Ask your WELDING questions here.

So we are talking about compound angles and multiple joints? No flat surface larger than about 6" or so? Will you be able to make all the welded joints a "lap joint"? Use 14 or 12 ga around the fill spout? Gasoline weighs 6lb/gallon so any sloshing will cause flexing in the joints/welds. And you know what can happen when anything is flexed enough times in the same place. 18ga is really limber and weighs 2lbs /sqf. 14ga is considerably stiffer, and easier to weld, and weighs 3.12lbs/sqft. 16ga @2.50lbs/sqft would be the min. I would use. So figure up the total sq/ft + add some for weld and see if the weight difference between buying one or doing your own is worth the time and trouble.

Depending on the design it could be more than heavy enough. I'd skip the lap joints and go straight butt welds. The guys I know who do that sort of stuff say laps make for joints that are harder to leak proof. Your leak could be 4" from where it's seeping at with a lap.

<BR>18 gauge is for sure fine, especially if you're shrinking the metal to make a typical fuel tank shape. Once the metal gets into a 3D curve/spherical shape it doesn't really flex.


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I only asked about 18 ga. specifically because I have some scrap from a "repurposed" heavy duty shelving unit. I already made some panniers for the DR out of it today. I have 4 large shelves left and then got to thinking about the tank...hmm...I wonder! Ha Ha!

So yeah, it was free, so my cost would be my time.

Whatever joint I need to make, if I decide to go for it, I will coat the tank with POR-15, 2 part epoxy to seal the inside.

I've never made a tank before, so I wasn't even sure what thickness OEM is. The stocker already has a big dent in the side, and if I screw it up completely, no big deal. Just order the Acerbis.

If I need to buy a heavier gauge, I can do that, too.

I plan on using a bag full of sand and a body hammer / hand dolly to finesse the shapes before welding.

I've never tried this before, but I like learning new things. I'm pretty sure I can pull it off, and if so, it opens many more possibilities for ideas down the road.

Post that on a new thread, or your other one, when you get going. Sounds very interesting.

Jim

Ya I'd like to see that too........... before any bondo is applied.

Will do.

I need to take some pics of recent progress to post to my rookie welder thread.

I've got my tubing bender all set up and I've been waiting 2 weeks for my tubing to show up to make racks for the DR.

Is there a trick to getting seamless welds (like around an exhaust fitting) with flux core mig? I can't for the life of me either a) get a good leak proof weld all the way around or b) get a seamless weld and not blow through it like its not even there.

Practice,practice practice.

A guy once ask me, "what the trick to sucessful brain surgery was", I told him to stop using a chainsaw...

I have been given a stainless mid pipe from a GSXR with carbon fiber Can that I want to put on my BWM F650 DAK I figure I can cut the Mid Pipe and then Cut the back section of the DAK pipe and weld the two together (or maybe have somebody do it)

I have a simple Lincoln AC buzz box for a welder

Questions are:

Can I use what I have to weld this pipe?

If So what rods would be recommended? I have no clue what type stainless this would be 300 / 400 series ect ?

If I can do this what would the recommended methods be?

Does your machine accept gas? If so, you may try switching from flux core to solid wire and shielding gas. You will have much less spatter and a more attractive weld bead.

You will need Argon/CO2 for mild steel, or Tri-mix gas for stainless.

Also, if doing exhaust work with existing tubing, make sure all the chrome is ground off the tubing, otherwise you will have impurities in the weld which will also cause the bead to not look the greatest.

I'm no expert, but I've discovered that on very thin materials it's best to lay a series of tack welds upon one another similar to the TIG welding process. I just did some 18 ga. mild steel using this method, and it turned out great.

edit - another thing I was just thinking of...too large of an arc length (the distance from the end of your torch to the welded surface) will also cause excess spatter.

So guys I have a broken R1100GS shock mount on the rear subframe and stranded in Nairobi (read Nairobbery) in Kenya.




















This part takes extreme abuse under 2up fully loaded bike on very bad roads and trails.

Any idea if there's any point bending it back together and welding it or will doing this just make it weaker and I'll have the same problem soon again? There's not much space to reinforce it - bottom recession needs space for shock movement, upper part is with seat mounts attached.

Or it's better to cut the complete mounting part off and CNC a brand new one - stronger than original? Cutting it out is quite complicated as you can see, so it'll be a risky business as well.

There's one CNC place here and some sorts of weldings are also possible.

Any idas, thoughts are highly apreciated since I'm currently a stranded traveller because of this.

Happy new year,
Margus

Since the exhaust tube is a thin wall your dick (stick) welder is just about useless unless you want a crappy looking, leaking and weak welds.

imo your only option would be to find someone to tig weld it. 300 or 400 sereis won't matter much as the welder will still use 308l filler.

I would reinforce and modify the existing on the seat side then cut away the seat to fit. Sacrifice a small chunk of the seat for the most important part, the frame.

Welded correctly it will be as strong as it was before it was broken. I think I would opt for straightening and bracing as best you can and then get a good weld on it.

I personally would straighten it, then weld it, then attempt to brace it the best you can. I don't think that this type of part would be a good CNC'ed part.

Take it to a welding shop. they should be able to make the repair. Any attempt to make this part stronger will only result in the next weakest link failing.

<BR>+1 on welding the cracked upper shock mount. Depending on access, you may have to cut off the seat mount bracket, make the weld to the shock tower, then reweld the seat mount bracket.

All the subframe material is low carbon (aka: mild) steel, it isn't hardened. It can't be be hardened because of the low carbon content. The heat from welding will not change its strength.


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i would put a lettle bevel on both edges of the break than bend it back into place and weld it. than grind the weld down close to flush, and take a peice of strap (3/4 x 1/8 or something like that) and lay it over the weld, like you are puting a back up plate on it. but you are not working on a flat surface so you are going to have to tack one end and heat hammer bend and weld the strap into form, i have heard this called fish plating