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Welding: How they got around it

Post and discuss the impact of technology on the creation of sculpture.

Welding: How they got around it

Postby C.R.Larkin » Fri Jun 24, 2011 8:48 pm

I have a "Minor" in art history, and have always been interested in Materials and technology of artists. Here is a favorite: How Renascence artists got around their inability to weld large sculptures together. I hope that this is what you want when you say "new technologies and old."

Going way back, welding was not available to sculptors doing lost wax or sand cast bronze. Although welding is described in India in the 300's, in Europe, and Western Art, the Black Plague and death of just about everyone gave the survivors the task of trying to figure out how the ancient people did the things they did. Focus on a small group of post Dark Age artists re-discovering technology that had existed years before. Say a loss of technology between about 500 AD (at maximum) to 1350 AD. Leonardo Da Vinci envisioned a plan to create a huge horse sculpture. But how was it to be cast if there was no welding?

Da Vinci planned the great Horse sculpture to be cast in one solid piece. The mold was to be held up by giant scaffolding, as big as a ship, that moved. Once again, the problem, technologically, was that metal casting came well before the ability to join metal through welding. Even in the early 20th century ships and large metal objects were held together by rivets. The Greeks attached one piece of metal to another using rivets, not welding. Rivets are fine, but not good for large objects. Welding was used in some ways but not on a consistent basis. During the Dark Ages the ability to weld in its earliest stages was most likely lost to Europeans.

An excerpt from Benvenuto Cellini's Autobiography describes the awesome details of the casting of his Perseus statue-- which he considered his masterpiece. The full sized investment was held by a scaffolding at the side of a building. (I believe it was a castle wall-- it has been 15 years since I read it). Above, the bronze was melted. As in the Greek manner, the armature was made of straw and sticks, and the covering (sculpted surface only) was of wax. The investment was of fine clay, hardened. The straw, sticks and wax were burned out over night, held up by a large scaffolding (the snow was beginning to fall--Anyone who loves sculpture should read the "Autobiography of Benvenuto Cellini", for it is an amazing time-capsule into the lives and thoughts of Renascence artists, Spoiler alert: Cellini is one of the most unlikeable characters in literature).

Perseus was cast large, and whole. That, in itself is a big deal. Here is an excerpt from Cellini's casting of Perseus. http://aliasclio.blogspot.com/2007/09/musings-from-cellinis-autobiography.html The large sculpture was cast in one piece, meaning that there was only one huge crucible of molten bronze, poured from above. The whole operation would have been a costly mistake if anything went wrong (as well as highly dangerous). The undertaking was of monumental proportions. I personally do not think any foundry could pour a solid bronze of this size today without welding.

Good info about early use of "welding." http://www.weldguru.com/welding-history.html
This link is a long very informative video about Da Vinci's horse sculpture. It shows how this brilliant artist sought to evade the need for welding by solving the problem of how to cast his extremely large horse statue.
http://www.youtube.com/watch?v=np94KcWUxqg

We artists who use lost wax casting owe a debt of gratitude to welding.

The Perseus, in case you do not know which sculpture I refer to: http://www.jssgallery.org/Other_Artists/Benvenuto_Cellini/Photo_Cellni_bronze_statue_Perseus_beheading_Medusa.htm
C.R.Larkin
 
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Re: Welding: How they got around it

Postby Richard » Sat Sep 17, 2011 3:15 pm

Thanks much for the post. I have downloaded the autobiography of Cellini from gutenburg, which I had been meaning to do for a year or so.

Richard
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Re: Welding: How they got around it

Postby Richard » Mon Sep 19, 2011 3:36 pm

I highly recommend that autobiography. What is most outstanding is the incredible energy the people had back during the beginning of the renaissance. They put us to shame, sitting around waiting to be entertained.

Richard
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Re: Welding: How they got around it

Postby C.R.Larkin » Fri Sep 30, 2011 6:39 pm

Thanks Richard. I am always interested in techniques and materials. Welding is ubiquitous these days, but it was unknown when a lot of the ancient pieces were made. I am also interested in the fact that after the dark ages, the artists and craftsmen had to re-learn everything over again.
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Re: Welding: How they got around it

Postby Randall » Sun Jan 22, 2012 9:07 pm

I found this site the other night due to the thread here on Cellini and thought I'd register even though it looks like there is very little traffic here...

I was with artspan as a moderator but they seemed to have mostly abandoned the forum and it's taken over by spam-bots.
I mainly work with architectural pieces in the Victorian and Art Deco styles, but have done a small amount of figurative work.
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Re: Welding: How they got around it

Postby Richard » Mon Jan 23, 2012 3:57 pm

Welcome Randall. I think that this forum could become active if just two or three people started talking regularly. I have tried several times but no one has responded much. I do figurative work in my studio here in Mexico, and I still have a studio in the US where I do mostly shaped work from highly polished stainless and aluminum sheet metal.

Richard
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Re: Welding: How they got around it

Postby Randall » Tue Jan 24, 2012 10:47 am

Thanks Richard, you are right, and often it only takes a couple or three users.

Back in the 90's I modelled a number of bronze dogs when I lived in Oregon, I used a foundry in Joseph Oregon (Parks bronze) and they used to cast them for me for around $110, artist supplied wax, patina ready casts returned.
I used to specify, er.. rather, insist ;) they be cast solid because I prefer the weight/quality feel to a heavy casting.
The dogs were about 6-8" tall average, except the one German Shepherd I made which was a fair but larger overall, and that one weighed about 25# as I remember.
They did a fine job casting these.

I also experimented with Brittania metal and home-cast a pair of dogs for bookends, the way I made my molds of these standing dogs was a bit old world- I made the models in plasticene, and then made hydrocal plaster piece molds of them, then I made positive rubber molds of the hydrocal pieces. I would cast 50/50 sand/plaster into those rubber molds, assemble the plaster/sand pieces and cast my waxes in those.
The 50/50 sand plaster molds were waste molds, they could be removed easily from the waxes by soaking in water and beaking the pieces apart.

I still have these positive master molds.
I'll post some photos.

I went to a then local college non credit class which was very nice, they had a small bronze foundry setup there too with a McEnglevan furnace, pyrometer, tongs and so forth, pretty basic but the instructor hadn't tried it, and it hadn't been used in some time.
Between the two of us we decided to try it out and made some plaster/sand molds and cast some bronze. We had little to go on for info in those pre-internet days and wound up with some fair casts having a number of defects- air bubbles mainly, so we weren't sure where we went wrong.
But it was a lot of fun firing that thing up and watching that liquid fire pour out into the molds.
It was pretty amazing how hot the cruicible felt even though we had on safety garb and were maybe 5-6 feet away with the two man tongs.
Last edited by Randall on Tue Jan 24, 2012 4:43 pm, edited 1 time in total.
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Re: Welding: How they got around it

Postby Randall » Tue Jan 24, 2012 10:54 am

Image

Image

And this photo shows one of the brittania metal casts I made, and a foundry cast bronze.

I cast the brittania in two plaster-sand waste molds that had been heated in the kitchen oven to I think 350 degrees for a few hours, set into a five gallon pail full of sand, and then filled from the bottom-feet.
They had a plaster/sand core in them held in place with a couple of brass pins.

I had to do a fair amount of chasing on them but they turned out surprisingly well.

Image
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Re: Welding: How they got around it

Postby Richard » Thu Jan 26, 2012 5:08 pm

Your dogs look great.

I have a foundry in my studio. I make my initial forms in oil based clay, make a mold of that in polyurethane rubber with a plaster mother mold, and pour the wax into that. I use traditional ludo investment. Here are my two furnaces:

Image

The large one is in action in the photo. I burn waste motor oil. At the far right is the investment to be poured. This particular pour was a disaster. When I poured in the metal it started foaming out of all of the holes like Alka Selzer. I had invested this piece six months ago and was just getting around to pouring it. All I can figure is that the chemical reaction over time between the steel chain I use inside and the plaster produced a compound that held bound water that wasn't released by the burn out. Here is what I got:

Image

Full of gas holes. Oh well. On to the next one.

Richard
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Re: Welding: How they got around it

Postby Randall » Fri Jan 27, 2012 1:10 pm

Interesting Richard, the SpeedyMelt furnace at the college was about the size of yours if not a tad bit larger, it was a natural gas furnace.
I don't see your bronze as having gas holes/defects, I don't think there's a cast made that comes out perfect, they all need some fixing and the like.

The instructor at the college was Ted Isto, I see he is still around with the arts group. We looked at a new thing back then, a ceramic shell system by Shellspen, it looked great but then we read that you had to keep the slurry in a constate agitation or it settled out and solidified, fine for a foundry using it all day but not for what we or I myself would be doing.

I discovered they are still in business, and now have a kit which seems like it would be ideal for casting a few small pieces at home. They apparently solved the agitation problem with a formula that doesn't have to have that done.

Check this out;

http://www.shellspen.com/metal-casting-kits.htm

The $149 kit has enough to cast 11 pounds of bronze, but that may be optimistic, so it might realistically be 7-8 pounds. That would be enough for one of my dog casts, and with the weight of a cruicible, tongs, and the total metal, that's probably all one man could manage alone without a tilting furnace, or overhead trolly system.

Their $229 kit is probably more realistic, and include enough "extra" materials to allow for a wax that comes a little too close to, or slightly over the size limit the smaller kit would properly cover, and allow for some waste/loss/spillage.

So with the ceramic shell part apparently solved with one of those kits, the other issue is the furnace and a burnout furnace.
With the brittania metal dogs I made, there was no wax to burn out since the mold was a plaster-sand piece mold, so only the water had to be removed.
Propane would be the viable thing here.

I know as you wrote- the usual method is an oil clay model, rubber mold/plaster shell to cast the waxes in, but at the time I wasn't confident with the mold rubbers I was using to do the mold of a standing four leg figure and deal with all the shims, not tearing the rubber etc.
In my case, making a plaster piece mold was quite easy, blocking off one section at a time with water clay, and filling it with hydrocal, no shims needed.
Most of them wound up being about six pieces- four smaller pieces and two halves.

I used Polytek urethane for the rubber positive block molds, I have them and they are still in excellent condition and can be used to cast some sand/plaster piece molds from.
One of these days I want to take some waxes out of them.
These days I use Smooth-on Rebound 25 platinum silicone rubber, the stuff is great, very soft with shore 25, and very, very strong- unlike almost every rubber I've used (except latex) but it's $200 for the two gallon kit, and for most of my models it takes the whole kit.

I have a kit on hand now and need another one, as I will be making two molds this week and when I order another kit.
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