Glue guns for non temp serious stuff? !!TEST RESULTS added!!

[gidon]

I recently upgraded my glue gun more out of curiosity than anything else and started looked into guns and glue.
My replacement gun (an Arrow TR550 at £19) is still classed as an introductory gun in a market place that has guns costing up to £1000! But wow what a difference to the old Bostik gun I had before!
The glue came out my old gun in blobs really - very viscous and not really usuable for anything apart from craft and very temporary jigs (with such a thick glue line). But this gun delivers the same glue at a much lower viscosity and in a far more controllable and constant flow rate. And with therefore far better results.
But if you start looking in this - hot melt guns are used a lot is industry for serious applications. With all sorts of glues suitable for all sorts of applications. There is even PU glue available now for glue guns.
So does anyone here use them for any real projects / tasks?
One hot glue company are sending me a free sample of some glue sticks which he reckons are on par with PVA. He told me that the trouble is most people's experiences with cheap craft guns and rubbishy glue puts them off hot melt. I'll see how I get on ...
Cheers
Gidon

 

[Gill]

So does anyone here use them for any real projects / tasks?

It depends if you regard scrolled projects as being real projects!

:lol:

I use my hot glue gun a lot, especially when stacking boards together for them to be cut simultaneously. It's also handy in situations where you don't want to have a clamp holding wood.

Gill

 

[Chris Knight]

Gidon,
That's an interesting question. I was aware of the industrial type hot melts but was not aware of anything worthwhile at the hobby end of the market. My glue gun gets pulled out once in a blue moon to tack a jig or some such and like your old one, I get blobs of glue that don't stick very well. In fact I use it when I don't want the strength of double sided tape!

 

[gidon]

Gill - sorry not worded very well. Guess I mean permanent applications - as a replacement for PVA or such like.
I too use it like Chris and you, for jigs and temporarily ganging up items.
But look at a site like thisand you can see that it has more serious applications - they're certainly not suggesting it's a temporary solution.
Chris many of the glues are available for standard 12mm guns. I think the PU needs a special gun.
I think the gun and glue stick are more important than I'd thought.
Cheers
Gidon

 

[Gill]

Sorry Gidon - it's so rare I get a chance to discuss something away from the scrolling board I got carried away by my enthusiasm .

Following your link, I get the impression that the hot glue applications for laminating must involve the use of pads which can be heated to melt the glue between the veneers and the base-board. It sounds rather more complicated than simply squirting a dab of glue from a gun.

Gill

 

[woodbloke]

I've found that the HGG is quite useful in the 'shop for quick stick applications...used mine recently to seal up a lot of the air holes on my K419 when I did an extraction mod. Beware tho', when the gun is really hot, the glue coming out is over 100degC :shock: - Rob

 

[dirtydeeds]

ive never seen hot melt glue guns as being "real" glue

except maybe for cardboard boxes

there again i dont make real cardboard boxes

 

[gidon]

Gill - some applications use hot melt sprayed too. But there are still lots of serious applications with standard 12mm glue sticks.
Yep - DD - glueing cardboard boxes with hot melt seems to be big business. Will have to remember that !
Rob - it idoes have quite handy filler properties - just glued on a missing foot to my keyboard! Would have needed Epoxy otherwise. Does get very hot - at least there's no temptation to try and glue you hand to anything !
Cheers
Gidon

 

[gidon]

Well I was interested in pursuing this a little further. I phoned up a company that makes these adhesives for industry and asked what glues he recommended. I had a very helpful chap who said he'd send me some samples. Well he did. It's not very scientific but one of the glues he sent does appear to be head and shoulders above what I've had from Screwfix / Axminster.

Here goes (NOT coming soon to a FWW near you ):

Well this is just a gratuitous shot of my new glue gun (which sparked my interest - see OP.) And its hi-tech stand - yep you guessed it - held together with hot melt glue .


I planed some scraps of pine for edge jointing.


Applied some of three varieties of glue to one piece and clamped firmly in my vice for 60s.


Here's all 3 joints glued up. You can probably see one BIG disadvantage with hot melt glue. It leaves a signicant glue line. One of the glues was very low viscosity. But see my conclusions for which one and whether it made a difference.


I left the joints for 1 hour. I've read that hot melt glue reaches 50% strength in 1 minute, 75% strength in 1 hour and 100% strength in 24 hours. I then very scientifically secured the join 1/2cm 'ish below the join for each joint and tried to push the joint apart with the piece of wood directly above the joint about half way up. The main idea was to see whether it was the glue or wood that failed. But also to see if I could detect any difference in the pressure required to break the joint.



***


Ok the results. First up Screwfix's "white" woodworking glue sticks. This joint felt like it was the easiest to break. It also had the thickest glue line. The glue did pull some wood off the other surface. But all the glue remained on one side of the joint as (I hope) you can see. (This may be because I was too slow pulling the joint together.)


Next up one of the samples from Tec-bond. Their Tec-bond 1x - low viscosity designed for wood and other stuff. It did appear quite fluid but not as much as I'd have thought. The joint took more pressure to break and seemed to break down the middle of the glue line - some glue remaining on both sides of the joint. So seemed to stick quite well to the wood but not so well to itself! This seems like a strange result and maybe leaving it to set longer would yield different results. But the joint was still pretty strong.


Last up is another sample from Tec-bond - their Tec-bond 23. This seems to be their favourite and the one their recommended (the one the sales guy compared to PVA). The glue line was about the same as the 1x stuff (both better than Screwfix's). But breaking the join gave a spectacular result - there was little if any glue failure - the wood failed on both sides of the joint. And that is before its full cure time! Sorry the pic isn't so good but I can take another if anyone is interested.


Ok my conclusions - all three glues gave a stonger glue joint than I'd have expected. Note that as I stated in my original post - I reckon you need a glue gun better than the £10 craft guns to get the glue to the correct temperature and to produce a decent flow rate. This Arrow gun was only £19 (but well made (in the USA)) and maybe I'd get better results with a more expensive gun.

The joints produced weren't temporary but I'd still never use a glue gun for a serious project - partly because the glue line is far too thick even with the low viscosity stuff (although its true gap filling properties could be useful sometimes). And mainly because I wouldn't trust it long term (heat, humidity variations etc).

But I would use the Tec-bond 23 stuff for jigs and workshop projects and would feel comfortable not adding fasteners on many occasions. And also for mock-ups of larger furniture projects it's perfect.

Unfortunately, with my new glue gun and any of these glues but particuarly the Tec-bond 23 - it's going to have to be carpet tape for joins that need to be temporary. Even a few blobs of the Screwfix white stuff I'm finding pulls up wood fibres when pulling apart.

Because of the short open times of this glue and the difficulty of ensuring an exactly even amount for each test, it's going to be pretty tricky to get accurate results. But hopefully this quick test has produced something to think about.

Might be of interest to someone out there. You can get the Tec-bond stuff here.

Cheers

Gidon

 

[woodbloke]

Gidon - thanks for doing those tests. I think as you say the biggest disadvantage is the huge glue line so IMO you can't really use the HMGG for a 'serious' project but the stuff is really useful for jig making and quick fix applications, it's also quite useful for gluing plastic together but the most useful thing is the gap filling properties when it's used to deliberately fill a void which would be difficult to seal any other way - Rob

 

[gidon]

No probs Rob. I played around a little more with the low viscous glue (1x)they sent me specifically for woodwork - it does give a pretty fine glue line actually. But still agree - I can't see it can be used for serious woodwork. Still it's fun playing .
Cheers
Gidon