Date: Thu, 13 Aug 1998 14:11:22 -0400
From: Joe Koepfinger
I have encountered my first cracked gas tank and would like the collective advice/knowledge of the BI list regarding repair technique.
It looks like the tank was repaired previously by brazing (gold colour). I have asked a guy here at work who is an excellent welder about brazing it again and he said that perhaps soldering would be better to avoid excessive heat which might warp or distort the metal.
Any thoughts/experience?
Date: Fri, 14 Aug 1998 02:22:24 -0400
From: Micro Dot
braze it. we do it all the time. triumph tanks constantly need repair
when either the back mounting tab breaks off, or the top seem is opened
in the front of the tank by the top triple tree when the fork stops fail.
you can heat things quit a bit before they warp, just make sure that all
the gas and fumes are out of the tank before you start. otherwise you will
know what a really warped
tank is.
Take the petcocks off and put the garden hose into the tank. run the hose with enough flow to easily overflow the tank for about a half hour. sand all the paint off the area your going to braze and have at it.
Date: Fri, 14 Aug 1998 01:17:17 -0700
From: John Mead
Don't forget to drill small (1/16 - 1/8) holes at each end of the crack,
making sure that the hole includes the end of the crack. This will
relieve the stress
at each end of the crack that caused it. When you braze the crack,
braze the holes.
John Mead
Date: Fri, 28 Aug 1998 08:07:20 -0700
From: Dennis Dyck
Good morning; My understanding is that silver solder is the stuff to use as it can be applied with relatively low heat (and consequently less metal distortion). I am assuming you had the tank de-chromed before you began repairs, as it will have to be anyway before it is re-chromed. IMPORTANT: If you are going to use the silver solder repair, it is essential to use solder which is cadmium free otherwise the solder will not take the chrome. Cad free solder is available from welding supply shops. A good idea would be to talk to your plater first; they know the process and will likely be able to give you helpful info also.
Cheers, Dennis
"Every man has to shoot his own dog"
Date: Fri, 28 Aug 1998 13:14:59 -0400
From: Latte' Jed
> Good morning; My understanding is that silver solder is the stuff
to
> use as it can be applied with relatively low heat (and consequently
> less metal distortion). I am assuming you had the tank de-chromed
> before you began repairs, as it will have to be anyway before it
is
> re-chromed.
> IMPORTANT: If you are going to use the silver solder repair, it is
> essential to use solder which is cadmium free otherwise the solder
> will not take the chrome.
> Cad free solder is available from welding supply shops. A good idea
> would be to talk to your plater first; they know the process and
will
> likely be able to give you helpful info also. Cheers, Dennis
The trick to this is that there are a bunch of solders called silver solder. Sometimes plain lead-free solder is called silver solder, and it's not good for anything structural. "real" silver solder melts around 1100F, sticks to most anything, including chrome, stainless steel, and galvanising, and is pretty hard. It can't be used with a soldering iron, even a propane torch is a bit too lightweight. It's also really fluid, so it's good when you need a lot of flow, like when brazing a tube inside a lug.
Date: Fri, 17 Jul 1998 10:41:18 EDT
From: John Weidmann
My apologies to all for yesterdays posting for looking like it was written
in
Klingon. Computers are not my field of expertise.
SEALING YOUR GAS TANK
This is something that I have done several times to cars with excellent
results that have lasted 10 years and counting. First a list of what
you will need is in order. Sloshing solution (sealer, not beer), 1 roll
duct tape, 1 cup small gravel, 2 bolts with the same thread size of your
petcocks, 2 quarts alcohol (isoproponal, not booze) 2 saw horses and a
6 pack of beer (minimum). If your tank is rusted through you will also
need; wire wheel, electric drill, fibre glass cloth and resin with hardener.
If you don't intend to repaint your tank, check the label on the sloshing
solution as to what it might do to your paint and take proper precaution
to protect the paint.
Start your project by removing the tank from the bike, draining the fuel and removing the petcocks and filler cap. Screw the two bolts into the holes where the petcocks were. Pour the gravel into the tank and seal the filler hole with the duct tape. Do not use the filler cap to seal this hole at any time during this project as you stand a chance of clogging the vent hole which will cause a vacuum in the tank and prevent fuel flow. This will cause your bike to faint at the most inopportune times. Agitate the tank like a set of maracas, rotating the tank as you do so. This is to make the gravel chip loose any rust, similar to sand blasting. After your arms are too tired to pick up a beer, you should be done. Remove the tape and bolts. Shake out all the gravel and crap that you have loosened up.
At this point, if your tank is perforated it is time to fibre glass over the perforated area. Grind the area to be covered with fibre glass with a wire wheel until it is clean, shiny metal. Follow the directions on the fibreglass kit for mixing and applying the resin and cloth. Wait until the fibre glass is fully hardened. Wash out the tank with soap and water. (dish detergent works well) Make sure you rinse out all of the soap. If you have a set of saw horses, put the tank on them with a garden hose in the tank and let it run. Next get as much of the water out of the tank as possible and reinstall the bolts in the petcock holes. Pour the alcohol into the tank and seal the filler hole with duct tape. Slosh the alcohol all around the inside of the tank as it will absorb any residual water. Drain the alcohol out and let the tank dry fully.
When the tank is drier than your mouth after an 8 hour ride in 95 degree weather in full leathers, you are ready for the solution. The label on the can of sloshing solution tank sealer will probably have all kinds of skull and cross bones with warnings about breathing the vapours. They are not kidding. This stuff will give you a horizontal view of the world faster than you can believe.
Reinstall the bolts in the petcock holes and pour the sloshing solution into the tank. Seal the filler hole with duct tape and rotate the tank in ever direction possible to make sure you have coated the entire inside of the tank. Place the sloshing solution can on the ground under the saw horses and invert the tank after removing the duct tape from the filler hole. Let the sloshing solution drain into the can and remove the bolts from the petcock holes. Draining may take awhile so force yourself to sit back and have beer. After about an hour the sloshing solution should have all drained out and left the film you want over the entire inside of the tank. Wipe any residue from the filler hole to ensure a good seal for the cap when it is reinstalled. It is recommended to leave the tank sit for 24 hours to make sure the solution cures. Do this with the tank inverted so none of the solution finds its way onto the threads of the petcock holes. Don't rush it.
Put the petcocks back in and remount the tank. It should now be ready
for use and give you a confident feeling that you are no longer riding
a potential
Molotov cocktail
Good riding---John Weidmann
'67 Etype roadster, '70 Etype coupe, '74 Norton 850 roadster