Water Casting Copper

Water Casting Copper

Postby Joe D » Sat Jan 31, 2015 6:41 pm

I have been experimenting with casting some scrap gas line copper as practice before i use my good 101 copper. After the first pour im glad i did because I keep getting air bubbles in the ingot. I use charcoal on top of the copper and i smack the water bucket after the pour. I am pouring from a graphite crucible to a steaming hot bucket of water. I am now wondering if there are air bubbles under the canvas that are causing issues or if it is just the nature of the copper. any advise will help.

Thanks Joe
Attachments
20150131-DSC00936.JPG
User avatar
Joe D
Registered User
Registered User
 
Posts: 49
Joined: Tue Jan 27, 2015 7:12 pm
Has thanked: 0 time
Been thanked: 3 times

Re: Water Casting Copper

Postby Karl Wunderlich » Sun Feb 01, 2015 4:44 pm

Hey Joe,
there are several options to get this kind of failure.

1. The water should be hot but not not boiling before you cast your metal in.
Avoid any air bubbles underneath the canvas otherwise the melt can jump back to you.

2. If you were overheating the melt the chance to get shrink holes is increased.
The metal should look like a calm oily liquid showing no bubbles or too much sparks or splashes.

3. There was too much distance between the crucible and the waters surface thus the melt absorbs gases while poured.

4. You might have had an contaminated copper containing traces of volatile metals as zinc or arsenic.
Wunder-Page
My Blog

"Simplicity is the ultimate sophistication." Leonardo
User avatar
Karl Wunderlich
Moderator
Moderator
 
Posts: 1520
Joined: Mon Mar 10, 2008 10:30 am
Location: Berlin
Has thanked: 14 times
Been thanked: 24 times

Re: Water Casting Copper

Postby Ford » Sun Feb 01, 2015 5:23 pm

Thanks Karl, what I would have suggested :biggrin:

also, if you have a lot of oxides on the copper to start these may be absorbed into the melt and coause gas bubbles too.

My feeling, looking at the surface crust, is that the metal was quite mucky perhaps.

What's your heating source?
"The artist yields often to the stimuli of materials that will transmit his spirit." Odilon Redon
my website
User avatar
Ford
Administrator
Administrator
 
Posts: 4869
Joined: Mon Mar 10, 2008 10:30 am
Location: Torquay, 'The English Riviera', Devon, England.
Has thanked: 217 times
Been thanked: 211 times

Re: Water Casting Copper

Postby Joe D » Sun Feb 01, 2015 8:05 pm

Thanks for the responses.

1 The water is quite hot before the pour. I cant give you an exact temperature but there is steam rolling off the surface.

2 I am probably over heating the metal. I have a pyrometer so if you have a rough idea of the best casting temp that would be great.

3 i have the mold around 6 cm away from the surface of the water.

4 God knows whats in this copper

My heat source is propane being burned in a neutral to reducing atmosphere.

I am casting into 2 layers of 18 oz canvas and i usually burn through the first layer.

Would Borax help? If so will it hurt my Crucible?

Here is an ingot i did just 30 minutes ago.
Attachments
20150201-DSC00939.JPG
20150201-DSC00937.JPG
User avatar
Joe D
Registered User
Registered User
 
Posts: 49
Joined: Tue Jan 27, 2015 7:12 pm
Has thanked: 0 time
Been thanked: 3 times

Re: Water Casting Copper

Postby Karl Wunderlich » Mon Feb 02, 2015 12:38 pm

Hi Joe,
reading your melt burns through the first layer of canvas,
made me think you may have not a suffiant layer of water between the canvas and the surface of the water.
That would explain the oxyd layer on your copper too. I think your canvas should be placed in about 10 depth.
Try to make sure none of the charcoal enters the bucket as it could be a source of gases (reducing the steam).
Building a kind of kiln around your blowtorch could further reduce failures.
Ah, I almost forgot: casting temperature around 1250°c, or a bit less, depending how long your way is from the torch to the bucket and also depending on the amound of copper.
Wunder-Page
My Blog

"Simplicity is the ultimate sophistication." Leonardo
User avatar
Karl Wunderlich
Moderator
Moderator
 
Posts: 1520
Joined: Mon Mar 10, 2008 10:30 am
Location: Berlin
Has thanked: 14 times
Been thanked: 24 times

Re: Water Casting Copper

Postby Joe D » Mon Feb 02, 2015 1:54 pm

Ok ill try these methods soon. I have been dropping the charcoal in to the bucket with the copper so that may have something to do with it. Would cleaning the top of the molten copper before the pour help? or would that just add oxygen? Thanks for the help!
User avatar
Joe D
Registered User
Registered User
 
Posts: 49
Joined: Tue Jan 27, 2015 7:12 pm
Has thanked: 0 time
Been thanked: 3 times

Re: Water Casting Copper

Postby Michael C » Wed Feb 04, 2015 5:24 pm

When you say "cleaning the top", do you mean there is stuff floating on the surface besides just the charcoal? If so then that means there is almost certainly something in there besides just copper mucking up the pour. Did you clean the original material before doing a melt or did it just get tossed into the crucible as-is?
User avatar
Michael C
Registered User
Registered User
 
Posts: 107
Joined: Wed Jul 24, 2013 4:02 pm
Location: Bethany CT, USA
Has thanked: 0 time
Been thanked: 7 times

Re: Water Casting Copper

Postby Joe D » Wed Feb 04, 2015 8:40 pm

Yes i mean the dross. If by cleaned you mean an acid bath then no i did not clean it but i did grind the surface of some of the plates i put in.
User avatar
Joe D
Registered User
Registered User
 
Posts: 49
Joined: Tue Jan 27, 2015 7:12 pm
Has thanked: 0 time
Been thanked: 3 times

Re: Water Casting Copper

Postby Glen G » Wed Feb 04, 2015 10:38 pm

Joe, I'd say YES definitely add a pinch of borax to the melt. And you should acid pickle the scrap before you melt it. Make sure there is no lead solder present too. Other than the bits of charcoal there should be no dross on the top of the melt.
"Have no fear of perfection. You'll never reach it." Salvador Dali
Glen S. Gardner
Pgh. PA
http://crafthaus.ning.com/profile/GlenSGardner
User avatar
Glen G
Registered User
Registered User
 
Posts: 475
Joined: Fri Jun 17, 2011 8:54 am
Location: Pittsburgh, Pa. USA
Has thanked: 20 times
Been thanked: 28 times

Re: Water Casting Copper

Postby Joe D » Fri Feb 06, 2015 8:18 pm

Thanks so much for the help guys. I did two more pours using the tips and methods you suggested and got increasingly better results. Not great but better. In the coming weeks i may go for broke and pour some of my 101 copper and hope for the best using the skills i have learned here. Thanks for the Help.
User avatar
Joe D
Registered User
Registered User
 
Posts: 49
Joined: Tue Jan 27, 2015 7:12 pm
Has thanked: 0 time
Been thanked: 3 times

Re: Water Casting Copper

Postby Glen G » Sat Feb 07, 2015 8:44 pm

Also keep in mind. That due to the very high melting point of straight copper it is always a booger to melt, cast or pour ingots. When you add
alloying ingredients the melt point drops considerably and it becomes quite a bit easier to melt and manage. But even with the C110, pickle it clean and use a bit of borax.
"Have no fear of perfection. You'll never reach it." Salvador Dali
Glen S. Gardner
Pgh. PA
http://crafthaus.ning.com/profile/GlenSGardner
User avatar
Glen G
Registered User
Registered User
 
Posts: 475
Joined: Fri Jun 17, 2011 8:54 am
Location: Pittsburgh, Pa. USA
Has thanked: 20 times
Been thanked: 28 times

Re: Water Casting Copper

Postby Joe D » Sat Aug 15, 2015 11:05 pm

Just to update, I have continued to work on my casting and i have found a process that works very well and i am now confident enough to attempt some shibuichi. however I have a few questions about the process for shibuichi.
1. I know that i should add the silver once the copper is molten with the bits wrapped in a paper packet. Will the silver percolate through any charcoal sitting above the copper?
2. do i put charcoal over the silver?
3. should i stir the charcoal or just let it sit for a minute while i get the mold ready? It is a 125 gram charge with an ounce of silver.
4. Just for future reference if i make shakudo can the gold go in at the beginning or should it be added later?
Any help is welcomed!
Thanks
User avatar
Joe D
Registered User
Registered User
 
Posts: 49
Joined: Tue Jan 27, 2015 7:12 pm
Has thanked: 0 time
Been thanked: 3 times

Re: Water Casting Copper

Postby Ford » Sun Aug 16, 2015 7:19 am

Hi Joe

yes, the silver will melt and then drip drough where it gets hung up. But you can give the melt a gentle prod with a carbon rod. A very dry stick or chopstick can be used too. Just make sure it's dry, wet wood in molten metal is not a calming experience, unless you really want to shake things up. No need to add more charcoal at that point.

You don't want to let the metal sit at liquidus too long once the silver has disolved. That's the trick, you should pour as soon as possible so that the silver isn't too finely divided. This will then give you nashiji, the characteristic graininess of the alloy.

With shakudo you can add the gold at the start, yes. save on the gold and only use 1% but also add 1% silver. This is an historically accurate alloy composition.

How is your patination coming along? 8)
"The artist yields often to the stimuli of materials that will transmit his spirit." Odilon Redon
my website
User avatar
Ford
Administrator
Administrator
 
Posts: 4869
Joined: Mon Mar 10, 2008 10:30 am
Location: Torquay, 'The English Riviera', Devon, England.
Has thanked: 217 times
Been thanked: 211 times

Re: Water Casting Copper

Postby Joe D » Mon Aug 17, 2015 12:29 am

Thank you very much. I will try to cast later this week (classes start tomorrow :BangHead:) I will post the results.
I just received some rokusho from Reactive metals last week but i havnt gotten a chance to work with it yet. I am sure i will have questions once i start down that rabbit hole.
Thanks again
User avatar
Joe D
Registered User
Registered User
 
Posts: 49
Joined: Tue Jan 27, 2015 7:12 pm
Has thanked: 0 time
Been thanked: 3 times

Re: Water Casting Copper

Postby Joe D » Sat Aug 29, 2015 5:37 pm

Being slightly spineless about committing silver to a cast I did a few more practice casts and was sorely disappointed. small little bubbles have formed mostly at the top of the ingot and i cant figure out where they are coming from. I haven't changed anything from my previous setups.
Gas forge
graphite crucible
wire brushed and pickled copper snippets
borax on top
Argon purge
canvas mold around 8 centimeters under very hot water.
smack the bucket when the copper goes in.

I have poured several other ingots that have turned out just fine using this same method. Do i need to add charcoal even with the argon? Does the borax left at the bottom of the crucible cause problems with subsequent pours? Is this a consolidation issue? would fewer pieces of copper in the beginning help (More like one solid lump)?
Any help would be greatly appreciated i am really pulling my hair out. and wasting copper.
http://imgur.com/a/L8iNi
Edit: Would these little bubbles make a difference once it's hammered out?
User avatar
Joe D
Registered User
Registered User
 
Posts: 49
Joined: Tue Jan 27, 2015 7:12 pm
Has thanked: 0 time
Been thanked: 3 times

Next

Return to Technique & Tutorials

Who is online

Users browsing this forum: No registered users and 3 guests

cron