A forum for owners of Yamaha TTR250 trail and enduro bikes!

BaronGreenback · Veteran Member

Brazing holes in fuel tanks.

Cubber · Super Guru

News Flash:-

BaronGreenback entered orbit yesterday whilst attempting brazing repairs to fuel tank.

It is possible to braze or weld a perforated fuel tank, but dangersous.

If it were mine I would SERIOUSLY think about soldering it.
If you cut a patch of tin, about the size sufficient to cover the area, remove the paint from the tank over the area, roughen the tank surface and tin the patch with solder you could then fit the patch by soldering it on.

This method would be safer than using a naked flame. wink

Martyn

BaronGreenback · Veteran Member

I'd heard soldering with silver solder is fine, but normal solder is too soft? Silver solder would require more heat than an iron could produce, so flames are imminent.
This is why I thought I may as well go the whole hog and use brazing rods instead of solder.
I don't intend on jeopardizing my safety...well, until I'm out riding the thing. The tank will be thoroughly cleaned, aired and the pet**** removed. A blast of Co2 will kill any risk of explosion. (I hope)

Haggis Hunter · Veteran Member

I have brazed vehicle fuel tanks in the past (petrol and diesel) but like Martyn says it's dangerous. We used to clean the tanks with steam and detergent and then clean them again just to make sure! then used nitrogen (I think) to purge the tank. The only problems I ever had was with stress cracks in the tank. You would end up with a creeping crack. The best way to to prevent that was to braze a patch over the whole lot.

I don't know what your skill levels are but only attempt it if you are happy you can do it, if not solder as Martyn suggests.

Peter

BaronGreenback · Veteran Member

Thanks for the advice. I wil try extra hard not to kill myself in a tank explosion :)

BaronGreenback · Veteran Member

It had to be done, all the scaremongering had me worried. Maybe I wasn't as bright as I thought etc.

:EDIT:

Ran out of MAPP gas, so this repair will have to wait until tomorrow. I tried with propane but it isn't hot enough.

-- Edited by BaronGreenback on Monday 8th of October 2012 03:08:46 PM

BaronGreenback · Veteran Member

On inspection I found two pin size holes. The metal around them is not badly rusted, just a touch of mild surface rust and pitting. Although I'm just a bit concerned at how thin the steel is, as these weren't deep pits, but still deep enough to cause a leak.

I washed the tank out first with carb cleaner, then with warm soapy water. Finally, I completely filled the tank with hot water, with a hose, and left the hose running in the tank for 15 minutes. After draining and leaving it to air/dry for a couple of hours all I could smell was washing up liquid. So I tested for residue by wiring an electric match into the tank, on a 15 foot wire, and detonating it behind the bin. No boom!

Tank is clear, prepped and ready for brazing.

TTRfan · Super Guru

BaronGreenback wrote:
I tested for residue by wiring an electric match into the tank, on a 15 foot wire, and detonating it behind the bin. No boom!

biggrin biggrin biggrin biggrin biggrin biggrin biggrin

BaronGreenback · Veteran Member

Handy tip:
Tyre levers are great for removing dents from the inside.

BaronGreenback · Veteran Member

It's done. Hole filled, filed and patched. Photos when I find my phone cable.

BaronGreenback · Veteran Member

Here are a few pics of my fuel tank repair.

The troublesome hole

Hole filled with silver alloy brazing rod

Nitromors sucks on bike paint! You can also see in this pic I used Granville petro patch over the patched area to prevent further leaks springing. The guy in the shop says he's been selling it for 25 years and never had a complaint.

Almost there.

white undercoat.jpg

Stupid boy used a white primer when it's to be painted white. I don't half make jobs hard for myself.

colour coat.jpg

Colour coat (x3), then a rub down, ready for lacquer. (3 coats)

Fitted

Granted, not the best of pics, but you get the idea.

Still don't know if it holds fuel yet.... evileye

-- Edited by BaronGreenback on Saturday 13th of October 2012 03:02:31 PM

TTRfan · Super Guru

Wow - tidy and thorough job there - hats off to you!

Make sure you use "petrol proof" lacquer and don't put on too many coats or your bright white will adopt a yellow tinge - don't ask how I know disbelief

Brian

BaronGreenback · Veteran Member

Thanks Brian. I made sure the laquer was petrol proof as I have seen first hand what petrol does to shiney new paint. I didn't know too many coats could leave a yellow tinge though, that's a handy tip.
I'm done with the clear coat for now. I have another can here for when I get the decals on.

TTRfan · Super Guru

I found my old thread here. It seems that only using two coats of lacquer prevented the dreaded yellow tinge.

Brian

domski1 · Senior Member

A great start to the restoration! Just over the last week there has been quite a few second hand parts appearing on eBay so a good time to do a bit of shopping for any parts needed!

Adam.

BaronGreenback · Veteran Member

domski1 wrote:
A great start to the restoration! Just over the last week there has been quite a few second hand parts appearing on eBay so a good time to do a bit of shopping for any parts needed!

Adam.

I was actually talking to the guy breaking the raid last week on gumtree, as he lives local to me. His prices are very good too. There are a few bits I'm going to buy off him.