|
|
|
|
| Author |
|
|
Registered
Join Date: Oct 2004
Location: San Diego
Posts: 4,870
|
Gas Tank Welding tips
I have to modify a couple of fuel tanks, I need to move the filler tube to the center and plug the old tube. I know this is done a lot around here to copy the early factory racecar look.
I have the new tubes and vent valves. My plan is to grind the areas clean, then use a holesaw to cut the hole, slide in the tube and do a MIG fillet weld around it. I plan to cut the old tube short and patch the end. The vents I have just require me to drill a hole and bolt in (they have rollover valves in them and are 1/2"). Does anyone who has done this have any tips or warnings to share? Should I use anything to seal it up after welding? Thanks 
|
||
11-30-2010, 07:18 AM
|
|
|
Get off my lawn!
|
Empty the gas first!
 I assume you have very dry tanks. When I had to add a vent tube to my El Camino tank I emptied all the gas, and let it sit in the sun for several days. Then I hooked up a flexible tube to the exhaust of my car. I let it idle and pump hot exhaust right into the tank for 30 minutes until the tank felt warm. I was a bit goosey when I first put heat on the tank. But no explosions!
__________________
Glen 49 Year member of the Porsche Club of America 1985 911 Carrera; 2017 Macan 1986 El Camino with Fuel Injected 350 Crate Engine My Motto: I will never be too old to have a happy childhood! Last edited by GH85Carrera; 11-30-2010 at 07:27 AM.. |
||
|
11-30-2010, 07:23 AM
|
|
|
Registered
Join Date: Sep 2001
Location: Columbus, OH
Posts: 1,011
|
Even empty, there will still be combustible fumes in there. Some people fill them with water, before working / welding on them. I chose to run exaust from my truck into it, via a duct-taped vacuum cleaner hose, when I was doing some welding repair on mine. I ran the exhaust through it the whole time I was working on it. I would not even want to drill a tank without evacuating the gas fumes from it.
__________________
Doug 79 SC Targa w/ ITBs, 2004 Cayenne Turbo |
||
|
11-30-2010, 07:28 AM
|
|
|
Registered
Join Date: Oct 2004
Location: San Diego
Posts: 4,870
|
I have been told to use dry ice to clear out the fumes and oxygen. I have heard of water too. Tanks have both been dry and stored out of car for 1 year+
|
||
|
11-30-2010, 07:30 AM
|
|
|
French Import
|
The old school was to slowly fill the tank with water as it pushed all the gasoline fumes out, then dry the interior with compressed air to avoid rust, before doing any welding. Other folks filled with sand (yup!) and then thoroughly cleaned out the tank. Fumes can remain in the tank for a very long time unless you properly vent them out, and will explode if ignited inside the tank.
Bottom line: be careful!
__________________
Gilles & Kathy Happiness is not having a Porsche in the garage... Happiness is having a Porsche on the road!  86 Porsche 911 Cabriolet, 2011 BMW 1200RT, 03 Saab 93 Cabriolet, 06 MB E350 Estate |
||
|
11-30-2010, 07:34 AM
|
|
Carrera
Car with no name
