What is pot metal and why is it so difficult to repair?
Pot metal is a smorgasbord of metals, zinc, cadmium, lead, magnesium, copper, aluminum, tin, iron and any other leftover metal with a low melting point. Low melting point is the key because what they did in the early 20th century was grab all the scrap metal put in a big pot and melted it. The the mixture was poured into molds. Smorgasbords of anything are hard to repair. Weld are usually done with like materials.
There is another reason why pot metal is difficult to repair. Bad engineering. Two examples. Vintage cars often had pot metal horn rims, very thin horn rims. Drivers who had to make a sudden stop where slamming on the brakes and blowing the horn was required would often break the horn rim. Because of the lack of adequate surface area broken horn rims is almost impossible to repair.
We’ve seen many pot metal pieces that had a slender shaft with a heavy top. If trauma occurs, there is little chance of a satisfactory repair. Again there is not enough surface area for the repair to create sufficient strength to be durability. Unfortunate because some of these pieces are beautiful.
Pot Metal Repair Video
Repairing Pot Metal
A Starter Kit is necessary to repair pot metal.
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A Starter Kit contains:
- An SI Structural Adhesive
- Our Activator/Accelerator
- General Instructions
Instructions for repairing pot metal
- Make sure that the ends or edges of the pot metal are clean and free of oil and grease.
- Take a wire brush to the ends or edges to remove the corrosion. You do NOT want to be so aggressive that you can the shape of the pot metal. A flush fit is critical to an adequate repair. When finished wipe with a soft cloth.
- Apply an SI Structural Adhesive to BOTH ends or edges. Pot Metal repair is the only time where we consistently recommend applying the adhesive to both ends.
- Firmly press the ends/edges for fifteen seconds.
- Spray the seam with the Activator/Accelerator
When possible wait twenty-four hours before putting into use. Choose your kit below.
When there are pieces missing
Because pot metal is so porous a break may often results in small pieces flaking off. The problem is that those missing pieces reduces surface area. IF there is enough surface area, you can use our Filler to fill in the gaps from the flaked off pieces.
Our Filler is a silica sand compound used to fill holes or gaps. To use, spread a thin layer of an SI Structural Adhesive on the problem area then sprinkle the Filler on. Repeat as necessary.
Choose a Basic Kit if you need the Filler
Belt and Suspenders Approach
Basic Kits include:
- An SI Structural Adhesive
- Our Activator/Accelerator
- The Filler
The Filler can be used to add 5-10% more strength. Apply the SI Adhesive to the seam of the break spreading the adhesive like you are covering a dry wall seam. Sprinkle Filler on. The second coat is the adhesive, then spraying the lightest mist of Activator/Accelerator possible.