OzVMX Forum

Clubroom => Tech Talk => Topic started by: Curtis on August 12, 2015, 11:37:47 am

Title: Plastic tank repair
Post by: Curtis on August 12, 2015, 11:37:47 am

Does anyone know what sort of plastic Fuel tanks are made from? Late 80s Suzuki specifically? ABS? Just trying to decide what JBweld to buy? Gota stick some captive nuts back in.  8)

Title: Re: Plastic tank repair
Post by: fred99999au on August 12, 2015, 04:37:49 pm

I would expect it to be polyethylene. Good luck getting anything to stick to it.

Title: Re: Plastic tank repair
Post by: Curtis on August 12, 2015, 05:04:33 pm

Polypropylene, Polyethylene, PVC or CPVC?

Title: Re: Plastic tank repair
Post by: Curtis on August 12, 2015, 05:05:58 pm

Sorry didnt read that properly, they do have a product that works with that.

Title: Re: Plastic tank repair
Post by: LWC82PE on August 12, 2015, 05:11:15 pm

I looked into various 'glues' for plastic fuel tanks several years ago. Yeah they do stuff that is ok for water tanks but getting anything to work long term with a fuel tank is a whole other ball game. Your best chances of doing this sort of repair is probably with Sikaflex  which sticks to anything and is resistant to fuel or plastic welding with the right filler rod. I think i would go with plastic welding.

Title: Re: Plastic tank repair
Post by: GMC on August 13, 2015, 11:07:49 am

Repaired a fuel tank a few months back that had a loose captive nut.
The insert was fine until I tried to drill out the broken bolt and then the insert spun.
I ended up using a Dremmel to bore some holes about 1.5mm Dia down halfway in the brass and plastic. I think Toolies call this a scotch key.
I think it was a engraving tool I used to do it. While you could do it with a drill bit you will find the the drill will naturally drift into the softer plastic and the hole needs to be half and half.

Then I just stuffed the gaps with Araldite and used some 1.5mm welding wire in the holes to lock it in place. The Araldite doesn't actually come in contact with the fuel, just the fuel residue that comes through the plastic.

Seems to have worked okay but I only put fuel in it once to then discover that the tank had been melted through onto the exhaust so it now just sits in storage.

(http://i15.photobucket.com/albums/a393/gmcloa/Repairs/KDX%20tank%20repair_zpszys5t68j.jpg) (http://s15.photobucket.com/user/gmcloa/media/Repairs/KDX%20tank%20repair_zpszys5t68j.jpg.html)

Title: Re: Plastic tank repair
Post by: Mike52 on August 13, 2015, 11:43:50 am

What about a simple " recoil"  type repair.
Should work ok providing you don't go through the plastic.

Title: Re: Plastic tank repair
Post by: Curtis on August 13, 2015, 01:24:15 pm

Very inventive, a bit different to my application as I have a large hole where the nut goes, it needs to be filed up. Helicoil wont help me. I guess ill have to give it a bit of trail and error!

Title: Re: Plastic tank repair
Post by: GMC on August 13, 2015, 01:48:16 pm

I might be able to do you a deal on a tank :o

Title: Re: Plastic tank repair
Post by: Curtis on August 13, 2015, 02:41:39 pm

haha..maybe...

Title: Re: Plastic tank repair
Post by: Nathan S on August 13, 2015, 03:05:36 pm

$600 and you end up with a ton of spares...

Title: Re: Plastic tank repair
Post by: Curtis on August 13, 2015, 04:15:19 pm

Ill have a look when im up there

Title: Re: Plastic tank repair
Post by: Mike52 on August 14, 2015, 08:46:49 am

Quote from: Curtis on August 13, 2015, 01:24:15 pm

Very inventive, a bit different to my application as I have a large hole where the nut goes, it needs to be filed up. Helicoil wont help me. I guess ill have to give it a bit of trail and error!

Ok , then what about a Keensert type insert.
Tap the hole in the tank to a standard size , get a bolt of that size , drill a hole up the middle of the bolt [ lathe job ] and tap the required thread in it.
Cut a bit off the right length.
Screw the  cut off bit into the plastic tank with some glue.
Vola.
All up cost ?
$5 ?