We woke up and ate a wonderful breakfast while watching the deer in the yard.
Then we took a 1.5 hour tour of the
Valley Bronze Foundry that was incredibly interesting. At the start they had this piece of salmon returning to spawn.
The foundry does primarily artistic works in bronze, but also does things like doorknobs and handles in stainless steel. The process starts with the artist creating the sculpture in wood, clay, or some other medium and then bringing it to the foundry. Step 1 is to take many pictures of the piece to capture all the detail as many steps of the process remove details that they have to add back in.
For step 2 they create a negative sculpture using a special plastic. Because they are limited to a size of roughly 2x2 feet per piece, they have to break larger works into smaller pieces and they weld them together afterwards. In addition, they have to account for how the bronze will flow through the mould for complex pieces. Quite a lot of skill involved.
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| The piece he is holding is the negative mould |
Step 3 is to create a wax model using the negative mould. First they pour in 200 degree F wax, then a layer of 190 degree F wax, and finally a third coat of 180 degree F wax (left to right).
Step 4 is to add in wax channels for the bronze to flow and air to flow out of the piece. The pieces are standing on funnels that will be used for bronze flow. The red tubes are for bronze and the black for air. The workers spend a lot of time using dental tools, soldering irons, etc. adding back in details that were lost in the precious steps. For leafs, they just get real leaves and cover them with a thin coat of wax. At this point you have one or more wax sculptures of the original piece.
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| Real leaves covered with wax |
Step 5 is to make the cement mould from the wax sculpture. They start with a very thin slurry and then work up to a special fine sand base cement over 7 - 9 coats. Since they have to dip the wax sculptures into the slurry bins, this is what limits the size of each bronze casting.
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| Thin slurry. Container size limits castings to around 2x2 ft |
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| Thicker slurry |
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| Fine sand with micro air jets on bottom so you can dip mould into it |
The '3' on the table above means these pieces have 3 coats of cement on them. On the lower shelf you can see several smaller pieces on a single 'tree' which is a funnel with a long tube on the bottom and pieces attached to its sides.
Step 6 is burning out the wax so it can be replaced with bronze. They do this in a big oven and recover the wax for use as the third coat in making the wax models.
Step 7 is the actual melting and pouring of the bronze. They use a special type of bronze that is 90% copper instead of the normal 80% copper. First they melt it to 2000 degrees F and then using a crane carefully pour it into the cement moulds. There will be several moulds on the rack behind the crucible that they fill at once.
Step 8 is to remove the moulds by carefully breaking them off the bronze piece. As bronze is relatively soft, they can not hammer directly against the piece, but break away what they can and then use glass bread sand blasting to remove the rest of the mould material.
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| Sand blaster is the box on the left side with moulds cooling down in the back |
Step 9 is to weld the smaller bronze pieces back into final piece. You can see a bear and foxes that still need to be welded together. They use a special welder that is between an arc and tig welder.
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| Sheep with weld marks |
Once all the pieces are welded together, they do a final detail touch up and sand blasting to remove all evidence of the welds.
Step 10 is to apply the 'patina' color. Basically different chemical washes will turn the bronze different colors. The temperature of the bronze determines the shade of the color. They can do all colors except for white this way - white color is airbrushed paint. So the worker takes a blow torch, heats up a small section of the piece and applies the chemical to get the desired color ( like the salmon at the start of the post). The artist typically creates a limited number of each sculpture.
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| Completed fox is 16 of 25 total |
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| This is not wood, but a bronze made from a wood piece |
After the color is applied, they either wax it (to get dull and shiny - buffed wax - finishes on same piece) or apply a lacquer (entire piece is shiny)
The last step is artist approval and then boxing up to ship to the artist patron who ordered the piece.
The foundry has created several famous pieces that are around the world such as:
I really enjoyed the tour. The guide was 3rd generation of the family running the foundry. If you know of anyone who wants to live way out in the country, they have a 6 month backlog and are looking to hire more people - all training provided.
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