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Old 10-08-2014, 06:15 PM
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Gojeep Gojeep is offline
MetalShaper of the Month March 2015, March 2020,, June 2022
Join Date: Nov 2013
Location: Eastern Melbourne, Australia
Posts: 2,689

Originally Posted by Oldnek View Post
Top job there Marcus, progressing nicely. Very neat job of boxing those rails. Also good to see you are a couple steps ahead of fabrication with pre-thinking things like Crossmember mounts and supports.

Cheers John
Thanks John. I'd rather take the extra time early on and have it go faster later when it doesn't need to be done then and take longer.

To help control distortion from the welding, I placed the two frame rails back to back with some 75x50x6mm, 3"x2"x1/4", RHS in-between. Also added additional spreader pieces where the tube was not central.

The welds were around 100mm/4" long and always balanced with the same sized weld top and bottom as well as in the same spot on other rail before moving on. This way they are pulling against each other while cooling down. I would then move forward at least a foot to a cool section of the rail and repeat. I never welded a new section that was still warm from the last weld.

I did longer welds around the area where the upper suspension mounts were welded in to balance the shrinkage it has caused on the opposite side of the rail

18 metres or 59 feet of weld later, all done.

The the weld was ground smooth. First with a 9" grinder and then followed by a 40 grit 5" flap disc to sand it just like the other side of the rail was done. More will be done later.

Was careful to remove as little of the weld as possible. That is why it has a sharper radius than the pressed corners, but rather have that than weaken it.

About 2/3rds of the frame is free of bends and wanted to keep it that way. In the end after being separated from the RHS, Rectangular Hollow Section for the non Australians, and each other, the rail had a dip of just over 1/2" from the welding. I have pressed this out slowly to bring it straight again. Applying heat opposite the weld would have fixed it also.

Got a small peak inside the end of the frame and can see good penetration all the way through without being excessive. Wiped away the white powder and was pleased to see that all the weld through primer was still intact and only a few millimetres each side of the weld had burned off.
aka. Gojeep
Victoria, Australia

Invention is a combination of brains and materials.
The more brains you use, the less materials you need.

Last edited by Gojeep; 08-01-2017 at 02:48 AM.
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