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How to Make A Bronze by the Lost Wax Process

Materials, products, processes, suggestions and tips involving how sculpture is made.

How to Make A Bronze by the Lost Wax Process

Postby mantrid » Sun Jun 26, 2011 2:07 am

I thought I would use this thread to show the process of turning a clay into a bronze. I think I'm at the stage with my dog sculpture where I can't do anything else but go onto the mould making stage.

I have already made the mould for the splashing water and cast it in wax. You can see it in the images. I am not that happy with it but cant seem to make it more realistic. I think the main problem is its looks too thick. Im hoping it will look better in bronze.


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mantrid
 
Posts: 45
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Re: How to Make A Bronze by the Lost Wax Process

Postby mantrid » Sun Jun 26, 2011 2:08 am

Heres the water splash mould making process

Original
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Clay wall around original
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First side of silicon rubber mould applied
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Clay wall extended
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First part of plaster mother mould applied
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Piece turned over and clay wall removed and washed and pouring cup attached
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Second half of silicon mould applied
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Second part of mother mould applied and pouring cup trimmed
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Mould opened for first time with original in place
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First wax copy made from mould
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mantrid
 
Posts: 45
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Re: How to Make A Bronze by the Lost Wax Process

Postby mantrid » Sun Jun 26, 2011 2:09 am

Dog mould steps.
Applying clay wall and pouring spout attached. A rectangular section has been gouged around th pouring spout, this will form a week point in the wax that I can cut out to gain access to the inside to pour in the core as this will be hollow.
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First side on silicon mould applied
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First part of upper mother mould applied and trimmed to shape. Petroleum jelly on the edge to stop the second part of the mother mould sticking
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Second part of upper mother mould applied and the piece turned over and clay wall removed
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First layer of second part of silicon mould painted on un-thickened to ensure it gets into all crevices etc. (did this for first half too but no picture)
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Rest of silicon thickened and applied over the top of first layer.
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First part of lower mother mould applied, trimmed and shaped. If done while still wet it is easy to cut.
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Finished mould tidied up (side)
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Finished mould tidied up (top)
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First wax cast
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Expanded view of mould parts and wax pattern. It hasnt been chased and sprued yet
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More to come later
mantrid
 
Posts: 45
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Re: How to Make A Bronze by the Lost Wax Process

Postby mantrid » Sun Jun 26, 2011 2:10 am

Wax sprued and ready for core (almost, see later). Im casting this one in a vertical position in the first instance to get a good head of pressure as the openings into the main part of the mould are limited to the back legs and where the knees meet the water splash. Also I want to be able to fit the shell in the furnace at the same time as the crucible to save firing up two furnaces.

The two thicker rods coming from the bottom of the water splash will be for attaching to the base. Usually I drill and tap a hole in the bottom of the sculpture and screw a threaded rod in. But here I dont have the thickness so I will cast them in place.
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Another view. Why such long vents? I'm hoping that there is sufficient head pressure to push some bronze up them to create some filler wire when I come to weld the back on.
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Detail of the cut out section. Also notice that when held up to the light there is some very thin patches that will need some more wax added before the core goes in (mostly its about 3mm thick and solid in the legs and tail).

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mantrid
 
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Re: How to Make A Bronze by the Lost Wax Process

Postby mantrid » Sun Jun 26, 2011 2:11 am

Bit slow with this one at the moment as I have to get some fresh binder for the slurry before I can do the ceramic shell. The severe frost this year has spoilt my supply, fortunately I was almost out anyway.

However, I have cast the core, so its all ready now.

For the sharp minded of you. The pins are copper coated steel so will be OK :)

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mantrid
 
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Re: How to Make A Bronze by the Lost Wax Process

Postby mantrid » Sun Jun 26, 2011 2:12 am

Further progress on the dog sculpture. Its been raining here all week AGAIN. However, today I was off work and the rain stopped, so I got myself set up to do the casting this morning. Below are pics of the results, but first some pics of the shell application.

First layer of slurry and stucco. The green/yellow colour is a pigment in the binder that changes to orange when the coat has dried
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Second layer
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About the 4th layer I think.
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Final layer of slurry to secure the particles of the last stucco layer stop them dropping off and leaving bits everywhere
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Another wax I did at the same time
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Same wax with some ceramic shell applied. This image clearly shows how the exposed surfaces dry much faster than the nooks. The orange indicates its dry enough for the next stage, yellow = still damp.
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I actually did three shells in total this run here are the two others besides the dog
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Two done one to go. At this stage I had to wait for another batch of bronze to melt.
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The aftermath. The little piece of rod on the left is my steel stirrer that melted and fell off. I had the furnace burning much longer this run as I was cleaning up alot of crudy left over bronze and also I needed to refill the crucible to do the three shells, so I think I was getting to iron melting temps.
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All stood up. It started raining again just as I finished taking this shot. Prefect timing. The quality of the castings is good on the female figures, which is to be expected as I have done these ones enough. The dog was better than expected for a first go. Some work to do on it which I will show when I get it sandblasted. I was pleased to see that most of the fine vents filled so I have some nice compatible welding wire to.
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mantrid
 
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Re: How to Make A Bronze by the Lost Wax Process

Postby mantrid » Sun Jun 26, 2011 2:13 am

After initial sandblasting I had to do more work than expected. Some bits of shell musthave broken off and settled in the head and ears. Despite the head being down they didnt float up and were trapped. The result was relatively large pits in the ears, top of head and one of the eyes. These are the worst places to try and repair. I had to weld bronze into the areas and resculpt

The light patches on the head are the repairs. Basically the top of the head, bottom eye and the top half of both ears had to be sculpted with a dremel from lumps of bronze welded into these regions.
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This shows the bottom of the water splash and the two rods I cast in place. I threaded only one as two to secure such a small piece would have been overkill. The other I cut down and it goes partially into the stone and acts to stop any roatation.
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This shows the dog on the stone base which I have roughly cut and drilled ready. The other light patches on the dog are where the pins secured the core in place. I had to use large sprues left over to fill the holes (used the small wire I made to do the back) hence the large welds.
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Other side. The bronze is dark at this stage due to the heat from the welding.
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Detail of the green slate with drilled holes. The slate doesnt look much at the moment but polished up to a nice grey/green colour.
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Detail of the hole on the reverse side of the slate, countersunk to take the nut.
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mantrid
 
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Re: How to Make A Bronze by the Lost Wax Process

Postby mantrid » Sun Jun 26, 2011 2:14 am

Almost finished this one.
Sandblasted with glass beads gives a clean surface for patination.
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Patina applied. This is just experimental Ive been applying it and blasting it off over the last couple of days. Please feel free to critique it or offer suggestions as its still experimental.

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This one was taken with the flash off and shows how the green of the water splash looks in a different light. Im pleased with the colour but not happy with the water as whole.The wax for it is cast separately so I can still play around with it but not sure what to do. I may reduce it significantly as someone I showed it to thought it was a bush.
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mantrid
 
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Joined: Thu Jun 23, 2011 1:45 am

Re: How to Make A Bronze by the Lost Wax Process

Postby mantrid » Sun Jun 26, 2011 2:15 am

Heres the finished piece. Base = polished green slate. I will rethink the water for the next one.
Dog Sculpture Animation
mantrid
 
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Re: How to Make A Bronze by the Lost Wax Process

Postby vincentaabronze » Mon Mar 06, 2017 1:20 am

So many steps to make a bronze!
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