To fix the typical leaky lower left seam from tanks that have sat for years.

Here's an example:

https://www.youtube.com/watch?v=Jf1Q8DJ-Awg


I'm guessing this would probably require a repaint since nearby paint wouldn't hold up under those temps but considering that a new tank from BMW is $1,000+ . . . 

I'm considering trying some of these:
http://www.ebay.com/itm/10pcs-1-6-2-2-4-3-2mm-Aluminum-Magnesium-Low-Temperature-Welding-Brazing-Rod-/112306475331?var=&hash=item1a25fcd143:m:m7vIZQxNff1T-SWUsaGHD_g

hmm  amazing product

I just wonder ...in the video the process utilizes the heat carried by the base stock

my question is. the aluminium tank is relatively thin and likely prone to cooling rather quickly or overheating in spots

would someone need really good skills to effect a repair on the tank ?

just askin !!

looks a winner product for our tanks indeed

There are demo videos arund that show the rods being used to fill a 2cm hole in a beer can.  I can't think of much thinner aluminum than that.

Point-Seven-five wrote:There are demo videos arund that show the rods being used to fill a 2cm hole in a beer can.  I can't think of much thinner aluminum than that.

What about aluminum foil?


(Sorry, couldn't resist.)

wow !!!

bit of info if trying to weld tank be it metal or alloy run a hose or place  inlet or filler hole over tail pipe of petrol car and run for few mins till you can see water vapor form will make tank not a bomb carbon monoxide kills the petrol fumes.also to get alloy to right temp you can use a small piece timber like match and wipe over heated spot till it blackens temp will be around 700f or if can get soot from oxy flame and heat till dissapear is correct temp also.

Alumiweld or some such trade mark has been around for decades.  I've personally seen demos of those rods' use welding (soldering, actually) irrigation pipe.  I've often wondered why K-bike owners rely on other fixes for leaky tanks. The Alumiweld process looks simple enough.  I've never tried to repair a tank myself because I've never had the need, but I have a collection of those rods in my tool chest in the event I need them.

I've tried the aluminium solder, it's very tricky to use. The temperature is critical, too little heat and it blobs and doesn't take well. Too much and you blow holes, I have  a son in law who used to do specialist welding and I'm going to try and get him to show me how. I'll report if I find any tricks.
Regards Martin.

I've had both of my K bike tanks leak at the low point on both sides over the last 3-4 years and all have been welded rather than use any sealant/repair goo.
The DIY rods are interesting and I have some and have played with trying to repair coke cans etc. but decided it was too risky for me to try on my tanks. I just inquired around various engineering fabrication shops and quickly identified a couple who did aluminium welding as part of their normal services.

My last repair on my K1100 tank cost me $30 at a local Maitland shop that I was put onto by Rickmeister. So at that price why risk messing with it myself. As far as the explosive risk goes, both shops that have welded my tanks have steam cleaned the tank then let it air dry before working on it. Naturally I removed all the innards myself.

As mentioned above, the downside is that the paint work around the weld is damaged and has to be rubbed back and repainted (I must get around to painting that little white patch on the left side of my K1100 tank).

Cheers

TIG is a better bet because the heat does not get to spread very much, low heat is slow heat and will spread right across the tank and damage far bigger area.
I repaired a few tanks recently with TIG and one had 7 holes, on all of them the paint was easily repaired with a small touch up.  I have used the low heat method and it isn't very friendly to the paint.

being a panelbeater and painter last 45 years both low and hot welding methods going to stuff paint for around 90 dollars au you can buy sealler that works fine for pinholes and do it yourself so there are options other than welding soft or tig.