Old electric boiler temp control.

[Mike Halmarack]

I've got a very old Swan boiler,240 volt. I have to make some rabbit skin a nd/or hide glue, which needs to be heated at lower than boiling point tempe rature. I need quite large quantities, to make ultra size papier mache trad itional wood working tools for a theatre project.The smell of the hide glue will add a sense of authenticity.

Will an in-line voltage regulator enable me to reduce the temperature of th e heating element in the boiler to various sub-boiling levels? The ones I'v e seen on Amazon are described as being 220vac and I'm not electrician enou gh to be sure these voltage regulators will be compatible.

Mike Halmarack

[Chris Hogg]

Presumably you're making it from RSG granules rather than boiling up rabbit skins! I'm not sure that what you call a voltage regulator is what you want. I think you need an energy regulator aka simmerstat, but most of those available are for specific cooker models, and although they'd probably work perfectly well if you get one that matches the wattage rating of your boiler (probably 2 or 3 kW), there are usually naked terminals sticking out of the back, so mount it in an insulated box. This might do

Alternatively, do what this guy does, using partially cooled boiling water from a kettle or even water from the hot tap

[tabbypurr]

and/or hide glue, which needs to be heated at lower than boiling point tem perature. I need quite large quantities, to make ultra size papier mache tr aditional wood working tools for a theatre project.The smell of the hide gl ue will add a sense of authenticity.

the heating element in the boiler to various sub-boiling levels? The ones I 've seen on Amazon are described as being 220vac and I'm not electrician en ough to be sure these voltage regulators will be compatible.

A thermostat would hold a steady temperature, at least +/- 5C or so. A voltage regulator won't.

NT

[Andy Burns]

wire a lamp socket in series with it, and try various e.g. 25W, 40W incandescent lamps to see what temperature you end up with?

[newshound]

+1. You don't need anything particularly clever when you have a big volume of water, as long as the controller will take the amps (or kW).

If you are after a specific temperature, there are loads of cheap but reliable temperature controllers on eBay, e.g.

That one uses a thermistor, better ones will use a thermocouple.

This set of stuff is ridiculously cheap

but needs a bit more wiring up. It comprises a temperature controller which you can set up to control to a fraction of a degree, a thermocouple, and a "solid state relay", i.e. a switch which will handle a 3 kW heating element.

[harry]

and/or hide glue, which needs to be heated at lower than boiling point tem perature. I need quite large quantities, to make ultra size papier mache tr aditional wood working tools for a theatre project.The smell of the hide gl ue will add a sense of authenticity.

the heating element in the boiler to various sub-boiling levels? The ones I 've seen on Amazon are described as being 220vac and I'm not electrician en ough to be sure these voltage regulators will be compatible.

Papier mache? Use PVA glue. A much better job.

[Chris Hogg]

Flour and water paste when I was a lad.

[Brian Gaff]

The thing is you need an alternative thermostat, but if its an immersion heater in a tank, just fiddling with the voltage for the current is somewhat hit and miss unless you use a thermostat. Brian

[Mike Halmarack]

Thanks all for the good and varied advice on this question. I'm sure the ideal answer is in there somewhere. Not being an electrician, it wiill take me a while to assess the possibilities suggested. Some of them sound like fun.

[dennis]

As long as the boiler is less than 2200W.

[Mike Halmarack]

That looks like a really good and easy to use piece of kit. Seems to have many possible uses too going by the reviews.

It's a feature of my inexperience in these things that has me wondering why the temperature control range ends just below water boiling temperature, at 99 C?

"Temperature control range -50 ~ 99 ° C / -58 ~ 210 ° F "

The 12" stainless steel temperature probe that comes with the alternative Inkbird Itc-308s model is said to have a temperature measuring range of: -50C~120C.

But the Temperature control range of this model is also -50 ~ 99 ° C /

-58 ~ 210 ° F

Do these descriptions suggest that there might be problems around water's boiling poit?

[Rob Morley]

Perhaps because it's a 2.1 digit readout.

[Mike Halmarack]

I expect you're right. Does that mean it's a digital readout limitation, or a control range limitation?

[Theo]

That appears to be a thermistor probe, rather than a thermocouple (which could do hundreds of degrees). A thermistor is likely to top out at a lower temperature, but well past 100C.

If the display is 2.1 I suspect it won't let you set the target temperature beyond 99.9. But if you're boiling water it's hard to go above that anyway (unless you want to boil dry).

I have one of the REX-C100 knockoffs mentioned upthread, which takes a thermocouple and in principle will go up to 1800C.

Theo

[Mike Halmarack]

Do you know if there will be a range of probes/sensors which will be compatible with this. There doesn't seem to be one with the kit, or am I missing something? Does the threaded end on the cable screw into one of the components in the kit?

[newshound]

It takes a type K thermocouple. Plenty on eBay. The "cold" end will have a couple of wires which need to be connected to the appropriate screw terminals in the controller (and the right way round).

[Mike Halmarack]

Thanks for the extra info. The right way round can sometimes be a bit of a mystery to me, though nothing fatal to date.

Just in case commiting to buy is the unretracable step before finding out the true cost, when this kit is described as £4.19 per unit, do you think that means £4.19 for the lot, or 4 x £4.19?

[newshound]

Slightly confusing site.

Seems to be £12 without the heatsink, £14 with. For 13A you might well get away without the heatsink if you screw the SSR to the side of your metal box. If you put it in a plastic box, then you probably need the heatsink.

Getting thermocouple polarity right is not difficult. One way round, it will display the right temperature (and will increase if you grip the tip with your fingers). The other way won't.

[Andy Burns]

£4.19 is the heatsink alone ...

[Mike Halmarack]

This project is turning into a wild goose chase. Now I see that they don't deliver to the Isle of Wight. though if it comes through Royal Mail I don't think it would cost them any more.

I'll probably ask them for a special delivery arrangement.