Boxed trailing arms

[Yoshi]

I've been thinking about switching to the boxed arms for a while now, but was under the impression it would take a lot longer to weld them up than to just building them out of tube.  I've seen them done different ways, with some that have quite a bit of internal cross plates, and some that have none at all, I wasn't sure the best way to go about constructing them, but I may go ahead and gets some drawings over to the plasma cutter so I can at least get a set built and see what I think.......

What's the most common thickness to go with?

[BDKW1]

Some well place bends cut down on welding time significantly.
 
bottom plate .156-.187
side and top plates .090-.125
internal ribs .060-.090
 
MC powered buggy's are going to be on the lighter side.
 
 

[01SANDRAIL]

The ones that I am building right now are made almost entirely out of 11ga. mild steel plate.
There are some other braces or (Ribs) inside as well. I am hoping to get them put together real soon. I am in the process of moving into the new bigger shop so as soon as that happens I am going to get some hood time and try them out. I know how long it takes to make a good set of tubular arms and I think these will be much faster. I will let you know once I have completed both sets that I am making.

[standfast]

If I were you I would make those top and bottom plates extend past the side plates and make them key together.  This
will give you a stronger inside corner weld as opposed to the more prone to cracking outside corner weld. BDKW1
suggested that to me after mine were already done and wished I could have gone back and used his advice.  Mine
have not cracked and I don't think they will but the idea made sense.  Then doing like that would make keying the parts
together easy and make assembly a cakewalk.  Boxed arms go together MUCH faster than tube arms.

[Doug Heim]

I believe I posted this up before but I will do so again as it may be a great refrence for someone to use if they wish. This is a set that I drew up in CAD to have cut for a race truck. These are the front lower control arms for a double A-arm 4X4 suspention...

[fabr]

Anyone want to show some pics  of the bung attachment/anchor  method they use in the sheetmetal.Seems to me like this is rarely addressed, and I'm curious as to how some of you have done it. . 

[Doug Heim]

the above arms are used with mono balls.

[BDKW1]

Anyone want to show some pics  of the bung attachment/anchor  method they use in the sheetmetal.Seems to me like this is rarely addressed, and I'm curious as to how some of you have done it. .

On A-arms, I do the side plate first and weld the insides with the mig and tig the outside edges.
 
On a trailing arm in the rear, I have 4 pieces the hit it. The inner to get tiged to the end and then the outer pieces  hit about half way down the bung and get tiged on.