Bronze casting... interesting range of techniques

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pullrich

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Powning is using standard jeweler's investment casting techniques.
If I were going to do a tutorial, I would at least learn how to spell the key words like "sprue" and "mould."
 
Bill DeShivs said:
Powning is using standard jeweler's investment casting techniques.
If I were going to do a tutorial, I would at least learn how to spell the key words like "sprue" and "mould."
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I agree with sprue, but apparently Mould and mold are both acceptable.
 
You spelling wizards have any experience with bronze casting? Would be great to read if so.
 
Yes, and gold casting, and silver casting.
My point was that if someone were going to the trouble of doing a tutorial, they would make sure their spelling is correct. Believe it or not, proper presentation goes a long way toward being taken seriously.
I actually saw a knifemaker at a BIG show that had a banner that said "Custom Knifes." It makes you wonder what other short cuts were taken.
 
I cast bronze in sand, I also do lost wax in jeweler's investment both by vacuum casting (I built a bigger version of the machine Jake has, and use the identical machine to what Jake has for vacuuming the investments) I have friends who claim to cast bronze in soapstone, I personally have only used soapstone for casting pewter

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I love the technique! I use the jewelers' (or dental investment) approach to lost wax casting.

I was a young buck when I first started working with lost wax casting back in the 70s. I made a vacuum chamber from a 1 gallon jug that I cut the bottom off of and whittled a plug for the neck which I inserted a tube through to introduce the vacuum that was pulled using a compressor from a refrigerator/freezer. I made my burnout oven with soft firebrick and old stove top electrical element coils. I cut muffler and tail pipes to make the flasks. You should have seen the centrifugal casting machine I made using a electric motor for the drive with a loose belt that would slip while I held the arm until I let it go and the belt would grab and spin it up. I used an enamel coated washing machine tub for the containment wall around the spinning centrifugal arm to contain any escaped molten metal. The rim at the top of the tub was a perfect lip to prevent any slung melt from flying up and out, not that I ever had any incidents mind you ;). The whole setup and processes were a hoot. I had a blast! I since learned how to do it all with genuine machinery used by the pros.

Fast forward to now, it can be kind of "cool" warming up the tang of the blade and melting it through the wax prior to carving and shaping it. I haven't worked at it enough, but believe the approach has lots of potential for carving designs and forms in or out of the wax. Seems like the technique would be great for take-down type knives. There is a shrinkage factor, thus the cast bronze (or silver, etc) pieces won't fit down and sit on the steel like the wax models used to cast them did. I have a friend who specialized in dental sculpting. He used some process to compensate for the shrinkage factor on the cast crowns. I sure would like to learn more about that!

What are your ideas and what kind of stuff would you like to do?

PS - I hear what you fine folks are saying about first impressions re spelling and agree (to a degree.) As a high school teacher I have learned NOT to judge a person's worth by his mastery of spelling and grammar. I have found those who are dismal at the written word sometimes excel at that which they are sharing information about, especially artists. I have also sometimes found the obverse to be true as well :barf: ;) :D.
 
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Phil Dwyer said:
What are your ideas and what kind of stuff would you like to do?
.
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I would be proud to pull off the peasant version of what Jake Powning does. I think his work is brilliant. I appreciate that he made the effort to lay out the procedures for a novice like myself. Because he did, I got it, more than I have from reading old threads and such. Makes it seem do-able even if you know you don't have the skill and gear that he does. The principles were there, right? That's why I loved the 'viking' link I posted. Speaks to how someone might get the job done without dropping thousands of dollars on shop gear. So, I figure I'll steer a course for some backyard foundry stuff and see how that goes. Nice of you to ask.
 
Bill DeShivs said:
Only because of common usage. Mold grows on cheese.
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In the UK mould grows on old food. Mold is simply the American spelling for both senses of the word. Like many American spellings, it is also the older spelling of the word. Not to mention the usage of "mold" in this context dates back to the 16th century before spellings were standardized, and in most American dictionaries, a casting mold is included as one of the definitions for "mold". So you can stop with the undue criticism there and showing your own ignorance when trying to point out the ignorance of another.
 
OK, Guys.
Enough of the spelling critique......the OP asked about casting.
The Moderator

FWIW, the older spelling of many words had a "U" to accompany the vowel. This came to be during the post revolutionary times when the Americans wanted to differentiate American english from British english. Many skilled trades, however, were apprenticed for a long time under people trained by older masters, and had to use the books published in England and Europe as the texts for their craft. Even today, many craftsmen still use the "U" in their spelling.
Gauge
coulor
mould
flavour
honour
etc.


Now - Back to out regularly scheduled post. ( and I pronounce it Shed-ylue)
 
If you want a very inexpensive way to get into casting with surprisingly good results, I have been doing sand casting with a product available through RioGrande Jeweler's supply called DelftClay for sand. It is an extremely fine grained sand with a really good binder that holds it together like a snowball. As sand goes it is expensive (40 bucks for 2 kilos if I remember) but if you separate out the charred sand and sift it you can re-use it many many times. With a little practice you can get extremely detailed castings. I made 2 part and 3 part molds (roughed up the insides of the frames so the sand doesn't slip through them) You make a master out of wood, steel, wax, anything you can pack sand around, make sure that the mold "drafts" (no undercuts or ledges that hold the sand, it helps if there is a slight negative taper from the parting line) and I use a 6 orifice rosebud tip OxyAcetylene torch for melting and a little borax for flux. Until I got into vacuum and centrifugal casting it was the only casting I did for a couple of years, and I still sometimes do it for one-offs

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(insert obligatory spelling mistake here)
 
Thanks for the Delftclay tip. I was wondering about good material for a mold. A moment on the google led to a nice demo page by the company. Curious thing about that demo, the Powning tutorial, and your remarks, is the use of frames. The viking bronze page seems to be showing frameless molds.
 
Thanks for the link. I will have to get some of the Jupiterbond and compare it to the Delftclay. I have in the past gotten the Grobet brand casting sand, and the stuff is slightly better than worthless. I have a can of it in my basement somewhere that I used once and will find and dispose of when we sell the house. One thing I forgot to mention earlier. DO NOT MELT BRONZE IN YOUR FORGE! I did it once and spilled some which ran down into my liner, the next day all of my steel started crumbling on the second or third heat. I asked the metallurgical engineers I worked with and they said that the tin in the bronze was likely making the steel red-short

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