Home » Public Forums » GMCnet » Water Tank fitting
Water Tank fitting [message #258231] |
Fri, 08 August 2014 21:43 |
thorndike
Messages: 406 Registered: January 2011 Location: Conifer, Colorado
Karma: 0
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Howdy all!
As you can see from this picture, the water fill tube leading to my water tank is not effectively connected.
For those that don't see the picture inline, the link is here: http://i.imgur.com/u5Cuayt.jpg
If you can't tell from the image, a PO took a standard PVC elbow and used a mess of silicone caulk to hold it in place. You can see the remains of what appears to be duct tape that was used to hold the fill tube to the water tank.
I would like to fix this in such a way that the fill tube is mechanically connected to the tank. Unfortunately, there isn't a large access hole on the top so I am unable to reach the inside of the tank. Has anyone solved this issue? If so, how?
Thanks,
Bob
Robert Peesel
1976 Royale 26'
Side Dry Bath
Conifer, Colorado
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Re: [GMCnet] Water Tank fitting [message #258232 is a reply to message #258231] |
Fri, 08 August 2014 21:53 |
powerjon
Messages: 2446 Registered: January 2004
Karma: 5
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Senior Member |
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Bob,
Get one of these Deck plates from West Marine.
or
http://goo.gl/Dr0vHQ
And mount it on the top of your water tank. This will allow you to get to the inside of the tank for cleaning as well as allowing you to repair your water inlet.
JR Wright
78 Buskirk Stretch
75 Avion
Michigan
On Aug 8, 2014, at 10:43 PM, Robert Peesel wrote:
> Howdy all!
>
> As you can see from this picture, the water fill tube leading to my water tank is not effectively connected.
>
> For those that don't see the picture inline, the link is here: http://i.imgur.com/u5Cuayt.jpg
>
> If you can't tell from the image, a PO took a standard PVC elbow and used a mess of silicone caulk to hold it in place. You can see the remains of
> what appears to be duct tape that was used to hold the fill tube to the water tank.
>
> I would like to fix this in such a way that the fill tube is mechanically connected to the tank. Unfortunately, there isn't a large access hole on
> the top so I am unable to reach the inside of the tank. Has anyone solved this issue? If so, how?
>
> Thanks,
>
> Bob
> --
> Robert Peesel
>
> 1976 Royale 26'
>
> Side Dry Bath
>
> Sterling, Va
> _______________________________________________
> GMCnet mailing list
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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Re: Water Tank fitting [message #258242 is a reply to message #258231] |
Fri, 08 August 2014 23:37 |
lotsofspareparts
Messages: 726 Registered: May 2014 Location: Arlington, WA
Karma: -9
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Senior Member |
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Don't do it, not with that type of deck plate. They are certainly not water tight regardless of what the listing says.
We use the exact plate at work and at best they are "water resistant". P.S. I do open hull assembly for Ranger Tugs.
If you fill your tank to the top, it will leak I guarantee it.
If it were me, I would walk the plumbing aisle at Lowes or Home Depot.
If you can find a 90 fitting that is male threaded and a base that is female threaded you can use 3M 5200 fast cure sealant as a gasket and screw the assembly to the tank with 316 SS sheet metal screws. I had to do this to a TT that I owned but can not for the life of me remember what the threaded plate was called, they were both a PVC material.
My 2 cents.
Jared
Jared & Tina Lazaron + 14yr old Daughter.....
77 Eleganza II "Recherché".....
73 Canyon Lands 230 "Elephant"
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Re: [GMCnet] Water Tank fitting [message #258256 is a reply to message #258242] |
Sat, 09 August 2014 09:24 |
powerjon
Messages: 2446 Registered: January 2004
Karma: 5
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Senior Member |
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Jared,
This mod or fix has been done by Rob Mueller, me and a number of others.
or
http://goo.gl/kdZQzO
The water tank in a GMC in not where it is exposed to the elements nor is it subject to mechanical abuse or walked upon. It is an atmospheric pressure tank with a vent to the outside. The example shown in the email I sent to purchase may not have been the best one to use. I went out and looked at the one that I got for the Avion and it is the same that Rob used this may be a better choice. This one has a rubber O-ring which creates a watertight seal. Maybe Rob will chime in here an tell if he has ever had any issues with water leaking from the top of his tank, I know I haven’t when I tested it after assembly.
or
http://goo.gl/ADLmLe
Just my experience with this application, yours may vary.
JR Wright
78 Buskirk Stretch
75 Avion
Michigan
On Aug 9, 2014, at 12:37 AM, Jared wrote:
> Don't do it, not with that type of deck plate. They are certainly not water tight regardless of what the listing says.
>
> We use the exact plate at work and at best they are "water resistant". P.S. I do open hull assembly for Ranger Tugs.
>
> If you fill your tank to the top, it will leak I guarantee it.
>
> If it were me, I would walk the plumbing aisle at Lowes or Home Depot.
>
> If you can find a 90 fitting that is male threaded and a base that is female threaded you can use 3M 5200 fast cure sealant as a gasket and screw the
> assembly to the tank with 316 SS sheet metal screws. I had to do this to a TT that I owned but can not for the life of me remember what the threaded
> plate was called, they were both a PVC material.
>
> My 2 cents.
>
> Jared
> --
> Jared & Tina Lazaron + 7yr old Daughter.
>
> 77 Eleganza II "Recherché" Winterfeldt 455, Holley ProJection, Doug Thorley Headers, 3in exhaust, Switch Pitch, Alcoas, ONAN 6.5 Emerald series, CMC
> Restoration
>
> GO SEAHAWKS!!
>
> Arlington, WA 98223
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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Re: Water Tank fitting [message #258258 is a reply to message #258231] |
Sat, 09 August 2014 09:51 |
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Matt Colie
Messages: 8547 Registered: March 2007 Location: S.E. Michigan
Karma: 7
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Senior Member |
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thorndike wrote on Fri, 08 August 2014 22:43Howdy all!
As you can see from this picture, the water fill tube leading to my water tank is not effectively connected.
For those that don't see the picture inline, the link is here: http://i.imgur.com/u5Cuayt.jpg
If you can't tell from the image, a PO took a standard PVC elbow and used a mess of silicone caulk to hold it in place. You can see the remains of what appears to be duct tape that was used to hold the fill tube to the water tank.
I would like to fix this in such a way that the fill tube is mechanically connected to the tank. Unfortunately, there isn't a large access hole on the top so I am unable to reach the inside of the tank. Has anyone solved this issue? If so, how?
Thanks,
Bob
Bob,
You have lots of problems there. (News Flash - Huh?)
By the color, I would guess that the tank was polyethylene. Nothing will stick to it without preparation.
The deck plate JR suggested might work without help, but only if it is mounted to a solid substrate. The tank goes not qualify. It may still weep if the tank is pressed up.
3M5200 will stick to the tank with "flame treatment" I will explain below, but it cannot be counted on for a long term leak-tight seal. It is also not listed as drinking water safe.
There are rubber tank grommets used in waste tanks, but I do not believe that any are drinking water safe. They are also planned only for the top of waste tanks.
For your consideration: (Thinking is the most cost effective thing to do.)
All are best if you can remove the tank and work on it in clear space.
First suggestion - Try to locate a local plastic fabricator to weld in a threaded bushing.
Second suggestion - See if you can get a large enough pipe tap and possibly thread the tank wall. You may be able to borrow a tap that size if you have a plumber-friend. Put air in the tank while tapping to blow the chips out. Use only teflon based thread paste and screw the new fitting in only hand tight.
Third suggestion - Yes, deckplates may leak, but notice this is the last suggestion. Get a deckplate. Drill it to accommodate 3 times as many screws as it was made to accept. Use only stainless (8-18) screws. Cut the tank top and Flame Treat the tank where the flange will sit. Find a drinking water safe sealant - 3m5200 is not one of those. Stick the flange in and then go find a rubber sealed bulkhead fitting for the tank wall.
About Flame Treating - This is what you do to paint or stick (non-structural) things to PE and PP things.
Mark the area that needs to be stuck to with something other than a grease pencil. This doesn't need to last long, but you need to see it to start. Take a propane torch and play it over the required area enough so you can see a change in surface texture and/or color. Let it cool. To test, drip water both inside and outside the treated area. There should be significant difference in the wetting properties. If you can not see this, do it again.
What you have just done is slightly burn the surface. So, now the surface that was poly-whatisit is no longer that material, but that surface is still part of the original material. Kind of like making it into primer.
Were I you, I would try real hard to stop at number one.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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Re: Water Tank fitting [message #258271 is a reply to message #258258] |
Sat, 09 August 2014 12:06 |
lotsofspareparts
Messages: 726 Registered: May 2014 Location: Arlington, WA
Karma: -9
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Senior Member |
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Matt Colie wrote on Sat, 09 August 2014 07:51thorndike wrote on Fri, 08 August 2014 22:43Howdy all!
As you can see from this picture, the water fill tube leading to my water tank is not effectively connected.
For those that don't see the picture inline, the link is here: http://i.imgur.com/u5Cuayt.jpg
If you can't tell from the image, a PO took a standard PVC elbow and used a mess of silicone caulk to hold it in place. You can see the remains of what appears to be duct tape that was used to hold the fill tube to the water tank.
I would like to fix this in such a way that the fill tube is mechanically connected to the tank. Unfortunately, there isn't a large access hole on the top so I am unable to reach the inside of the tank. Has anyone solved this issue? If so, how?
Thanks,
Bob
Bob,
You have lots of problems there. (News Flash - Huh?)
By the color, I would guess that the tank was polyethylene. Nothing will stick to it without preparation.
The deck plate JR suggested might work without help, but only if it is mounted to a solid substrate. The tank goes not qualify. It may still weep if the tank is pressed up.
3M5200 will stick to the tank with "flame treatment" I will explain below, but it cannot be counted on for a long term leak-tight seal. It is also not listed as drinking water safe.
There are rubber tank grommets used in waste tanks, but I do not believe that any are drinking water safe. They are also planned only for the top of waste tanks.
For your consideration: (Thinking is the most cost effective thing to do.)
All are best if you can remove the tank and work on it in clear space.
First suggestion - Try to locate a local plastic fabricator to weld in a threaded bushing.
Second suggestion - See if you can get a large enough pipe tap and possibly thread the tank wall. You may be able to borrow a tap that size if you have a plumber-friend. Put air in the tank while tapping to blow the chips out. Use only teflon based thread paste and screw the new fitting in only hand tight.
Third suggestion - Yes, deckplates may leak, but notice this is the last suggestion. Get a deckplate. Drill it to accommodate 3 times as many screws as it was made to accept. Use only stainless (8-18) screws. Cut the tank top and Flame Treat the tank where the flange will sit. Find a drinking water safe sealant - 3m5200 is not one of those. Stick the flange in and then go find a rubber sealed bulkhead fitting for the tank wall.
About Flame Treating - This is what you do to paint or stick (non-structural) things to PE and PP things.
Mark the area that needs to be stuck to with something other than a grease pencil. This doesn't need to last long, but you need to see it to start. Take a propane torch and play it over the required area enough so you can see a change in surface texture and/or color. Let it cool. To test, drip water both inside and outside the treated area. There should be significant difference in the wetting properties. If you can not see this, do it again.
What you have just done is slightly burn the surface. So, now the surface that was poly-whatisit is no longer that material, but that surface is still part of the original material. Kind of like making it into primer.
Were I you, I would try real hard to stop at number one.
Matt
Bob,
The first suggestion is the best one.
18-8 stainless fasteners are junk and are only intended to be used during interior marine construction or such that they will not be exposed to the elements. Stick with 316 stainless as I mentioned above.
Matt is also correct that 3M 5200 is not recommended for use on a potable water system, the views on this can vary from person to person as I believe there is no harm in using it as a gasket material just so long as there isn't globs of it sitting on the bottom of my water tank.
Contrary to what some believe 3M5200 WILL in fact stick to PE provided it is used as a gasket and is secured. My only prep was to clean with Acetone.
And lastly, regardless of what sealant is used we never DRINK the water out of our potable water system, and I have a stainless water tank. Yuck!! We shower with it and do dishes and that is pretty much it, otherwise it is bottled water.
Jared
Jared & Tina Lazaron + 14yr old Daughter.....
77 Eleganza II "Recherché".....
73 Canyon Lands 230 "Elephant"
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Re: Water Tank fitting [message #258333 is a reply to message #258271] |
Sat, 09 August 2014 22:34 |
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Matt Colie
Messages: 8547 Registered: March 2007 Location: S.E. Michigan
Karma: 7
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Senior Member |
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lotsofspareparts wrote on Sat, 09 August 2014 13:06Bob,
The first suggestion is the best one.
18-8 stainless fasteners are junk and are only intended to be used during interior marine construction or such that they will not be exposed to the elements. Stick with 316 stainless as I mentioned above.
Matt is also correct that 3M 5200 is not recommended for use on a potable water system, the views on this can vary from person to person as I believe there is no harm in using it as a gasket material just so long as there isn't globs of it sitting on the bottom of my water tank.
Contrary to what some believe 3M5200 WILL in fact stick to PE provided it is used as a gasket and is secured. My only prep was to clean with Acetone.
And lastly, regardless of what sealant is used we never DRINK the water out of our potable water system, and I have a stainless water tank. Yuck!! We shower with it and do dishes and that is pretty much it, otherwise it is bottled water.
Jared
Jared,
I know you have been doing some boat work, but you are not counting on the fact that the screws are going into a potable water tank, and as such they will be just fine for decades....
According to 3M's 5200 MSDS, it contains two kinds of iso-cyanates. Not something I would even want to wash with and the will leach out in fresh water.
I have, on several occasions now, disassembled PE holding tanks (in boats) where I could removed the flange that the manufacturer put on and then peal off the 3m5200 (that is what the manufacturer told me they used) as cleanly as if it were a rubber gasket. I redid the joint by flame treating and have not had any returns in seven years. The original only lasted two at best.
We do drink out of the potable tank. We have a 23 and do not have for storage or disposal of that much bottled water. Instead, I like to regularly clean the system with H2O2 or Ozone (not O3 but O++) and we think the tanked water is great and it cost a lot less.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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Re: Water Tank fitting [message #258335 is a reply to message #258242] |
Sat, 09 August 2014 23:07 |
Otterwan
Messages: 946 Registered: July 2013 Location: Lynnwood (north of Seattl...
Karma: 0
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Senior Member |
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lotsofspareparts wrote on Fri, 08 August 2014 21:37Don't do it, not with that type of deck plate. They are certainly not water tight regardless of what the listing says.
We use the exact plate at work and at best they are "water resistant". P.S. I do open hull assembly for Ranger Tugs.
If you fill your tank to the top, it will leak I guarantee it.
Jared
Jared - My aluminum landing craft has a self bailing deck and is designed to run completely awash. Meaning I often have 2" to 8" of water on deck. It has a sealed 3 chambered hull, each chamber has one of those deck plates. I've never had any water get in. I do checked them after each use, and clean and lube the o-rings with Dow 111 Silicone Grease. I realize that you are talking about water getting out while I am talking about water getting in, but I wouldn't think that would matter.
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: Water Tank fitting [message #258337 is a reply to message #258333] |
Sat, 09 August 2014 23:17 |
lotsofspareparts
Messages: 726 Registered: May 2014 Location: Arlington, WA
Karma: -9
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Senior Member |
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[quote title=Matt Colie wrote on Sat, 09 August 2014 20:34Jared,
I know you have been doing some boat work, but you are not counting on the fact that the screws are going into a potable water tank, and as such they will be just fine for decades....
[/quote]
Not doing some boat work, I have been building $300k-$700k yachts from 29' up to 43' for almost 10 years. 18-8 fasteners will not rot as long as they are allowed to oxidize continuously which means they must constantly be exposed to air. They can not oxidize under water and they will rot. It is really easy to spot manufacturers that use 18-8 fasteners on the exterior of their boats, they all have rust trickling from the base of the screw and those are subjected to rain water and wash water. They will rot eventually. For the few extra cents per screw, I prefer 316.
Jared
Jared & Tina Lazaron + 14yr old Daughter.....
77 Eleganza II "Recherché".....
73 Canyon Lands 230 "Elephant"
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Re: Water Tank fitting [message #258338 is a reply to message #258335] |
Sat, 09 August 2014 23:26 |
lotsofspareparts
Messages: 726 Registered: May 2014 Location: Arlington, WA
Karma: -9
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Senior Member |
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Otterwan wrote on Sat, 09 August 2014 21:07lotsofspareparts wrote on Fri, 08 August 2014 21:37Don't do it, not with that type of deck plate. They are certainly not water tight regardless of what the listing says.
We use the exact plate at work and at best they are "water resistant". P.S. I do open hull assembly for Ranger Tugs.
If you fill your tank to the top, it will leak I guarantee it.
Jared
Jared - My aluminum landing craft has a self bailing deck and is designed to run completely awash. Meaning I often have 2" to 8" of water on deck. It has a sealed 3 chambered hull, each chamber has one of those deck plates. I've never had any water get in. I do checked them after each use, and clean and lube the o-rings with Dow 111 Silicone Grease. I realize that you are talking about water getting out while I am talking about water getting in, but I wouldn't think that would matter.
Your aluminum 3 chambered hull is sealed with ABS twist on deck plates with that little 1/8 rubber gasket and 6 #8 SMS fasteners......
Hmmm, that sounds a bit fishy to me and certainly doesn't sound like it would have come that way from the manufacturer
I would imagine a craft like that would have 5in-6in inspection plates made from aluminum and secured with 6-8 1/4-20 flat head MS fasteners.
That seems odd to me.
Jared
Jared & Tina Lazaron + 14yr old Daughter.....
77 Eleganza II "Recherché".....
73 Canyon Lands 230 "Elephant"
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