Custom Holding Tanks

64MCI · May 11, 2020, 05:38:27 PM

Hey all,

I'm looking for some replacement holding tanks for my MC-5. The fresh and black tanks I have are 115 gallons, made from 1/4" polypropylene, and were likely built in the late 1970s when my bus was converted.

I'd like to replace them, but none of the "off the shelf" tanks that I've found online have similar dimensions. I've found some polypropylene sheets locally to make the tanks myself for $420. I'd also need a plastic welder ($70 at Harbor Freight), welding rod, tank fittings, and some practice. So, somewhere in the neighborhood of $600 for both tanks if I build them myself.

Before I pull the trigger to build them myself, I was wondering if anybody has any recommendations on a shop that does custom tanks?

Thanks,
Jed

richard5933 · May 11, 2020, 05:49:32 PM

I priced them out a couple of years ago, trying to accomplish something similar to what you're looking for.

I was able to find a place that could do the custom tank, and the price for one was slightly more than what you're looking at to do two yourself.

Any reason in particular that you are going to replace them? Can they be given a once over, scrubbed down, and put back in service?

dtcerrato · May 11, 2020, 05:58:01 PM

We have dealt with El Monte plastics a couple times with excellent results.
They will custom fabricate anything you want including taps for all the in & out fittings. It is not cheap...

64MCI · May 11, 2020, 06:16:58 PM

Quote from: richard5933 on May 11, 2020, 05:49:32 PM
I priced them out a couple of years ago, trying to accomplish something similar to what you're looking for.

I was able to find a place that could do the custom tank, and the price for one was slightly more than what you're looking at to do two yourself.

Any reason in particular that you are going to replace them? Can they be given a once over, scrubbed down, and put back in service?

Yeah, from what I've been able to find, it would be $1200+ and I really don't want to spend that much just on tanks. I'm redoing the whole water system, so I have plenty of other things to spend money on.

Few reason for replacing them...I think they're probably 40+ years old, at some point they're going to crack. Although maybe they'd still last longer than my welds.

Also, The dump valve and some of the other fittings are not where I'd like them. I know I could cover them and make new holes, I'd just rather not. And finally, I'd like to make them a little taller and not quite so wide so that I can gain some storage space in the bay without losing tankage. So overall, no huge reasons to replace the tanks, but a few small things that kinda add up.

luvrbus · May 11, 2020, 06:39:07 PM

It is easy with a good plastic welder but not a Habor Freight welder they are not much better than $10.00 hair dryer from the Dollar store

bronson · May 11, 2020, 07:20:02 PM

I had a couple tanks made by a small shop in Martinsville Ohio. One tank was a black water tank for the bow of my boat. Drew up plans and they built exactly what I needed. Second was for the condensor of AC system i built for the same boat. Can't remember exactly but I think they were around $150 each. If south west Ohio is close for you I can see if they're still around.

richard5933 · May 12, 2020, 03:10:54 AM

Quote from: 64MCI on May 11, 2020, 06:16:58 PM
Yeah, from what I've been able to find, it would be $1200+ and I really don't want to spend that much just on tanks. I'm redoing the whole water system, so I have plenty of other things to spend money on.

Few reason for replacing them...I think they're probably 40+ years old, at some point they're going to crack. Although maybe they'd still last longer than my welds. Also, The dump valve and some of the other fittings are not where I'd like them. I know I could cover them and make new holes, I'd just rather not. And finally, I'd like to make them a little taller and not quite so wide so that I can gain some storage space in the bay without losing tankage. So overall, no huge reasons to replace the tanks, but a few small things that kinda add up.

Funny how similar our thinking sounds on this.

The tank on our bus which were installed by Custom Coach are still in great shape. The color has yellowed every so slightly, but overall things have held together since 1974. There was a split/leak on one seam where the vertical walls meet the top of the tank, but when I looked at it more comfortably it was clear that the weld was never done correctly from the factory. I got it welded up with my little Amazon plastic welder and it's been good since.

I thought at first that the way the bronze flanges were attached by being screwed to the side of the tanks using rubber gaskets was sure to fail, but not yet. I took them off, cleaned, and then reinstalled using new silicone gaskets.

I also initially wanted to have them made taller/narrower to use the space above them, but after working on the plumbing a few times it was clear why CC had left the space above them. Any less and the tanks would have to be pulled much more often.

If you have a commercial plastics supply house near you, that might be a good place to find a local fabricator if you want to get some prices. They would know of small shops in your area that you'd never find on your own, and perhaps one of them is slow right now due to the Covid crisis and can make you a good deal on a new tank.

Jim Blackwood · May 12, 2020, 09:20:50 AM

Gary, would that be Brown's?
I've been thinking about plastic for my gray and black tanks. Fiberglass might be another option. It's possible to buy cured sheets that are very durable and stiff, though I haven't checked on sizes and prices lately. That would leave the seams and fittings which shouldn't be much of a challenge. I'll probably be doing some glass work this summer anyway and already have the white suits.

I wonder about these plastic welders. What exactly are we talking about here, and how do they work? Seems like the end of the panel would have to be fully melted, and then the last panel might be tough to do.

Jim

luvrbus · May 12, 2020, 10:10:05 AM

Quote from: Jim Blackwood on May 12, 2020, 09:20:50 AM
Gary, would that be Brown's?
I've been thinking about plastic for my gray and black tanks. Fiberglass might be another option. It's possible to buy cured sheets that are very durable and stiff, though I haven't checked on sizes and prices lately. That would leave the seams and fittings which shouldn't be much of a challenge. I'll probably be doing some glass work this summer anyway and already have the white suits.

I wonder about these plastic welders. What exactly are we talking about here, and how do they work? Seems like the end of the panel would have to be fully melted, and then the last panel might be tough to do.

Jim

The cheap plastic welders use heated air and a melting tip and are not so good.good plastic welders are exspensive you use those like you are brazing two pieces of metal together only with plastic and a plastic rod,I use a friends plastic welder that does plastic fab work he paid almost 3 grand for his plastic welder it is nice but you need to use one a lot for that price

ol713 · May 12, 2020, 10:24:19 AM

HI;
Try also, Ardemco. They are a BCM advertiser. Got mine from Ardemco a lot of years ago and no problems.
Phone (800)253-0115. They are in Costa Mesa, Ca
Good luck

64MCI · May 12, 2020, 11:01:24 AM

Quote from: bronson on May 11, 2020, 07:20:02 PM
I had a couple tanks made by a small shop in Martinsville Ohio. One tank was a black water tank for the bow of my boat. Drew up plans and they built exactly what I needed. Second was for the condensor of AC system i built for the same boat. Can't remember exactly but I think they were around $150 each. If south west Ohio is close for you I can see if they're still around.

I'm in Minnesota. I should have mentioned that.

Shipping from Ohio would likely be too expensive. Thanks though!

64MCI · May 12, 2020, 11:17:55 AM

Quote from: Jim Blackwood on May 12, 2020, 09:20:50 AM

I wonder about these plastic welders. What exactly are we talking about here, and how do they work? Seems like the end of the panel would have to be fully melted, and then the last panel might be tough to do.

Jim

Here is the basic idea:
https://www.youtube.com/watch?v=HvV9a3lEe2g

buswarrior · May 12, 2020, 12:05:45 PM

Google is your friend.

Search "rectangular box tanks"

Long ago, water bed heaters were suggested to be put down under the tanks for freeze protection...

Who has a rig that did this, and does it still work?

Happy coaching!
Buswarrior

TomC · May 12, 2020, 12:23:39 PM

I used Ronco Plastic tanks directly from the factory. https://ronco-plastics.com/product-category/boat-tanks/ . I had them make 2-98gal for my fresh water, 115gal for my gray, 69gal for black. All are rectangular tanks and all are white plastic so you can see through them. Specify heavy duty for a thicker wall. You can pickup from the factory and watch them spin weld the fittings. Highly recommend this company. I use the simple tank level gauge of being able to see the level through the plastic. If you do use this, don't tell them one of the tanks is for black tank-otherwise it will have carbon black in it and you can't see through it. They do this since some people get weirded out seeing floaters in the tank. Good Luck, TomC

richard5933 · May 12, 2020, 02:05:38 PM

Quote from: luvrbus on May 12, 2020, 10:10:05 AM

The cheap plastic welders use heated air and a melting tip and are not so good.good plastic welders are exspensive you use those like you are brazing two pieces of metal together only with plastic and a plastic rod,I use a friends plastic welder that does plastic fab work he paid almost 3 grand for his plastic welder it is nice but you need to use one a lot for that price

The plastic welder I've got is a specialized heat gun with about 1/2" outlet. There are various metal shoes that go on the outlet, including some that you can use to feed the plastic welding rod. I've been able to use it to make some pretty decent test welds on 3/8" material. The key I found was using a plastic welding rod made of the same stuff as the tank, so I just used a table saw to rip cut narrow strips of it to use. Takes a bit of practice, but if you go slow enough it works.