Thermocouple Type S Price Insanity

[Hyn Patty]

Good Lord!  I looked at prices for a replacement thermocouple type S for my larger Skutt kiln less than two years ago and they ran $50.  But I needed to order backup parts for my smaller Olympic that I use far more often so I put it off.  I figured it was only $50 so I could pick up one a bit later.  Now I'm looking at ordering one and now they are all priced $300 to $400 each!!   I know things got a bit more expensive, even two to three times more than they were pre-COVID, but this is inexcusable.  Anyone have a sane explanation as to why the cost of these suddenly went crazy?

Any of you know of anywhere that somebody can order one without spending several hundred dollars for it?  I mean, this seriously makes no sense at all.   I'll keep looking because I must but I am completely mind boggled.  I can still get a type K thermocouple for around $20 to $25 so what the heck?

Edited July 19, 2023 by Hyn Patty

[Hyn Patty]

See below, I managed to find some that are a lot cheaper but not sure if they will work in my Skutt.  Some general info comparing K type thermocouples to type S:

Type K thermocouple specs:

 K Type Thermocouple positive leg is composed of 90% nickel, 10%chromium and a negative leg is composed of 95% nickel, 2% aluminum, 2% manganese and 1% silicon. These are the most common general purpose thermocouple with a sensitivity of approx 41µV/°C.

Type S thermocouple specs:
Platinum thermocouples (Type S) have one wire made from pure platinum and the other wire made from a platinum-rhodium alloy with 10% rhodium. They have characteristics similar to those of Type R devices, with a quoted measuring range of 0°C to +1750°C, measurement sensitivity of 10 μV/°C, and inaccuracy of ±0.5%.

But type K sheds little flakes of black metal into my glazes and I HATE that.  So I have to clean the tip of the thermocouple with a wire brush and vacuum out the specs before every glaze firing.  Even so, I still sometimes get black specs in really expensive pieces I produce.  Gah.

 

Edited July 19, 2023 by Hyn Patty

[Hyn Patty]

Found these too but the base isn't the same and I'm curious if I can rewire it safely to swap out just the themocouple itself and reuse the base on my old Skutt themocouple.  Anyone tried that? 

 Themocouple S on Ebay

Only thing that worries me about that one is that it is made in China and may not hold up well, I don't know.  I also found this handy chart for comparing different kinds of thermocouples, what they are used for, temperature ranges, and what they are made out of:  Thermocouple Comparison Chart

Edited July 19, 2023 by Hyn Patty

[Hyn Patty]

Well, I ordered one and all told cost me about $15 with free shipping.  When it arrives in August I'll swap it out and run some test firings to see how well it works with my kiln.  It's normally used in a kiln that can fire up to 1300 degrees celsius so maybe it'll do all right.  If it does well I'll report here and I'll order an additional backup to store. 

I double checked the price of platinum and it has gone up about two hundred dollars an ounce in the past two years but not nearly enough to justify this huge price leap.  BUT, the price of rhodium has gone nuts so that probably answers my own question.  But it doesn't explain why USA made thermocouples are crazy expensive now but ones made in China are dirt cheap.  Assuming they are in fact still produced using platinum and rhodium...

Edited July 19, 2023 by Hyn Patty

[neilestrick]

I don't know who was selling type S for $50, but the ones I get from L&L were at least $150 at their lowest that I remember, about $250 two years ago, and are now $400. In addition to the thermocouple itself, you'll also need type S thermocouple wire all the way back to the controller. Also set your controller for type S. As to whether or not it will last, who knows? It all depends on the thickness of the wire in the sheath and the quality of the construction. Worth a try for $15, though.

The other solution to the flaking thermocouple is to install a ceramic protection tube. If you use a closed end tube you'll have to figure out what offset to program in the controller to compensate for the insulation factor (usually around 15 degrees), or you can get an open end tube that still keeps the flakes from getting in the kiln but doesn't require an offset.

[dhPotter]

@neilestrick Where can an open end tube be purchased? I looked on Olympic website and did not see any kind of tube and they only had type S thermocouple, $545 - $655.

L&L has the open end tube for $57. Will this tube work on an Olympic 2327 HE? 

[neilestrick]

5 hours ago, dhPotter said:

Where can an open end tube be purchased? I looked on Olympic website and did not see any kind of tube and they only had type S thermocouple, $545 - $655.

L&L has the open end tube for $57. Will this tube work on an Olympic 2327 HE? 

Yes, you can use the L&L tubes, you just have to drill out the TC hole. Also, the tubes have a flange on the outside, so L&L uses little ceramic spacers behind the TC block (screws go through them). You need two for each screw, so 4 total. You can see what I'm talking about in THIS VIDEO. Technically you can do it without the spacers, but things snug up better with them.

[ZachL]

How did it work out? I am likely going to try my luck on a $40 type S from AliExpress.