Welding advice.

[Warthog]

I have acquired some 30mm x 5mm steel flat bar and I am in the process of making a Jerry can bracket and mount for my Ural.

I won't be doing the welding, but I am prepping all the lengths of metal that I will then bend and twist to that , once welded, they will form my can holder.

I am measuring up the Jerry can and cutting the bar accordingly. I am giving myself a bit of extra for now, but once I start working the metal down to the exact lengths I want so that the jerry can is snug, do I need to allow any length variation for the welding so that the finished article is the size I am planning for?

In other words, if my Jerry Can is 37cm wide, do I need to allow any extra metal for the weld, or should I even take a bit off to account for the material the weld will lay down?

I don't want to slave as I have been today for it all to be a few mm too small for the can to fit!!!

[Wee Bro]

5 mm mild steel is heavy enough to weld wilthout worrying about twisting or distortion and you can also grind a channel in the joining surfaces (5mm is very strong and will allow for this) so the weld wont protrude past the surface of the metal.
As long as your mating surfaces are prepped and bevelled a little to form a groove then I wouldnt worry too much. What you weld is what you will get.

[Warthog]

5 mm mild steel is heavy enough to weld wilthout worrying about twisting or distortion and you can also grind a channel in the joining surfaces (5mm is very strong and will allow for this) so the weld wont protrude past the surface of the metal.
As long as your mating surfaces are prepped and bevelled a little to form a groove then I wouldnt worry too much. What you weld is what you will get.

Hmmm...

Seems I may have to get those metal files out.

OK, so if I understand correctly, say I am welding the end of one flat-bar length to the face (ie the 30mm wide surface, not the 5mm surface) or another, I would need to file the end I am welding to a mild groove and on the surface of the other a mild groove to match so that the welding material collects there?

Is this what you mean?

Cheers.

[Wee Bro]

Ooops sorry no, that would be if you were joining two flats into a T shaped join. Just keeps it tidy. I would make the pieces to fit the jerry can the way you want them and get them welded up. Sounds like you are paying very good attention to preparation (which is the key) so I wouldnt worry about the welding end of things too much.

[Mr NiceGuy]

Don't have the fit too snug as the fuel expands pushing out the cans and if fit is too snug they're a sod to get out. The locking mechanism should be used to hold the can in place rather than the snugness of the fit. You can always use thin rubber spacers to keep the can from rattling.

[Warthog]

Ooops sorry no, that would be if you were joining two flats into a T shaped join. Just keeps it tidy. I would make the pieces to fit the jerry can the way you want them and get them welded up.

Fair enough. Actually this just means less work, so good!!

Don't have the fit too snug as the fuel expands pushing out the cans and if fit is too snug they're a sod to get out.

In both cases, I plan to give it a bit of space: maybe 3-5 mm play either way. I had not even thought of exapnsion of the fuel, only that I have a history of designing a nice idea and cocking up on basic maths and measurements!!! That way I'd have more space than too little: always better.

Thought of padding it out with foam, or draft excluder tape for windows. As for the locking mechanism: no idea yet, except that I will try and build it so that it also blocks access to the can cap, so syphoning fuel while we sleep won't be possible.....


If it looks OK, I'll post pics in the end. Won't be for a month or so I reckon...