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Wish I knew more about control equipment. It does appear the PID may handle the load but I don't see the switching rating for the timer.

Maybe Fred Tellier will stop by. He will know

Regarding the bridge removal.... I use the pid when removing a bridge or fingerboard. I set the temp at around 225

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Joe Beaver
Maker of Sawdust

The pid unit looks good but I would get a type J or K thermocouple to use with it, you can get long probes that will go into the center of the bending sandwich. one similar to this is what I use http://www.ebay.ca/itm/K-Type-Thermocouple-Probe-Digital-Thermometer-Stainless-Steel-SensorSpiral-Cable-/310676340909?pt=LH_DefaultDomain_0&hash=item4855c0c0ad
As for the timer get a bathroom timer from Home depot these are all you need.

Fred

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Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

Save a bit of money and it's simpler and requires no programing only twist the dial to what you need.
Is it a thermister or a thermocouple in your blanket, the controller needs to be programed for it.

Fred

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Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

So the question is, is it possible to control a heating blanket with a dimmer switch and a timer to make sure you don't leave it running too long?

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Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

Yes.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Tai, that is the setup I used for years. What I did was put a thermometer on the blanket and test various settings. Then mark on the dimmer where they are. Works OK but thermacoupler is better.

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Joe Beaver
Maker of Sawdust

That PID does take these thermistor inputs: "Input: Thermo Resistor: PT100, Cu50". But the temp the thermistor senses will be inside the blanket -- generally higher than the temp at the wood surface. So I'd go with a TC like Fred says. I like the wire type TCs, as the larger sheath pushes the blanket away locally. E.g., http://www.ebay.com/itm/310382864123

Also agreed on the wall timer. I've been using one like this: http://www.homedepot.com/p/100685852
as it has a 3 position switch and doesn't require 'turn past' like the springed ones.

One odd thing on that PID and SSR combo: The PID spec says, "Main Output: SSR: Open circuit: 4V, Closed Circuit: 24V 40mA DC". I.e., it outputs 4V for off and 24V DC for on.
While the SSR says, "Input Voltage:DC 3-32V", so it should be on at 4V and at 24V DC.
But they've sold a bunch of these, so probably the PID doesn't push enough mA at 4V to switch the SSR.

I generally like SSRs except for 2 things: the 'click' of a regular relay is often helpful to know what it's doing, and when an SSR fails (rarely), it normally goes closed circuit. I like to wire a light in parallel to the load to monitor what the SSR is doing.

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David Malicky

I wired the Thermocouple to the controller direct as it was too much trouble to order a female receptacle for it, remember you will need a type K for a K or J for a J. The thermocouple is actually the contact point of 2 dissimilar wires and the type of wire is what makes it a K, J etc. I just pushed the plug onto the terminal strip on the controller and tightened the screws, you can also strip the insulation off and attach.

For the blanket I just used a duplex receptacle.



Fred

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Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

There's no reason you can't use a Router Speed Controller/Rheostat (RSC) along with a PID. My blanket gets very hot, very fast and the RSC kept the temps in check, preventing any overheating, while I learned about, and got the PID dialed in. Also if your temp probe should fall out for any reason the RSC will prevent overheating.

Another nice touch is a main power and blanket power switch. It allows you to shut everything down very quickly if something goes awry and you can adjust all the setting on the PID with no power going to the blanket. When you're happy with the settings and ready to go, power up the blanket.

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Thank You and Best To All

Nice setup Larry, your box is much prettier than mine. I need to add a bypass switch to the timer to mine as I use the controller with my hide glue pot and resetting the timer is a pain.

Fred

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Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

I couldn't have done it without your help, and a friend who helped me wire it all up. Those couple extra switches really makes life easy in the heat of a bending session.

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Thank You and Best To All

Of course, but with a separate switch you can turn on the main power, which activates the PID but sends no power to the blanket. Then you can set your PID and after the PID is set, just turn on the blanket and you don't have to mess with plugging/unplugging the blanket - just leave it plugged in all the time. Your main power plug is usually unplugged when not is use so there's no real danger leaving the blanket plugged in.

If you overheat or have any other problems you can instantly turn off JUST the blanket with the switch saving all your PID settings and be ready to go right away.

But basically to repeat it's just a way of not having to plug/unplug the blanket if you need to cut power to it quickly. Haven't found a down side yet.

EDIT: It also allows the blanket to be 'ramped up' during the initial heating stages if your blanket is heating too fast - just cycle the switch off and on till you get up to temp. There might be a PID setting that will also do this but I'm not that literate in its total operation.

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Thank You and Best To All

Yes, many controllers have a max ramp rate setting (degrees per minute or hour), and also a max output setting (% on time, functionally similar to a router speed control). Either one helps the sides get to temp at the rate you want.

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David Malicky