Official Luthiers Forum!

Who uses a temp controller when bending to maintain constant temperature? If so which one do you employ?
Considering upgrading the “thermometer method”:)
Thanks
B


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I’ve been using one of these for the last 10yrs. The thermocouples are the weak link. I buy replacement ones on Evil-bay

https://www.lmii.com/bending-heating/19 ... -volt.html

That’s the one I was looking at.
I can manage without one, but as I put together a new area I’m wanting to get away from “I manage” ha


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I assembled my own which I found, after the fact, used the same digital controller as shows up in the LMI tool. Lots of time spent. If I had the money to spare, I'd buy the LMI device and concentrate on building guitars. And yes the controllers are luxury itself to watch, holding temperature within a degree! Sure beats light bulbs in a box.

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Peter Havriluk

The LMI unit is a solid design. If you’re so inclined, you can build your own with readily available parts, but there’s no guarantee you’ll actually save any money doing so. See:
http://luthiersforum.com/forum/viewtopic.php?f=10117&t=49239&p=683778&hilit=Controller#p683778

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As an additional safety feature, I added a pair of motor rated digital timers that are wired in series. I used to use a single rotary timer but after a while it began to stick on, very not good!

M

Put my own together, been using it for 4 1/2 years now.
http://www.luthiersforum.com/forum/viewtopic.php?f=10117&t=47715
Made a basic wooden box with gaps for heat dissipation and stuck everything inside.
Bought a mechanical timer switch in B & Q, use that on the supply for safety.
https://www.diy.com/departments/diall-1-hour-mechanical-timer/800766_BQ.prd

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Michael, is every tool you own bad ass?

I don’t understand anything you just said haha


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I think he means electronic belt and braces - if one fails to stop, the other should work. Chances of them both failing on the same run are very small.
I never, ever leave my shop when I'm side bending anyway.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Perzactley!!

I don’t leave my shop either but I have gotten distracted...

It’s one of the best reasons to have a CNC.

I can confirm. Every tool in Michael's shop is indeed bad ass. As is his shop.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Hey Michael, care to share a link to those eBay thermocouples you’re using?


Pierre

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Pierre Castonguay

On Amazon, these work well (although I buy mine from Amazon.ca):
https://www.amazon.com/uxcell-Measuring-Thermocouple-Sensor-3-3Ft/dp/B00J2N3QQQ/ref=sr_1_11?dchild=1&keywords=K-type+500c&qid=1601328736&sr=8-11

Main thing is rating of 500°C(800°F) or higher. I consider these to be consumables. My handheld temperature meter uses the same K-type thermocouple, so I usually have it running alongside my blanket controller.


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I have the parts to put a controller together, but haven't gotten around to it--I babysit the bender when I'm using it anyway, so manual has always been fine (although I did get the parts together for a controller....). Using John Hall's basic method has always worked well for me. For you folks who are using controllers, Is it really enough better to use the controller when you're already watching it closely to make it worthwhile?

Dave

Dave: my answer is yup, the digital controller offers precision that can't be otherwise approximated. Ain't no way I'm going to manually hold a heat blanket to 300 degrees, plus or minus a half-degree, even if I had an electronic thermometer driven by a thermocouple in the stack in the bender. I've got that setup on my bending pipe and it's not anything close to similar to using a digital controller.

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Peter Havriluk

I’ve been building a bending station with a dedicated bench and now I think I’ll add a shelf for a controller.... if it makes my building more precise and avoids potential issues (cracking from not enough heat or scorching from too much) I’m in


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Michael's old shop was badass. I'm sure the new shop is badasser.

Pat

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Pat

So, where are you guys getting your heating blankets? I’ve seen some on eBay, most are from China for about $100. Are these any good?

I have been using a Keenovo side bending blanket 5W/sq.in. for 5/6 guitars now and have had no problems so far.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I have both but find the thermometer a lot easier. The issue with PID transducer , if it is attached to the blanket you only know heat at that point
with the thermometer you can move it and check other points. No matter how good with the water on the wood temps vary until the wood dries off so
be sure you know your blanket. 5 watts per in will have less temp drop than a 2 1/2 .

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Keenivo is the brand I’m looking at on eBay.

I've been using the keenovo blankets for about a dozen guitars. I also use the temp controller. It's OK, but you definitely need to keep an eye on things. Not nearly as good as what I hear the LMI controller does.

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Tony Thatcher
Bozeman, Montana