment bolted to the table; this is often galvanic corrosion between dissimilar metals. I try to minimise this by oiling the surfaces with plain mineral oil before installing vises, etc; actually Vaseline works the best in my experience.

Tramp oil from the machine will accumulate in the coolant; when the machine is not in use and the coolant is stationary it becomes low in dissolved oxygen and then anaerobic bacteria start chomping on sulfur compunds in the oil and create a foul smell. The solution is to keep the coolant aerated by installing a tee in the coolant lines back to the tank so you can run the coolant pump occasionally just circulating the coolant in the tank. Some people suggest aquarium bubblers but they do not give very strong circulation.

It is almost impossible to prevent a tacky build up on the machine even if you do try blowing the residue off; I have found methanol, aka methyl alcohol or methyl hydrate, which you can buy in gallon cans at The Home Depot will quickly dissolve the residue so it will wipe off.

When the machine is running with coolant a fine coolant mist is created which gets all over the place leaving an oily residue on everything in the shop; this is a common feature of machine shops. It also leaves a residue inside your breathing passages and it is not unusual to find yourself coughing or feeling a bit of throat irritation when the machine is operating. This is not good and if you are going to be using the machine intensively a mist extractor is a good idea. Alternatively, wear a mask of the type that is used to try and avoid airborne infections.

Some people are sensitive to some coolants; if you find your skin gets dry, rough or sores develop switch to a different coolant. Even if you only use the machine occasionally switching may be a good idea because frequent short exposure can gradually increase the sensitivity until it becomes unmanageable.

[RICHARD ZASTROW]

Ref: #4 beege above. AMEN BROTHER !!!!!!!!!!!!

When I started in this machining arena our blow-off air hoses did not reach our machines. No quick disconnect fittings allowed. A lead hammer to "tap" a piece down was permitted BUT if you hit the vise handle disciplinary action followed.

Your work area was clean. If you had time to stand still, you had time to sweep, wipe and clean. You were responsible to remove all burrs you created.

Granted, machining speeds were lower and we had more time between cycles. But cycle times aren't so short that the same couldn't happen now.

How times have changed !!!!!!!

Sorry, soap box was handy. LOL

Dick Z

[cncjunky]

If were all talking about keeping are machines from rusting from the coolant then you can:
add more coolant solution to your water mixture, thats what I did with my coolant and it reduced rust to almost 0%, but coolants very.
You can blow the chips off as stated, then wipe down bed ways, etc., then take some WD40 and spray it all over the affected areas from the coolant, then wipe down with a clean rag, after each use. Using these steps should keep rust from occuring.

[cncjunky]

Originally Posted by Geof I have used water mixed coolant for a few decades and have learnt to even ignore the manufacturers suggestions sometimes. If your water is cold when you mix in the coolant sometimes a paint stirrer is helpful. If your water is 'hard', i.e., a high mineral content you may find the coolant will not mix well and during use may form a scum. The only solution to this is to use better water; using a water softener may or may not help. I have never had to solve this problem but one way it could be done is to get the large bottles of water for use on water coolers, just make sure the mineral content is very low. Your 15 : 1 ratio sounds about what most coolant manufactures suggest; that is between 5 and 10%. My experience with aluminum is that going up to between 10 and 15% can sometimes give better results especially if you are running fast with deep cuts and high feeds. If you are doing a lot of tapping even higher sometimes helps but then the residue left after the water evaporates gets to be too much of a nuisance. You will very likely get a rust forming if you have the concentration around 5%; the film of coolant that is left behind is simply to thin to prevent rust. It is practically impossible to prevent some corrosion between the contacting surfaces of equipment bolted to the table; this is often galvanic corrosion between dissimilar metals. I try to minimise this by oiling the surfaces with plain mineral oil before installing vises, etc; actually Vaseline works the best in my experience. Tramp oil from the machine will accumulate in the coolant; when the machine is not in use and the coolant is stationary it becomes low in dissolved oxygen and then anaerobic bacteria start chomping on sulfur compunds in the oil and create a foul smell. The solution is to keep the coolant aerated by installing a tee in the coolant lines back to the tank so you can run the coolant pump occasionally just circulating the coolant in the tank. Some people suggest aquarium bubblers but they do not give very strong circulation. It is almost impossible to prevent a tacky build up on the machine even if you do try blowing the residue off; I have found methanol, aka methyl alcohol or methyl hydrate, which you can buy in gallon cans at The Home Depot will quickly dissolve the residue so it will wipe off. When the machine is running with coolant a fine coolant mist is created which gets all over the place leaving an oily residue on everything in the shop; this is a common feature of machine shops. It also leaves a residue inside your breathing passages and it is not unusual to find yourself coughing or feeling a bit of throat irritation when the machine is operating. This is not good and if you are going to be using the machine intensively a mist extractor is a good idea. Alternatively, wear a mask of the type that is used to try and avoid airborne infections. Some people are sensitive to some coolants; if you find your skin gets dry, rough or sores develop switch to a different coolant. Even if you only use the machine occasionally switching may be a good idea because frequent short exposure can gradually increase the sensitivity until it becomes unmanageable.

Not all coolants get that foul odery smell, it depends which you go with. The one I go with is a good all around coolant, I can't think of what it is, but I paid about $500.00 for a 55 gallan drum. It does'nt get that rotten smell that others I've used do and does'nt require you to run a arriator "aquarium pump" to keep from stinking. What I use is " ValCool TurnTech Blue part #23170822" I actually think the stuff smells half good, not to bad on the skin either, and above all else it does a good job!!