Mist vs. Flood coolant

[rogerfries]

I know this is probably one of those Coke vs. Pepsi things where some people have preferences, but when should you be using flood coolant vs. mist coolant? I have an old Boss 5 which does not do a good job of recovering/containing coolant so Mist is obviously cleaner, but flood is probably better? When do you need flood coolant? It seems Aluminum would prefer flood as it probably need lubrication more than cooling?

I'm sure you've already figured out that I'm a hobby user and not "Real" machinist.

Thanks!

[ichudov]

I made a Lexan enclosure for my Bridgeport Interact, and I am now free to use coolant with all of it collected back into the sump via enclosure.

http://igor.chudov.com/projects/Brid.../23-Enclosure/

[rogerfries]

I'm sure I'll make some Lexan guards, but my sump is shallow and I think a small amount of debris in the screen will cause it to overflow. On the old Boss machines the lip that would contain the coolant actually slopes down at the sides where the return is. I was running the pump at a pretty slow rate under ideal conditions and it was close to overflowing.

Here is a pic showing my table:
http://picasaweb.google.com/Roger.Fr...94957469303986

Anyway, very nice guards and I will make some similar ones, but the question remains. When can you get away with mist and when do you need flood?

Thanks!

[D-Money]

I guess it all depends on how much of the coolant you want to breathe. I, for one, will NEVER use mist coolant. Flood coolant has the "oomph" to clear out the chips, and the sheer volume to keep the cutter nice and cool.

Mists of virtually anything can become explosive. Look at how many flour-mills have exploded over the years. :O

[ichudov]

Guys, I used flood but not mist. (to be exact, I used mist without understanding and it was a disaster).

So, a question. When using mist coolant, how much air flow should I expect? Should aluminum chips fly all over the room? What should be the input PSI?

[rogerfries]

So two strong votes for Flood. Does anybody like mist? I don't know enough to have an opinion at this point. So far, I've just been using a squirt bottle.

[skullworks]

When hogging with a corn cob type rougher the RPM is reduced and the feed is a bit higher. Flood here works wonders about eliminating head buildup when the tool is immersed in a pile of gravel chips. Also due to the lower rpm and chip type the coolant is not "flung" all over.

On the flip side I am looking into the Fog Buster type coolant delivery - Its not Flood, but not Mist either. More of a low pressure air delivered microstream.

[Karl_T]

Here's one vote for mist. It has 90% of the benefit of flood and a fraction of the mess. My machines are not enclosed and i make a lot of very large parts so small guards around a vise aren't useful.

The one problem with mist is fog, so i built my own fogless unit.
http://www.machinistblog.com/zero-fog-mister/

Karl

[kewl_cat]

I started out trying to use mist. Not very effective whatsoever on aluminum. I did not like the cloud of mist around the machine for me to breathe. I built lexan guards around the old Boss 5 machine and built a flood coolant system for it. A Little Giant pump, a tank and some rubber lines and a ball valve from Lowes. It has been working great for 2 years. Cost me about $80 and some parts laying around the shop. I also made screens over the table drains.

[rogerfries]

Well it sounds like I need both flood and mist. My machine has a mist pump on it already and I'm adding flood also (kinda always planned on having both anyway). The one thing that seem strange about the flood pumps. Most of the pumps are 110 volt AC submersible. I always thought electricity & water where not the best of friends. Any safety issues here? I plan on hooking it up through a GFI outlet and I was planning on using a 5 gallon plastic bucket for the tank. Anything safety wise I should consider? Is a plastic tank ok, or does it need to ba a grounded metal tank?

Just seems wrong plugging in something and tossing it into a tank of water.

[kewl_cat]

No issues here with the submersible pump. My 120V AC pump has been submersed in a 20 gallon tank for two years. Just plugged to a standard grounded outlet.

[HawkJET]

Originally Posted by rogerfries Just seems wrong plugging in something and tossing it into a tank of water.

Submersible pumps are commonplace. No need to worry if the pump is designed to handle the liquid it is submersed in. Oil can affect some polymers that are used in the gaskets and seals. So keep that in mind. A GFI is a good idea (belt & suspenders).