There are some techniques I use for metal casting. Please note that metal casting is pretty dangerous. All of this is just for information. Dont’ use those techniques. I wont be responsible of any disaster that might happen if you try metal casting.

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Window handle restoration

Mechanical engineers say : 80% of material failure are due to fatigue. What is fatigue? When a mechanical part is subjected to repeated load below ultimate strength but above fatigue limit. In other words : pull the handle once, no problem; pull a thousand times it breaks. That’s what occurred to iron casted handle. The upper ring which forms the pivot is split into two. I will cast a new handle, using the broken one as pattern but with a rebuilt ring carved in the mold.

Crémone0 Crémone1Crémone2Crémone4Crémone5The first run is made of aluminum alloy, a kind of prototype. Final parts are castes in bronze.
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Bronze casting !

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Sand molding technique – spare part for a tractor

Molding is the operation that produce the mold cavity thank to a pattern.

Today, I’m asked for a spare part for a John Deere 4650. The front axle pivot was damaged by friction :

The aim is to obtain a part which will fit in the void and prevent further damage of the pin or the bore.

In order to built the mold we need a pattern. This is a part that look like the wanted one but is not made of the same material. In this case I use a two compounds silicone past that I force into the void. After it hardens,  I’v got my pattern:

Moulage en silicone bi-composant du logement de pivot usé

For economical purpose, the today’s part will share its mold with an other one. It is a replica of a casted part.

Les deux modèles moulés aujourd'huiToday’s patterns

A classical material for metal casting mold is silica sand (SiO2). Indeed it has many advantages, the first one :  it’s refractory. But sand alone is not consistent. That’s why it is added with bounding agent. In this case it is oligo-clay and oil. This mixture becomes very constant when rammed in a flask, and can be recycled at 90%.

The two patterns are set into a flask and powdered with talc.

Modèles et châssis
Talcage

They are covered with sieved sand.

Tamisage du sable de contact

Ramming begins with fingers.

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After the first contact layer, I add sand (no need to be sieved) and use the rammer.

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This operation has to be performed in a spiral way, from sides to center. Otherwise the sand is not well rammed.

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The operation is repeated until rammed sand level is higher than the flask. Then I use a flat rammer. A mallet will also do a good work.

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I finish with leveling the sand with a corner iron.

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The flask is turned over.

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I carve the sand in order to found the parting line.

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The sand is powdered with talc and the “drop” or upper flask is set up and filled with sand exactly the same way than the drag.

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The the mold is opened in order to remove pattern and carve sprue, runners, gates, risers, vent holes…

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The mod is blowed to remove sand grain, and closed.

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melting is an other article

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After shake out, here are the parts, with ingots of exeding metal and patterns:

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And finally, our John Deere is repaired.

Montage de la pièce finie

Bibliography

Here is a little bibliography about metal casting. Mainly in french, it contains some english books.

Metal casting

  • Le bronze d’art et ses techniques – J.P.Rama – Vial 2003
  • Moulage et fonderie d’art – D.Lambert – Vial 2002
  • Pour le fondeur d’alliages légers – H.le Breton – Dunod 1954
  • Pour le fondeur (fonderie de fonte) – F.Ouvrard, H.le Breton – Dunod 1953
  • Manuel pratique du fondeur de fonte – H.le Breton – Dunod 1966
  • Précis de fonderie – L.Goujon – Béranger 1932
  • Manuel pratique de fonderie – J.Duponchelle – Dunod 1923
  • Fonderie, éléments fondamentaux – L.Giai-Brueri – Dunod 1983
  • Fascicules technologiques du mouleur fondeur – G.Derouet – Librairie Delagrave 1927
  • Traité pratique de fonderie – A.Lelong, E.Mairy – Béranger 1912
  • Fonderie d’Art – D.Lavie
  • Fonderie – L.Guillet – Ecole centrale des Arts et Manufacture
  • Album de défauts de fonderie – G.Hénon – ETIF 1952
  • Défauts de fonderie – F.Boussard – Dunod 1952

Metallurgy

  • Métallurgie structurale théorique – H.Cottrel – Dunod 1955
  • Aide mémoire de métallurgie – R.Cazaud – Dunod 1964
  • Métallurgie – C.Chaussin, G.Hilly – Dunod 1962
  • La métallurgie – U.le Verrier – Société française d’édition d’art (date inconnue)
  • La métallurgie artisanales – M.Séry, C.Moretti – Vial 2014
  • Les chantiers du fer – G.dalstein – Serpenoise 2001

Refractory

  • Matériaux et produits refractaires – A.Granger – Béranger 1910
  • Les matériaux réfractaires – J.Lachnitt – PUF 1983
  • Making crucibles – V.Gingery – Gingery Publishing LLC 2003

Patination

  • The colouring, bronzing and patination of metals – R.Hughes, M.Rowe – Thames & Hudson 1982

Pattern making

  • La technique du modèle de fonderie – J.Masviel – Dunod 1927
  • Cours de technologie d’atelier – volume 5 : modelage – A.Druot – Eyrolles 1941

Molding

  • Guide du moulage – J.P.Delpech, M.A.Figueres – Eyrolles 2007
  • L’art du mouleur – A.Tesson – Baudry 1897
  • Etude de moulage type – H.Coste – 1951

Furnaces

  • Iron melting cupola furnace – S.Chastain – 2000
  • Small foundry furnaces – S.Chastain – 2002
  • La fonderie amateur – T.Aspin – Pratiques d’atelier 2010
  • Crucible furnace – D.Gingery – Gingery Publishing LLC 1988
  • La pratique du cubilot – G.Joly – ETIF 1948
  • Gas burners for foges, furnaces & klins – M.Porter – SkipJack press 2004

Forging

  • C’est en forgeant… – R.Strozzini – Emotion primitive 2007
  • Art et techniques de la forge – H.Bergland – Vial 2007
  • Custom knifesmaking – T.Mc Creight – Stackpole books 1985
  • The art of blacksmith – A.Bealer – Castle books 1995

Bronze melting

Winter recipe:

3kg of bronze (CuSn12) – 1kg of butane gaz – lot of fresh air- a pinch of charcoal…

45 min in the furnace, is the soup hot enough ? stir, skim and serve at 1150°C
Fusion1

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