Re: Brazing carbide

On 22/02/2026 17:30, Jim Wilkins wrote:

"David Billington"  wrote in message news:10nf3et$24dkv$1@dont-email.me...
>
I've got a small Gallenkamp Hotspot kiln bought for enamelling but good
for heat treat as it'll go to about 1050C, and a 18" top loader ceramic
kiln which gets used for larger pieces such as normalising CRS when
required. Both are controlled with PID controllers with thermocouples
which are added on and the kilns plug into them and the power controller
set to 100%. One is just ramp/soak the other can take more complex
heat/soak/cool if required.
>
------------------------------------------
>
That's a better approach with more control.
>
My enameling kiln draws 2 KW and in an hour would double my average daily electricity use. I try to avoid consuming that much unless there's no alternative (lathe, mill) and use my stock of free firewood instead, trying to develop skill in the old methods on uncritical hobby jobs.
>
I bought this model of tube furnace minus the controller for about 1% of this price. It draws around 500W warming up and heats the small volume quickly, then its thick insulation holds at low duty cycle.
https://cbisurplus.com/product/lindberg-54233-59545-type-54233-1500aoc-heavy-duty-tube-furnace-w-59545-control-console/ >
>
The 50mm tube is meant to be Pyrex, I have car exhaust pipe and stainless flange-end sanitary (brewing) tubing for it, if necessary the tube could be evacuated or filled with inert gas. The size was good for tempering a long narrow froe blade of 5160 at 175C, twice for an hour each. I intended it for custom long drills and reamers.
>
Its thermocouples are Type P (Platinel), a near but not exact match to type K. My on/off controller doesn't have a P setting so I read temperature with a Type K alarm indicator that does. This gear is all from auctions or flea markets and often needed some repair or fiddling to work right. Reseating the socketed ICs fixed the 'broken' 5 channel Type K readout that monitors my wood stove from the kitchen.
>
>

It occurred to me when I was posting that last reply that you have to deal with your electrical energy budget issues and that might make you favour a different solution if available, not something I have to think about so much with a 240V 32A supply in the workshop, more in the house.
Looks to be a nice furnace but what you have must be a lower temperature model. 1500C would likely be a Mullite liner and SiC elements. AIUI SiC are fairly easy to control with a phase angle controller and take care of the change in resistance while heating and element ageing.  MoSi2  elements get more involved due to their characteristics  but not required for 1500C usage.
I'd not heard of type P before as never run across one. Here in the UK/Europe R and S are common for higher temperature applications, it seems often US made stuff uses larger gauge K type to provide longer life at elevated temperatures. For the Gallenkamp I use a K, the other furnace I have an N type as more durable at the higher temperatures I may have been using as that one goes to 1300C or would do if I replaced the elements as they're old but it does what I require currently and will make 1100C if needed.
Reseating socketed chips is one I use as well. I've saved a woman I know quite a bit of money as when one of her temperature controllers gave a thermocouple failure alarm I asked if she had pulled the guts and reseated them, she wasn't aware you could do so RTFM. Others offered to sell her a replacement. The Cal Controls ones I and she use and maybe other makes allow the guts to be pulled from the panel mounting which wipes the contacts and they had just become oxidised as only solder coated so that was all that was required to get it working again, it's now part of her yearly service routine. I've seen banks of them on plastic extruder lines so the ability to hot swap the controller guts is useful, saves having to pull the panel apart. IIRC those were on RS485 so the settings could be re-established remotely.