Projects '40 Ford frame repair, Welding advice?

Looks like my 39 Mercury frame, it's rusted through on the same spot.
Mine was full of sand, dirt and other sh.t
No reason not to weld it, after all it's only metal

 

almost done with the outside of the frame, just a few spots to fix on the "X", hopefully rolling soon.....

 

Looking good man!

 

Here are some pictures from my 40 frame repair.

 

I would fix that myself. The reason people say you need a jig is because frames will warp when you weld on them. I use a 4x8 table made out of wood (built like a brick shit house) some scrap angle iron over top the rails screwed down to the table. Built frames this way several times and no warping. Works good.