Tips and Techniques
How to make a ground pod.
By Maurice Blibaum
I was looking to buy a ground pod and I thought I found the perfect one when I saw the Skimmer. The Skimmer is a 10-1/2" round, by about 2" deep aluminum pan much like a frying pan (hmmm) with a small round disk in the center and sells for about $125.00. The shape seems to be perfect for sliding around in all kinds of sand or muck and feeling at the time like $125.00 was too much, I had the brilliant thought (especially since I have a machine shop) that I could make one cheaper!
Well, off I went to find an aluminum frying pan. I happened to find one rather quickly at the Restaurant Depot for $13.00 that was exactly the same size and shape. The only thing wrong is that frying pans come with handles and I did not want a handle on my ground pod (in hindsight it might not be such a bad idea. I would look for one with a wide C shaped handle like on some large pots or woks. I did eventually add an eye bolt so I could hang it from the outside of my pack). So out comes the drill to drill out the rivets holding the handle on. Once the center of the rivet is gone a good rap with a hammer knocks the handle free. Now I have three roughly quarter inch holes in the side of my pan that need to be filled. Originally I was going to weld them shut but decided against it. I thought too much trouble, heat and warpage so I turned my own aluminum plugs on my lathe and pounded the $%#@^ out of them till they expanded completely in the hole. I probably could have just put some small carriage bolts with nuts to fill the holes but I’m a bit anal and wanted them totally flush, so I proceeded to grind and sand the protruding bits of plugs flush with the pan. The outside proved to be easy using files and sandpaper. The inside was another story. After trying many different grinding type power tools none of which had the right shape to cleanly blend the plugs I had to resort to small hand rasps and tedious manual sanding to get them basically flush. Now I had to drill the 3/8" center hole to mount the pan in the lathe to power sand the interior. The result is shown below.
You can just see the outlines of the 3 holes
Next I had to make the small disk for the center of the pan. This has two functions – to raise the center a bit, so if you want to mount a Wimberley quick release clamp, you can turn the little knob, and also to make the center bolt captive so it doesn’t just fall out when you unscrew your Wimberley head.
I made this disk out of aluminum about 5/8" thick. It could have been a little thinner but I don’t think it really matters that much. I had a round of aluminum 2-1/2" in diameter that is a little larger than the base of the Wimberley head. Alternately you could use plexiglass/lexan or even wood although the softer the material the worse it will hold a thread. Drill a 5/16" through hole in the center and tap with 3/8-16 tap. If you don't have or can't tap a hole, you can drill a larger hole part way through to house a nut. Countersink both sides a bit so the edges of the holes are not sharp. I chamfered the edge to blend into the base of the Wimberley better.
Center disk on stand ready for paint
I was contemplating getting the pan hard anodized but realized quickly that with just this one pan, the cost would have been prohibitive, so after blending, I prepped the aluminum with Alodine, an anti-corrosion treatment used in the aircraft industry. This was probably not really necessary but I had some so…
Priming the aluminum to accept paint is a good idea and you can probably get a good aluminum primer at your local home center, hardware or automotive store. I used a 2 part epoxy primer also used in aviation, that I had laying around for a few years. I bought a Preval sprayer $6.00 (a self contained aeresol sprayer with a small bottle attached that you can fill with all sorts of paints) and is basically a throw away unit.
Pan prepped and alodined waiting for primer
Epoxy primer curing under heat lamp
Putting the pan under a heat lamp will accelerate drying and result in a harder finish faster. After 2 light coats I let it cure overnight under the lamp. The next day I sanded and painted the pan and disk with 2 coats of flat black rustoleum spray paint.
Center hole/stainless screw and countersink
3/8"-16 x 1-1/2" Stainless screw purchased at West Marine supply.
Stainless screw flush with bottom
Pan thickness 0.150" Wt. 28 oz.
The finished pod works with Wimberley head as is, but to attach quick release clamp the center bolt needs to be cut down to protrude about 3/8".
Some final thoughts…
Frying pan $13.00 (next day I saw a black one at Marshalls for about $24.00),
Preval spray pack $6.00
Black spray paint $6.00,
Stainless bolt $1.50.
Time for all the run around approx 1.5 hrs
Machine shop time worth $80.00 hr- 2 hrs.
Other time painting/sanding- 2 hrs.
This pod performs exactly like the Skimmer, weighs a little over a 1/2 pound more but is tougher and once on the ground where it should be it's pretty much identical. In hindsight I would have been better off spending the $125.00 and going out to actually take pictures instead.
Lots of time could have been saved if I purchased the black pan from Marshall's and either left the handle on or just cut it off and sanded the sharp edges. The center disk wasn't really that hard to make and didn’t take up much time at all. I’ll be glad to help any member of the club who wants to try this and does not have the proper tools or know how.