Adding an Auxillary Fuel Tank

[Jim-ME]

I know I need an additional outrigger to add an extra tank but, my frame is galvanized and if I weld the outrigger to the galvanized frame I will loose the benefits of the galvanization. Is there any way I can bolt the additional outrigger to the frame in order to keep the galvanization intact? Thanks in advance.

[KingSlug]

You would need to grind the galvy off the frame to weld the outrigger to the frame, as you cant weld steel to zinc. I would drill through the frame and bolt the outrigger to a backing plate on the inside of the frame. I might also suggest some body adhesive to add strength and provide corrosion protection between the backing plate, outrigger and frame. Also start with a galvy outrigger and use the right bolts.

[Chris McKnight]

Weld

If you're going to drill through the galvy you might as well weld through it.

If it were me, I'd grind the galvy coating off, spray the ground areas with weld-through cold galvanizing compound, weld the outrigger on, then spray the welds with cold-galvanizing compound and maybe even a little POR-15 on top for good measure. If all the joints are sealed up, then the chance of corrosion between the outrigger and rail is minimized.

You might burn off a little zinc inside the rail from welding, but if you drill holes through the rail, you've got the same issue. I understand the desire to do things right, but keep in mind that the original frame probably lasted 30+ years ungalvanized...

If you wanted NO change to the galvanized frame, you could weld a flange and bolts to the outrigger so that the bolts pass over and under the frame to a backing plate on the inside of the rail. So basically, the whole thing wraps around the rail instead of passing through it. One issue here is that there is not much clearance between the rail top and the floor panel, but I think there might be just enough.

Chris

[yorker]

LR had a bulletin of sorts for retrofitting the fuel tank and outrigger p# 607075, it suggested Riv-nuts(p# 501224). If I get a chance I'll scan it in.

http://www.fourfold.org/RoverWeb/lro/Year-1995/950908.html#28

Personally I'd weld the outrigger on and then seal the weld. there is a stick of sorts that you can use to seal galvanizing after it is welded.

Remember fumes made while welding galvanized steel isn't good to breath, a blacksmith died last year from it apparently... Soooo do it in a well ventilated area.

[leafsprung]

the dealer installed ones are all bolted on, the factory ones (military) are all welded. Id be tempted to bolt it in your case. I havent had any issues with the one in my 5 door and it was installed 35 years ago

[Jim-ME]

You have all been very helpful with ideas and recommendations. It will be a while yet because I want stainless steel fuel tanks. You imput will give me a lot to chew on.
Jim