Advice on patching frame

[farmer]

The frame on my 91 has gotten pretty tender behind the drivers side front leaf spring hanger, about the size of an oreo cookie, and I've enlisted the help of one of my buddies who worked at a fab shop for a couple years to help me get it taken care of.

Question is what do you guys think is the best way to patch it?
He wants to cut out the section like this \_/ and just butt weld in a new piece with 1/4" plate, with no fishplates of overlapping metal.
I've always thought that best and only way to cut and patch is fishplate it anywhere possible?

 

[scooter]

I would fish plate. My .02.

 

[Explorin94]

^^AGREE^^

Fish plating would be the strongest way to do it.

 

[brinker88]

Remove fuel tank/s and fish plate it on the BACK side of the frame as well as patch the hole. Fish plating the back side of the frame allows the hanger to be bolted back on in the proper spot. You will need longer bolts. Absolutely NO vertical welds on the patch.

3/16" should be sufficient enough.

 

[alwaysFlOoReD]

And no sharp angles on the fishplate, round them off. The reason is to prevent a high stress area prone to cracking. Also make sure as brinker 88 says, if possible no vertical welds, tho my cage is attached with vertical welds on 2"x6" onto the frame....no signs of cracking yet. A diamond shape<> with rounded points on the ends is best.
Good luck,

Richard

 

[whissiswheelin]

Agree with fish plates i have seen them done this way as well > <

 

[farmer]

How thick is the stock frame, 1/8" right? I just picked up a sheet of 1/4" plate so thats what im going to use to do it.
What I'm wondering is how I should fishplate the backside of the patch piece if the patch is thicker than the frame.

 

[alwaysFlOoReD]

Make the patch flush where you are going to fish plate.

Richard

 

[farmer]

So I got the gas tank out today and found alot more than I expected...