Deadly hot glue gun

[angelcruiz]

Hello,

I wanted to share with you a scary, but not unexpected security fault I have just discovered in a cheap chinese hot glue gun. Well, it doesn't even deserve to be called a security fault. It's just a hazardous deadly shameful evil-minded "tool".

I always doubt about the safety standards of such cheap tools, but seriously, this is nuts.

Today, I was applying some hot glue over an aluminum surface. I was grabbing the piece with one hand, the gun in the other and, as I approached the tip of the gun to the metal, I felt that unmistakable tingling of electric current through my hand. First, I just thought the gun might be leaking some current, so I checked the voltage at the tip and... 180V RMS.

Next, I measured the resistance between both plug pins and the tip and, sure enough, one of them was shorted to it.

This is the weapon, in all of its inglorious shame.



I still can't believe such a dangerous thing, and who knows how many like it, are being sold through Amazon without any regulation.

Every time you plug one of those to the wall, you have 50% chance of having a live mains voltage exposed pointy metal nozzle. With this in mind, who cares about the 28 AWG wire, or the 1/4 watt resistor it uses to supply the led.

Btw, ¿any budget, reliable and, juuust a little bit safer, hot gun?

Thank you all.

[angelcruiz]

Well, It turns out it's not a purposely made hazardous tool.

As you can see in the images below, after further inspection, it has a heating element, which is supposed to be insulated from the tip with some (oh my) kaptom tape . But it has being punched somehow and it's making contact with the nozzle. Who'd ever figure 

[wraper]

Seems like some metal debris got in and then pressed into insulation by that removed clamp. However such equipment must pass hipot test at factory which would show the issue even if it was not shorted at the time.

[Benta]

Cheapness has it's own price. I hope you've learned this now.

Buying quality is one moment of frustration (price) and decades of happiness.
Buying crap is one moment of happiness (price) and a time of frustration afterwards (no reason to mention decades here...)

[NiHaoMike]

If the rest of the gun works well, I would opt for replacing the heater with a low voltage cartridge heater of the kind used in 3D printers, then add a temperature sensor and microcontroller as a PID controller. It would heat up really fast and have the option of being battery operated.

[james_s]

Cheapness has it's own price. I hope you've learned this now.

Buying quality is one moment of frustration (price) and decades of happiness.
Buying crap is one moment of happiness (price) and a time of frustration afterwards (no reason to mention decades here...)

The problem is that once cheap stuff floods the market, everybody else cheapens their offerings to compete, or to extract all the profit they can from an established brand before the reputation crumbles. It's hard to know what you're getting anymore.

[coppercone2]

https://surebonder.com/products/pro2-60mil-60-watt-18-volt-cordless-professional-heavy-duty-full-size-hot-glue-gun-milwaukee%C2%AE-version

[bob91343]

I hate battery operated tools.  My Sears glue gun has held up for many years.

[Whales]

I had a friend once who had a glue gun you could only plug in for 10sec or so, otherwise it would get ridiculously hot and start smoking the glue.  I suspected it was labelled 240V but really had a 120V-calculated heater inside.

[NiHaoMike]

I had a friend once who had a glue gun you could only plug in for 10sec or so, otherwise it would get ridiculously hot and start smoking the glue.  I suspected it was labelled 240V but really had a 120V-calculated heater inside.

Or it was designed for fast warm up but the thermostat is defective.

[angelcruiz]

If the rest of the gun works well, I would opt for replacing the heater with a low voltage cartridge heater of the kind used in 3D printers, then add a temperature sensor and microcontroller as a PID controller. It would heat up really fast and have the option of being battery operated.

Good idea for a fun little project 

Cheapness has it's own price. I hope you've learned this now.

Buying quality is one moment of frustration (price) and decades of happiness.
Buying crap is one moment of happiness (price) and a time of frustration afterwards (no reason to mention decades here...)

The problem is that once cheap stuff floods the market, everybody else cheapens their offerings to compete, or to extract all the profit they can from an established brand before the reputation crumbles. It's hard to know what you're getting anymore.

Absolutely. In Amazon, for example, the first two pages are full of crappy guns like mine for under 20$. Same shit, different shape.

https://surebonder.com/products/pro2-60mil-60-watt-18-volt-cordless-professional-heavy-duty-full-size-hot-glue-gun-milwaukee%C2%AE-version

Looks nice. At 60W it should melt the glue pretty fast.

Thanks!

[amyk]

The expensive ones are probably the same in construction, only better in quality control.

The insulation may have been fine at the factory test, and then the debris slowly punctured through after cycles of thermal expansion/contraction. Either way it is not difficult to renew the insulator.

IMHO the fact that the tip is hot(!), so you wouldn't normally touch it anyway, makes any real hazard rather low.

[coppercone2]

thats how you get a unsafe product, you add a whole bunch of 'user would probobly'

The user ends up doing everything possible.

Here is one, some kid has glue dripping on his arts and crafts, so he gets a butter knife from the kitchen to scrape off the excess glue so the next joint can be made cleaner. The only worry in his mind is to clean the knife after so his mom does not yell at him. Great idea, its polished metal, should clean easily, won't scratch anything. It's not even that unsafe that he would get yelled at from using since its dull.

Hmm, its not coming out, maybe a paper clip would work. How many people that buy this super cheap shit have a set of picks and nice insulated handle or ceramic tools? Or, maybe I can get some glue on this paper clip so I can make a very small bond if I am fast enough.  Paper clips and pins ARE the #1 object that would be around a hot glue gun. Wow cool school themed art project with office supplies... the crappy guns drip so hard you practically apply the stuff like sheet rock compound.

I spend a little extra around electrical tools that might be around water or excess heat. Angle grinder (hot welds, gas flames), automotive buffer/polisher (you are working on a car in the yard and hosing constantly during/after working), metal saw (so many jagged edges while doing thin metal work). The car buffer bothers me the most because the procedure is to drape the thing over your shoulder while working on a wet car.. defiantly worth a little extra for the safety. Hot glue gun feels like a good candidate for this too because the tool usually weighs like a few ounces and its connected to a mains cord. The cheap ones feel like they are on a spring because they are so light and the cords suck so much.

[ConKbot]

Coppercone actually knocking it out of the park there. My go-to for cleaning off a glue gun tip is a utility knife, and plenty of those are die-cast metal, and even the plastic ones can have a metal button and  spring for the retract mechanism.

[station240]

Seems like some metal debris got in and then pressed into insulation by that removed clamp.

That aluminium clamp looks like it was made using CNC, or like milling process.
The metal debris was left inside that metal shaped, which was then pressed into the coil.

Removing all metal debris is a vital part of making electronics and electrical devices.
Yet time and time again, we get junk with floating solder balls and screws, metal swarf in everything from enclosures to lithium battery cell casings.

The entire hotglue gun itself is unsafe, for AC mains anyway. The only part correctly built is the LED, the rest of the connections are soldered, unsecured and uninsulated, the fuse is a joke too.

[S. Petrukhin]

I have been using "Elmos EGG-120" for many years