Dan's '66 Tradewind Improvements

[TouringDan]

I DRILLED A HOLE IN MY GRAY WATER TANK

Boy do I feel stupid. I filled up my "street cleaning" gray water tank to see how long it would take to empty through the 3/4" ball valve and when I looked underneath the Airstream my heart sank. Water was leaking out of the belly pan under the gray water tank. At first I asked myself how this could be. I had leak tested the tank before I installed it. Well it was a good thing that I thought about removal of the belly pan when I installed it. I figured that I may need to do this some time, but I figured it would be years later, not days later! Anyhow it only took 15 minutes or so to remove all 15-20 of the large flange 3/16" pop rivets and get the belly pan out of the way. There it was, a hole in the belly pan. If it had been about 1/4" further away from the belly pan it would have missed it (photo 1- sorry upside down).

So how to fix this? I had a bit of experience here. I had a crack in my polyethylene fresh water tank and tried to fix it with epoxy. It did not work. I went ahead and replaced the fresh water tank. I now carry the empty fresh water tank in the back of my truck when we go camping. It is much easier to fill than moving the trailer. I went to the auto repair store and looked at the epoxies. They all said their product works on all plastics except polyethylene. I went to the internet and learned that the only way to fix it is to weld it. I see that I can go to Harbor Freight and buy a cheap welder for $16.99. The problem is that it does not come with polyethylene filler which you have to have for this to work. I can get polyethylene welding material for $10.99 from Amazon. This is how I will fix it if my first option does not work. That option is to try TremPro 635. It is a polyethylene caulk that is incredibly sticky and I want to try this first. I have applied the first coat to the hole and the surrounding area (photo 2). I then will put two more coats on and use screen material to strengthen the patch. In a week or so I will test it to see if it leaks. If no leaks, I will install the belly pan. If some time in the future it leaks, I will remove the belly pan again and weld the leaking area once and for all. I just want to try this other option to see if it works- just curious.

All in all, a much easier problem to fix than i initially figured.

Dan

[rasmuw]

If your repair does not work well, try this product:

http://www.plastex.net/index.php

There's a dropdown menu with polyethylene repair.

[dbj216]

You are not the first forums who have had this problem. Misery loves company, right? You assessment of polyethylene is correct. There are very few adhesives that will stick to it.

I worked in a rotomolding shop for 4 years. We "reworked" a lot of polyethylene tanks with a "welder". Actually not much more than a soldering iron. The polyethylene is a thermoplastic material that will fuse with new material and be as good as original. I think the melt temp is around 400F. We would heat the sides of the hole until it was quite droopy, and then take a stick of polyethylene and add material to it until the hole was closed up. It was a glob of plastic. But we could shave it flat again, no problem. I believe ABS plastic is the same way. Some Airstreamers build their own tanks out of ABS sheets and weld the seams.

If I recall correctly, the waste water tank in the 66 Trade Wind was a two piece tank. It had a thermoformed bottom and sides, and then a lid "welded" to the "pan". I don't know what the material was, but it didn't look like polyethylene to me. The freshwater tank in my Trade Wind did look like polyethylene.

Inca Plastics in California is one of the original rotomolders, I believe invented the "spinweld" process, and supplies the RV industry with scads of water tanks, including supplying Airstream way back then. I mention them as I saw "How to repair a polyethylene tank" drop down on their website.
Here is a link. It may help you. I plan on buying new black and gray tanks for my 75 Overlander from Inca Plastics.

http://www.incaplastics.com/

At least you can consider your waste water tank "holy" now.

David

PS: Here is a photo of the black tank I dug out of my 75 Overlander. The toilet flange mounting "spinweld" must have failed through the years. Some owner tried a fiberglass patch. It didn't work.

[TouringDan]

Originally Posted by rasmuw

If your repair does not work well, try this product:

http://www.plastex.net/index.php

There's a dropdown menu with polyethylene repair.

Thanks Wayne. I will keep that product in mind. However if my home brew patch does not work, I will probably just go ahead and weld up a patch for the hole because I know this will work. BTW, I did look at the pull down menu for a polyethylene repair and the patch kit #3000 was like $49 unless I missed something. Yikes! Have you used this product?

I did put a second coat of Trempro 635 on my patch along with some fiberglass drywall tape to give it some strength (see photo). I believe my patch will work, but at the same time I am not very confident. If it does not work I will do a plastic polyethylene weld to seal the hole permanently.

Thanks again for your suggestion.

Dan

[TouringDan]

Originally Posted by dbj216

The polyethylene is a thermoplastic material that will fuse with new material and be as good as original. I think the melt temp is around 400F. We would heat the sides of the hole until it was quite droopy, and then take a stick of polyethylene and add material to it until the hole was closed up. It was a glob of plastic. But we could shave it flat again, no problem.

If I recall correctly, the waste water tank in the 66 Trade Wind was a two piece tank. It had a thermoformed bottom and sides, and then a lid "welded" to the "pan". I don't know what the material was, but it didn't look like polyethylene to me. The freshwater tank in my Trade Wind did look like polyethylene.

Inca Plastics in California is one of the original rotomolders, I believe invented the "spinweld" process, and supplies the RV industry with scads of water tanks, including supplying Airstream way back then. I mention them as I saw "How to repair a polyethylene tank" drop down on their website.
Here is a link. It may help you.

David

David

Thanks so much for verification that polyethylene tank holes can be welded to repair them and also explaining the technique used.

My gray water tank looks to me to be a one piece tank (see photo) but I really don't know as I know nothing about plastic tank construction. The photo also shows the cross member support and the front of the bumper cover that fits between the cross member and the bottom of the floor. This is the culprit that carries water from the front of the bumper cover to the floor and rots it out unless the joint between the front of the bumper cover and the rear exterior panel of the Airstream is caulked properly using Trempro 635.

[rasmuw]

Originally Posted by TouringDan

Have you used this product?

No. It's a product I read about on a BMW forum I frequent. All the broken ABS plastic on my car was repaired with Plast-Aid, which is similar to the basic Plastex kit. The polyethylene kit is a different setup.

[dbj216]

Hi Dan: I'd give your Tempro patch a shot. The gray tank is rather small and doesn't have a lot of water weight on it. And if you starting seeing drips from the belly pan and it isn't raining, all you're out is some time a belly pan rivets. You likely can "weld" the hole shut with the tank in place. You're good at working on your back.

The reason I question the tank material and process is that flange around it where you mounted it to the subfloor (good idea). You can't rotomold a flange like that. Rotomolding makes hollow parts. It is difficult to make a solid feature as the plastic powder just doesn't like to flow into tight cavities in the mold. That flange made me think the bottom of the tank was thermoformed with a flange, and then a top "welded" to the flange. Airstream is big in thermoformed parts. Just look in your bathroom: sink and tub for sure. My Overlander bath is all thermoformed ABS plastic. Light, cheap molds, pretty strong, flexible, and low cost. What's not to like?

David

[TouringDan]

BATHROOM CLOSET SHELVES

I decided to add 2 shelves to the bathroom closet above the water heater. I also needed to replace one of the pie shaped shelves in the left cabinet that had self destructed after 52 years and the top of the cabinet that was water damaged by a leak from the bathroom vent (see photo).

I used some nominal 1/4" maple plywood from Lowes. It was about $25 for a sheet. I am sure that I will need to replace/add some more shelves for the Tradewind.

David- I agree with you completely about my polyethylene home brew patch and the construction of the gray water tank. It makes sense.

Dan

[dbj216]

Funny, just today I decided to take out two shelves in my Overlander bath cabinet. I figured the DW would want the hanging space for bathrobes and the like. The Overlander has a lot of storage space in the overhead lockers, behind the vanity mirror, and a shelf under the sink. Plenty of space for a safety razor and tube of toothpaste. What else does a guy need?

David

[TouringDan]

WET FLOOR REPAIR

I needed to move the water pump slightly to make room for installing the disk brake hydraulic pump. This started another sequence of project creep. The fresh water tank is located under the front window behind the gaucho. I first noticed that the floor by the pump and next to the water tank was wet. I found that the cause was a leak at the inlet to the tank. The flexible white hose that feeds water to the tank (photo 1) had loosened up over time. This evidently has been leaking for a while. This is a real problem as we boondock mostly and even if we have public water available we usually just use the fresh water tank and pump. So every time we go camping we fill up the tank and since the inlet has been leaking the water goes right onto the floor. I removed the gaucho frame, the bottom of which was very wet. Of course I need to repair the gaucho frame now. Under the gaucho was some green patterned vinyl. The plywood floor under the vinyl was very wet (see first photo). The wet floor extended to the right gaucho panel which had damaged the bottom (photo 2). The water had also gotten under the cork floor that was in front of the right side of the gaucho and damaged the flooring causing a gap between the floor tiles (photo 3).

When I installed the cork floor (posts 3-7), I applied 3 coats of polyurethane to the plywood to protect it. What I learned is that any water that gets on the polyurethaned plywood floor will not penetrate the plywood but will be absorbed by the cork floor base and will damage it. The cork floor base seems to be like particle board. I am glad that I sealed the plywood floor. This just means that the water will damage the floor covering and not the plywood floor. So I have applied 3 coats of polyurethane to the plywood floor that will be under the gaucho and the fresh water tank and the pump area (photo 4). I now need to install some new cork flooring. I bought a little extra; I hope I have enough and that it matches ok.

Note that the square hole in the floor is a cold air return to the furnace. There is also one in the bathroom.

Dan

[dbj216]

Project creep is so typical of vintage Airstreams. I had to patch the floor close to the water pump on my Trade Wind some years ago. It has the same cold air return as your trailer.

Just this week, while removing the old reciprocating water pump in the Overlander, I discovered floor rot in front of the curb side wheel well. That's going to be a big project to repair. The galley cabinet is in the way along with the sink drain plumbing. Ugh.

I know you will whip this project out in no time flat.

David

[rasmuw]

Originally Posted by TouringDan

I commented earlier on Airstream's method of supporting the gray tank was to install a metal pan under the tank that would rust out over time.

Dan--I'm revisiting the attachment of the black tank (gray tank in your renovation) since I am now attaching plywood to the frame and want to install gray and black tanks in the process. Was your original metal pan made of galvanized steel or something else? What gauge was it?

[dbj216]

Hi Wayne: I'll bet Dan's and my black tank pans were the same galvanized steel. It was quite thin, maybe less than 18 gauge. It was also quite rusted.

David

[TouringDan]

Originally Posted by dbj216

Hi Wayne: I'll bet Dan's and my black tank pans were the same galvanized steel. It was quite thin, maybe less than 18 gauge. It was also quite rusted.



David

David & Wayne

I was hoping that you (David) would chime in as I thought mine was galvanized steel that had rusted but I had no idea about the thickness.
In looking at your photo I see that it was bolted to the floor. I will never understand why Airstream did not just bolt or screw the black tank flange to the floor. This is what I did. I just see no reason for a pan.

Dan

[dbj216]

Possibly one reason for the pan was to insulate the tank "compartment" and heat it. I did have a "cold air return" passage through the tank pan. Another reason is some protection from road debris.

When the floor rot took over, my tank pan fell into the belly pan. The previous owner bolted a piece of pipe to the frame trying to hold the whole mess up off the road.

I agree with Dan that the tank flange is adequate to hold the Trade Wind tank up as long as the plastic hasn't become brittle with age.

Newer rotomolded tanks don't have flanges as it is not possible with the process. Airstream often used the tank pan as the support for the tank. My 86 black and gray tanks are supported by the tank pan only. (Well, the toilet flange connection, vent pipe connections, and drain pipe connections also kinda, sorta support the tank.)

David

[rasmuw]

Dan and David--thanks for your thoughtful replies.

The black tank I hope to use came out of a '68 Sovereign I scuttled a few years ago. I can't remember what the pan looked like, but I'm sure it wasn't in good condition or I would have kept it. Today I retrieved the white bead styrofoam base that was below the tank. It's in reasonably good condition, so I placed it underneath the tank and measured the total height: 7 3/4". This certainly won't work unless I take an electric knife or another device to the foam. The dimension required for my '67 is 6 5/8".

I found a picture of a '67 or '68 pan, and it didn't even have the flanges as the '66 did. The support for the tank was a thin piece of galvanized steel set on two 1" angles about 58" wide. The foam probably spread the weight out to an extent, but how much? The whole system doesn't seem up to a 16 gallon tank, but they did last until the pan rusted so I guess Airstream knew what they were doing.

The second option is to screw it to the floor as Dan did. Was the top of the tank originally touching the underside of the floor? I'd like to make sure I don't have to worry about the toilet flange being too high.

The third option is a new tank, which would help getting the waste plumbing to the curbside as David did to his '66.

[dbj216]

Tank position relative to the floor depends on the toilet flange connection to the tank. Many old tanks have a female pipe thread spin weld in the correct location on top of the tank. The toilet flange male pipe fitting threads into this spin weld, and then is screwed to the 3/4" subfloor. The clearance hole in the subfloor accommodates the toilet flange and spin weld clearance.

I think I counted 11 different toilet flange configurations on the Vintage Trailer Supply site last month.

Once you have a toilet flange and tank connection that works, then you can determine if the tank bears tight to the subfloor bottom or if you need more clearance, like a piece of 1/2" plywood or something.

I've seen styrofoam around waste water tanks in all three Airstreams I've torn into. I assumed it was cheap insulation, not a tank support. And all three trailers have had a tank pan either to contain the heat, or to support the tank.

My Trade Wind tank has some sort of steel bulkhead connection to the top of the tank. I think the toilet flange held the tank in position pretty well. I also think the tank was way too thin. The tank pan didn't have much weight to carry. The toilet was some sort of complicated affair of slide valves and plumbing. I bet it weighed 50 pounds.

So Dan, being the logical type, says heck with a flush toilet and tank and goes for the Curve.

David

[TouringDan]

Originally Posted by dbj216

I also think the tank was way too thin. The tank pan didn't have much weight to carry. The toilet was some sort of complicated affair of slide valves and plumbing. I bet it weighed 50 pounds.

So Dan, being the logical type, says heck with a flush toilet and tank and goes for the Curve.

David

I really strive for simple and light. That is the Curve toilet plus no need for a black tank.

I think the original tank will be fine for us, but it doesn’t hold very much water- about 16 gallons. I can always replace it at some time in the future. It will be easy enough to remove the belly pan under the tank and just replace the tank. I will probably go with a custom made tank, maybe even make it myself. I think it will hold about 30 gallons. I would have a 2” outlet so it could tie into the 2” drain line from the shower and sinks.

I actually have the belly pan under the tank removed now as I am trying to stop a persistent drip from the outlet valve. I have a video but it doesn’t seem to want to load.

Dan

[dbj216]

TouringDan: You ain't gonna make it big in Hollywood as a producer if you think your video of a leaky valve going drip, drip, drip will go viral. It's like watching corn grow or paint dry. Not the most exciting show around.



David

[TouringDan]

David

You are correct. Probably a good thing it did not load.

It is frustrating though. I installed the new gate valve on the gray water tank and now it drips a bit. I am just really mad at myself that I didn’t test it before I installed the tank. My error.

Dan