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Michael Smith
12-22-2011, 04:12 PM
I wanted one of the temperature controllers that LMI sells but was having a hard time parting with the $200 that it would cost me after CA sales tax so I decided to build my own. The parts I bought cost me about $50 and were all purchased on ebay. I made sure shipping was included and used only buy now. The controller cost $26.99 the relay $8.99 the switches were about a $1.50 each. I bought all the parts from US sellers so as to not have to wait for parts from Hong Kong. I had the GFCI, which offers no ground fault protection with a blanket, I only used it because of the shape and because I already had it. A decorator square receptacle would have worked just as well. You can buy five thermocouples for $12 and 1 for $1.99.

Before I go any further here are the admonishments
If you can't tell by looking at the outside of this unit how it is wired you should not attempt to make it. If you live in the lands of 230 volt wall current your risk of self destruction is greatly increased if mistakes are made. Aluminum sides should be grounded. Etc, etc. etc.

This unit can be used with PID on or off. It doesn't really seem to be necessary to use PID to exactly target the desired temperature. It only overshoots by 6 or 7 degrees F before coming back down using a rigid stainless thermocouple. I suspect less with a wire thermocouple. The lower red switch turns on the blanket directly the upper green turns on the control unit and it's functions. The aluminum panel is 1/8" aluminum front and back, I had laying around. The body of the unit is 5/8" quartersawn red oak. It took me a better part of a day to put this together. The hardest part to find is a type K thermocoupler panel receptacle. I am not using one here and wired directly to the controller. I decided I like the unit so well I am going to fork over the $5 for the type K receptacle and the $8 for shipping. The unit works well and I will also use it to control the temperature of my bending iron.

Timbuck
12-22-2011, 10:38 PM
Great stuff Michael...I will be building one of these after the New year celebrations...I have all the parts here in my drawer ready to assemble (Got them weeks ago)..But not the K type TC panel receptical...so i'll have to search one of those up. ...I also bought a hand held digital thermometer c/w TC , but I dont know where I'm going to use that yet. :)

bobds78
12-23-2011, 03:47 PM
Hi Michael, congrats! Fantastic unit! I have been searching for a unit for a while now as I need it for my modified bending iron that I've gotten from China. I replaced the 50watt (somewhat cheap looking) heating element with a 325watt 240V unit. It heats up in minutes! I had my knuckles and few fingures burnt over a few places. Damn its a hot little devil!

So I need really need a temp controller. I thought of building one myself but I didn't have the know-how. Would you be kind enough to share a wiring diagram and a parts list?

Thanks in advance

Michael Smith
12-23-2011, 04:24 PM
My point in posting the temp controller was to show it could be built fairly inexpensively and be as full featured as the LMI unit. I don't think I can diagram the wiring expertly enough to allow someone to safely build it who needed a diagram to follow. I'm not trying to be arrogant or unhelpful but faulty wiring can be bad news.

Timbuck
12-23-2011, 10:48 PM
My point in posting the temp controller was to show it could be built fairly inexpensively and be as full featured as the LMI unit. I don't think I can diagram the wiring expertly enough to allow someone to safely build it who needed a diagram to follow. I'm not trying to be arrogant or unhelpful but faulty wiring can be bad news.
Especially when wiring relays..there are several different types and formats.

bobds78
12-24-2011, 06:31 PM
Especially when wiring relays..there are several different types and formats.

True, and fair enough. I think you guys are overly cautious. I can agree that you are cautious not to bring unwanted incidents to fellow UU members, appreciate that very much. But if you can safely do it DIY on your own, I think its only fair to say that, as adults (I really mean this!), I think we are capable of handling it.
After all, you put all the parts together in a nice box 1st, well before you plug it in and have a test, isn't that right?

Having said all that, thank you very much for sharing the unit. I don't think its that difficult to build one, provided one gets enough informations. I don't mean to be rude here! But merely saying, if I can't get the help here(isn't this is what the UU is for? Fellow UU members helping other UU members?), I would have to work harder and dig further. Ha ha...:p

Anyways, thanks guys

Have a nice Christmas!! Its giving time my friends! or have you forgotten?