Fuel tank repair - generating ideas

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

I'm trying to repair a large hole in the side of a fuel tank on an RD350 YPVS. It's about 1 by 2 inches, caused by me thinking that if I cut back to the good metal I'd have something thick enough to weld to. I'm not looking for aesthetic perfection, but I do want a reliable fix.

The tank is stripped back to bare metal, which helps. I've had the following ideas for sorting it:

1. Fiberglass. This is probably a very poor idea, I have no idea how fiberglass stands up against petrol. I can probably get in behind the hole to get a patch on, then I can patch to that from the other side of the hole. Inside would then be treated with petseal or similar for a seal. Outside can be painted.

2. Steel plate, held on with epoxy. This would be an external plate, with chemical metal or similar holding it on, and a smear around the outside acting as filler as well. I'm not sure how the stuff stands up over time, and how it is for fuel resistance. Again, would be petsealed from the inside and painted from the outside.

3. Aluminium alloy plate. As above, but I happen to have some of it in the right thickness, and it's easier to shape.

Anything I do is going to be petsealed inside, in the hope that it will give me a protective layer, like fitting a plastic liner inside the tank.

BanditsHigh · Worse than a woman Joined: 21 Mar 2005 Karma :

Get it done right and weld a new plate on ... overlap it if you need to Thumbs Up

Remember it's not just the fuel you need to worry about. If using an epoxy then it'll expand/shrink at a different rate to the metal and will come undone at some point ... guaranteed to be on a winters night when it's freezing cold and pissing down Laughing

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

As said, welding isn't an option. This is a 20 year old Japanese tank, so the metal is thin and weak. Even on 25 amps all I'm doing is blowing holes in it.

tatters · Exxon Valdez Joined: 04 Jan 2004 Karma :

Have you tried brazing a plate over the hole?? l,ve patch 2" holes on steel exhaust end cans and aluminum engine cases using a Map gas torch and low temp rods.

Petseal is nasty stuff starts to flake off the tank after a while and clogs up the fuel tap

much better stuff available like this, worked great on a cracked BSA A65S tank

https://www.frost.co.uk/item_Detail.asp?productID=8232&frostProductName=Fuel+Tank+Sealer+(US+Quart%2C+946ml)++
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Robby · Dirty Old Man Joined: 16 May 2002 Karma :

Good man Tatters, hadn't thought of brazing.

I'll have a look for a torch and some rods while I'm out and about today.

G · The Voice of Reason Joined: 02 Feb 2002 Karma :

https://www.haggul.com/ProdImage/25%5C499662.jpg

https://www.global-b2b-network.com/direct/dbimage/50295326/Ratchet_Tie_Down.jpg

Sorted.

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

Well, large karma cookie for Tatters. The braze job worked.

The rather ugly looking plate is watertight. Of course, I ran out of brazing rods so the assorted other pinholes in the tank aren't sealed, so I'll have another run over them when I have more rods, then some tank sealant to finish off.

Skim of filler over the plate, repaint. Possibly in Hammerite, with a brush.

https://www.bikechatforums.com/files/26042009112.jpg