Jump to content

Recommended Posts

  • Moderator

Try, Try Again

 

So I made a whole bunch more copies and a new tree.  This time, I made certain to get it stuck all the way into the base (something that was very difficult).  I invested it and everything went well.  So continuing from there:

 

Here is the flask after the investment has hardened, with the base and sleeve removed, ready to go into the kiln:

 

post-140-0-21063900-1486438847.jpg post-140-0-72570600-1486438847.jpg

 

 

I placed a metal tray and screen into the kiln to catch the dripping wax, placing the flask on it with the opening down:

 

post-140-0-30858200-1486438848.jpg

 

 

The first stage of the burn out is to heat it at 300 degrees for an hour to melt out all of the wax.  After this, I removed the metal tray and screen and placed the flask on the fire brick posts.  Then the kiln ramped up to 1350 degree F for two hours.  This vaporized the remaining wax and cured the investment, leaving it dry and gas permeable. After that, I gradually dropped the temp to 200 degrees and let it sit for 2 hours to let the flask cool.

 

Meanwhile, I prepared the pewter to be melted in my hot pot.

 

post-140-0-86257900-1486438848.jpg

 

 

When the pewter was melted and the flask cooled sufficiently, I took the flask and placed it in the vacuum machine.  I turned on the vacuum, let it get to full pressure, then poured in the pewter.  The vacuum was strong enough that the pewter made a sucking sound as it got drawn into the mold; a good sign.  Here is a photo of the finished pour, with the pewter button showing in the investment.

 

post-140-0-46361100-1486438849.jpg

 

 

I poured the remaining pewter into a heated metal ingot mold:

 

post-140-0-01056000-1486438850.jpg

 

 

I let the flask cool for about 10 minutes, then dropped it onto a bucket of cold water to quench it. Then, after about 20 minutes of scrubbing with a brush, I had all the investment removed.  The cast was perfect!!!

 

I give you the TREE of DOOM:

 

post-140-0-55141100-1486438850.jpg

 

 

:bday: :bday: :bday: :bday: :bday: :bday: :bday: :bday:

 

  • Like 20
Link to comment
Share on other sites

  • Replies 211
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Sweet!!!  Great work!

 

One little trick I forgot to mention for precision talc-ing is to take an old sock and dump some talc into it.  Then, when you want to apply talc to a surface, simply slap the surface lightly with the loaded sock.  You will leave behind a thin, controlled layer of talc that can be built up with multiple slaps!

 

I'm loving seeing this come together more and more!  ::):

Link to comment
Share on other sites

  • Moderator

Sweet!!!  Great work!

 

One little trick I forgot to mention for precision talc-ing is to take an old sock and dump some talc into it.  Then, when you want to apply talc to a surface, simply slap the surface lightly with the loaded sock.  You will leave behind a thin, controlled layer of talc that can be built up with multiple slaps!

 

I'm loving seeing this come together more and more!   ::):

 

Yep, I've got that.  Saw an old guy on a YouTube video do that and thought it was a good idea. Thanks.

 

 

Now I need to sculpt something else to practice on so I can get better at making and cutting molds. I'm thinking of doing a dragon head, but am having artist block on the design. I want it to be the head of a pokey-tool (i.e., a long pin to clear clogged dropper bottles) that I can cast in bronze or silver and give to friends.  I have the long pins I need for the pokey part, I just need a head design (bust) that is not too complex and can can be molded in a single mold (I am trying to avoid having to mold the horns separately).

  • Like 5
Link to comment
Share on other sites

Sweet!!!  Great work!

 

One little trick I forgot to mention for precision talc-ing is to take an old sock and dump some talc into it.  Then, when you want to apply talc to a surface, simply slap the surface lightly with the loaded sock.  You will leave behind a thin, controlled layer of talc that can be built up with multiple slaps!

That's called a "pouncing bag". They were used during the Renaissance, filled with ground charcoal, over cartoons (preparatory drawings) that had had pinholes pricked in their lines, to transfer a dotted-line version of the cartoon to a wall or panel to be painted, a sort of Renaissance carbon paper if you will.

 

I believe there are surviving Raphael drawings that still have the pin pricks.

  • Like 6
Link to comment
Share on other sites

 

Sweet!!! Great work!

 

One little trick I forgot to mention for precision talc-ing is to take an old sock and dump some talc into it. Then, when you want to apply talc to a surface, simply slap the surface lightly with the loaded sock. You will leave behind a thin, controlled layer of talc that can be built up with multiple slaps!

That's called a "pouncing bag". They were used during the Renaissance, filled with ground charcoal, over cartoons (preparatory drawings) that had had pinholes pricked in their lines, to transfer a dotted-line version of the cartoon to a wall or panel to be painted, a sort of Renaissance carbon paper if you will.

 

I believe there are surviving Raphael drawings that still have the pin pricks.

This is how my grandmother transferred her sketches to canvas prior to painting.

  • Like 4
Link to comment
Share on other sites

Wow, I go one day without checking this thread for updates and look what happens!  :o)

 

Awesome tree of skulls!  Isn't it great when a casting comes out exactly the way you hoped?

 

So was that a complete full length burnout for a mold that size like you would have to do for a bronze casting, or did you shorten the burnout time due to the low melting point alloy you were casting?  I ask because from what I have read, some people have had good results with less burnout when using metals like aluminum, which pour significantly less hot than bronze but also much hotter than pewter.  If an investment mold for aluminum can work well without turning into a molten metal volcano when if has only been burned out at 500F for a couple of hours, it's likely that a mold for casting pewter would also not need a compete burnout.  Might be worth looking into, I would not take my word for it necessarily as I have not done any lost wax and have only read about it...  Def. wear your asbestos raincoat & umbrella if you decide to try it!

 

Many of us backyard green sand molders use an old sock full of talcum powder or chalk-line dust as a parting compound delivery tool for sand molds as well; it keeps the two halves of the molds from sticking together and the sand from sticking to the pattern, so that the mold can be opened and the pattern drawn out without breaking the mold cavity before closing it back up to be poured.  You can buy fancy parting dust and a special purpose-made bag for this from foundry suppliers, but I never heard of anyone using anything other than an old sock, even if they were using "real" parting compound.  That is interesting about the other artistic uses of socks full of powder; I had no idea.

 

The dragon head paint-bottle-tip poker sounds super cool, making tools is fun!  Looking forward to seeing how that turns out.

 

Kang

Link to comment
Share on other sites

  • Moderator

Wow, I go one day without checking this thread for updates and look what happens!  :o)

 

Awesome tree of skulls!  Isn't it great when a casting comes out exactly the way you hoped?

 

So was that a complete full length burnout for a mold that size like you would have to do for a bronze casting, or did you shorten the burnout time due to the low melting point alloy you were casting?  I ask because from what I have read, some people have had good results with less burnout when using metals like aluminum, which pour significantly less hot than bronze but also much hotter than pewter.  If an investment mold for aluminum can work well without turning into a molten metal volcano when if has only been burned out at 500F for a couple of hours, it's likely that a mold for casting pewter would also not need a compete burnout.  Might be worth looking into, I would not take my word for it necessarily as I have not done any lost wax and have only read about it...  Def. wear your asbestos raincoat & umbrella if you decide to try it!

 

Many of us backyard green sand molders use an old sock full of talcum powder or chalk-line dust as a parting compound delivery tool for sand molds as well; it keeps the two halves of the molds from sticking together and the sand from sticking to the pattern, so that the mold can be opened and the pattern drawn out without breaking the mold cavity before closing it back up to be poured.  You can buy fancy parting dust and a special purpose-made bag for this from foundry suppliers, but I never heard of anyone using anything other than an old sock, even if they were using "real" parting compound.  That is interesting about the other artistic uses of socks full of powder; I had no idea.

 

The dragon head paint-bottle-tip poker sounds super cool, making tools is fun!  Looking forward to seeing how that turns out.

 

Kang

 

No, I actually held the 1350 degree burn out about an hour longer than I would have actually needed for that flask. From what I have read, when vacuum casting, it is important to do the full burnout, or the investment will not become porous enough for the vacuum to work through.  It did suck a bit though from a time perspective.  I started the burnout at 11:30 am and poured the metal at 9:00 pm.  But, it gave me an excuse to spend the entire day sculpting in my studio; I had to watch the kiln after all, just in case.

 

I have the "Real" parting compound, in an old sock.  :poke:  I also just got a jar of Castalldo parting cream, which supposedly works better for parting than talc.  We'll see...

 

Oh, and after getting paid for some recent sculpts, I decided to invest in a melt furnace, since the kiln I have is really too small for bronze (though it will be good for purifying gold and silver). I got one that I can change crucible size in.  I bought both a 60 and a 30 oz (gold weight) crucibles. It just came yesterday.  Here is a picture:

 

41TponZ%2BlXL._SY300_.jpg

 

(Mine is stainless steel, not black and my crucibles are about the size of the big one)

  • Like 5
Link to comment
Share on other sites

  • Moderator

So I came to a spot in my current project where I need about 70 thorn-like spines.  I really didn't want to spend 10+ hours sculpting them all, so I sculpted 6 and then cast them:

 

Sculpt with sprue:

 

post-140-0-29577200-1486957837.jpg

 

 

Wax copies:

 

post-140-0-85649300-1486957837.jpg

 

 

Wax tree, ready for investment:

 

post-140-0-39716200-1486957838.jpg

 

 

Final cast (pewter):

 

post-140-0-90855900-1486957838.jpg

  • Like 12
Link to comment
Share on other sites

 

Sweet!!!  Great work!

 

One little trick I forgot to mention for precision talc-ing is to take an old sock and dump some talc into it.  Then, when you want to apply talc to a surface, simply slap the surface lightly with the loaded sock.  You will leave behind a thin, controlled layer of talc that can be built up with multiple slaps!

That's called a "pouncing bag". They were used during the Renaissance, filled with ground charcoal, over cartoons (preparatory drawings) that had had pinholes pricked in their lines, to transfer a dotted-line version of the cartoon to a wall or panel to be painted, a sort of Renaissance carbon paper if you will.

 

I believe there are surviving Raphael drawings that still have the pin pricks.

 

not sure about Raphael, but there is evidence of it in the Sistine Chapel from Michaelangelo's work.

 

Also, yay tree of thorny death.

  • Like 1
Link to comment
Share on other sites

So cool!  Looks like the spike-thorns came out nice...

 

Thanks for the correction about how you need a full burnout of the investment even for low-melt alloys, due to the vacuum assist requiring the mold be porous - so obvious now that you said it!

 

The new furnace looks like an electric, at least I think I see a coiled resistance wire poking out the top in the pic... that'll be a really nice clean & quiet way to get you some pots o'shiny hot metal goo!  Even less reason now to worry about the dissolved gasses I was false-alarming about upthread.

 

Keep it up, you're doing great.  This is all going to feel even more rewarding when you start using the castings you made yourself to push your other work to new heights.  Melting and pouring bronze will be similar, but very noticeably hotter to get close to.  I had the pinky of my heavy leather welding glove get so hot the leather shrivelled up on me when I was skimming a pot of molten aluminum bronze just before pouring my First Men axe blade, which was only maybe a 10 seconds of being that close up.  That's why I always keep a second set of gloves handy...  So I can toss the one that is burning my finger (I got a small blister, not the first nor the worst) and glove up again ASAP to keep working.  Of course I was dealing with a bit larger amount of molten metal, but I am sure you'll be impressed by the difference even working with smaller volumes.

 

Kang

Edited by Kang
  • Like 2
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...