Need ideas for making a mold / dam to pour epoxy into for steering pedestal base

As you can see from the images below, the base of my Edson steering pedestal is almost gone from corrosion. I was hoping I could replace just the base (because it looks like a separate part) but I called Edson and they don’t carry that part. In spite of most of the base being corroded and gone, the column is still solid with no movement. So, I was thinking of chipping, grinding and sanding away the loose stuff with the column in place and create a dam about 1 1/4” tall where the base should be and fill it with a mixture of epoxy, white opaque and milled fibers. After that I’ll round over the edge and finish sand and it should be good to go for another 25 years.

I’ll be pouring the epoxy in place and directly on to the cockpit sole (I think) which means the dam won’t have a bottom or a top - just sides. That means the dam will be a ring with an inside diameter of approximately 10 1/2” and will be about 1” tall.

Got any ideas for how to make this dam or ring thingy and how to keep it in place until the epoxy cures?

thanks

 

How is that base attached to the boat ?

 

There are 4 bolts that go through the cockpit sole. It’s also supported by the 2 bolts forward of the column. I really don’t want to remove it.

 

Cut a hole in a piece of MDF of about the right thickness for the job and slightly too thick is better than too thin.Make sure it has a touch of draft and give the edge a couple of thin coats of shellac-after de-nibbing the surface it might be good enough to mould from,but if not a careful wrapping with brown parcel tape will work for releasing it and a quick waxing will help.Take note of which way the draft needs to go and you should be able to hold it in place with a dab or two of hot melt glue.If the boat is too far from power for this to be feasible a few tabs of wide masking tape on the sole will be useful for blobs of polyester body filler and should release when needed.The bottom edge of the MDF will need a small radius all round the inner edge to stop the epoxy pour from running out and a piece of fence wire will probably give about the right sort of edge.At which point you can pour your mix.If its viscous enough you may be able to sweep the correct cross section all round the pedestal-if not it will be a job for another day.When cured a few wedges round the periphery should get the MDF clear.

 

The bolts, which I’d guess are stainless steel, are the root of your problem, and are very likely in bad shape too.
I’d invest the effort to remove the whole pedestal and replace or repair it.
The sole may be damaged as well.