RO Water Tank - Beer Keg?

[Pete Deal]

I use RO water to mix my coolant. Generally I make 5 gallons at a time and it takes about 6 hours for my home brew RO system to make a 5 gallon bucket of water. Also, I'm still entertaining the idea of adding anodizing to my shop so the RO system would be pretty integral to this.

I'd like to make an improvement where my RO water went into about a 10 gallon tank which I could set up high and have a plastic line with a hand valve off the tank that I could just gravity feed into a bucket as needed. Ultimately could put a level switch on the tank to refill as needed but for now just all hand valves.

I was looking what might make a good tank for this. I had in mind something plastic but don't see anything cheap nearby. Could get a plastic drum for $50 or so. Then I was looking around and it looks like I can get an old straight wall stainless beer keg that's about 15gallons for about $150 or so on ebay. Seems like a heck of a nice tank for the price. I think I would tig weld a few ports into it for my purpose. A good thing about stainless I think is that since no light can get in it ought to grow less stuff.

Anybody ever converted a beer keg into a tank for other uses? Or got insight into the intricacies of RO water storage?

 

[crossthread]

You might want to keep your eyes on Craig's list. I see plastic food grade barrels all the time for free here locally.

 

[kineticmx]

RV fresh water tank. Available in all shapes and sizes at a low cost. Check ebay and amazon


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[gbent]

Shipping can be a killer. Look at local farm supply stores for FDA approved tanks sold for spray tanks, same thing as RV fresh water tanks. Multiple sizes available. I don't know about recent prices, used to be cheap. Any translucent tank will eventually run into algae problems, but you can see the problem. Metal more expensive and harder to see slime problems.

 

[Pete Deal]

Well I think problem solved. I had lunch with some old work buddies and one of them says he can get me about a 10gal poly tank that was used as an RO tank for exactly this purpose. This looks promising.

Still, a stainless beer keg with a little simple tig welding seems like it would be a cadillac for this purpose. Shipping is free for the one I saw.

Thielmann Stainless Steel Keg, UV Resistant, 15.5 U.S. Gallons, Half Barrel | eBay

 

[janc]

Beer kegs work great for a variety of uses, you don't even need to weld for some uses, the pipe to the bottom (spear) and the valve are quite inexpensive, you can take out the check ball in the valve and flow in both directions, one thing to note is the fittings on the valve are often BSP thread, but they usually come with a hose barb adapter.
You should be able to pick up a keg on craigslist for $50 or so.

hydrostatic pressure test, burst test | Laboratory Testing Inc.

 

[camscan]

Well I think problem solved. I had lunch with some old work buddies and one of them says he can get me about a 10gal poly tank that was used as an RO tank for exactly this purpose. This looks promising.

Still, a stainless beer keg with a little simple tig welding seems like it would be a cadillac for this purpose. Shipping is free for the one I saw.

Thielmann Stainless Steel Keg, UV Resistant, 15.5 U.S. Gallons, Half Barrel | eBay

have you approached your local bar owner? Over here they always have kegs from different breweries which they cannot send back.

 

[Milland]

Still, a stainless beer keg with a little simple tig welding seems like it would be a cadillac for this purpose. Shipping is free for the one I saw.

Thielmann Stainless Steel Keg, UV Resistant, 15.5 U.S. Gallons, Half Barrel | eBay

Only issue I can see is you'd want to passivate the internal surfaces that were heat damaged from the welding. Otherwise there may be leaching/corrosion from the aggressive RO water.

 

[boslab]

I suppose stainless would do but it’s no good in polished water plants, you have the water demineralisation of the steel till the pipes disintegrated, amazing to see, same applies to distilled water, eats steel
Polypropylene is preferred
Mark

 

[Kalispel]

We use a 275 gallon IBC tote. Food grade totes are available from lots of sources. We put a mechanical float switch in the top and it stays topped off.

We had a 20 gallon pressure tank from a well water system. It was nice because the water was pressurized but there was never enough stored. We use RO for coolant and to replenish evaporation in a small coating system.

 

[Overland]

Can I ask a couple of questions please ?

I'm guessing RO is reverse Osmosis ?

What kind of water are you starting with ?

What's the benefit for coolant ?

Just curious, "need to know".
Thanks,
Bob

 

[Kalispel]

RO is reverse osmosis.

Our water comes from a well. It is full of minerals. It will ruin the chemical baths and will leave deposits on surfaces. We run it directly in a cutting table and it looks like an alkali lake over time as the water evaporates.

RO filters are relatively inexpensive compared to de-ionizing systems. A 200 gallon per day system is about $1500.

 

[Pete Deal]

Yea and my water is good government water but, as I understand it, if you keep dumping water with dissolved minerals into a tank and topping it off over time as the water evaporates the mineral content of the water in the tank continues to rise since the minerals stay behind as the water evaporate. This interferes with the coolant's ability to do what it does. So the goal of the RO is to minimize the amount of dissolved minerals being dumped into the tank. I use Trim E206 coolant and I've spoken with their tech support and the above is their recommendation.

In this case I don't think the goal is the highest purity of water but only to reduce the amount of dissolved solids as much as can be done reasonably.

Also, I used to work in a large pharma plant. We had lots of purified water systems. Very fancy stuff most of it. Some some of the tanks were plastic and some stainless. Also, the piping was a combination of plastic and stainless. Yesterday I called the guy that designed many of these systems and asked him about the tank/material choice and he said stainless or plastic was fine.

Another source for really nice little stainless tanks are old soda kegs. Not exactly sure what they are called technically. But these have a nice cam lock top that can be removed for cleaning. Most of these are about 5 gallons though. I think 10+ gallons would be ideal for me. Regarding the 275gallon totes- that's way beyond me. It's just me working here.

 

[Kalispel]

The only reason we store 275 gallons is because we run a couple coating systems that have heated tanks. One operates at boiling point. It can use a lot of water even with lids to catch the condensate. A 55 gallon plastic barrel would be enough but the tote can be forked and moved easily. 10 gallons would be plenty for our CNC machines.

 

[BoxcarPete]

Might be worth considering a submersible UV light to keep microbes down if you just want to keep topping it off forever. In that case, it would be better to go with stainless than plastic.

 

[triumph406]

55 plastic drums are avilible here on CL anywhere from free to $10 ea, that's what I would use.

 

[Pete Deal]

55 plastic drums are avilible here on CL anywhere from free to $10 ea, that's what I would use.

Got a few. Too big.

 

[mnl]

I have two 10 gal. RV tanks for RO water. They weren’t super expensive including shipping and they came with pipe threaded ports. They seem to be out of stock right now, but they have other sizes. I’m sure they are also available from many sources.

https://www.pplmotorhomes.com/parts...-tanks-fittings/small-plastic-water-tank_T161

 

[Pete Deal]

I have two 10 gal. RV tanks for RO water. They weren’t super expensive including shipping and they came with pipe threaded ports. They seem to be out of stock right now, but they have other sizes. I’m sure they are also available from many sources.

https://www.pplmotorhomes.com/parts...-tanks-fittings/small-plastic-water-tank_T161

That does look like a good option. A buddy says he can get me one of these for free:

14 Gallon Polyethylene Tamco(R) Tank - 12" L x 12" W x 24" Hgt. (Can Ship UPS) | U.S. Plastic Corp.

 

[garyhlucas]

RO water has no algae or bacteria. No food for it to grow either. It gets in through the tank vent. Use a very fine HEPA grade filter and it should stay pristine.