Does anyone know the type of plastic on the following tanks?
I have two tanks with cracks from a 1978 airstream soveriegn 31 ft CB as follows.
Water Tank
INCA 562
T1237 600833
and
Sewer Tank
INCA H323
T1244 600843
imp gal 18.32
What type of plastic are these? Polyethylene? Is there only one type of polyethylene. My welder says it has to be the same rod type.
Looks like you have the model numbers already from the old ones - if not exact matches at least a start - they ought to be able to look them up. Don't know what your welder is going to charge...but you might want to just get new ones that'll last another 30 years. Also, you could call Inca, Tel # (909)923-3235 and ask them the material if you are determined to weld them.
From their website:
Quote:
All of our tanks are molded in one piece out of a tough polymer resin.
Shari
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These tanks are made from Polyethylene. Many RV and other plasitc fabricating houses have small welding machines with proper plastic filler rod which can weld a tank almost as good as new. You however should look into what stress caused the original failure and support the tank properly to prevent future failures.
Does anyone know what type of plastic was used for the grey 30 gallon water tank in a 67 Caravel. I have the same problem trying to determine which plastic welding rod to use.
Take a small cutting off the tank and do a burn and sniff test. Light the sliver with a lighter. Blow it out gently and chemically smell the smoke that ocurrs. The smell of a candle indicates it is polyethylene. Polypropylene has a sharp smell. Usually these tanks are made from low density Polyethylene.
I did not try this but Believe that these burn tests are the way to do it. I dropped the tanks at my welders a few months back and followed up at one point. At that point I think we had figured out that the water tank was polyethyles but the black tank was possibly polypropylene. I brought him some polypropylene rods (cost about $10.00 for a small bundle at an auto paint supply store). Have yet to follow up on how he made out - I have been busy getting the frame welded and reparing floor (see my other post on frame access and repair I think).
Note that my grey water tank seemed O.K. and did not send for welding. On the grey water I noticed P.P. scralwed on it in felt marker. The tank had more of a grey color similar to the black water tank so this may indeed be a clue that the grey and black tanks are polypropylene.
Note that I tried contacting INCA or its predecessor. Even though I had all the tank numbers they could not tell me what the tanks were made from.
Thanks for responding. I will give the burn test a try. Re-read my post and see where my discription of the tank would be confusing. The tank in question is the potable water tank located up front under the settee. The tank is made from a blue-gray colored opaque plastic. Only mark on the tank is shield shaped logo with the letters WPOA inside and the number T1285 above the shield. Googled WPOA but didn't get any hits that made sense. The tank appears to have been rotomolded. Thanks again.
These tanks are made from Polyethylene. Many RV and other plasitc fabricating houses have small welding machines with proper plastic filler rod which can weld a tank almost as good as new. You however should look into what stress caused the original failure and support the tank properly to prevent future failures.
Thanks for responding. I will give the burn test a try. Re-read my post and see where my discription of the tank would be confusing. The tank in question is the potable water tank located up front under the settee. The tank is made from a blue-gray colored opaque plastic. Only mark on the tank is shield shaped logo with the letters WPOA inside and the number T1285 above the shield. Googled WPOA but didn't get any hits that made sense. The tank appears to have been rotomolded. Thanks again.
That gray colored 30 gallon water tank, was the absolute "worst" water tank ever used.
They failed in as little as 90 days.
Airstream replaced thousands of them in warranty.
Through out the years, many attempts to repair them have been tried.
I am not aware of a single repair, that had much of a extended life.
I'm in the middle of doing this repair on the black tank in my '75 Sovereign (black tank) and '77 Safari (water tank). I emailed Inca and they said the tanks were Low Density Polyethylene. I obtained some LDPE and a cheap hot air welder, but have had zero luck in getting my practice materials to bond. A local shope said that getting old LDPE to weld is usually not very successful.
As an alternative, I've picked up some 3M Scotch Weld 8005 and will give that a try on my practice materials. All results will be documented in a not-yet-created thread "Tank Repair." (yes, I am an optimist most of the time.)
The Scotch Weld isn't cheap and you'll need about $50 in application tools if that's the way you go. The good side is that it seems capable of creating structural joints between all polyethylene and polypropylene types.
Andy is right about the difficulty of repairing these tanks. This will be my fourth attempt (first at plastic welding, all the others were patches of different kinds). But like Zep I'm an optomist. I would like to believe that for once I will actually be able to repair something for less than the cost of buying a new replacement. The Scotch Weld product looks like a good possibility for accomplishing a cost effective repair. I see that some boat owners have had success using Scotch Weld 8005 to fix polyethelene water tanks on their boats.
I had no luck with INCA. Who did you speak with? Were they able to trace your tank I.D.s or did you have numbers?
Andy,
Do you know if the 1978 black tank and water tanks of the poor quality you are referring to? The black tank seems more grey; the water tank seems more blue/ green in comparison.
DFK,
I think I may try the Scotch Weld if all else fails.
regarding INCA, I just emailed them and several days later I got my answer. It was just a general question, since I hadn't removed the tanks--I can see and fix the weld through the hole in the floor.
BTW, I haven't actually received the Scotch Weld yet--the chemical itself was on back order, so my whole order is sitting....and waiting.
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