Info on building electric furnace ?

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M

Mech

Member
Joined
May 5, 2020
Messages
21
I picked up a bunch of heating elements [ these are coiled wires in-beaded in aobut 1/2" thick fire brick with groves for the coils .
Many sizes 4"x 6" , 8" x 10" and other types & shapes of heating plates .
These have resistances between 9 Ohms & 24 Ohms .

My main uses are for controlled temps - something around 400 - 600 F for burning / ashing IC chips --- want to avoid mixing melts in chips , to easier to recover gold , and silver if any .

Next is for smelting / refining gold & silver - somewhere around 2200 F .

I have saved some PID controllers with solid state relays on Amazon , running around $40 for PID , relay & temp sensor .
These are labeled for 120v & 240v .

So looking for other DIY oven builders to double check the matching of the above ?

Also from my research , seems there are about 3 types of fire brick 1st just home fireplace brick [ I have built & rebuilt fireplaces for people ] 2nd a type of fire brick that is resistent to caustics - acid / base , 3rd then a light weight brick that is also soft for shaping etc. .
Most of my searches only come up with the 1st , very seldom #2 or 3 , so looking for sources for #2 & 3 ?

I am going to build ovens in 30 lb propane tanks - have already cut the tops off .

Then shape bricks for fit in tank , then set in the heating elements and weld a method of holding controller on the side of the tank .
 

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  • IMG_0197 2.HEIC
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Mech said:
I picked up a bunch of heating elements [ these are coiled wires in-beaded in aobut 1/2" thick fire brick with groves for the coils .
Many sizes 4"x 6" , 8" x 10" and other types & shapes of heating plates .
These have resistances between 9 Ohms & 24 Ohms .

My main uses are for controlled temps - something around 400 - 600 F for burning / ashing IC chips --- want to avoid mixing melts in chips , to easier to recover gold , and silver if any .

Next is for smelting / refining gold & silver - somewhere around 2200 F .

I have saved some PID controllers with solid state relays on Amazon , running around $40 for PID , relay & temp sensor .
These are labeled for 120v & 240v .

So looking for other DIY oven builders to double check the matching of the above ?

Also from my research , seems there are about 3 types of fire brick 1st just home fireplace brick [ I have built & rebuilt fireplaces for people ] 2nd a type of fire brick that is resistent to caustics - acid / base , 3rd then a light weight brick that is also soft for shaping etc. .
Most of my searches only come up with the 1st , very seldom #2 or 3 , so looking for sources for #2 & 3 ?

I am going to build ovens in 30 lb propane tanks - have already cut the tops off .

Then shape bricks for fit in tank , then set in the heating elements and weld a method of holding controller on the side of the tank .
Click to expand...
Hmm, for ashing chips I'd go to 600 C not F
 
There are light weight fire insulating bricks, what you call type 3, available in several heat tolerance ranges. Where are you located? Bricks can be inexpensive if you pick them up yourself, and costly to have them shipped. Most brickyards will carry fire bricks in type 1 and 3, but you may have to order Silicon Carbide, or other specialty high temperature bricks and crucibles.
 
The step up in light weight insulated fire bricks goes from 2000 F, to 2300 F, then up from there. If you cannot find the 2300 F locally, DFC Ceramics, in Canon City, Colorado supplies me with everything a smelting/assaying person could want, short of the specialty ceramics. dfcceramics.com .
 
Ceramic fiber blanket makes a much lighter and faster to heat furnace, FYI.

It's also cheaper to ship than firebrick.

You still use a small chunk of firebrick on the bottom, to hold your crucible.
 
olawlor said:
Ceramic fiber blanket makes a much lighter and faster to heat furnace, FYI.

It's also cheaper to ship than firebrick.

You still use a small chunk of firebrick on the bottom, to hold your crucible.
Click to expand...
Can that be used in electric furnaces, as the OP is asking about?
 
goldshark said:
The step up in light weight insulated fire bricks goes from 2000 F, to 2300 F, then up from there. If you cannot find the 2300 F locally, DFC Ceramics, in Canon City, Colorado supplies me with everything a smelting/assaying person could want, short of the specialty ceramics. dfcceramics.com .
Click to expand...

goldshark - thanks for posting this info about DFC Ceramics - nice selection of products :cool:
goldshark said:
dfcceramics.com
Click to expand...
I had to copy & paste that in order to get the web address you provided instead of just clicking on it - so here is a direct link to make it easier for members

https://dfcceramics.com/index.php
The problem I have with their web site is it does not show prices for their products &/or a way to order direct from their website so ether have to call them or message/email by way of "contact us" link on website or go to their store - all very inconvenient methods for trying to purchase a product a person is looking for --- nice selection of products but then have to go jump additional hoops to get price & make order :mad:

Kurt
 
Not sure how the site handles pictures - what I put into the post seems to be a download ?
Rather that a viewable here ?

I posted a picture of the box of ceramic heating elements I bought
lots of goodies in there the seller kept putting more in the box as we talked , paid $85 - very good deal , he use to custom glass making for the company lab he use to work at .

I do have some of the blanket stuff - for another project , but will not hold / mount the ceramic heating elements .

With the link to DFC site & info here , there are even more choices than I knew about [ which is some of what I am looking for - if I walk into a place that handles what I'm looking { seems like the buyer needs to know more than the selling these } ] .
In order to get the product that suit my project .
Ya would be nice to go to a site & find prices .

I have searched locally before & found very little , tried again yesterday and found a possible store front - to avoid shipping - but again service sucks these days , I have worked in many trades & found almost total ignorance at people behind the counter , example auto parts shops - YOU NEED TO KNOW FAR MORE THAN THEY DO many / most of the time to get a project going ;(

I have some thought on making this project even a bigger deal - doing volume , starting with a 5 gal bucket of IC's and to get them ashed in one load - thinking of making a larger oven with a rotating separator to evenly cook & separate silicon dies - bigger ideas keep getting me in trouble ;)
Same with another 5 gal bucket of memory cards - low heat to get IC's to drop off boards - this is half built in a 20 lb LP tank with a 3rd of the side cutout for heat , then a 1 gal paint can mostly cutout with chicken wire - used to let the IC's fall out while the paint can is rotating inside of the LP tank .

Lots of projects , this post is getting too long .

Thanks
 
Well now I need to learn something new AGAIN ;)

As usual no searches were a direct reply to changing a desktop photo to jpeg - result assumed not on desktop .
 

Attachments

  • IMG_0197 2.jpeg
    IMG_0197 2.jpeg
    2.9 MB · Views: 3
Mech said:
I picked up a bunch of heating elements [ these are coiled wires in-beaded in aobut 1/2" thick fire brick with groves for the coils .
Many sizes 4"x 6" , 8" x 10" and other types & shapes of heating plates .
These have resistances between 9 Ohms & 24 Ohms .

My main uses are for controlled temps - something around 400 - 600 F for burning / ashing IC chips --- want to avoid mixing melts in chips , to easier to recover gold , and silver if any .

Next is for smelting / refining gold & silver - somewhere around 2200 F .

I have saved some PID controllers with solid state relays on Amazon , running around $40 for PID , relay & temp sensor .
These are labeled for 120v & 240v .

So looking for other DIY oven builders to double check the matching of the above ?

Also from my research , seems there are about 3 types of fire brick 1st just home fireplace brick [ I have built & rebuilt fireplaces for people ] 2nd a type of fire brick that is resistent to caustics - acid / base , 3rd then a light weight brick that is also soft for shaping etc. .
Most of my searches only come up with the 1st , very seldom #2 or 3 , so looking for sources for #2 & 3 ?

I am going to build ovens in 30 lb propane tanks - have already cut the tops off .

Then shape bricks for fit in tank , then set in the heating elements and weld a method of holding controller on the side of the tank .
Click to expand...
Would go for F instead of C
 
Not sure if you can tell on your end - I'm using a Mac , I assume [ we know what that means ;)
So figure instructions would be a little different .
I am on many forums groups on many subjects , seems there are just too many ways to do the same thing ;)
At least one requires using - not sure cause I do not use their attachment system , I have to use a separate storage site to link to , or something like that .
Making too many steps to share - so I don't on that site .

Now if I can only get some of these [ too many ] projects finished ;)

Thanks again
 
The original picture format, (the one that doesn’t show up), is a proprietary Apple format and isn’t very compatible with much else. Same as with an iPhone. It is possible to change the actual options to auto save pictures in other formats as you take them making them more widely accepted.
 
Mech said:
Not sure how the site handles pictures - what I put into the post seems to be a download ?
Rather that a viewable here ?

I posted a picture of the box of ceramic heating elements I bought
lots of goodies in there the seller kept putting more in the box as we talked , paid $85 - very good deal , he use to custom glass making for the company lab he use to work at .

I do have some of the blanket stuff - for another project , but will not hold / mount the ceramic heating elements .

With the link to DFC site & info here , there are even more choices than I knew about [ which is some of what I am looking for - if I walk into a place that handles what I'm looking { seems like the buyer needs to know more than the selling these } ] .
In order to get the product that suit my project .
Ya would be nice to go to a site & find prices .

I have searched locally before & found very little , tried again yesterday and found a possible store front - to avoid shipping - but again service sucks these days , I have worked in many trades & found almost total ignorance at people behind the counter , example auto parts shops - YOU NEED TO KNOW FAR MORE THAN THEY DO many / most of the time to get a project going ;(

I have some thought on making this project even a bigger deal - doing volume , starting with a 5 gal bucket of IC's and to get them ashed in one load - thinking of making a larger oven with a rotating separator to evenly cook & separate silicon dies - bigger ideas keep getting me in trouble ;)
Same with another 5 gal bucket of memory cards - low heat to get IC's to drop off boards - this is half built in a 20 lb LP tank with a 3rd of the side cutout for heat , then a 1 gal paint can mostly cutout with chicken wire - used to let the IC's fall out while the paint can is rotating inside of the LP tank .

Lots of projects , this post is getting too long .

Thanks
Click to expand...
What do you plan to do with the smoke coming from pyrolizing the chips?
You'll need an afterburner to completely burn all smoke.
 
kurtak said:
goldshark - thanks for posting this info about DFC Ceramics - nice selection of products :cool:

I had to copy & paste that in order to get the web address you provided instead of just clicking on it - so here is a direct link to make it easier for members

https://dfcceramics.com/index.php
The problem I have with their web site is it does not show prices for their products &/or a way to order direct from their website so ether have to call them or message/email by way of "contact us" link on website or go to their store - all very inconvenient methods for trying to purchase a product a person is looking for --- nice selection of products but then have to go jump additional hoops to get price & make order :mad:

Kurt
Click to expand...
I live in Colorado, so a visit to their facility is not too difficult. I have spoken with the head of sales about starting an online sales site. Apparently, they have so much business world wide, an online small order is not in their business model. They sell in cartons (100's ) of pieces at a time. Since most of these units are fragile, they prefer to ship by the secure pallet load, to lessen the damage. Perhaps somebody on this site could buy by the case, and divvy into smaller parcels for resale. But then again, it could turn out like somebody buying a 55 gallon drum of Nitric, then selling in quart containers, not worth the head ache. The 1 positive with the ceramics, no haz-mat charges, except on some of the specialty flux components.
They don't show pricing because they have customers who buy one case, others may buy 10 cases more frequently, resulting in a bigger discount. Typical business point.
They are easy to work with, once you understand their business model.
Their quality is some of the best I have worked with. I purchase just about everything I need from them
And no , I have no affiliation with them, just a very satisfied customer.
Thanks for adding the proper address, it worked in some of my prior posts, don't know why it didn't work this time.
 
Not sure yet , any suggestions are welcome .
Maybe some type of fuelled exhaust pipe much less need for controlling heat / vs. not blending all the metal in the IC's .
 

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