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Discussion Starter #1
Any of you guys that have the MM full's...Did you weld just where MM shows in the destructions or, did you go whole hog, and weld up all the seams in the floor rail first (LCA Boxes and rail overlap), then grind it (Welds) down flush and weld everywhere that the sub makes contact with the pan? Do you think it would make that much difference to weld the P*SS out of it?
 

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I did grind down areas to improve the contact of the subs to the frame rails in the rear(makes welding better/easier too). I had already welded up my torque boxes and some of the seams around the area as well...
 

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I had this done on 2 cars and spoke with a metallurgist (friend of mine) as well as a stuctural engineer...both told me to follow the MM instructions and indicated that increasing the length of the bead would likely only add heat/weakness to the design...
 

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Discussion Starter #5
MM Subs Welding

Yeah if you went nuts and put too much heat into the rails I can definitely see how you could hose the metals properties.

I tore into mine today with a 1/2 pound spool of Mild steel Flux cored and let me tell you it was a PITA. There is a gap at the rear due to the rails having reinforcing from the rocker panel that doesnt extend the full width of the rail. this causes a gap at the interface and filling that gap with a MIG and 2 dissimilar metals proved to be a little much on my limited welding experience. I used the whole spool and only finished drivers side rear. a B-load of welding grinding and rewelding to fill the voids in the gap. I ended up adding a plate to the inside on the rear because I was worried that i had weakend the rail and wanted to get more support in the un molested material further up the rail.

You always see welders and they look like they can barely figure out how to breathe on a regular basis but, after today, i have a lot more respect for the dudes.
Definitely an art.
 

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There is definitely an art to welding on the underneath of the car with barely enough room for your mask and hot metal falling in your face! It is difficult to weld to the sheetmetal in the Ford floorpan and framerails. You must completely remove all paint, rust, etc. Putting quit a bit of heat into the weld area and moving quickly helps. Definitely do not make complete seam welds down the length. 1" stiches will be fine.
 

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Discussion Starter #7
MM Subs

Jack
I struggled with the Amperage first and burnt throught the rail in a couple of small (3mm) spots (thats why i added a plate inside rear) until i figured the wire speed and tip movement was too slow for that amperage. I then sped both up and managed to get decent penetration in both materials. Just like everything else...Learn by doing and sometimes by F'ing up. Thanks for the input. BTW they fit well. Let's hope they cut the mustard for a hard core commuter :cool:
 

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I recently purchased their updated full length subframes, and a mig welder off ebay. I bought some metal stock to practice on before attempting the job. I did a set of subframes with a stick welder years ago and it was a big pain.
 
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