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Hooking up my DI system - softened water or hard?

sirAIG

Aluminum
Joined
Jan 10, 2019
Location
State College
Got a Di system I am ready to hook up. The question now is do I run softened or hard water. The company I got my system from is small and marketed mainly at providing a spot-free rinse system for folks who like to wash their cars/rvs. The guy has not dove into machine tool usages. He says softened water will help prolong the life of the resin, as it has less things to filter out. My questioning which water to use is because I have heard that Di doesnt do well with salts over time and that ultimately you could be sending concentrations of salty water into your machine.

Anyone have any experiences/knowledge on this subject? I'd love to get it plumbed in this afternoon or tomorrow morning. Have a sump to get filled.
 
I have two Agie wire EDM's and use tap water in both of them. Never had a problem. I use a resin exchange service and the tanks last a long time so the cost of resin is negligible. Just use tap water, you are overthinking it.
 
DIs are important for EDM where water conductivity must be very low and the water is continuously filtered in a closed system.

Overkill for mill/lathe coolant, IMHO. You're better off running an RO system which provides very clean water, just not quite as clean as DI. In fact, the trace amount of minerals in RO water might be beneficial.

RO's long term cost should be much less than that of DI because the only consumables are some cheap mechanical and carbon prefilters. The RO membrane, which does the bulk of the work, should last years with minimal maintenance other than flushing, which simply requires a turn of a ball valve.
 
it shouldn't matter what kind of water you feed to the system. The deionizer should remove whatever ions are in the water, whether it be sodium, calcium, iron or whatever. The difference between hard and soft water is the type of ion. The important characteristic is the resistivity which should be low. As part of your process control you should have resistivity measuring device that will tell you when the ion bed needs to be changed.

Tom
 
DIs are important for EDM where water conductivity must be very low and the water is continuously filtered in a closed system.

Overkill for mill/lathe coolant, IMHO. You're better off running an RO system which provides very clean water, just not quite as clean as DI. In fact, the trace amount of minerals in RO water might be beneficial.

RO's long term cost should be much less than that of DI because the only consumables are some cheap mechanical and carbon prefilters. The RO membrane, which does the bulk of the work, should last years with minimal maintenance other than flushing, which simply requires a turn of a ball valve.

I think you might be right, but when I switched to Synergy 735 the rep was adamant on us getting a DI setup for it. Which we did and it only cost 2K, so we were happy to pay that because since then our coolant has not had any bacterial issues whatsoever and works quite well. I think it is less about the Synergy 735 and more about going from extremely alkaline and basic city water to proper clean water for metalworking.

Since our water in is bad but output is good, I doubt OP needs anything specific as far as worrying about water hardness
 
Appreciate everyones input. I made my decision towards DI over RO a while ago. For what its worth, I got my DI tank for 400 bucks to my door. Its good for 2000 gallons/1 year. New resin is 190. after having battled surface rust problems for 6 months on my new mill a year ago, I saw all problems go away by switching to 100% DI water. It sold me I suppose. Either way, 400 to get in, 200 a year doesnt sound bad at all to me.
 
Appreciate everyones input. I made my decision towards DI over RO a while ago. For what its worth, I got my DI tank for 400 bucks to my door. Its good for 2000 gallons/1 year. New resin is 190. after having battled surface rust problems for 6 months on my new mill a year ago, I saw all problems go away by switching to 100% DI water. It sold me I suppose. Either way, 400 to get in, 200 a year doesnt sound bad at all to me.

2000 gallons, seems low?

What is the "resin" you speak of? The filter bag?
 








 
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