Cheap Thermostat AND Timer for a Fox Side Bender.

[Phil]

I built my Fox side bender many many years ago, before heat blankets were invented.

I think that my bender would NOT get a thumbs up from the Occupational Health and Safety guys today. It works for me, but I would not recommend my design to newbies, or even oldies because of the way I heat the wood and controll the temp.
Lots of Watts inputted via light globes & temp measured with a mercury thermometer. There has to be a better option...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Here is a cheaper possibility. It has Heatiing, plus a Timer - up to one hour, plus Temp controll - 125 to 250 degrees..... all for $39.00. Available from BigW and K-Mart right here in Oz.

You will need a screwdriver, half an ounce of brain, and a medium degree of courage, because I have not tested this out myself.

http://www.bigw.com.au/home-garden/smal ... 000266511/

Seems to me that if you remove the electric stuff off the oven and attach it to your side bender it will be a cheaper option than importing expensive stuff.

DISCLAIMER. I could be wrong.


Phil.

[woodrat]

Phil...could I borrow your disclaimer? It could come in handy!

John

[Localele]

I would be worried about the fat from the chicken getting into the timber of the side set and making it harder to French Polish.

[kiwigeo]

Looks like a half baked idea to me

[charangohabsburg]

Here is a cheaper possibility. It has Heatiing, plus a Timer - up to one hour, plus Temp controll - 125 to 250 degrees..... all for $39.00. Available from BigW and K-Mart right here in Oz.

You will need a screwdriver, half an ounce of brain, and a medium degree of courage, because I have not tested this out myself.

$39 is very tempting. That thing might be worth a trip to Oz. How much is the brain and can I get it also at BigW and K-Mart? Screwdriver and courage shouldn't be a problem though.

[liam_fnq]

While you're there can you get me some socks and jocks. The washing machine keeps puting holes in mine.........

[Dominic]

I've got an old clothes dryer down stairs that I recon would do the same thing. Its got a timer and heat setting knob. But really, I am eyeing off one of the new LMI units. Not the whole bender just the controller. Charles fox demonstrates one of his new one sided benders in a recent GAL journal. Simple to make and I've seen a really cool way of doing cutaways on youtube so I have some jigs to make.
Good luck with it
Dom

[ozwood]

Hi Dom,

If your half proficient with electronics you could make one.

http://www.ebay.com.au/itm/220913738795 ... 1438.l2649

http://www.ebay.com.au/itm/250956520181 ... 1438.l2649

http://www.ebay.com.au/itm/Thermocouple ... 3a571c638f

https://secure.vividcluster.crox.net.au ... owcart.asp

Not the thermo couple is bigger than you would want , but you get the Idea.

Cheers,

[Kim]

I had always intended to build a temp control box from day one and went with the option to have MEI build-in a "J" type thermocouple when ordering my heat blanket way back when. As I recall it only cost a few bucks more and seems to work really well. Should the thermocouple ever decide to shit itself, which can happen as the paired dissimilars in a "J" type are, + = Copper/Nickel, - = Iron, and pure iron can become brittle and can then break if you flex it around a lot, I can always use a replacement thermocouple from ebay and then insert the paired manually within the sandwich as many do now.

In hind sight if I was to order another blanket, I would opt for a "K" type thermocouple as it has the same temp read range, but the paired dissimilars being + = Nickel/Chrome, - = Nickel/Aluminium, are probably more robust. One thing to keep in mind when working with either "J" or "K" type thermocouples is that the wiring colour codes are standardised for the USA, white and red for "J" type, yellow and red for "K" type and in each case RED is NEGATIVE.
. Regardless of that, if you get yourself a half decent digital heat controller to begin with (Omron make very good gear), it will have internal switches so the user can select between F and C read-out, 20 second or 2 second temp monitoring, ON/OFF or PID supply switching and "J" or "K" type thermocouple compatibility.

On that here's a bit of info people who don't currently know may find interesting. The acronym PID stands for Proportional, Integral, Derivative. The short of it is that the processor inside the unit 'learns' how to control the temperature to closer tolerance over its timed cycle...in other words, the unit 'learns from its mistakes' with each error forming new parameters within which it will switch power on and off to best match the set-point. 'Eventually', the PID process whittles down the margin of error between 'too hot' and 'too cold' to maintain the set point to within just a few degrees, and it will continue to try and improve its performance until you eventually make it brain dead again by switching off its power supply....next time you turn on the power, its remembers as much as a new born........zip.

So this means if you switch your digital temp controller to function as a PID seeking to have it maintain temp to the closest degree possible, the controller will need time to learn how to maintain the selected 'set-point'. To do this the device will need to operate for around 20 to 30 minutes in very much the same conditions as it will be during the actual bending process. This is to say that at the very least, the blanket would need to be placed between the forms for a preheat session of approx 30 min 'before' your set to go, and then, you would need to get the sandwich into the form and re-clamped 'before' the PID had a chance to learn new lessons from being exposed to the much cooler air in your workshop....bet a few of you never knew that one did ya..

So why bother??? Well for starters, pre-heating a solid form is not such a bad idea ..... but 30 min??? Anyhow as mentioned earlier, your digital controller should be switchable so you can turn 'off' the PID process and simply have the unit function in straight on/off control mode. Would that still be as accurate as PID mode I here you ask?? Well no it's not...but the unit does still read the same current variations coming from the same thermocouple and uses that information to switch on, or off every few seconds as required and that process, whilst not as accurate as PID, does maintain the set-point closer to the mark than any other method that is not PID can 'and'...as I understand, because the circuit is either fully on, or fully off at any given point in time, your equipment will love you because in the world of electrics, I'm told that nothing burns stuff out faster than under supply and therein lay the issue with rheostats/router controls etc.

But perhaps that's only an issue for motors and the like where they are designed to operate with a certain current, and when they are speed controlled by reducing that supply, it can cause them to overload when they become bogged down in work for lack of torque? Perhaps Liam would be kind enough to give us a sparkys view and clarify how under supply damages things and whether or not the use of a rheostat could affect the longevity of something without windings such as a silicone heat blanket??

Cheers

Kim

[woodrat]

I've got an old clothes dryer down stairs that I recon would do the same thing. Its got a timer and heat setting knob. But really, I am eyeing off one of the new LMI units. Not the whole bender just the controller. Charles fox demonstrates one of his new one sided benders in a recent GAL journal. Simple to make and I've seen a really cool way of doing cutaways on youtube so I have some jigs to make.
Good luck with it
Dom

Hi Dom, can you elucidate us re the links to your YouTube cutaway vids....Thanks

John

[kevjed]

Thanks to all for the guidance on making a thermostat for the heat blanket. Here is my take based on the LMI version.
Please get an electrician to wire yours up for you. I've just got to mount the plugs in the rear face plate and close the thing up.
It was fun learning how to make it and now I'm looking forward to using the thing.

[charangohabsburg]

Looks nice.

Please get an electrician to wire yours up for you.

I reckon that only the electrician for the wiring would cost more than the whole unit bought from LMI, plus the fun for building the thing would be gone completely.

[kevjed]

I agree. I thought that I'd add the electrician thing to cover my self and the owners of the forum just in case some bunny fried himself by having a go at the 240v stuff. Every one needs a friendly electrician to look over things before they go bang.
lol

[charangohabsburg]

Yes, I would go after you!



I have several court cases pending against ANZLF members because they didn't tell me to contract a carpenter instead of using a chisel!

But you're right, don't do it if you don't know how to do it.

Stay save.

Cheers,