Bronze Casting Workshop

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Bronze casting (2024)

When casting at Maiale, you must provide your own plaster, wax for spruce

Grinding slurry (baked slurry) until very fine, place bucket under grinder, pull out black handle slightly so that v fine slurry may drop into bucket. Each bucket roughly one litre. Or wait is that 10 lol. Then one silver cup of chamotte in each black bucket.

Attaching sleeve to base: 5dl of plaster to just seal the bottom. This is 50ml and NOT 5 liters as I misunderstood.

Add water, mix thoroughly and then plaster 2 cups

Form touches base of mould then lift up by 2-3cm

You have to hold the form in place until the pour sets so the form doesn’t sink or float. You cannot do this alone.

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Wax forms and spruce

I think I made the spruces too long? Too much volume

The main lesson is these forms should have been sand casted flat. Because it is very easy to shape bronze after. A lot of pain blood and tears and costs could have been avoided. But I am learning lol.

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Patina

Bead-blasting

Blow torch to thoroughly heat bronze cast

Spray liver of sulphur on cast to achieve desired patina

When cast is dry, apply a solution of benzine and beeswax onto cast w a brush

Allow to dry for two days

(Benzine/beeswax alternative is nafta which only takes one day to dry)

Thanks to Ricky at maiale foundry for helping out!

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Invest in soldering iron?

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Nålfil fyrkant Bernstein tools / Diamantfilsats? / precision needle file set

Rotary file bit sicillage? Carbide burr ?

Aluminium sides protection for bronze piece when placed in vise/skruvstäd for steadying

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Monday 20230424

KKVMM Malmö / Maiale konstgjuteri - w Robert, Clara & Rique

Wax model (use Joel svenssons vaxfabrik - blend of beeswax and pine resin) / model needs to be strong enough to withstand slurry pressure. + attachment of spruce. Stickiness of resin helps to prevent cracks & aids attachment. Wax thickness should be 4mm-5mm minimum. Hollow wax models (pictured small pumpkin with spruce attached) will be filled with slurry and needs to be stabilized with small pins/nails. (Wax will be burnt out so baked slurry mixture is held in place)

Spruce system (ingjort) - fallande / stigande (weight of bronze means it travels to the bottom of tube first, and then rises?)

Spruce 1-2cm (some space so as to not damage model) but not too much that bronze must travel more than necessary

Try to imagine flow & movement of bronze

Clean off bits from large wax tubes with knife.

Soldering iron to attach spruce system. Attachment of spruce - must be “soldered” all around so slurry cannot enter.

Hot air gun/candle wax shaping, heat shaping tools.

Entry of bronze pour through wax cup, then thick wax tube: unobstructed flow

Points and tips which may be hard for bronze to reach - can attach blue small vents (luft-?)

Vents blue wax 5.0 wachsprofile auf roller wp 250g bredent bredent.com

Kostnader för brons tillkommer med 165 kr/kg (+moms) samt vax till modell med 635 kr/kg. (+moms).

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Wednesday 20230426 Mould-making

Sleeve - appropriate size for cast. Clamp to attach. Chicken wire to reinforce mould.

Spray wax model with alcohol

Investment:

Make a 4:1 part of (4dl) freshly ground fine slurry mix to 1 dl of plaster in silicone cup. Mix in water with hand until smooth. First layer to be painted onto wax model needs to be thin, and avoid air bubbles as much as possible - apply quickly. Thickened slurry can be used to seal bottom edge of sleeve on the ground. Make more slurry for coating wax cast subsequent layers, subsequent layers can be thicker. Work fast. Model needs to withstand slurry.

Slurry mix + 3L of chamotte red clay

First slurry pour into sleeve. Lower coated wax model into the sleeve until it touches the ground and then bring it up. Hold in the place as more slurry mixture is poured in.

Kiln / burnout over the weekend

Pic of two part mould for Joanna's small braid dipped in wax

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Friday 20230428 patina demo:

Finishing wire brush

Cutting off spruce w angle grinder

Sillage?

Sand-blasting bronze cast prior to patina treatment

Blow torch > heat > cast

Heat patina/blow torch: oil slick/rainbow

Ammonium chloride: green

Ferric acid: red

Liver of sulfur: black

Floor wax to finish/ beeswax

Mushroom casts: some which appear to be gold are aluminium bronze cannot be patina-ed

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Tuesday 20230502

Casting

Sand at the bottom in case of any cracks

Sleeve or frame for mould. Cover entry point for the pour (no sand must enter). Pack sand into frame/sleeve. Greatest pressure at the bottom.

Pre-pour preparation: Vacuum any loose plaster/sand on surface, air blast entry points.

An hour after pour: collect cooled bronze residue. Remove sand from frames/sleeves.

Begin hammering all over plaster/clay form on wheelbarrow. Remove chicken wire separately (burnt out slurry will be reused). Remove as much of plaster/clay for re-use as possible before water blasting.

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Water-blasting cast to remove clay/plaster/slurry residue

Bead blasting cast for better visibility (switch is upper on the right) gloved hands direct hose towards cast, pedal to activate blasting

Polishing (begin with block) gently angle cast towards wheel

Finishing: cutting off spruce system w angle grinder/cutting disc, grind cuts,