Silicon Blanket

[joel]

I got a 240V blanket from Omega in the States. Even with doubling the price due to postage and the much weaker AUD at the time (about 0.75 US), it was the cheapest option around by far. The down side was it took quite a while for them to make it and send it out.

[Lillian]

Joel, did you get a custom blanket or go with one of the stock sizes? I remember it took a couple of weeks for it to get to me, but it wasn't bad. I have no idea how much of that time was eaten up in transport.

[Allen]

I got a 240V blanket from Omega in the States. Even with doubling the price due to postage and the much weaker AUD at the time (about 0.75 US), it was the cheapest option around by far. The down side was it took quite a while for them to make it and send it out.

Omega was one that I emailed about a month ago and got the blank stare. Gave me a long song and dance about hooking a couple up in series and that should do the trick with the voltage. I may have got the new guy, but it sure didn't seem very professional of them. Kind of put me off of any follow up with them.

I've emailed MEI back to get a quote either way with the thermostat and without. Will let you all know what the outcome is.

[joel]

I found their customer service to be excellent, with quick replies to emails. They make a 240V version as a standard option to their standard sizes (36" x 6" is a standard size). You just have to look through their catalogue description for it.

The Omega part number for mine is SRFG-636/5/240V.

That's 6 x 36 inches, 5 watts per square inch (making it a 1080 watt blanket), 240V.

It did take a long time to get it. Ordered in Feb. It was supposed to be made in April, but wasn't made until May. Finally got it in July (due to the 6 to 10 week postage by ship). I still haven't used it yet Work, uni, and family have taken all my time this year.

[joel]

Just found the receipt.

The blanket was $76 USD, and postage was $39 USD. Grand total $115 USD. Which at the moment isn't that much more in $AUD

Also got a nifty conversion calculator as a free gift.

[Kim]

A couple of thing to consider when ordering a blanket. For a few bucks more, you can have them build in a "J" type thermocouple and stipulate that the wires exist the blanket from an extension tab.

The "J" type coupling will not change how you do business now however it will allow you to wire the blanket to a digital heat controller should you decide to go down that road later. These controllers are very accurate and can be found for a reasonable price on the bay, but you do need to be careful that the unit you acquire is for a "J" type sensor and that it is rated for the volts and wattage to match your blanket. Sounds like a bit of futzing about but you can then set the temp to where you want and enjoy an accurate digital readout from the front of the control unit. With a timer and bit of record keeping, this will let let you set and forget for each type of wood you use with a proven cycle.

As for the extension tab, the "J" type coupling has special alloys in the sender wires that can get brittle after being cycled through hot and cold after a time. By having these thermo send wires exiting an unheated part of the blanket, you avoid those associated problems.

Just a thought for next time maybe or for the noobs.

Cheers

Kim

[Paul B]

I'm doing it backwards. I already have a PID controller and thermocouples that I, er, found.

Didn't realise the blankets were so cheap. Might take the plunge next year.

[Allen]

That's a lot more info than I've ever been able to find. Thanks for the heads up Kim. I'll make some more inquires.

[sebastiaan56]

Many Thx Joel,

Ive ordered the same and the current price is USD$121, pretty good with the Aussie nearly at parity, makes me think about timbers as well....

[Kim]

I have a blanket from these guys http://www.michaelsenterprises.com/, and yes they do 240v. In fact you will probably find that, along with Omega, these guys are supplying the usual suspects at trade.

Anyhow, I had a quote from them almost exactly 2 years ago for a 5 watt per inch 36" x 6" custom blanket with the extension tab I mentioned above exiting the wires from the centre to keep them from obstructing the form and an embedded "J" type thermocouple with 6' leads and supply wire, back then, $87.33USD each exclusive of shipping to AU.

I have just sent Jim Foote of MEI an e-mail to get an update and will post the current price when known.

Cheers

Kim

[Allen]

Good on ya Kim .

[Kim]

Here we go, 1100 watt = just over 5 watts per inch, tell'em Kim from Aussie sent ya. I imagine that these would be even cheaper if you forgo the "J" Type Thermocouple and just stick with a router control

Hi Kim,

Following is the updated price you have requested.

6" x 36"
240 Volt 1100 Watts
6 Ft. Silicone Leads w/Tab
6 Ft. Type J Thermocouple Wire .......$88.41 per unit

Ship Date: 2-3 weeks on receipt of purchase order.

Thank you,

Jim Foote
MEI
Phone: 208-835-9955
Fax: 208-835-9954
E-mail: heaters@michaelsenterprises.com
Website: www.meiheaters.com

[Allen]

Well, the order is in to MEI for the blanket that you got a quote on Kim.

Can you hazard a guess as to why their PID controller is $480, and ones that I see on ebay are all under $100, most under $50. Are we talking the same thing? Having never seen one, or for that matter having any idea how to use one, I'm just flying in the dark.

[Kim]

Allen,

You need to look on ebay USA, I bought a couple of Omron units for $100 shipped a few years back, the local price back then was around $600 AU each. Most of the $50 units you will see are superseded or excess NIB stock and are fine. But, you MUST look carefully that the model number has been accurately listed as there are literally thousands of differnt kinds of these things available.

Once you have a known model number, then you search the manufacturer's site for that model to check the specs to ensure it is in fact 240v, "J" type thermocouple compatible, and will handle the wattage you intend to throw at it. Here azom.com/details.asp?ArticleID=1208 is some basic info on thermocouple technology that may give you an idea of where you are heading with this. It will all be quite confusing to begin with but stick at it and a pattern will appear which will lead you to the right unit for you. The ones that I have are now soo dated you would only find then secondhand so I will not bother listing the number.

If you do wish to go down this road, you will need to understand that the accuracy of the PID is 100% reliant upon maintaining the correct alloy and polarity in the circuit wire all the way from the blanket, to the PID. This means that when you make a control box to house the PID, timer and voltage relay unit that will be necessary for this system to function, you will need to have "J" type wire running from the rear of the PID to a "J" type panel mounted quick release connector. You would also need a "J" type male plug to fit onto the wires running out from the blanket that will plug into the above-mentioned quick release connector.

The idea here is to allow you to quickly unplug the blanket from the control box for easy storage and to also quickly change to a variety of blankets for different task using the same PID set up.

So, you will need the blanket with "J" type as ordered, a matching PID to be searched out on Ebay USA, a solid state relay with heatsink, probably once again from Ebay USA but this guy, Karl, is local, has good prices and is a great bloke http://www.karlslittlegarden.com:80/ so check with him first.

You will also need a "J" type male pin connector to go on the end of the wires coming from the blanket, I got mine local but you may want to enquire with MEI, a panel mount female connector to fit into a hole that you will drill into the panel which makes up the back of your control box, (MEI?) A short length of dual core "J" type wire to run inside the control box and connect the female panel mount connector to the rear of the PID (MEI? or local) a timer of some sort, I have an old darkroom timer but am planning to find a digital unit, maybe from a microwave? And last of all, besides a few standard 240v plugs and a bit of wire the custom built control box which has been well ventilated at the top rear.

Once you have all the bits, and have made the housing box from ply to hold the timer, controller and relay neatly in place, take them to a mate who is competent with electronics to hook things up if you are not confident yourself. For that part it is worth noting now that the colour codes for the "J" type thermocouple wire are RED = Negative (yes that is correct, red IS negative) and WHITE = Positive.

Like I said in the post above, it is a bit of futzing about, but doable and if you wish to just wire the blanket without the thermocouple relay or timer in the loop, it will work just like any other if you use a router controller like most.

Cheers

Kim

[Allen]

Thanks for all that Kim. Looks like there is more to learn. Now I know why MEI's is the price it is. Just saves all the futzing about.

[Dennis Leahy]

Looks like the Omron temperature controllers (or at least this one) can handle 240V:

E5CS-RKJ

Dennis
p.s. Remember not to worry about sellers that won't ship to your chunk of the planet. I will.

[Kim]

p.s. Remember not to worry about sellers that won't ship to your chunk of the planet. I will.

Exceptionally nice of you Dennis, thanks M8

Cheers

Kim