Since pot metal — a die-cast combination of several metals including zinc— is frequently found in items that must endure different applications, there are unique challenges associated with this type of preservation. There are several key steps in the restoration process that play a vital role in preserving their longevity and restoring aesthetics.
Pot Metal Refurbishing Explained
Initial Assessment:
The first thing to do is determine whether the extent of pitting and corrosion can be fully repaired before initiating restoration. Their size and depth can be very different, which again affects the way in which they are restored5.
Preparation:
The first stage of pot metal restoration is to strip off any plating in place. This is typically done using a technique known as electro-stripping, where sulfuric acid strips away previous layers14. The Outcome: This is very important to have a clean surface for next treatment.
Surface Treatment:
The surface may show instances of traces such as pits or scratching once the area has been removed. Acknowledging that these things can be fixed by sanding or grinding down the spot14. Where called for deeper pits can drill out and filled back in with silver solder which is stronger than the parent metal 5,6 (Fig.
Copper Plating:
Then a thicker layer of soft copper plating.pot metal restoration (ad) This not only covers up any remaining blemishes but also serves as an undercoat to later plating steps 25. While copper plating assists with the adhesiveness of subsequent layers.
Final Plating:
After the smooth finish is achieved and unified, additional layers of plating – often nickel then chrome are used to plate copper. This multi-layer system increases life and gives good looking similar to the metal, newly painted15.
Pot Metal Restoration Challenges
Material Sensitivity: Pot metal melts at a low temperature and can become distorted or develop an unsightly color when repaired. 2 It is critical to use proper soldering techniques which do not introduce excessive heat.
Intricate Pot Metal Parts: Much of the pot-metal automotive items are detailed, complex shapes that could be problematic in restoring them without damaging fragile areas4.
Corrosion: MacIsaac says that even new old stock (NOS) parts can show pitting caused by air bubbles wrapped when the casting process took place, making restorations problematic5.
Conclusion
Pot metal is delicate and you need to have a light hand when working with it while employing correct repair methods. Restoring a piece to the maximum level of natural finish can be arduous, but if stripping is done properly and followed by surface treatment with copper plating before final coatings all aging metals will only need a touch up or two.