Used Polyethylene Drums for Holding Tanks

[DavidInWilmNC]

I've come across a couple of polyethylene tanks (55 gallon drums, actually) that originally contained car wash soap.  I've been thinking about using one of these for a holding tank (grey and black combined initially then adding a larger grey tank).  Securing it so it won't move around will be no problem.  My question is how to attach fittings, especially the one at the bottom that drains the tank.  I removed a nice stainless flange with a 1" lip that seems to be the correct size for the drain valve from the original MCI tank.  Here's what I'm thinking to do:  cut a hole in the tank near the bottom, mount the flange to the tank with polyurethane sealing it, and use the stainless bolts with stainless nuts and washers on the inside to keep it tight.  I assume polyurethane will adhere well to polyethylene.  I suppose I can do a test and see how well it holds.  If not, I can cut a rubber gasket to mount between the tank and flange.  I'm not as concerned with the inlets and vent on top, as they won't have the pressure (or leak potential) that the fitting on the bottom will.  I saw a fellow in Timmonsville that did this and he had no complaints.  I just can't remember how he set up his drain.  I'd love to hear any thoughts or ideas on this.  Thanks.

David

[TomCat]

That sounds like a lot of work when the fittings can be spun welded in the tank in about 1 minute each.

Jay
87 SaftLiner

[DavidInWilmNC]

That sounds like a lot of work when the fittings can be spun welded in the tank in about 1 minute each.

Jay
87 SaftLiner

For some reason, I was thinking that spin welding was somewhat more involve.  If it's that easy, I'll give it a shot.

Thanks.

edited to add:  What tools are required?  I see that a fairly strong rounter is needed.  I'm not sure what tool is used to grip the fitting and mount in the router.

[TomCat]

I don't think you need too much...router, hole saw, fitting chuck, fittings. I didn't want to buy the tools needed to do it on an ongoing basis, so I went to the local RV shop, and had it done in just a few minutes. About $20 per hole, fitting included. Not gonna leak.

Here's what the drivers look like.
http://www.dyersonline.com/pc-2206-162-spin-weld-driver.aspx
http://www.dyersonline.com/pc-2207-162-spin-weld-boss-driver.aspx

Jay
87 SaftLiner

[Stormcloud]

I just completed installing 2 plastic 'car wash' drums in  my MC7..1 as a grey only, and the other as a grey/black tank. I used toilet flanges (slightly trimmed) to bolt to the tanks, with polyurethane sealant. Only glitch was I didn't get enough polyurethane on the bolt heads on the inside of the tanks as first, causing a very minor leak (Not Acceptable!) so I had to redo the gunk on the bolt heads. The tanks seem to work well, and dump quickly with 3" valves on each, the grey dumps into the black first, then out the drain hose. Although not yey plumbed, the grey will overflow in to the black if required.

We have 100gal of fresh water on board, so the combination of 2x55gallon drums may well be adequate.

Lots of luck...

Mark

[TomC]

Round is always a good shape, and I imagine the price is right.  If you made a rectangular tank to the same dimensions as the drum you could carry 15 more gallons.  Doesn't sound like much until you are carrying to drums-that's 30 gal difference with rectangular tanks.  Good Luck, TomC

[DavidInWilmNC]

I just completed installing 2 plastic 'car wash' drums in  my MC7..1 as a grey only, and the other as a grey/black tank. I used toilet flanges (slightly trimmed) to bolt to the tanks, with polyurethane sealant. Only glitch was I didn't get enough polyurethane on the bolt heads on the inside of the tanks as first, causing a very minor leak (Not Acceptable!) so I had to redo the gunk on the bolt heads. The tanks seem to work well, and dump quickly with 3" valves on each, the grey dumps into the black first, then out the drain hose. Although not yey plumbed, the grey will overflow in to the black if required.

We have 100gal of fresh water on board, so the combination of 2x55gallon drums may well be adequate.

Lots of luck...

Mark

Mark,
How did you use the toilet flange for this?  Was this for the bottom port or for the top inlet?  Can you post a pic as to how you attached them?  I'd appreciate it a lot.

David

[DavidInWilmNC]

I'll check and see if I can find a shop to spinweld a fitting.  If not, would the polyurethane sealer work on polyethylene?  Thanks.

David

[TomCat]

David,

Call around to a few RV shops, I'm sure you'll find one. I got a hit on the very first place I stopped.

Jay
87 SaftLiner

[Stormcloud]

Here's a photo of the two tanks I installed in my MC7. You can see how the toilet flanges were slightly modified, then bolted to the tanks (with lots of polyurethane to prevent leaks).

A very inexpensive waste water system, seems to work well. I still have to plumb the vents and overflow, but it is useable as is.

Mark

[pvcces]

Aside of welding, does anyone know of any way to make a good bond to polyethylene?

Thanks.

Tom Caffrey

[DavidInWilmNC]

Here's a photo of the two tanks I installed in my MC7. You can see how the toilet flanges were slightly modified, then bolted to the tanks (with lots of polyurethane to prevent leaks).

A very inexpensive waste water system, seems to work well. I still have to plumb the vents and overflow, but it is useable as is.

Mark

Looks good.  That's what I'm talking about doing along with a grey bypass to a garden hose adapter for those times (and places) where we want to let some of the grey water drain directly.  I'll cut a couple of 2X8's to the curve of the tanks to make a 'stand' to angle the tanks towards the drain.  I'll also put a sheet of pink closed-cell foam with plywood over it on the bay floor to help keep the tanks from freezing.  If the size of pipes didn't give away which was your black tank, the color of the tanks sure does! 

Aside of welding, does anyone know of any way to make a good bond to polyethylene?

Thanks.

Tom Caffrey

That's exactly what I'm wanting to find out.  Spinwelding will work fine for some applications, but for others, I'd like to make sure before I start using various sealers.

David

[cody]

Just as a thought, I know holding tanks are expensive, I'm going thru the process now of replaceing mine with larger tanks, Bontrangers has a great deal on regular factory tanks, I ordered mine from them, the drawback is it costs more to ship them than to buy them lol.  I've got one thats a 75 gallon tank coming in that is new, complete with the discharge factory installed and the knockouts in place for the infeed and vent, they have a mounting flange built into them and the cost is only 50 bucks per tank plus shipping.  Doesn't seem to matter what shape or size, the price per tank is still 50 bucks lol. I thought about using the plastic drums because I can get them locally but after I figured out how much time and work it would take to install them, this was the best way for me to go.  Tim at Bontrangers has really gone out of his way to help me find the stuff I need and I'll recommend them to anyone, I'm not trying to make this sound like a commercial, I'm just so pleased with how dedicated they are to helping me, I've bought a bunch of stuff from them now.