Temperature Control for Hot Glue

by HilldaFlyer | December 15, 2015 | (13) Posted in Tips

Temperature Control for Hot Glue

Control the Temperature of your hot glue gun with a light dimmer switch from the hardware store.

I have found that there are times when I didn’t want that hot glue as hot as gun can get it. Some hot glue guns get the glue so hot that the foam melts on contact and can burn skin.

The formulation of Readi-Board and EPP foams withstands hot temperatures pretty well, better than the EPS insulation foam (purple or pink foam insulation). My experience is that they melt under the heat of the typical 40 Amp hot glue gun. With this contraption you can dial in the voltage and get your favorite temperature. All you need is a light dimmer and an outlet from your local hardware store.

The inexpensive light dimmer switches that you find at hardware stores are driven with a switching mechanism. Basically, it turns the current on and off for variable amounts of time depending on the position of the knob. The dimmer is turning the power to your light on and off really fast, but the overall current flow decreases as the frequency of power traversing to the filament decreases causing the glowing filament to cool (dim). A hot glue gun is essentially a 40 watt light, a heated filament wrapped around the glue melting chamber. Decreasing the amount of electrons flowing through the heating element will reduce the amount of heat.

Here is a phot of the one I made.

The wiring diagram is very simple. The positive AC line (highlighted red) runs through the dimmer switch before going to the outlet. The ground (black) bypassed the dimmer and goes to the ground side of the outlet.

With this unit set at 65 volts (somewhere around 5 o’clock on the dial), the hot glue flows but doesn’t melt the EPS foam. It is also cool enough to get it on your skin without burning, could be a benefit when working with kids. The downside is that the low temperature settings will not allow the glue gun to deliver high quantities of glue, but this is good for short joints. Glue guns with large heated chambers can still deliver a good quantity of glue.

Here is an example of how it worked. On the left is hot glue delivered from the hot glue gun set at 65 volts. On the right, the same glue gun delivering glue after 120 volts, you can see the bubbles from the air being released from the foam melting. To the far right are the indentations left from the hot glue after peeling it off. Even the cooler glue holds the foam really well, as long as the pieces or joint is created before the glue gets too cool.

I hung the unit on a 2x4 within arm’s length next to my build bench. Note the computer screen so I can watch the build videos at my build bench. Man cave complete!

To hold the hot glue gun I cut a chunk out of a piece of ½ inch foam and mounted it on the dimmer. I also added a night light so I could tell when it was on. The light has saved me quite a few times from walking away and leaving it on.

Another tip is the hot glue holster.

This simple contraption is a 2 inch pipe hanger screwed to the side of my build table. The hot glue drips into the trash can under the holster (not shown). The masking tape on the handle can be removed and replaced when it gets gooped up with hot glue (or other foreign stuff like epoxy). Sometimes my hands, or gloves, get pretty messy while building.

Happy Building!

HilldaFlyer - December 2015
















COMMENTS

brandonfoust725 on January 1, 2016
Great article!
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The-One-Who-Never-Crashes on December 17, 2015
Another lovely article! Thanks for sharing your innovation! :)
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paultbg on December 23, 2015
For the less DiY skilled people there are off the shelf easier solutions like this:

http://www.ebay.co.uk/itm/291633730688?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
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ttprigg on December 18, 2015
Thanks for sharing - the monitor next to the workbench is brilliant. My wi-fi signal does not reliably make it to the shop so I end up wearing a path back to the house and the computer--- Seeing your set up makes me want to increase the signal....

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HilldaFlyer on December 18, 2015
Yup, sure helps to have it sitting there. The keyboard and mouse are mounted on a tray under the bench. The computer is actually Ethernet cat6 from my router, but I'm just 30 feet from the router in the basement. Your shop must be a long ways from the router. I get signal up to 200 feet away. Good luck.
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Wretch on December 22, 2015
Hi,
The problem of only regulating the voltage is that, once the gun cools down (by pushing out glue) it will take a long time to heat up again due to the limited voltage.

A better approach is to actively control the temperature using a thermistor and a opamp.
For the schematics check https://dl.dropboxusercontent.com/u/29942579/Hotglue/schematics.jpg

The components i'm using are:
- a thermistor; http://www.banggood.com/10-Pcs-3D-Printer-Thermistor-NTC-100k-100ohm-Match-MK2a-1-Sensor-p-932646.html
- AD822AN opamp
- solid state relay
- potmeter (5K)
- resistor (10K)

Photos of my glue gun with the temperature control:
https://dl.dropboxusercontent.com/u/29942579/Hotglue/1.jpg
https://dl.dropboxusercontent.com/u/29942579/Hotglue/2.jpg
https://dl.dropboxusercontent.com/u/29942579/Hotglue/3.jpg

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flying-coqui on December 17, 2015
Another way is opening the hot glue gun and use a potentiometer to control the power
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HilldaFlyer on December 18, 2015
Sounds like a great idea. Do you have a design you can share? I'd sure be interested to see how it works.
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flying-coqui on December 19, 2015
Visit this link: www.pinterest.com/pin/348536458641944119/ then select the below direction (plus.gogle.com)
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Route66flyer on December 31, 2015
A light dimmer is a potentiometer.
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flying-coqui on December 31, 2015
Yes, just that is a big one for bigger purposes, but a smaller one can be more versatile and easy. For example if you go to a friend house and dont have the dimmer you can't use it. But if you had a smaller one into the hot glue gun is more versatile.

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Temperature Control for Hot Glue