Hot glue test

[firestang]

Hi,
I've been playing about with the pontoon design for a week or so and thought to myself , hmm. I have a commercial grade hot glue gun ($60) and a lot of glue sticks. Mind you i also have about 40 kilos of resin in drums and all the proper stuff as well.

So we went to work making a test model roughly a third the size of the plans. Stitching as normal and then tacking with the hot glue then making the fillet with the hot glue once fully tacked.

A couple of things we found
1/ hot glue is extremely hot
2/ if you run a tool like you do when smoothing a fillet spreading the glue while still hot works well.
3/ And this is the one that surprised me.
When all the glue was in and we tried to pull it apart there was no way on earth we could break the glue away from the ply.
The ply cracked outside the edges of the glue, that stuff was solid as steel. Granted we weren't using a good quality ply but it worked rather well.
One we finished using the glue has had the seams from the outside filled with resin and flour as normal.

For something that wont be seen it would be ok, but it does not sand at all, gums up the sandpaper.
For taking in small blobs, smoothed then covered with normal fillet material it may work . Its fast , sets in about 2 minutes once applied.

[DanT]

I like this idea. I too have access to industrial glue guns. Does epoxy stick to the hot glue?

[firestang]

That's something i haven't tried fully. The fillet mix stuck great on the outside of the seams but maybe that's because of the exposed ply around it.
Ill check that on Monday

[tx river rat]

I just got through cleaning off tacks of hot glue on seams and to hold the bulkheads in, I want do that again
If you try to sand it the heat melts the glue and smears it every where. then it is a mess to clean off.
Ron

[firestang]

spot on there tx. I think internal tacking for areas not seen is the go for it

[Oldsparkey]

I just got through cleaning off tacks of hot glue on seams and to hold the bulkheads in, I want do that again
If you try to sand it the heat melts the glue and smears it every where. then it is a mess to clean off.
Ron

One kayak I made ( not a Jem Design ) said to use the hot glue to hold the frames and bulkheads in place. They did say to use just spots of it and not a lot. I found out why when I went to remove the frames , what a mess and job. Used a knife then a scraper and finally sandpaper to remove the glue .... Never Again.

Chuck

[firestang]

We learnt a bit more today about the hot glue caper.

It looks to be able to stitch ok and does take some adhesion depending on the type of glue but.
We had an issue with the mix of the fillet material where it didn't set, what we found was that it ate the glue away whereas when the mix was right and it went off properly it didn't effect the glue.

So all in all it was a good experiment
This is what we were testing it on, you can see the failed hull in the background. V hulled pontoons, hopefully



The reason for the fail in the mix was , number one me, not enough catalyst and the catalyst was left open overnight. It was the first fail in mix for a couple of months

[woodman]

So you tack it in places (like little 1/4'' spot welds) pull the stitching wire and then epoxy fillet over the entire seam....

[firestang]

That is what we did with the one in the foreground, well we actually stitched it properly and had the gaps set right and then tacked it with glue first. It was solid as a rock and we were almost tempted to run glue all around all the seams. It is solid with the proper fillet material over the glue so that one worked very well.
We built them from the top (side with mount screws) up rather than the normal way as we didn't have a pattern for the bottom hull shapes.

The one almost sanded didn't have the worry about the glue being eaten away by the resin for some reason. All i can think of was the amount of time it took to go off.
What we will do next week is test some glue that will have glass resined over it and see what happens. No big deal for us if it doesn't work as the ply is scrap.

I know full well its not the preferred way it's done but no harm in giving it a go and letting people know if it worked or not. Not sure id risk it on anything id be sitting in though

[goanywhere]

Thanks firestang. I am about to make a couple of outriggers myself. Only small ones (4') with a deep V hull. I am thinking of using hot glue to install a mini bulkhead in the centre to help define the rounded shape at the top.

I did an experiment tonight with hot glue on some scrap ply. I simply joined a piece to another in a 'T' join. I used a bead of hot glue either side, waited until it cooled and then bent it over until the join failed. I found that the glue remained intact and the ply splintered leaving some still attached to the hot glue.

This is as strong as a wood join can get. I think hot glue could be used for several applications in a S&G kayak. Fitting sub-frames, and bulkheads are just a couple of them. I haven't tried sticking things pre-coated with epoxy, I'll try that as well.

The photo isn't very sharp but the destruction is still visible: