Glue gun teardown (~$20 60w)

[adam1213]

specs: 60w, often falls over just to lack of side support, slow to warm up, no longer dispenses glue when pushing button to do so. The nozzle occasionally tries to fall out.
http://www.bunnings.com.au/products_product_glue-gun-kit-crescent-240v-60w-w6glue-sticks-ngg60d_P5810347.aspx  (the one I have is branded differently to the one bunnings is selling)

The reason it no longer dispenses glue properly is that the yellow part is broken

There isn't much to the glue gun. Just a simple heater. I am not sure if there is a feedback mechanism for temperature given the low price of the glue gun.


Based on the recommendation on glue guns in https://www.eevblog.com/forum/reviews/good-hot-melt-glue-gun/msg78853/#msg78853
I am currently consider getting the Steinel GlueMatic 5000 or Steinel GlueMatic 3002 to replace it.

Once I get a replacement I might open up the metal part

[amyk]

Are those wires leading from the base uninsulated or is it just a trick of the lighting?

[george graves]

You paid way too much for that!   

[adam1213]

Are those wires leading from the base uninsulated or is it just a trick of the lighting?

Good point. From the picture its impossible to tell.
Just took it apart again. The wires have a clear insulator around them which is hard to see.

[Psi]

slow to warm up

The glue gun I've got says on the side '110-240V'.
Its got no smarts inside, just a resistive element.

If you run it at 110V you just get less heat and it doesn't work well at all.

[jaqie]

ceramic elements use the same amount of watts nomatter the voltage applied, within certain limits that is.

[adam1213]

slow to warm up

The glue gun I've got says on the side '110-240V'.
Its got no smarts inside, just a resistive element.

If you run it at 110V you just get less heat and it doesn't work well at all.

I am in Australia so it is running on around 240 volts (some day it might be 230 volts but not yet)

*note: This glue gun is labelled 230v

[Psi]

ceramic elements use the same amount of watts nomatter the voltage applied, within certain limits that is.

Interesting, i'd never heard that before.

Makes perfect sense though, having a PTC.

[SeanB]

The heater is a ceramic PTC unit wrapped in kapton sheet, with electrical connections by 2 half round aluminium strips that have the lead wires crimped into a slot in them. Simple and self limiting with a fast warm up time. Most common electrical failure is the PTC element fractures into powder and then it goes short circuit. Most common though is the handle or the other plasrtic breaking. Handle failure is almost always caused by being impatient and trying to push glue out before it is properly melted.

[adam1213]

Handle failure is almost always caused by being impatient and trying to push glue out before it is properly melted.

This is probably how I broke it. I have a feeling it may have broken the time I plugged it in with an extension cord, waited and tried to use it to discover I had left the power off. A better glue gun would have some indication that it is ready to use. This one often emits a smell from the glue sticks when it has warmed up. This is the main hint I get that its ready.

[johnwa]

I had the same model glue gun, and I have seen exactly the same failure mode. I actually made up a replacement part - a copper strip with a nut and some wire soldered to it.

This worked well for a while, but one day I plugged it in and there was an almighty bang - the heater had shorted! So I bought another one, unfortunately the only one I could find was exactly the same model. I saved the home-made metal link out of the old one, so I am prepared for that failure, but I guess the new one will probably explode eventually as well. 

[adam1213]

I had the same model glue gun, and I have seen exactly the same failure mode. I actually made up a replacement part - a copper strip with a nut and some wire soldered to it.

Great way of fixing it. I replaced my glue gun with the Steinel GlueMatic 5000 which appears to also use metal for this purpose (based on an illustration I found in a Steinel catalogue)

In my case I decided against fixing the glue gun as there was so little it did right e.g. inability to dispense small amounts of glue, dripped, fell over, started to have the nozzle fall out and break. I though it did well in terms of meeting safety requirements but perhaps not.

[T4P]

Pretty sure it's one of those ceramic PTC glue guns that are self limiting with a slow warm up time (I have a simple 5$ 40W one myself, works pretty well)

DX sells some 10-odd dollar ones with feedback and ... 100W!
Usually when they emit smells it is most probably your glue definitely not the glue gun or else it might be a sign that the shell is melting/softening 

[profmason]

If you are in the US, I really like the grizzly H6260.  250W seriously heavy duty weight about 1 kg.  http://www.grizzly.com/products/Hot-Melt-Glue-Gun-Kit/H6260   We have used it around the hacker space for everything from gluing down wires and potting connectors, doing setups on the CNC router to attaching the gaskets on the sandblasting cabinet.  The yellow high temperature glue they sell is also pretty good.  The gun takes the same size threaded tips (I believe 7/16") as the major brands, so you can replace the default tip with your pleasure.

[peter.mitchell]

I bought some random 60w gluegun off ebay about 5 years ago, based solely on the number of included glue sticks and price... was $15 with postage and came with 50 sticks. still works, can't complain.

[bustedcap]

the glue gun is ready to use when the glue dribbles out the nozzle

[Alana]

Had a few of those, including one in the first post.
Wires are insulated with transparent something that is heat-resistant. For heat control - those are el-cheapo ones and i doubt there is one, but if there is it must be based on PTC effect. Mine just heats up to - if to believe whats shown on the box - 200deg C and stays around there.

[lpc32]

So the higher wattage ones are supposed to do the initial heat up quicker, and to dispense more rapidly?
How are 20W ones for light usage?
Any reason to prefer either 7mm or 11mm glue sticks?
Any reason to have adjustable temperature (e.g., 100-220C)?

[george graves]

I don't use hot glue much, but "Applied Science" has a good recommendation that I would trust.  Skip to 4:13.

[RobertHolcombe]

So the higher wattage ones are supposed to do the initial heat up quicker, and to dispense more rapidly?
How are 20W ones for light usage?
Any reason to prefer either 7mm or 11mm glue sticks?
Any reason to have adjustable temperature (e.g., 100-220C)?

Yep, higher wattage will heat up faster and work longer as it is able to maintain working temperature at high feed rate

20W is fine for light usage provided you're OK with waiting for it to heat up and not expecting to go through entire glue sticks, you'll find if you feed too fast the gun can't keep up

7mm vs 11mm - depends on how much you need to dispense at a time, if you require precision then 7mm, if not 11mm. Another point may be that a lower wattage gun may handle the lower volume of 7mm sticks better than that of 11mm, would be interesting to test

I haven't used an adjustable temperature gun before but I imagine its useful to regulate the viscosity or maybe if you're gluing something that is heat sensitive

[Alex Eisenhut]

Interesting, I'm getting into the foam-core RC airplane hobby and a good glue gun with the right glue is essential.

[lpc32]

Thanks.

[djQUAN]

Most common electrical failure is the PTC element fractures into powder and then it goes short circuit.

Yeah, I've had an old gun fail while I was using it. It exploded and shot the glue stick back at me.