Graphite crucible breaking down quickly

Discuss casting techniques
User avatar
Messerbr
Solus Expert
Posts:163
Joined:Tue Jan 05, 2016 2:54 pm
Location:North Carolina
Contact:
Graphite crucible breaking down quickly

Postby Messerbr » Wed Dec 13, 2017 7:53 pm

So we're working on updating our casting method to use a vacuum machine and a smelter for more controlled temperatures. We're running into an issue of the graphite crucible breaking down rather quickly and I was wondering if anyone else has run into something similar. it seems that we are having some graphite pieces fall into the flask as we pour the metal in. Picture of the crucible is below. I dont have a before and after, but before the latest melt the graphite walls were pretty smooth and this is what it looks like now. The other two we have are a lot worse.
Attachments
IMG_20171212_144328.jpg
IMG_20171212_144321.jpg
Chalamba
Novice
Posts:47
Joined:Sun Jan 24, 2016 12:11 am

Re: Graphite crucible breaking down quickly

Postby Chalamba » Wed Dec 13, 2017 8:31 pm

Poor quality graphite, that is it.
I found a rather good producer from China and I am happy with their quality and price 2kg cruicable is if I remember correctly 18$.
User avatar
Messerbr
Solus Expert
Posts:163
Joined:Tue Jan 05, 2016 2:54 pm
Location:North Carolina
Contact:

Re: Graphite crucible breaking down quickly

Postby Messerbr » Wed Dec 13, 2017 9:07 pm

Do you remember the name of the producer?
Chalamba
Novice
Posts:47
Joined:Sun Jan 24, 2016 12:11 am

Re: Graphite crucible breaking down quickly

Postby Chalamba » Wed Dec 13, 2017 10:33 pm

Here you are:
Look what I found on AliExpress
http://s.aliexpress.com/BV7vYzyE
User avatar
rkundla
Solus Master
Posts:308
Joined:Sat Jan 09, 2016 6:01 am

Re: Graphite crucible breaking down quickly

Postby rkundla » Thu Dec 14, 2017 1:20 am

I bought a small one to try to make metal shot from my scrap silver and after the first time I fired it with a torch, it started to disintegrate. Bought it on eBay so it isn't top of the line, but it really surprised me.
eg123
Novice
Posts:74
Joined:Mon May 23, 2016 6:55 pm
Location:Silver Spring, Maryland

Re: Graphite crucible breaking down quickly

Postby eg123 » Thu Dec 14, 2017 3:04 am

"I bought a small one to try to make metal shot from my scrap silver and after the first time I fired it with a torch, it started to disintegrate."

Looks normal to me.
They are "not" meant to be used with a torch.
User avatar
rkundla
Solus Master
Posts:308
Joined:Sat Jan 09, 2016 6:01 am

Re: Graphite crucible breaking down quickly

Postby rkundla » Thu Dec 14, 2017 3:06 am

eg123 wrote:"I bought a small one to try to make metal shot from my scrap silver and after the first time I fired it with a torch, it started to disintegrate."

Looks normal to me.
They are "not" meant to be used with a torch.


Well that explains it! I read somewhere you could do it, but it struck me odd how quickly it broke apart. :p
Chalamba
Novice
Posts:47
Joined:Sun Jan 24, 2016 12:11 am

Re: Graphite crucible breaking down quickly

Postby Chalamba » Thu Dec 14, 2017 6:36 am

Tourch - no, no!
It is not ment for that, take a cley cruicable for tourch melting or if tou need to melt bigger ammounts, or you need it for vacuum casting get an electric furnace.
User avatar
ken3dcad
Novice
Posts:37
Joined:Fri Jul 03, 2015 12:44 pm
Location:Central Texas
Contact:

Re: Graphite crucible breaking down quickly

Postby ken3dcad » Thu Dec 14, 2017 10:29 pm

I'm surprised your torch stayed lit while heating inside that deep crucible.
User avatar
Messerbr
Solus Expert
Posts:163
Joined:Tue Jan 05, 2016 2:54 pm
Location:North Carolina
Contact:

Re: Graphite crucible breaking down quickly

Postby Messerbr » Fri Dec 15, 2017 3:15 pm

About how many casts should be expected when using graphite crucibles with a smelter? The one that is broken down the worst was used maybe 10 times

Who is online

Users browsing this forum: No registered users and 8 guests