Coolant Bubbler

Coolant Bubbler

Coolant is the unloved child of CNC. Nobody likes to think how important is is until it's too late. Long and short of it is you cannot have CNC without some type of coolant. Here is a list of the things that coolant does for you: Keeps the cutter cool. Without coolant cutter life is measured in seconds (possibly minutes, NOT hours). Keeps the material (aluminum mostly) from sticking to the cutter. Lubricates the machine. We run a lubri-coolant which is keeps the machine ways lubed during operation. To be exact, there are a number of soaps in the brand we use, which washes all the oil away. Washes away all the chips. With all these benefits coolant provides shouldn't you give it a little love.

	Tucked below my mill is the unloved coolant tank. It's just a plain 20 gallon Rubbermaid container. The drain pipe runs back down to it from the table. The grey tube that actually goes into the tank is just a few wraps of 40 mil PVC, it keeps the coolant from splashing when going back into the tank, yet allows us to pull it out.

	Isn't it lovely. There are some pockets of tramp oils, but not a complete layer. Nothing too bad.

	Here is what we picked up at Wal-Mart. Pump $9.89 2800cc/min, includes 2 1 way valves 25' tubing $3.49 Air stone $1.89 Tee's $0.89 Total:$15.16 Lastly, a scrap block of aluminum and some zip ties.

	Since there is no gravel (hopefully) in the bottom of your tank to keep the bubbler from floating, you will need to zip tie it to the block of aluminum.

	Plumb the system. This was truly the tough part.

	Bubbler in action.

Miscellaneous Thoughts
We run a 700 GPH pump, after line and head loss we have about 300-400 GPH hit the table. There are times when we feel this is not enough. We run a semi-synthetic called SYN-Lube GM. We like it, it doesn't smell bad and we've never had it go rancid. And it's pretty much non toxic, if you can get over the taste you can drink it. Most of the time it's the anaerobic (non oxygen) bacteria that makes the smell. A thin layer of tramp oils form over the top of the coolant and the smelly bacteria thrive in the oxygen-less environment. The bubbler uses 3.5 watts, if you pay 15 cents per kilowatt the bubbler will cost you about 40 cents a month to run. High grade coolant costs 15 bucks a gallon. It takes 1 gallon of coolant and a lot of water to fill the tank. Most folks would rather build a bubbler than deal with tank of rancid coolant.