Visit our Popular Forums

Re-Pete · 03-16-2020, 03:12 PM

I've f'd up. I knicked my oem black tank while screwing down my flooring. To repair it correctly I need to know the exact type of plastic it's made with. Mothership has no records before 1999. So, I'm looking for some help here.

Lumatic · 03-16-2020, 03:37 PM

Strange Mothership can't (or won't) tell you. I thought back at least to the 70s they were all polyethylene. I would try Airstream dealers repair departments, Vintage Trailer Supply and Inland RV. I will follow this with interest since I have a 93. My 71 had a polyethylene tank.

Re-Pete · 03-16-2020, 09:56 PM

Quote:

Originally Posted by Lumatic

Strange Mothership can't (or won't) tell you. I thought back at least to the 70s they were all polyethylene. I would try Airstream dealers repair departments, Vintage Trailer Supply and Inland RV. I will follow this with interest since I have a 93. My 71 had a polyethylene tank.

Lumatic Thanks for your reply. How crazy is it that Airstream kept such poor records up until 1999, Or maybe they all got wiped out due to Y2K, Hahaha.

I passed on your recollection to Bob with Virginia Plastic Welding. He's the repair guy I called. He's two hours away, so it won't be cheap, about $350 I believe, but hey he's coming tomorrow morning.

BTW, I actually called Vintage Trailer Supply right after I posted my thread here and they also told me it was most likely Polyethylene. So your timely reply was a nice conformation. Bob felt that is probably the case as well. I'm sure he'll come loaded for bear, so he can handle any contingency.

Here is a picture of my boo boo. I'll try to remember to get a picture of the repair and post the after picture/s.

Bubba L · 03-16-2020, 10:32 PM

Pete, this may not help, but I had a belly pan rivet tail wear through the bottom of my grey tank in the 66. I kept seeing drips periodically. I peeled back part of the belly pan and saw the hole. I went to tractor supply and got a livestock water trough repair plug. I installed it and it hasn’t leaked in four years and it’s on the bottom not the top. It would be a better fix to weld. Just a thought. Good luck

Re-Pete · 03-16-2020, 10:48 PM

Bubba, Thank you. This is in a weird spot being right on the edge. Repair guy will be here tomorrow to weld it closed, so I think I'll just let him do what he does. I appreciate your input. I'm tucking it away for future reference I hopefully won't need.

BobnGayl · 03-17-2020, 11:33 AM

In the late 70's I worked with RV tank suppliers and ABS sheet extrusion companies in the southern Michigan and the Elkart, Indiana area. At that time holding tanks were made from ABS plastic, not Polyethylene. (ABS is Acrylonitrile Butadiene Styrene co-polymer. It is tough stuff and used for DWV pipe, appliances, and some electronics and tools.) The water tanks were PE but holding tanks were not. ABS is very easy to patch - just buy some pipe cement that says ABS on it. Many are compounded for multi-plastic use including ABS and PVC but some are only for PVC, so read the label and get one that is for ABS. You can buy ABS sheet many places, both on line and in some hardware stores. Based on the small size hole you have, you could probably just weld right over it with the cement alone.

So how do you tell if your tank is PE or ABS? ABS will soften and get sticky when in contact with the pipe cement I just mentioned, or with acetone (nail polish remover) and will also suffer damage when in contact with gasoline.

Polyethylene is much more solvent resistant than ABS, which also makes it trickier to weld. You can weld ABS with solvents, but for PE, it's usually a heat process. If you want to repair the hole yourself, you can buy ski bottom repair sticks that are made to fix scratches and gouges in the bottom of skis. In that case you melt the stick into the hole and use a clothes iron or soldering iron to smooth is out. You can also use a hot melt glue stick - hot melt glue is typically polyethylene and ethylene-vinyl acetate (EVA) co-polymer and will adhere nicely to PE. Hot melt glue comes in many flavors and varieties compounded for different purposes. Some are very soft and melt at a low temperature so it's safer for kids to use and others are compounded to be much tougher and harder and typically have a higher melting point. Given the size hole I see in the picture, I would go the hot melt route if it were me. If you take this approach, make sure the material surrounding the hole is softened with the hot melt glue gun just before you add new material. That will ensure the new material sticks well to the old.

Re-Pete · 03-18-2020, 11:36 PM

Thanks BobnGayl you obviously know your plastics. Hot glue. Something to remember.

So, I was actually lucky enough to get it professionally repaired Monday. The company that did the repair is Virginia Plastic Welding and the owner operator is Bob Leuchtmann. I learned that the tank is high density polyethylene (HDPE).

We made a new friend yesterday and had out hole repaired as well. He did a nice job and he was very reasonable considering the distance he traveled to come to us (2 hours each way). He was very meticulous, cleaning and prepping the area with a Dremel tool before making the repair. I'm a strong DIYer, but I yielded to an expert this time. I watched the entire process and feel very satisfied that I made the right call.

Here are a few pics.: This first one is part of the prep process.