Temperature control for heat strips

How to make a Bow, a String or a Set of Arrows. Making equipment & tools for use in Traditional Archery and Bowhunting.

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rodlonq
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Temperature control for heat strips

#1 Post by rodlonq » Mon May 11, 2015 9:56 am

Going to try overriding the simmerstat on my laminating heat strips with this digital thermostat. It has adjustable set point & dead-band and works on both heating and cooling functions between -20C and 100C. It also displays the current temperature of the probe and is just over $20 posted. Has anyone tried this? Seems like it could also be ideal for converting a chest freezer into a home brew keg fridge (or meat chiller) :biggrin: .
http://www.ebay.com.au/itm/281280638271 ... EBIDX%3AIT
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Cheers... Rod

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bigbob
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Re: Temperature control for heat strips

#2 Post by bigbob » Mon May 11, 2015 11:17 am

I bought two of them Rod and cooked both trying to wire them with my extremely limited knowledge of circuitry. ! Think they would work though if someone like yourself hooked them up properly!
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Nezwin
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Re: Temperature control for heat strips

#3 Post by Nezwin » Mon May 11, 2015 11:42 am

I use one of these in my hotbox -

http://www.ozbow.net/phpBB3/viewtopic.php?f=34&t=15146

My heat source is lacking but the controller works perfectly. I'm looking into getting one for the home brew, a little down the track.

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greybeard
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Re: Temperature control for heat strips

#4 Post by greybeard » Mon May 11, 2015 3:16 pm

Hi Rod,

It looks like a neat unit but I was wondering about the diameter of the probe and if it would distort under the pressure between the metal strip and the glass back.
rodlonq wrote:......Seems like it could also be ideal for converting a chest freezer into a home brew keg fridge.....
When modifying the freezer to take my beer kegs I removed the freezer thermostat and replaced it with a drink chiller thermostat. From memory it cost about $25.00.

Daryl.
"And you must not stick for a groat or twelvepence more than another man would give, if it be a good bow.
For a good bow twice paid for, is better than an ill bow once broken.
[Ascham]

“If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?” [Einstein]

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rodlonq
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Re: Temperature control for heat strips

#5 Post by rodlonq » Mon May 11, 2015 4:35 pm

greybeard wrote:Hi Rod,

It looks like a neat unit but I was wondering about the diameter of the probe and if it would distort under the pressure between the metal strip and the glass back.

Daryl.
Hi Daryl,

I drilled a hole into the middle of the form the same diameter (sliding fit) as the probe, right next to the lower pressure strip. I reckon the temperature there will be much the same as the bow so it is more than accurate enough, considering the whole lot is at steady state for a couple of hours. I have a similar hole in all my forms so I can use the one probe for them all. This means I don't have to worry about the probe during lay up and I put it in the hole when I turn on the heat strips. I intend to swap the thermometer probe pictured for the thermostat controller probe.

Sorry about the photo quality, it is a very small section cropped out of a larger photo and blown up.

Cheers... Rod
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greybeard
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Re: Temperature control for heat strips

#6 Post by greybeard » Tue May 12, 2015 4:32 pm

Hi Rod,

I was using a probe thermometer between the pressure strip and glass on the top side towards the end of the bow.
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For some unknown reason I decided to use a probe at either end to see if there was a temperature and sure enough there was about ten degrees difference.

I colour coded the probes and swapped their positions with the next bow and sure enough there was a similar temperature difference.

With my next glueup I will lay a heat strip in from each end to see if that balances the temperature.

Alternatively the temperature difference may not be big enough to worry about.

Daryl.
"And you must not stick for a groat or twelvepence more than another man would give, if it be a good bow.
For a good bow twice paid for, is better than an ill bow once broken.
[Ascham]

“If a cluttered desk is a sign of a cluttered mind, of what, then, is an empty desk a sign?” [Einstein]

I am old enough to make my own decisions....Just not young enough to remember what I decided!....

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rodlonq
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Re: Temperature control for heat strips

#7 Post by rodlonq » Tue May 12, 2015 5:43 pm

That's interesting Daryl. I have never tested the temperature at different locations. Being a resistive heating element the heat strips should have fairly uniform power density, at least that is what I have found with similar silicone heating devices in the past. I might drill some more holes and have a look, can't really do any harm. I would do the same thing with a probe like yours instead of sticking it between the pressure strip and the glass.

Cheers... Rod

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rodlonq
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Re: Temperature control for heat strips

#8 Post by rodlonq » Tue May 12, 2015 5:53 pm

I tell untruths :smile: . I have the probe under the top pressure strip on my straight laid form.
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Cheers... Rod

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