Pajero Owners Club of South Africa

Ok, forgive the uber dumb question, but how is one supposed to weld the internal ribs of the box section? You still need quite a lot of room to get the rod into the spaces assuming you weld the outer "skin" on last.

Refer to my post.

"Puddle" welds.

Weld the outer (40mm ?) to the one outer cover plate.
Weld the webs to the first cover plate and (40mm ?) cover.
Mark the webs on the second outer cover plate.
Cut a few slots / drill holes in the positions of the webs. (The slots / holes now align with the webs)
Weld the second outer cover plate's perimeter to the (40mm ?)
Weld the holes / slots by puddle welds to the webs.
Grid off the excess.

Aaah...lighbulb moment - never heard of the concept of puddle welds.... So effectively you are exposing the edge of the inner web by the slots or holes in the "skin", and then filling those holes up. Right?

SimonB wrote:Aaah...lighbulb moment - never heard of the concept of puddle welds.... So effectively you are exposing the edge of the inner web by the slots or holes in the "skin", and then filling those holes up. Right?

Right!

I believe the correct term is slot welds or plug welds.

This also presents the opportunity of using slot-and-tab construction so that the structure jigs itself. The tabs are sized to protrude only halfway into the slot. This allows the structure to be pieced together like a jigsaw puzzle so that the slot welds can be completed. Laser cutting of piece parts is advisable for accuracy.

I accept that as usual Gerrit knows more about mechanical issues than I do!

The slot and tab is obviously the best, but out of range for the average backyard fabricator.

Simon,
Remember our previous discussion about aesthetics on a bumper?

The attached photo shows ARB's bumper for the Isuzu D-Max.
See how the design 'picks up' on lines and angles of the vehicle.
Based on my requirements, that is good design!

Well I have realised my bumper project is further away than anticipated I am going to need some considerable practice with the welder before I am proficient enough to build a bumper. I spent all of yesterday fiddling with various bits, but am far form doing anything satisfactory.

I would consider myself 'reasonably' competent with a arc welder, but if I have to build a bumper now, I would only tack the bits together and have it welded by a professional workshop.