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 Post subject: Non-conductive material search?
PostPosted: Mar Sat 18, 2017 1:43 am 
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Joined: Nov Sun 06, 2016 4:03 pm
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Although not radio related, I think the masters here would know what to use.
I am restoring a lead melting pot, 110V, has a thermostat rated at 1600W.
There is one of those old plug in type cords that supply the current like the old clothes Iron , electric skillet ,etc.
It plugs into 2 round stud terminals that is(was affixed) to a tin cover, metal shield.
The material had to be non -conductive because both terminals were screwed to it.
and it had 2 more screws that affixed it to the tin shield for strength to allow you to plug and unplug the cord.
I need to find a piece of material to build a new one. probably 1" wide and 2 Inch's long , 3/16" thick perhaps.
It needs to be strong enough to hold the terminals for the cord plug in, non -conductive and be able to withstand high temperatures from the electrical current and the cast iron melting pot that is less than 3/4" away.
Any suggestions on which to cut a piece of material from? Electrical junction box , terminal block, Bakelite, ????
I think this was actually a piece of asbestos when new, now its gone.
Thanks
Ron


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 Post subject: Re: Non-conductive material search?
PostPosted: Mar Sat 18, 2017 3:43 am 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: S. Dartmouth MA 02748-1225 USA
INSULROCK®

It is a machinable, non-compressive heat and electrical insulator. Check with McMaster-Carr, a call because they, generally do not put manufacturers names to materials they sell.

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 Post subject: Re: Non-conductive material search?
PostPosted: Mar Sat 18, 2017 3:45 am 
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Location: Vancouver Island, Canada
Do you know any potters? Some connectors of that type were made from porcelain.

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 Post subject: Re: Non-conductive material search?
PostPosted: Mar Sun 19, 2017 1:16 am 
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I don't think I could drill porcelain, I have looked for Insurlock but not much luck.
Do you think a piece of Mica board would work?
Ron


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 Post subject: Re: Non-conductive material search?
PostPosted: Mar Sun 19, 2017 4:06 am 
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Location: San Diego, CA
I would say phenolic is your best bet. It is readily available in bar shapes so just cut off the length you need. It is easy to machine and was used extensively as an insulator back in the day.
Rick


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 Post subject: Re: Non-conductive material search?
PostPosted: Mar Sun 19, 2017 4:26 am 
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Ronniet wrote:
I don't think I could drill porcelain, I have looked for Insurlock but not much luck.
Do you think a piece of Mica board would work?
Ron
If you can discover the thermal and mechanical specifications it may work fine. IMHO it probably has a resin binder...

It has occurred to me that a piece of asbestos shingle would work fine. These shingles were a popular home siding product if properly installed with rust proof fasteners could last 100 years. They are no longer sold because if cut or broken free asbestos particles are released. Try contacting a home re-modeler. They may have a a job residing a home, removing this type of siding. Laws now dictate that it has to be removed as hazardous waste...

See: McMaster-Carr

https://www.mcmaster.com/#machinable-ceramic/=16tdrsc
Size Tolerance Stock # Price
1/4" -0.010" to 0.010" 8479K41 $16.66

Check out its physical strength, be sure it will not break apart as a terminal strip...

Also, a piece of brake band or pad may work, but may not be a good electrical insulator or be too brittle to drill...

I had access to this type of material when employed, often much was discarded as scraps...

Phenolic will go up in smoke over 500F. Lead is over 800F and temp will eventually reach that if pot is on for many hours.

I have a 18" sq panel, 3/16" thick, of raw phenolic and linen re-reinforced phenolic (very strong). I would cut off what you need for postage, but I think it will go up in smoke eventually...

Let me know via PM

Chas

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 Post subject: Re: Non-conductive material search?
PostPosted: Mar Mon 20, 2017 5:16 am 
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Joined: Dec Sat 24, 2011 9:17 pm
Posts: 906
Location: Vancouver Island, Canada
Need Bakelite?
Attacking an old telephone handset would get some people pretty upset. :x
Find an old cook pot with a thick Bakelite handle at a thrift store. Easy to drill and shape with a rasp.

I pictured a potter making holes before firing the clay, but, right, you want to make it yourself. Good luck.

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 Post subject: Re: Non-conductive material search?
PostPosted: Mar Mon 20, 2017 7:55 pm 
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Location: Ashhurst, New Zealand
Tufnol, sometimes called SRBP, synthetic resin bonded paper. It's what the electricians make electrical distribution panels out of here.

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 Post subject: Re: Non-conductive material search?
PostPosted: Mar Mon 20, 2017 8:08 pm 
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Joined: Dec Mon 20, 2010 5:14 pm
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Location: Central Pennsylvania
Glass, ceramic tile and porcelain can be drilled without out too much difficulty with the right bit, the right cooling fluid, water is especially good for glass and low pressure, low rpm

The old school way to drill glass was to use a brass tube spinning in a slurry of oil or turpentine and abrasive such as silicon carbide or carborundum.

A section of ceramic floor tile might be exactly what you need.


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 Post subject: Re: Non-conductive material search?
PostPosted: Mar Mon 20, 2017 9:37 pm 
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Location: Georgia
Here are some ceramic blocks of various sizes and shapes. One might be suited to your needs.

http://www.surplussales.com/Antennas/Ceramic_stof.html

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