This is my hobby.
I am just showing DIY that you can fix it yourself. Saving $$ and having the satisfaction of you did it. Some folks pull the bodys off. Some folks put other frames under them. You can do it that way if you wish and have the room and the tools to do so. :]
As for the frames repair, The entire reason I do this is to improve my welding skills. Anyone can weld in the standard position. Learning how to weld upside down and on non clean new steel takes time.
If you take you frame out and sandblast it. You still need to cut the rot out and get rid of oxide in the inside of the frame along with sealing the frame holes. So plating the inside with a new bottom would accomplish this. Plus if you ever need to put new body mounts on you have steel to weld to as the plates are inside the frame and easy to weld to.
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