Hazards of 360 brass?

[ewest]

Hello -

I've been cutting a LOT of 360 brass in my shop lately - Of course it mills great and all that and I'm having no trouble, but I'm wondering about the ~4% lead content, disposal of swarf, leaching of the lead, coolant, etc.

Usually, I'll cut the brass dry with compressed air coolant / chip clearance. It fills my machine with chips, and that's all well and good, and sometimes I'll run some coolant on it. The thing is, I notice that my coolant gets all blue green from reacting with the stray chips of brass. (I'm using Premiere 600 from Motor Oil Inc, 1:25 with NYC tap water) I know the blue is from the copper, but what about the lead leaching out? Is my coolant now saturated with god-only-knows? Getting coolant on my skin or having drops of it spraying around and evaporating are just a fact of life, and these small drop, if they go in to a mist, in theory will leave behind whatever was dissolved in the coolant as an airborne particle if they evaporate, or...well just go straight in to my lungs.

I try to do my best to keep spray and odors down - Ventilation in my shop isn't all that great to begin with.

Does anybody have any thoughts on this matter? I'd rather not be slowly contaminating myself for the sake of some jackass hinges.

[Geof]

You are correct; Getting coolant on my skin or having drops of it spraying around and evaporating are just a fact of life, and these small drop, if they go in to a mist, in theory will leave behind whatever was dissolved in the coolant as an airborne particle if they evaporate, or...well just go straight in to my lungs.

Should you worry, in particular should you worry about the lead content?

The answers are No, Maybe and Yes.

No I do not think you should worry, specifically, about the lead content. The lead is tightly tied up as part of the alloy and unlike copper does not react very readily with water. Even the copper does not dissolve into the water very much, the blue tinge you see represents very little copper oxidizing and going into solution. The lead needs a more acidic solution than just water to dissolve appreciably and also a higher temperature. If you were to sprinkle a spoonful of swarf into your morning orange juice and boil it for a few hours you might extract enough lead to cause harm over a period of several years.

Maybe you should worry about inhaling a mist of coolant particles, not because of anything added to them from the machine but because the coolant itself is an oil and depositing tiny droplets of oil in you lungs can cause problems. If you are only encountering these conditions of coolant mist for a short period of time on an infrequent basis and you do not notice any throat irritation and do not have a history of asthma or respiratory problems you probably do not need to worry; although wearing a mask like the ones supposed to prevent inhalation of virus particles is not a silly idea.

Yes definitely you should worry if you notice throat irritation, coughing or a runny nose after working in your shop and you should improve your ventilation, do whatever is necessary to minimize the formation of the mist, maybe rig and extractor hood drawing air and mist away from the immediate region of the cutter; much like you might do for wood dust, and wear a mask.

[ewest]

Thanks for the reply - The chemistry is a helpful piece of information . I'm not really sure what the pH of my coolant is, but I seem to remember in my communications with MotorOil that it was NOT acid. Anyway, I NEED a vent in here, so it's not a bad idea. So far there's no irritation, but the Monday morning smell can get pretty rank at times...

Thanks!

[Geof]

Originally Posted by ewest ..... the Monday morning smell can get pretty rank at times... Thanks!

This is a different issue and is normally due to anaerobic bacteria flourishing when the collant is still; they metabolize sulfur compounds in the tramp oil and make the rotten stink. I think it is exacerbated when brass is machined because both the zinc and the copper oxidize readily and consume all the oxygen in the coolant when it is not be agitated. A nice powerfull aquarium bubbler may help by agitating the coolany and adding oxygen.

[skullworks]

To be honest the biggest factor I worry about is the size of the dent it makes in my wallet.

All joking aside - one thing you might look at is a different drill point geometry for use in brass that won't pull a part out of a vise. People who have had it happen will understand.

Not only will this address a safety issue - it will also change the chip to a more powder like form instead of a wire type.

[ewest]

I don't worry about the price - it's what the client specs. Also, never really have a problem with stuff tearing out of the vise. For drilling I use cobalt 135 degree split point stub drills almost exclusively. The other thing that works real nice are those Onsrud single flute aluminum router bits. Not only do they haul ass through material, they produce a good finish in "less than rigid" setups. My biggest concern was that I was breathing lead dust or lead tainted coolant seeping through my skin. BUT from what I have heard in this thread, I'm going to have to find another excuse for my stupidity....

Thanks again!

Andy