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Old 07-07-2008, 05:17 PM   #1
3 Rivet Member
1972 23' Safari
Dearborn , Michigan
Join Date: May 2007
Posts: 117
New Blackwater tank

I got one of the new fiberglass tanks from Andy. It looks great and is a pretty good fit, not perfect but close enough to fudge.

I don't have the galvanized pan or any Styrofoam. The old tank was just sort of in there and held in place by the bathroom floor parts. The PO mentioned something about it being replaced but I doubt the place he took it would have replaced it with an original tank.

Should I hold it in place with some Styrofoam insulation or would something else work better?

On the new tank, I have the vent and the toilet flange fiberglassed in.

I am debating whether or not to put in the sensors and if I do, what holds them in place? I am not sure if they are supposed to be fiberglassed in or whether tightening them down is all that I need to do. They look like they are abs plastic with a rubber stem for the bolt to go through.

The other question is whether they are worth putting in or if there is a better solution that doesn't require putting holes in the side of the tank (I have a problem with this, I just rebuilt the whole back section of the floor and frame).

I have a feeling I will be fixing the control panel (the old tank never registered anything regardless of how full it was) before I get everything working if I use the sensors.

Tom Bray
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Old 07-09-2008, 08:19 AM   #2
1 Rivet Member
1965 28' Ambassador
Minnetonka , Minnesota
Join Date: Jul 2008
Posts: 17
more questions and no answers

Hi Tom,

I don't have answers as I am pretty much a rookie with blk tanks. Just questions for ya. I just got my tank from Andy too and am currently taking the journey. So..."fittings fiberglassed in." Does that mean cutting the hole and using fiberglass resin as the adhesive or is there more to it than that?

Next - Did you receive a vent, toilet and drain fitting (3 pc) with the tank, or just drain and toilet fittings...cause that's all I got from them (no instructions). Anyway, how does the drain mate up to the tank? My tank and toilet were completely gone so I have nothing to refer to. The drain and valve were kinda suspended by the grey water drain coming in from the side, but the valve was sorta shot....the bolt holes were rotted away.

Anyway, maybe you can point me in the right direction...or not.


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Old 07-09-2008, 08:48 AM   #3
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1969 23' Safari
New Orleans , Louisiana
Join Date: Aug 2007
Posts: 699
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I think the black tank should be supported from below as the closet flange may not be strong enough to handle the stress. You'll also want some warm furnace air circulating within the box if you do any cold winter camping. But mostly its a support issue, IMHO... I tried to make sure my bath floor did not press down on the tank either, which may lead to cracking. This 10-page thread may help:
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Old 07-09-2008, 10:57 AM   #4
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1969 31' Sovereign
1951 21' Flying Cloud
Alex , Oklahoma
Join Date: Jan 2007
Posts: 360
Images: 10
WE just put in a new black tank. The tanks is suppose to set within a pan and the styrfoam fills in the space between the pan and tank. Our pan was totally rotted out and our tank leaked at the vent. We think because the pan wasn't supporting the tank the weight was on the vent and toilet. Had a new pan made at a sheet metal shop for about $50.00. Then put in new alum angle bars to support the pan. Now if we have to work on the black tank, we unbolt the back bar and drop the pan&tank.
1969 Sovereign
1951 Flying Cloud SS#7062
AIR #18751
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Old 07-09-2008, 10:11 PM   #5
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1972 23' Safari
Dearborn , Michigan
Join Date: May 2007
Posts: 117
As far as what came with the new tank, there were the two rings that need to be glassed into place. What the very short set of directions said was to go to an auto parts store and get a Fiberglass patch kit. Follow the directions and glass in the two fittings in their appropriate locations.

The larger hole uses a 4" hole saw. Use a sharp saw and take you time. Rock the drill a little to help it cut. The smaller hole was just a hair larger than the standard hole saw (I don't remember the exact size) and I had to file the hole out a little bit to get it to fit. Just try and keep the hole round and check it often so it doesn't get too big.

The directions on the fiberglass patch kit (it came from Bondo) recommended for a standard repair to use 2 layers of cloth. I figured that would be about right for holding the rings in place. First sand the area, put down some resin, soak one of the pieces in the resin and place it over the fitting. Then place the second piece on top of that and coat it liberally with more resin. The resin seems to come off of the threads and the inside of the vent without too much hassle. I am a bit concerned that it may have come off too easily.

After the fiberglass dries, make sure you sand it down. Any edges of the fabric that are sticking up are extremely sharp.

I also purchased the new sensors for the detecting tank level.

I talked to the service person at Inland and he said to drill holes so that the sensors just go in (3/8" I think he said) and insert them. Tighten the nuts and they will seal. We discussed putting a second nut on each one to hold the wire in place.

We also discussed how to hold it in place. He recommended some cushioning on the bottom and a little bit to hold the sides in place. He also recommended using some of the padding that goes under laminate floors or a couple of layer of that red paper (also used under floors) for underneath the tank.

I don't have the steel pan that goes under the tank, I don't remember if it was there when I took the tank out originally, I don't think it was. I am contemplating putting down some of the left over vinyl flooring under the tank and have it come up on the sides part of the way, that should accomplish both keeping any potential leaks from making a mess inside the camper and cushioning the bottom of the tank.

I have to be careful not to raise the tank up by much or the waste valve won't go clear the floor. The Thetford valve fitting on the bottom of the tank is much closer to the tank than the old one was, making a potential interference with the thickness of the floor.

I also noticed that the tank isn't perfectly flat so I am going to shim the small area that doesn't quite sit on the floor so there is no tendency for it to rock back and forth.

This evening I finally go the tank into the correct position so that I can put the valve on. The new waste valve fitting is probably 1/4" farther from the edge of the tank than the old one is and it is very close to the frame. Now I have to rebuild the parts that will hold it in place and support the cover where the toilet goes.
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Old 07-10-2008, 07:24 AM   #6
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1965 28' Ambassador
Minnetonka , Minnesota
Join Date: Jul 2008
Posts: 17
OK, so that's what I got too. 2 rings and the tank....but still no instructions. I also talked to the Inland tech and he's guiding me thru this as well. He gave me the low down on "glassing" in the rings. Your description is exactly what he said.

I'm still debating on the sensor. We really don't do extended trips. Usually just weekends at local Bluegrass festivals. And there's just the 2 of us. Besides, the Misses usually makes me go out to the portapotties any way....must be an old couple thing. Mean while I'll look thru some of the threads on sensors and see where others have gone down the tubes with that.


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