Fix cracked tank? help

[Sirwalshalot]

Is this worth trying to salvage? I live in the Seattle area and I can't find anyone who does plastic welding. I've read a couple post about the harbor freight plastic welder but that is last resort. A new tank is 495 and I would prefer not toss this one if I can salvage it.

Thanks,
Ryan

[truxpin]

I may be wrong,so don't quote me on this.... But, I believe one cannot weld the tanks due to the type of plastic they are made from. Seeing the cost, hopefully I am wrong....

[A W Warn]

I think that tank is repairable.
It could be a DIY project, depending on your skills.
Plastic welding kits are available.
Google search will turn up some interesting video.

[lewster]

Contact URETHANE SUPPLY. They are the masters of plastic repair and have the tolls to help you perform the repair, along with the required techniques.

[Lumatic]

Since you can get at the tank I think the Harbor Freight plastic welder should be your first and best fix. If you have it out, remember it is a 40 year old tank. I had a similar split (from overfilling) last year and tried a spray on product like Flex-Seal. We will see if it holds up to TV commercial standards. I had to cut out a window in the plywood tank support to get at it. If that doesn't work I will have to drop the tank. If I have to go through the work of dropping the tank I may go with a new tank rather than a repair.

[JimGolden]

That looks like a pretty big crack. But, let me give you, just maybe, some good news:

3M makes a glue that will glue polyethylene. You won't see it at Home Depot or Lowes. You will need to find a 3M Sales Rep. It comes with this nifty neato squeeze tube that meters out the resin and the hardener in the exact ratio at the same time (a double barrel squeeze tube with different sized barrels).

The fresh water tank in my 34' had a crack in the top of the tank about an inch long. I got some white polyethylene sheet, about 1/4" thick, and cut a 3" by 3" square. I then roughened up the top of the tank where the crack was with sandpaper, and did the same to the 3x3 square, then glued them together with the 3M miracle glue. Ten years and 25,000 miles later, no problems of any kind.

I don't forget the ID number of it as it's been so long. You can probably Google it and find out. But, 3M does make a glue that will glue this tank.

Best of luck,

[Sirwalshalot]

Originally Posted by lewster

Contact URETHANE SUPPLY. They are the masters of plastic repair and have the tolls to help you perform the repair, along with the required techniques.

Thanks all for your response.

I will contact urethane supply and update the forum with what I choose to do.

Ryan

[Foiled Again]

Also - shop around for a replacement tank. That $495 sounds like it's coming from the factory. Truth? The factory contracts out for tanks - doesn't make them. So, do some Google searching IN and outside of the Forums. I've been reading here for a long time, and more than once someone found a custom tank maker who'd to a whole new tank for a fraction of the amount quoted by the dealer or factory.

Regarding patching - I too drank from the garden hose as a child - and rode a bike without a helmet - and never heard of a child safety seat until I was a teenager, so I tend to not be fanatical about using germacidal soap, etc. You're repairing a gray tank, so your only concern is that it not develop a sneaky leak any time soon. If anyone reads this thread and has a problem with the water supply (white) tank, take care with any sealant you use to make sure it's safe to use on a tank that holds drinking water.

Paula

[Belegedhel]

Check with Inca Plastics for a quote on the tank. They were the supplier of many of the tanks used in the 70's trailers, and they can probably make you one up exactly like what you have.

As for repairing that tank, I would guess it is a lost cause. I have one of the HF plastic welding kits and have played with it extensively. My conclusion is that it is extremely difficult, and technique sensitive to get a weld that is as strong as, say, a rotomolded corner. Your tank cracked because it is 40 years old. Even if you manage to repair that crack, it is pretty likely that it is ready to crack someplace else.

good luck

[Inland RV Center, In]

Originally Posted by Sirwalshalot

Is this worth trying to salvage? I live in the Seattle area and I can't find anyone who does plastic welding. I've read a couple post about the harbor freight plastic welder but that is last resort. A new tank is 495 and I would prefer not toss this one if I can salvage it.

Thanks,
Ryan

Ryan.

Yes, a replacement tank is not cheap, but neither is anything else for your 1973 Airstream.

That tank crack, because it's old. Repairing it is some what foolish in that it will continue to crack. When that happens, you then will go through the same issues as your having today.

When will another crack show up ? Most likely on a trip. Then, more problems will be added along with the tank problem. Welding old plastic tanks does not cure the fact that the tank is simply aged out, and will continue to crack. Best long term correction, is to replace the tank. Why ?? You then can kick the tank issue to the curb, and perhaps find something else to worry about.

Again, it's a large sum to correct, but so is, as another example, replacing the axles. But most owners are aware that torsion axles only last about 25 years, or even much less if the trailer was parked and not moved for a couple of years or more.

Owning an Airstream, in time, does cost money to keep it going, but most owners understand that when they purchased it. Maybe not in labor, but certainly with parts.

Andy

[e5earley]

I would attempt to fix it first. Other than your time and effort to install you have nothing to lose. I wouldn't invest in the harbor freight welder. The best I have found is a soldering iron used for stained glass.

I have welded quite a bit of plastic. Mostly atv fenders. Try to find an area of the tank where you can shave some plastic off. It will make the best filler material. The filler rods that come with the welding kits may be incompatible with the tank plastic. I would drill a small hole at end of crack to stop it from cracking further. Then use your iron to tack weld the crack every few inches. Then form a v in the crack with your iron. Now you can start using your filler material to weld the crack, pushing the plastic in from the sides of the v. Now you can check for leaks and fix any problem areas. The final step is where you'll get your strength. Take a piece of aluminum window screen cut larger than the crack area and using your iron, embed it into the plastic.

[Jacob D]

Many auto body shops now do plastic welding because so many cars have plastic fenders and bumpers.

[A W Warn]

Originally Posted by Belegedhel

Check with Inca Plastics for a quote on the tank. They were the supplier of many of the tanks used in the 70's trailers, and they can probably make you one up exactly like what you have.

good luck

I appreciate the information on Inca Plastics. That's a good source!

http://www.incaplastics.com/page15.html

[tjdonahoe]

I believe snap -on sells a plastic welding outfit, the harbor freight one is also good....

[dbj216]

I purchased my new gray and black water tanks from Inca Plastics. They took my order and delivered as promised. Download their on line catalog and see if they don't have the mold to make the tank you need.

David

[1970 Safari]

I did some research a while back and came across this product:

INSTA Holding tank repair
Bonds to all types of plastic

Made/Distributed by SR Specialty Recreation

Made in the USA (YEAH!!)

Part number IP48

The patch is 4x8 inches, I think there may have been other sizes.

I ordered it through the local RV supply house in my area (not Camping World).

I contacted the company and spoke with them about the ability of their product to adhere to the "slippery" plastics and was assured that it would perform well.

I followed the directions and cleaned the area for the patch really well. First with water and cleaner to remove the dirt and let it dry. Went back with lacquer thinner and cleaned it twice...I wanted it to really stick well...smile

Heated the area slightly with an industrial heat gun until just warm to the touch and applied the patch and rolled it well with a J-Roller (used to roll down various things in the building trade.

It has been holding on the top of my black water tank for over a year with no leaks, of course there is NO pressure to speak of on the top of the tank.

This saved me having to cut all my water lines to remove the tank. I did remove the toilet and the rotted support wood that caused the tank to flex when someone sat on the toilet leading to the crack.

The product was pricey, but the cost of new tank and the labor to R+R it was MUCH more!

Hope this helps

Rob

[Sirwalshalot]

Originally Posted by dbj216

I purchased my new gray and black water tanks from Inca Plastics. They took my order and delivered as promised. Download their on line catalog and see if they don't have the mold to make the tank you need.

David

How much did it cost? I emailed them last week and haven't heard back.

Ryan

[dbj216]

Hello Ryan,

IIRC I paid about $250 a tank. I purchased two 26 gallon "T" shaped tanks that I could hang from angle irons between the frame rails. Shipping the bulky tanks was expensive as you can imagine, but they were lightweight enough for UPS ground.

I thumbed through their PDF catalog until I found the tanks that would fit my Trade Wind. These tanks were only 17" wide and that would fit in the "narrow" frame bay beneath my selected toilet placement.

I recommend you find the tank that will fit your plans and then call them to place your order. That's what I did.

By the way, installing these waste water tanks was a BIG project for me. Belly pan and old insulation down, replumb the drain lines from bath sink, shower, kitchen sink, new toilet relocated to a spot between the frame rails, hang the tanks, determine the locations where the vents and drains enter the tanks, install SeeLevel senders, do the final assembly, install new Valterra drain valves and then test for leaks, and finally build a tank cover and run heat to the "tank compartment". Big, really big. Thank God the system works as planned.

David

[RumbleStrip]

Originally Posted by JimGolden

That looks like a pretty big crack. But, let me give you, just maybe, some good news:

3M makes a glue that will glue polyethylene. You won't see it at Home Depot or Lowes. You will need to find a 3M Sales Rep. It comes with this nifty neato squeeze tube that meters out the resin and the hardener in the exact ratio at the same time (a double barrel squeeze tube with different sized barrels).

The fresh water tank in my 34' had a crack in the top of the tank about an inch long. I got some white polyethylene sheet, about 1/4" thick, and cut a 3" by 3" square. I then roughened up the top of the tank where the crack was with sandpaper, and did the same to the 3x3 square, then glued them together with the 3M miracle glue. Ten years and 25,000 miles later, no problems of any kind.

I don't forget the ID number of it as it's been so long. You can probably Google it and find out. But, 3M does make a glue that will glue this tank.

Best of luck,

This is the comment I was hoping to find! Thank for the detailed answer. We are just uncovering our tanks and were wondering what to do if there were cranks or leaks.