| What are the stock black water tanks made of? [message #252929] |
Sun, 22 June 2014 12:50  |
Otterwan
Messages: 946
Registered: July 2013
Location: Lynnwood (north of Seattl...
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Looks to be ABS. Anyone know for sure? Need to repair a small hole and want to make sure I get the right stuff.
1977 Birchaven, Lynnwood WA - "We may not be able to stop all evil in the world, but I know that how we treat one another is entirely up to us."
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| Re: What are the stock black water tanks made of? [message #252940 is a reply to message #252929] |
Sun, 22 June 2014 14:42  |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
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Otterwan wrote on Sun, 22 June 2014 10:50Looks to be ABS. Anyone know for sure? Need to repair a small hole and want to make sure I get the right stuff.
Polyethylene plastic weld it for repairs generally a large soldering iron will work and a piece of polyethylene if you don't have a plastic welder
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: [GMCnet] What are the stock black water tanks made of? [message #252941 is a reply to message #252938] |
Sun, 22 June 2014 14:45 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
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emerystora wrote on Sun, 22 June 2014 12:36The GMC Manuals say they are polypropylene. Although someone had reported that early models might be polyethylene but I don't know if that is correct.
Emery Stora
77 Kingsley
Frederick, CO
On Jun 22, 2014, at 11:50 AM, David Orders wrote:
> Looks to be ABS. Anyone know for sure? Need to repair a small hole and want to make sure I get the right stuff.
> --
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. Wasn't you that said you used a milk bottle to repair one? I prefer a cutting board.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: What are the stock black water tanks made of? [message #252954 is a reply to message #252929] |
Sun, 22 June 2014 18:12 |
Galen
Messages: 146
Registered: November 2011
Location: New Virginia, IA
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I don't have any idea if mine is original or not, and I think most of us are in that boat, as who knows what refit tanks may have been added over the years. I asked the same question a couple years back, and got the same answers. I ended up using this info, and other websites like it: http://www.boedeker.com/burntest.htm
By doing the burn and float tests, I determined mine was PE, and was able to weld a patch in where the sending unit hole was, and weld another patch over it.
Galen Briggs
New Virginia, Iowa
1978 Palm Beach
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| Re: [GMCnet] What are the stock black water tanks made of? [message #252958 is a reply to message #252957] |
Sun, 22 June 2014 19:07 |
James Hupy
Messages: 6806
Registered: May 2010
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I have worked on many GMC tanks, both original and aftermarket. They are
plastic. Plastic, depending upon environmental effects, as well as what is
stored in them, has a finite life. That life varies somewhat with the
material that they are composed of, BUT, NONE OF IT LASTS MUCH OVER 30
YEARS. How old is your coach? Take the darn things out measure them
carefully and order them new. You will never regret having done so. If you
"Band Aid" them, I can assure you that you will be back under the coach
sooner than you want to be. But the choice is yours, it is your money,
spend it wisely on the things that are important to you. But for me, I
absolutely hate to mess with unsanitary plastic tanks. I much prefer to
start with a new tank, plumb it to the outlet and worry about something
else breaking. JWID.
Jim Hupy
Salem, OR (on the road with the Route 66 Rolling Rally
78 GMC Royale 403
On Sun, Jun 22, 2014 at 6:55 PM, Emery Stora wrote:
>
> On Jun 22, 2014, at 2:56 PM, David H. Jarvis wrote:
>
>> Someone wrote in the other day about using ABS Oatey? 3889L.
>>
> It might hold temporarily but it is not a permanent fix.
>
> Emery Stora
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| Re: What are the stock black water tanks made of? [message #252961 is a reply to message #252929] |
Sun, 22 June 2014 19:40 |
gbarrow2
Messages: 765
Registered: February 2004
Location: Lake Almanor, Ca./ Red Bl...
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David,
If you can get at the area needing repair without removing the tank I don't think it matters what the material is. If you go to any rv supply place or look on line you will find a "Holding tank Repair KIt" that consists of some fiberglass cloth, sand paper, and a tube of black goop(probably epoxy) for less than $50. I repaired a crack in the lower rear edge under the support brace on my 76 Palm Beach 12 years ago. took abour 12 hour and it has never leaked since. I used the same stuff to repair a leak in another coach I delivered for a new owner. As far as I know that repair has never failed in 5 years.
If, on the other hand, you need to remove the tank for any reason I would follow Jim Hupy's advice and just install a new one.
I had to remove the black tank on my 76 Eleganza to access the brake line "T" hidden behind it. Nothing was wrong with the tank(other than age); but since it was out I replaced it with a new one.
I'm a certified cheapskate and will save a nickel whenever I can. But I absolutely abhor paying for anything twice.
Gene Barrow
Lake Almanor, Ca.
1976 Palm Beach
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| Re: What are the stock black water tanks made of? [message #252962 is a reply to message #252929] |
Sun, 22 June 2014 19:42 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
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If you have the tank out you could cut a little of the excess off it and melt it to the hole or crack that way you can be sure you have the correct material. According to the chart Galen posted mine is not polypropylene as it was easy to set on fire and it didn't have an acidic odor.
Roy Keen
Minden,NV
76 X Glenbrook
[Updated on: Sun, 22 June 2014 23:37] Report message to a moderator |
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| Re: What are the stock black water tanks made of? [message #253007 is a reply to message #252929] |
Mon, 23 June 2014 10:10 |
Dennis S
Messages: 3046
Registered: November 2005
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Otterwan wrote on Sun, 22 June 2014 12:50Looks to be ABS. Anyone know for sure? Need to repair a small hole and want to make sure I get the right stuff.
Same reply to several threads on black tank material ...
I have mentioned this before -- when I took my original black tank (1973) to the plastic tank shop I told them it was polypropylene per the manual. But they determined it was polyethylene when they welded new bungs on the top.
Dennis
Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: What are the stock black water tanks made of? [message #253032 is a reply to message #252929] |
Mon, 23 June 2014 15:26 |
bwevers
Messages: 597
Registered: October 2010
Location: San Jose
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As a temporary fix, I used Oatley ABS glue on mine. It's still holding after 2 years (Knock on wood).
There's not too much pressure in there to make it leak.
Regards,
Bill
Bill Wevers GMC49ers, GMC Western States
1975 Glenbrook - Manny Powerdrive, OneTon
455 F Block, G heads
San Jose
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| Re: What are the stock black water tanks made of? [message #253035 is a reply to message #253019] |
Mon, 23 June 2014 15:31 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
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A Hamilto wrote on Mon, 23 June 2014 11:25Otterwan wrote on Sun, 22 June 2014 12:50Looks to be ABS. Anyone know for sure? Need to repair a small hole and want to make sure I get the right stuff. My maintenance manual says:
"WATER TANK REPAIR
The tank is manufactured from polypropylene plastic. Except for small, clean punctures the tank is not repairable . Polypropylene resists all common adhesives that may be used in patching or plugging. However, on small punctures a Well-Nut may be used. Enlarge the hole enough to insert the Well-Nut and tighten enough to close up the hole to make it waterproof."
Probably the right advice but I fixed a 6" crack in my holding tank with a welding torch and a soldering iron along with a hunk of poly to melt into it. The damage was from putting in body pads that were too thick. I even had to lower the tank some as the dump line wouldn't fit thru the frame . I think they may be referring to the fresh water tank tho.
Roy Keen
Minden,NV
76 X Glenbrook
[Updated on: Mon, 23 June 2014 15:35] Report message to a moderator |
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