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fotochop · 01-27-2008, 03:15 PM

My cracked '69 Safari blackwater tank has the Plastic Resin Code "1" on it, in a circle though, not the rounded triangle that you would see today (don't know if that makes any difference), which Wikipedia tells me is a type of PET/PETE:

http://en.wikipedia.org/wiki/Polyethylene_terephthalate

I've researched quite a bit here and some say you can weld/repair it, some say you can't. I don't know if this is "cross-linked" or not. I'm anxiously awaiting a post from Zep saying you CAN ;-) with the new Scotch-Weld setup as I would be willing to plunk down a c-note on the kit if the tank is fixable.

I'm not looking forward to trying to fit new closet flange and two vents on a generic new tank. I'd rather use the old one and fix it.

Maybe we have some chemists/renovators who can shed some light on the nature of Code 1 PET/PETE and it's weld/fixability.

gratefully,

Wabbiteer · 01-27-2008, 04:41 PM

Sorry for the unappetizing view but believe me the tank has been hit with industrial strength chlorine - and the slag on tank bottom remains from either prior repair or from the factory...

I will be razor trmming the weld area notch out plus shave the sharp corners back on my '73 BW tank and use the shavings to hot-air weld it back into the area next to the flange that is cracked... AND add a thick layer of new rod or milk jug plastic over top of that...

At least that is the ready plan at the moment...

Inland RV Center, In · 01-27-2008, 04:56 PM

Quote:

Originally Posted by fotochop

My cracked '69 Safari blackwater tank has the Plastic Resin Code "1" on it, in a circle though, not the rounded triangle that you would see today (don't know if that makes any difference), which Wikipedia tells me is a type of PET/PETE:

Polyethylene terephthalate - Wikipedia, the free encyclopedia

I've researched quite a bit here and some say you can weld/repair it, some say you can't. I don't know if this is "cross-linked" or not. I'm anxiously awaiting a post from Zep saying you CAN ;-) with the new Scotch-Weld setup as I would be willing to plunk down a c-note on the kit if the tank is fixable.

I'm not looking forward to trying to fit new closet flange and two vents on a generic new tank. I'd rather use the old one and fix it.

Maybe we have some chemists/renovators who can shed some light on the nature of Code 1 PET/PETE and it's weld/fixability.

gratefully,

New plastic tanks are available.

Andy

bedfords · 01-27-2008, 07:43 PM

fotochop,

Can you post a pic so we can see what your dealing with. The flange in normal operation shouldn't have any load on it. I saw Zep's glue. It is very strong. The hot air welding was the way I went. I definitely think you have options to try before buying new. Good luck and let me know if you have anymore questions.

bedfords

Kajtek1 · 01-27-2008, 09:02 PM

I've been dealing with old tank like that and the plastic turned out to be ungluable, while over the years it lost the strength parameters making re-welding a bad option.
In another words I believe Andy knows what he is talking about.

FreshAir · 01-27-2008, 11:39 PM

I got a new tank from Inland. It was pricey but worth it. The time I would be fitting a generic tank in was spent camping.

FrenchBern · 01-28-2008, 02:10 AM

Since it is use thermoforming I would attempt to weld it as I did with my refrigerator water intake solenoid last summer. After different attempt at gluing/epoxing I decided to weld it with hot air and failed. As a last result I tried welding it using a 5" magnifying glass and the sun on a clear sunny day. Lo and behold it was welded in 15 minutes and it was much easier than with a welder and saved the C note. After 6 months, the repair is still holding the 85 pounds water pressure in this house. Just sharing a fact.

Ganglin · 01-28-2008, 05:32 AM

Quote:

Originally Posted by FrenchBern

As a last result I tried welding it using a 5" magnifying glass and the sun on a clear sunny day. Lo and behold it was welded in 15 minutes and it was much easier than with a welder and saved the C note.

Now that's creativity....

dwightdi · 01-28-2008, 08:04 AM

I do not think PETE had been invented yet in 1969 so the material code is likely just an internal code used by the manufacturer. I gave some hints on how to generically identify an unknown plastic on one of the other threads dealing with repair of the tanks. Basically you would need to take a shaving off the existing piece and do a burn and sniff test. Polyethylene smells like a candle you just blew out. Polyproylene has a smaller flame and a sharp odor which you could compare to a known sample of PP which you could obtain from looking at the recycle symbol on a more modern product and look for the PP designation. Pete/Pet is usually clear and marked with a 1 on the inside of the triangular recycle logo.

fotochop · 01-28-2008, 08:06 AM

I think my first attempt will be welding (if it doesn't work I can always fall-back and buy a new tank, although the cost seems steep) and I love the magnifying glass approach but may go with a soldering iron instead. I got a reply from the president of Urethane Supply, copied below fyi. Their website is geared toward plastic fender repair, but very informative. Products are affordable.:

Dear Mr. Olivier,

Thanks for your inquiry. The "1" code does stand for PETE with regard to the plastic recycling code, but I don't know if that was a standard back in 1969. Most holding tanks are made of PP or PE, as these are most inert and resistant to chemical attack.

All are thermoplastics and thus weldable, however we don't offer any PET welding rod. Try using a soldering iron to melt the crack back together. If you think it might be PE or PP (waxy in appearance, not glossy like PETE), try our ATV Fender Welder. It's the best way to fix PE. You can buy PP rod separately (5003R2) to go along with the welder.

Sincerely,
Kurt Lammon
President

Urethane Supply Company
1128 Kirk Rd
Rainsville AL 35986-6028 USA
tel: 800-633-3047
tel: 256-638-4103
fax: 256-638-8490
www.urethanesupply.com
kurt@urethanesupply.com

safari57 · 01-28-2008, 07:43 PM

Fotochop

Try welding it first. I suspect you will come up with the results you want. I have seen very old tanks repaired and they have lasted a very long time and in my own case have had very good success. The key is to take your time with the welding and don't blow bigger holes.

You know you can get a replacement if this doesn't work out - but it will.

Let us know how you make out with this.

Barry

fotochop · 01-28-2008, 07:50 PM

Quote:

Originally Posted by safari57

Fotochop

Try welding it first. I suspect you will come up with the results you want. I have seen very old tanks repaired and they have lasted a very long time and in my own case have had very good success. The key is to take your time with the welding and don't blow bigger holes.

You know you can get a replacement if this doesn't work out - but it will.

Let us know how you make out with this.

Barry

GOOD advice. Great advice, in fact. Here's what I ended up doing:

http://www.airforums.com/forums/f36/...tml#post511474