Official Luthiers Forum!

Hi guys,
I purchased a bridge heating blanket from LMI,
However they were zero stock on the temp controler.
I was strongly advised by LMI not to use this blanket
without a temp controler, and I agree !!
Can I use a light fixture dimmer shitch and make my own
temp controler ??
Does the LMI temp controler work like a dimmer switch
or does it sense the temp and turn the blanket on and off ??
Thanks
Gregg

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Gregg

Gregg: I use a high wattage dimmer and find it works for me.See what others have to say.Time control very important,you can't leave these things running without protection.
Tom.

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A person who has never made a mistake has never made anything!!!

get a router speed control they are better than a variable resistor. They are a vsi switch. The variable resistor becomes part of the circuit. I have found that blankets will last longer with a VSI switch than a resistor.

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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

Thanks Guys !!
John,
Can you please expand on this VSI ??
Im not familiar with a router speed control .

Gregg

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Gregg

I've used a heat blanket without timer for 10 years. Just
can not walk away. I never turn my back on it when I'm bending.
I would recomend using one tho...

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Lance@LuthiersForum.com

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

http://www.bluescreekguitars.com/catalo ... 20a&page=2
That a VSI switch does is send short bursts of current . This actually will control the voltage to the blanket ,and this controls heat. As Lance says also you should use a timer in conjunction with the controller. The variable resistor will control voltage by resisting it , this become part of the circuit and you can lower voltage to the blanket. I used one when I fist started making these and found that the resistor will shorten the life of the blanket. It also uses more current than the VSI as the resistor becomes part of the circuit.
Check out this link for an explanation and see how one works in a bending unit.
http://www.youtube.com/watch?v=JFNy93PM0Kc

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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

Thanks Guys !!

Gregg

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Gregg

FWIW .. most common light dimmers are NOT variable resisters - they are chopper circuits, which as John points out, chops the voltage into short bursts as required when you turn down the knob .... check it out for yourself, put a voltage meter on a dimmer output - it always reads 120 or so (unless you have a very fast meter) .. why, because the meter isnt fast enough to see the chops, all it sees is the still present peaks and so reads 120 ...

I have been using one from HD for about 5 years now .. no failures on either (600 watt dimmer, 550 watt blanket - 2.5 w/sq inch, 6x36)

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Thanks
I use and sell blankets that are 5 watts per inch so you need a good 1000 watt capability.

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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

Yep .. right on John .. the HD cheapos are only 600 watts .. unless you like smoke !!!!

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Gregg,

I have a spare LMI blanket heating controller that I don't use that I'll let you have real cheap if you like.
It's effectively brand new - only used a couple times before I changed my hardware to a different method.

Let me know if you're interested.

Cheers,
Dave F.

P.S. I am a fully paid up classified section member, so we can move it on over there if we need to.

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Cambrian Guitars

"There goes Mister Tic-Tac out the back with some bric-brac from the knick-knack rack"

Actually Home Depot does have a cheapo 1000 watt dimmer.
Its a slide next control to an oversize rocker switch.
I've used one for the last 5 years with no problems.

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Keith MacKenzie
Location: Florida
"To err is human to really screw up you need tools"

Just to add to this it's a good idea to mount the dimmer in a large 4x4 metal box with a metal cover as this
helps the dimmer get rid of its heat.

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Keith MacKenzie
Location: Florida
"To err is human to really screw up you need tools"

Thanks Dave,
However I bought one in town yesterday.
My new blanket and Router speed control worked perfectly, the bridge came off in about 10 minutes,
no damage not even a scratch !!
I have another question, with the bridge off how do I remove the glue on both surfaces ??
Do I need to sand in-order to remove all traces of glue ??
Will some glue still remain in the grain and fibers of the wood ??
How do I asure I will get good adhesion ??

Gregg

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Gregg

I would scrape the bottom of the bridge clean (scraper or razor blade), and use a SHARP chisel to clean up the top area. I dont sand either of these ...

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"