Bimetalic domes

Sure you can do this, but get a few of these, as the odds of getting it right the 1st time is slim. Steve

How important is the overall size of the sensor?

You might find one of the sort that used to be used in kitchen appliances, that could be inserted in a grill, waffle maker, cookpot, etc. These have adjustable settings, which (I assume) are varied by changing the pressure on the sensor.

right the 1st time is slim.

make a

contacts.

grinding

destroy

According to patent "Laser adjusted set-point of bimetallic thermal disc" it is done at production , for precise adjustment, but no specific details of patterns/which surface/degree of variation. I'm more interested in adjusting otherwise useless batch made for set point of 16 degree C up to

If you could find the patent for the controller I described (it's a famous patent, from a man who patented many devices in the 50s and 60s), it might show how this is done.

details

to

probably a John Taylor

I'm not sure. The guy I'm thinking of is American.

Interesting , but no further forward. Looks as though these froststats will remain froststats. Surprising ping and bounce as much as six inches on change of state, the loud ping is somewhat damped when inside the casing. Need freezer spray to change the state of these discs (hysteresis and all that). When back to body temp I tried grinding a spot in the centre of the concave side, no change in set temp. Tried 4 diametrical marks on the concave side , no change in response. Tried deeper but small 8 cuts just on the perphery, now no ping but slowly migrates from one state to the other , still requiring freezer spray. I wonder how they "weld" these 2 materials together.

Like this?

or this?

I don't think so (but I'm guessing). Grinding might change the deflection or force but probably not the transition temperature. Below some force level, it simply will not transition. My guess(tm) is that the transition temperature is controlled by the curvature which is rather difficult to modify.

Note that some discs are "manual reset" or "single operation" and act as thermal fuses.

Search Google for "bimetallic snap disk".

(etc...) I tried to find the vendor of the actual discs, which might include design information, but couldn't find anything useful.

Have you considered fire alarm heat sensors? They use a bimetal switch internally.

Gunner

"IMHO, some people here give Jeff far more attention than he deserves, but obviously craves. The most appropriate response, and perhaps the cruelest, IMO, is to simply killfile and ignore him. An alternative, if you must, would be to post the same standard reply to his every post, listing the manifold reasons why he ought to be ignored. Just my $0.02 worth."

I belive "Clixon" in the UK make these.

That is 'Klixon', which was a division of Texas Instruments.

Now it's a division of Sensata

Thanks for the spelling correction and link. Its a lot of years since I played about with them. They were very popular in water heater circuits at one time.

Probably by electroplating one of the meterials onto the other.

-- Jeff Liebermann snipped-for-privacy@cruzio.com

They still are, but a lot of their thermal motor starters are discontinued.

will

casing.

all

the

on

other ,

materials

I would have thought friction welding, probably many to a spin and then press cut to small discs

This might be the correct answer, but there are fill-metal/reducing atmosphere/heat solutions that might do a kind of brazing for lower cost if you get the materials right. Explosive welding is used for US coins because it was possible to mimic the electromagnetic properties of silver well enough to keep lots of vending machines in service. I've gotta believe the requirements for a thermostat bimetal system are loose enough to allow for alloys that don't require explosive welds.

I was under the impression that two sheets of material were hot rolled together and the discs just stamped out complete with the dome shape.

to

at

would

The use I see them is located fairly loosely in a well in a bakelite disc that is itself located loosely in the bakelite outer housing