Welding Tips and Tricks

Hi. I have a pretty large tractor with a 7' wide rear scraper blade. The blade has a curved shape and is 3/8 inches thick. The problem is, the blade is not quite wide enough. I need an 8' wide blade. I need to add 6 inches to each side so that I end up with 8'. The blade is approximately 15 inches tall, with a 4 inch high hardened edge that bolts on the the very bottom and runs the full length of the blade.

My plan is to cut 20, six inch long, pieces of 1-1/2" wide, 3/8" thick flat bar, 10 for each side. By arranging the flat stock at a slight angle, I can re-create the curved shape. Sort of like pie cutting, or lobster-backing and exhaust pipe, which I have done. It works really well for making curves. I will simply fill in the bevel in the back of each long joint with weld metal. As far as the hardened edge at the bottom, I would just cut that in the middle and at a 6 inch filler piece to make it 8' again. That way I have the hardened edges at the outside lower corners where they are needed most.

My question is, can I simply butt-weld (well beveled of course) the extensions to the end of the blade and leave it at that? Or do you think I would need to add some kind of brace to the back side to resist the pretty sizable load on the outside ends of the blade to keep them from bending? I would TIG weld it because that's what I have. I know it's a lot of welding for TIG, but I need the practice and that would be a lot really perfect practice.

I've always heard that a proper weld is as strong as the base material. But to my common sense, it seems like it should be braced from behind. What do you think?

Any advice would be appreciated.

Thanks!

I would overlap on the backside by 3"

Wouldn't bother me to just double bevel and weld. 6" is not a lot of leverage.

Any chance you can just stick weld it with your machine? It would be fast by comparison

Although, tig at high amps with a 1/8" or 5/32" filler wouldn't be too bad.

Yes, I could stick weld it, but part of the reason I want to do it is to get TIG practice. I kill two birds with one stone. As I have been thinking about it, I've about talked myself into welding some real thick angle iron horizontally on the back. But like you say, 6 inches isn't much so I suppose I could try it and if it starts to bend, then I could brace it. Maybe that would be the way to go. Try it and see. Thanks for your input.