Bender's Head - eye shroud

The fiddliest bit of the project - the shroud which goes around Bender's eyes.
I first planned on building this part using slices of extinguisher and simply flattening the round section onto a mold/pattern/former, and then cutting and welding it on - sounded good in theory, but nearly impossible to do in practice without resorting to heavy equipment, or forging temperatures. - sorry no photos of that attempt - all evidence was taken to the tip months ago.

The second (and successful) attempt was to use a "built up" approach. I split some of the pipe I used for the arms and legs longitudinally, and inserted pieces of sheet in between the pipe halves to form up the shroud. In the photo below the two halves of a shroud are seen on the left, and a completed shroud on the right.

I didn't bother making the sheet the same length as the pipe halves since I knew the pipe had to go back to the centre line of Bender's head, where as the sheet did not. In the next photo the marking for the intersection with the head has been marked with a cheap whiteboard marker. (I grab the cheap ones whenever the discount store is in town - I use them for marking metal if I need to have contrast, or the ability to erase the lines (if on smooth metal) - I basically use whiteboard markers like chalk on rusty metal, or prussian blue on smooth. - I do use chalk as well, just whatever suits, or is within reach at the time)

The waste material is cut away, and the shrouds are ready for fitting to the heads.

A sharp observer will notice I have not cut the corners at the back of the shroud too accurately, and have instead commenced thinning the metal from the inside. Knowing the pipe has wall thickness of around 4mm (just under 3/16"), it knew a smooth transition would require the metal to be thinned considerably.

Fitting the shroud to the heads was fairly straightforward. I attached an eye-plate to the head, and then labeled one head "A", and the other "B". I then marked each shroud with a corresponding letter, and marked the top surface of the shroud so the shroud would always be placed on the same head, the same way up. I then worked around the seam touching up grinding, thinning, and contouring until the fit was less than 1mm (~1/16"). I also marked the head so the indestructible red paint could be ground away for the welding.

A note about the red paint... I don't know what NuSwift used, but that paint is amazing. It prevented rust for over 20 years, is hard to remove, and doesn't burn very well. In the welding photos a margin of only 1/2" can be seen between the weld, and the unburnt paint. I weld salvaged material a lot, and the epoxy paints favoured by local industry burns to a margin of at least 1" when I weld comparable thickness metals. The interior of the extinguishers had another paint inside which was pretty good at well... a thin grey paint which was found failed in only 3 of the 40 extinguishers I cut open.

Back to fitting the shrouds on...
Once fitted, the shrouds were welded in place (see photo below), and I then ground and rewelded to try and build a neat consistent fillet.
The fillet is just visible in the photo below. I placed the eyes on the plate, and bolted it in for testing the fit and look - perfect!!


The next thing to do was the liberal application of bog (automotive body putty - "bondo"), and a lot of sanding and general clean up of welds, fits, and general appearance.
I didn't take photos since the amount of dust generated from the process coated everything with a lovely dust, and I didn't want the camera filled with it.
My approach to the preparation for painting was to sand back all rust, and paint, and then apply a skim coat of bog, and then sand back so the surface was smooth. I predominantly used a flap wheel on my grinder for the aggressive work, and used files, knives, and sandpaper for the finer work.

Looking back, I know I missed a few spots here and there - I'll be the first to admit I simply wanted to get this project finished, and weighed the effort for perfection, versus the return on my time. As I said a few times to people, "it's a lawn ornament, not a show piece. I can always go back and strip him back to metal and refinish him if I change my mind."

Next article... painting. I'll discuss the colours I used, and masking the "fiddly bits"

Bender's Arms

The arms were made from the same size pipe as the legs, but needed a significantly more aggressive curve coming out from the shoulder. I marked up the 12,2,and 10 o'clock line as I did with the legs, but placed the cut lines closer in the are with the tightest curve. When I cut the 300 degree segments, I cut them wider by using the 2.5mm wheel, and making distinct V cuts, instead of simple straight cuts. The cut, but not bent, arms are shown on the welding table.


The welding table will be the subject of a page in the future, I'm rather pleased with how it turned out.


A closeup of the cuts showing the V cuts in the 300 degree segment. As I bent the pipe I had to tweak these cuts here and there to get the tighter curve for the upper arm.

As with the legs, I omitted to photograph the welding process, but it basically was grind out the cuts to remove the surface rust, then weld the cuts closed, and fill the open cut on the 60 degree segment cuts. The welded arms are seen laying on the ground in the last photo in the legs pages.

Now to make the shoulder/arm joints...

These shapes were made in the 4mm sheet I'd used everywhere else. The one on the left is the ellipse shape to match the arm pipe when cut at 45 degrees, the one on the right was welded into the shoulder joint (see the body page for this). The central bolt will be used for retaining the arm, and the smaller bolt will engage with one of the eight radial holes to lock the arm in one of eight positions. The photo shows the nuts I used to hold the bolt heads in place until they were welded in place from the back.

The above photo shows the ellipse plate welded to the arm pipe. I cut the arm at 45 degrees and then tack-welded the ellipse plate in place before grinding the closer fit, and then finishing the weld.
How did I mark the 45 degree cut on a the curved pipe? - A trick I read about used by blacksmiths was employed. I filled one of the quench buckets near the door with water to the brim, then carefully laid the pipe into the surface of the water so the waterline would mark the 45 degree line. Then I removed the pipe and highlighted the line with engineer's chalk. - The original blacksmith trick used coal dust floating on the water's surface to mark the line, but the rust on the pipe showed the line for me.

The "nut" on the central bolt was whipped up by welding a short length of 3/4" pipe to the nut, and then slotting the end for a scrap of sheet. A few tack welds and I have a long-reach wing-nut.
The photo below shows the wing-nut being used from inside the body to hold the arm in place at the shoulder joint.


A progress photo of the arms and legs attached. The arms were later shortened since I had deliberately made them longer than needed until I finalised the design for Bender's hands.



Next... Grabby and Squeezy - a.k.a Bender's hands

Bender's foundations - feet, legs, base - part 2

Once the pipe for the legs was cut and curved, I welded the cuts and welded the legs to the foot cups on the base. I didn't think to photograph it, but the next step was marking the top of the legs to be level with the base, and at the appropriate height. To do this marking, I used the trick used by cabinet makers, (and dressmakers) of using a block of "stuff" with a pointer and marker contacting the legs, and then rotated everything around to completely mark the legs. In this case the block of "stuff" was the body previously made, packed to height with some pieces of timber.

Once the legs were trimmed to the correct height and level, I tested the fit with a plywood disk I used to test the body of roundness.

A photo of the "high tech" tool stand I used to keep the tools off the welding table whilst I was working. The three grinders proved quite useful since the 9" (230mm) grinder was used with the 2.2mm wheel, the 4.5" (115mm) with a standard grinding wheel, and the 5" (125mm) with the 1mm cutting disks. Yes, I used the faceshield and earmuffs... I value my eyesight and hearing, and see too many of my friends from industrial backgrounds with hearing loss from exposure to these kind of jobs.

The leg joint plate was made by placing an appropriate strip of sheet on top of the crotch plate and drilling all four clearance holes at once. I then marked through the curved (elliptical) ends of the legs, and split the strip with two tabs - one on each leg, both pointing towards the middle of the crotch plate. I then welded captive nuts, and bolts in the joint plates so each leg has one bolt, and one nut for securing it.

The welds were ground back and touched up prior to painting, but the above photo shows the captive bolt on the left, with a nut spun on, and another bolt spun into the captive nut on the right.
I choose a single bolt for each leg to make alignment during assembly easier, but I wanted the extra strength of two bolts, hence the second bolt added into the captive nut.

As always, I like to stack the pieces together to see how my progress is going. This what Bender looked like at the end of the day making the legs. It's obvious I had been picking at all parts of Bender instead of completing one part, and then another.
Until the next installment...