Pinhole leak

**rok-the-boat** · 19th November 2006, 09:31

I have a pinhole leak in my tank. It has been rubbed down to the bare metal. Any advice on the best course of action? Solder, brazing, welding? And who is good in Auckland to take it to?

And where is the best place to buy welding equipment and supplies? I have been toying with the idea of learning how to do it for ages. Anyone recommend a basic welder for starters?

**Ixion** · 19th November 2006, 09:44

BOC in Gt South Rd will sort you on a welding kit. Youll have to decide if you want gas, arc or MIG.

But for a pinhole in the tank, your best bet is Araldite (with acknowledgement to Mr WINJA). Quick cheap easy and works well. Do NOT try to weld or braze a fuel tank unless you know EXACTLY what you are doing. You will kill yourself. It can be done but it is no job for a novice.

**stanko** · 19th November 2006, 09:57

If you take it to a radiator repair place they can sort it out.

Like Ixion said dont practise welding on a fuel tank as it is potentialy explosive.

A good start to buying a welder would be a Lincoln SP170 mig (you can get the same welder from Liquid arc) You can run it with CO2 for a shielding gas , that way you can own the gas bottle and its only $20 to fill it compared to Argoshield which is $80 per fill and about $10 per month to rent the container.
Some people use flux cored mig wire , I dont really like it as it leaves a mess , but then you dont need the expense of gas bottles.

You could get a stick welder , but be prepared for really manky welds with slag inclusions etc. Cheap but maybe not good for nice work.

TIG welding is slow and expensive , but can have really awesome results. Its like the electric version of Oxy Acetaylene. If the welder is a DC welder then you are limited to Steel and stainless, if you get an AC tig then you can do aluminum as well.

When you get a welder also get a fire extinguisher, you will be amazed how much shit catches fire

**Ixion** · 19th November 2006, 09:59

And cut your hair. Trust me on this.

**Paul in NZ** · 19th November 2006, 09:59

if it is a pin hole caused by rust - the whole area will be a bit suspect.

If you want a long lasting job it can be welded for sure OR use a tank sealer / liner like POR15. It will clean out the inside of the tank, kill the rust and protect it.

As Ixion says - please don't weld it until you have a little more experience - old petrol fumes tend to go boom... and NZ already has a couple of Darwin awards - we don't need anymore OK?

**Ixion** · 19th November 2006, 10:06

Coming back to the welder thing, you need to work out what you want to do with it.

For welding light weight steel (eg car panels) MIG is far the easiest. Plain stick welder will give good results for about 12 guage and heavier , but that's fairly heavy stuff.

But none of the electric welders have the versatility of oxy. With oxy you can weld almost any guage , braze (I braze more than I weld), silver solder, heat things up (fit bearings etc), burn off paint, weld aluminium and stainless, even zinc carb bodies (need a bit of experience and skill for that, mind).

But the learning curve on oxy is a lot harder than MIG . So figure out what you want to do , unless you can afford all three.

**rok-the-boat** · 19th November 2006, 10:19

First, I was not thinking of welding the tank myself. Anyway, it has been off the bike for ages, has been totally stripped, and was dunked in a very dilute mild acid for a couple of days to disolve all rust. I as a bit dubious about that, but my mate assured me it was good practice. Anyway, apart from the pinhole, the tank is fine.

Welding - I just need to be able to weld things like exhast baffles that I am experiementing with, and other odds and sods such as a car floor panel etc. I was not thinking of alluminuim, but if I had a kit that could do that so much the better, especially if I could repair engine covers for example.

I am not interested in the messy rod welding - I have tried that and it is a mess and hard to control. My brother had one where the weld wire came out of the front of the machine as you welded - that seemed easy enough to use. Dumb question - what is the flux on the rods for? And, is that what the CO2 is for on the wire welder?

**stanko** · 19th November 2006, 17:29

Originally Posted by rok-the-boat

Dumb question - what is the flux on the rods for? And, is that what the CO2 is for on the wire welder?

The flux and the gas do pretty much the same job, they form a protective layer around the weld pool to prevent it oxidising. If you forget to turn on the gas the weld is all shitty and porous and dosent sound too good while you are trying to figure out whats going wrong.

**Expert** · 19th November 2006, 18:15

There is some good advise on this thread from people who have obviously used the kit.
My observations for what they are worth are:-
Mig welders (the wire comes out the front) very versatile and number 1 choise for general workshop for mild steel, car panels, not much heat distortion bacause of very localised heating. Get a gassed one for best results.Small cheap ones are crap on aluminium.
Stick, Mma, or arc where you use the stick, cheap to buy but difficult to control on light metal, you can get an attachment for these machines called a carbon-arc torch, this is a sort of handle which has two carbon rods coming out of it and the arc jumps between the two and is a heating source. I've seen it used for all sorts with some practice brazing, soldering, welding/brazing aluminium, heating and bending metal bits, don't need any gas, good for a budget.This attachment will work on any machine with a MMA (stick)function, like a tig welder.
Oxy/gas is very usefull and can do all the carbon-arc torch can and better but creates a massive amount of heat which distorts car panels like crazy for the in-experienced.
I got one of these AC/DC tig welders so i can weld aluminium and you can't believe how much you can make out of ally untill you have the kit. Expensive to buy and a slow and laborious task for thin steel sheet like oxy/gas though. I've heard tell that there is an attachment available to turn a tig into a plasma cutter which is handy for car panels although that should work on any high frequency sources like those inverter MMA welders that you can get cheap.
I would reccomend gassed mig and get some argoshield gas coz it's worth the extra cash.
Weldnz down in onehunga,auckland now do a machine with tig,stick mig and plasma all in one, you pays your money...........................

**R6_kid:Me** · 19th November 2006, 18:25

get a needle slightly bigger than the pin hole (needles are generally bigger than pins) and push it in till it blocks up the hole, if your missus has a sewing kit then its a free fix!

**rok-the-boat** · 19th November 2006, 18:59

Sounds like I need to learn on a Mig welder then. But the suggstions of araldite and pin, perhaps in combination, could be the ultimate bodge. But I am not keen on bodges.

You know, I once bought a car only to find out the rear brake lines had been hammered flat to 'cure' a problem. Hope I haven't given anyone a bad idea ...

**R6_kid:Me** · 19th November 2006, 19:48

Originally Posted by rok-the-boat

You know, I once bought a car only to find out the rear brake lines had been hammered flat to 'cure' a problem. Hope I haven't given anyone a bad idea ...

wtf... that person should have hammered themselves flat to cure the gene pool.

**Motu** · 19th November 2006, 21:03

Like Paul says,a pin hole just doesn't spontaniously appear,there will be corrosion around that hole.I wouldn't go near it with a MIG,just a blob of filler with the gas then dress down.Bronze is easier but I find it causes cracking around the area,and once you put bronze on there you have to stay with it.Then do the POR15 kit,I find it's better than Kreem.I've had tank liner in one of my tanks for over 5 years and the bike has been tossed down banks many times.

**Ixion** · 19th November 2006, 21:10

I've never had cracking problems, but I can believe it might happen. A bike tank is a pretty deep drawn bit of sheet metal, theres going to be a shit load of unrelieved stresses in the metal, heat a bit up locally and they're going to redistribute.

If working on a tank (I always braze, never weld) I like to heat the whole tank up until its just too hot to hold my hand on. Then heat the area round the hole a bit hotter still,then I stick a bit of bronze wire into the hole itself, so it sticks out, then just touch it with a very hot flame for a moment and let it spread. Add a bit more wire if needed and cool slowly. Buggers the paint of course and sometimes I've done a "local" job, where its a mounting lug or something.