Full sheets of micarta and g10 liners

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Nov 28, 2014
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Anybody glue up full sheets of micarta/g10 and g10 liners? I use a good bit of natural canvas micarta and orange/white liners and it adds a whole day to the process glueing them together. Just wondering if the success rate doing full sheets and not having any voids or thick glue joints in areas.
 
Yeah, we laminate full sheets daily in production here.

My process:

Pull it down to a vacuum table and deck the shine off on a mill. However you want to go about doing this, you need to get the shine off the sheet.
Clean with alcohol
Wet both surfaces with epoxy, a good sized dab on both surfaces spread with a card (I'm using west systems now since acraglas isn't what it used to be)
Lay the liner on an accurate flat surface
Apply about 30 grams of epoxy to the center of the liner and feather it out a bit with a card being careful to avoid undulations creating air pocket traps
pop any significant air bubbles (air, torch etc)
Lay the sheet onto the liner
Apply a heavy weight to the center until the epoxy starts to flow out of the seam
Apply additional weights across the sheet


This process has evolved over time to be what it is. We almost never have air bubbles or gaps or pockets and the bond is very good. The key is removing the shine, wetting both surfaces and then using enough epoxy that it flows out of the joint with weight. Much of the epoxy is "lost", but it's this waste that contains most of the bubbles.


One thing that I like about this approach is you're casting the shape of the surface that you're setting the work on into the finished sheet so your finished work is often flatter than the sheets you started with. I used to use a surface plate for this but we now have accurate machined plates. I level those plates so the work doesn't float around a lot. Some wax on the plate keeps the epoxy from sticking to the plate too much. It pops off with a tap from a wood chisel.
 
Yeah, we laminate full sheets daily in production here.

My process:

Pull it down to a vacuum table and deck the shine off on a mill. However you want to go about doing this, you need to get the shine off the sheet.
Clean with alcohol
Wet both surfaces with epoxy, a good sized dab on both surfaces spread with a card (I'm using west systems now since acraglas isn't what it used to be)
Lay the liner on an accurate flat surface
Apply about 30 grams of epoxy to the center of the liner and feather it out a bit with a card being careful to avoid undulations creating air pocket traps
pop any significant air bubbles (air, torch etc)
Lay the sheet onto the liner
Apply a heavy weight to the center until the epoxy starts to flow out of the seam
Apply additional weights across the sheet


This process has evolved over time to be what it is. We almost never have air bubbles or gaps or pockets and the bond is very good. The key is removing the shine, wetting both surfaces and then using enough epoxy that it flows out of the joint with weight. Much of the epoxy is "lost", but it's this waste that contains most of the bubbles.


One thing that I like about this approach is you're casting the shape of the surface that you're setting the work on into the finished sheet so your finished work is often flatter than the sheets you started with. I used to use a surface plate for this but we now have accurate machined plates. I level those plates so the work doesn't float around a lot. Some wax on the plate keeps the epoxy from sticking to the plate too much. It pops off with a tap from a wood chisel.
Thanks for the detailed approach! My process is very similar but not as precise since I don’t have a mill. I take 60 grit belts on my platen and manually run them across to get the shine off both pieces. However, I don’t wet both pieces but will do this moving forward. I clamp my pieces to a machined piece of 3/4” aluminum plate until the epoxy comes out. I will try the torch method to remove bubbles and help thin the epoxy in the winter. I do heat my shop but it’s definitely thicker at 70° than 95°. I also use g flex but as I mentioned before the 24 hour curing period adds a whole day to the process per knife. I guess I should think ahead a little more! I tend to finish the blade and then move to the handle which is not the most efficient way to do things for sure.
 
What about glueing up the liners/parts with CA or speed bonder structural adhesive? Then onto fixing with epoxy to tang as usual. Saves you the wait for epoxy to cure..
 
Thanks for the detailed approach! My process is very similar but not as precise since I don’t have a mill. I take 60 grit belts on my platen and manually run them across to get the shine off both pieces. However, I don’t wet both pieces but will do this moving forward. I clamp my pieces to a machined piece of 3/4” aluminum plate until the epoxy comes out. I will try the torch method to remove bubbles and help thin the epoxy in the winter. I do heat my shop but it’s definitely thicker at 70° than 95°. I also use g flex but as I mentioned before the 24 hour curing period adds a whole day to the process per knife. I guess I should think ahead a little more! I tend to finish the blade and then move to the handle which is not the most efficient way to do things for sure.

I might should add: be careful with that torch though. We have alcohol soaked paper towels laying around due to the cleanup. Bo once set a pile of those towels on fire with the torch. This was back when we were still using wax paper instead of renwax on the plates for release, so there were piles of them too. Fantastically flammable. Could have burned the damn shop down. Fortunately I had just installed fire extinguishers. That fire got big really fast. Those fire extinguishers saved the day.


...we don't use a torch anymore...
 
What about glueing up the liners/parts with CA or speed bonder structural adhesive? Then onto fixing with epoxy to tang as usual. Saves you the wait for epoxy to cure..

I don't have the same confidence in CA that I do in good epoxy. Long term, high end epoxy is tough to beat in this application. It's used on boats and airplanes. Super glue, not so much.
 
What about glueing up the liners/parts with CA or speed bonder structural adhesive? Then onto fixing with epoxy to tang as usual. Saves you the wait for epoxy to cure..
I feel that if I don’t have enough confidence in ca for the scale to steel bond then I shouldn’t use it anywhere. Although I have used it once on a knife for my son and it’s actually worked very well!
 
A structural adhesive like Loctite 326 that sets in 3 min with an activator has a shear strength of 15N/mm2. I think good CA has about the same. Convert that to lbs per knife scale surface area and you end up with ridiculous loads. I really think we are a little too nervous about the gluing and bonding sometimes in this community.
I made my first knives with Loctite 5 min epoxy and none show signs of failure yet.
 
A structural adhesive like Loctite 326 that sets in 3 min with an activator has a shear strength of 15N/mm2. I think good CA has about the same. Convert that to lbs per knife scale surface area and you end up with ridiculous loads. I really think we are a little too nervous about the gluing and bonding sometimes in this community.
I made my first knives with Loctite 5 min epoxy and none show signs of failure yet.
My main experience has come from removing scales from knives that I’ve scratched while finishing. I always used quick setting epoxy and to be honest it’s so much easier. The squeeze out on the front of the scales can be peeled off with the right timing leaving a perfect and flawless seam. When using quick setting epoxy all I had to do was drill out the corbys and smack the back of the handle on my bench and the scales popped right off. So clean I could reuse them easily. When I pulled the scales on my first knife that I used gflex it literally tore the wood off in chunks. The wood was the failure, not the epoxy. Is it overkill? Probably so, but the cost isn’t much different so I use gflex.
 
A structural adhesive like Loctite 326 that sets in 3 min with an activator has a shear strength of 15N/mm2. I think good CA has about the same. Convert that to lbs per knife scale surface area and you end up with ridiculous loads. I really think we are a little too nervous about the gluing and bonding sometimes in this community.
I made my first knives with Loctite 5 min epoxy and none show signs of failure yet.
Some things that we do are likely overkill, but if the price and effort is similar then I figure why not? Brad from Peters' asked if I wanted the full "Bladesports toughness protocol" on heat treating what would be mostly a display piece... I said Of Course!
 
I was talking primarily about using CA or speed bonder between handle parts, like scale and liner, to save time. I think it would be a great trick there, and I intend to start doing that. No more clamping up multi-part handles with epoxy for 24 hrs..
As I said above, I would also use epoxy for the scale/tang adhesion though.
 
I was talking primarily about using CA or speed bonder between handle parts, like scale and liner, to save time. I think it would be a great trick there, and I intend to start doing that. No more clamping up multi-part handles with epoxy for 24 hrs..
As I said above, I would also use epoxy for the scale/tang adhesion though.
I worry just as much about liners separating as fo the handle and tang. I will do some testing with the epoxies you mentioned and see how they do.
 
If any part of the handle separates when using CA glue, the handle comes off or allows a gap which water will get into. That leads to corrosion, even on SS blades. I guarantee your customers will not be impressed. If they don't send the knife back for repair, you will never know about the problem, although almost for sure, they will tell their friends. There goes your reputation for quality.
 
Ca glue doesn't hold up to water as well as good epoxy and probably doesn't age as well in general.

Cheap epoxy will eventually let go.

Slow set epoxy is generally more durable over time.

If the work is important to you or the end user, why skimp?
 
I keep cheap Loctite 5 min epoxy in the shop all the time. I actually buy it in bulk. I love the product and it's an integral part of my process. Its low strength and constantly poor adhesion makes it perfect for fixturing applications where I need something that will cleanly let go every time. Very useful stuff! But would never use it in the construction of a knife.
 
If CA or some speed bonder would work for handle parts, to save a fair amount of waiting time and not loose durability, I'd be interested. I'm gonna try some on my own kitchen knives next year and see how it holds up.

I found this thread from a few years back, seems like quite a few of the experienced and respected makers here use it without problems:

https://www.bladeforums.com/threads/super-glue-and-liners.1380330/
 
I use CA glue and have not encountered any issues. Granted I have not been making knives for very long, but as long as coverage is even on the piece it’s solid. Was told by several long established makers that it was their process as well, so it seems like personal preference.

I tried to peel a few sets apart and it was not possible without using a chisel. Even then, there were some parts of the liner than would sheer off before separating. I also try to use corbys or mechanical fasteners as often as possible because I like the handle to be overbuilt.
 
If CA or some speed bonder would work for handle parts, to save a fair amount of waiting time and not loose durability, I'd be interested. I'm gonna try some on my own kitchen knives next year and see how it holds up.

I found this thread from a few years back, seems like quite a few of the experienced and respected makers here use it without problems:

https://www.bladeforums.com/threads/super-glue-and-liners.1380330/
You are free to experiment, but with Nathan's clear and firm responses above, I would just write it down and go with that.
 
Going on 10 years using Bob Smiths CA line with zero issue with G10 liners and handle materials.

Sand surfaces to 50 grit, lay down the BS Max-cure CA glue and hold to set then spring clamp.

When cured you can take a hammer to it and I have.
On more then one occasion I have removed a scale/liner epoxied to a tang with a hammer and guess what lets loose first? The tang epoxy bond, not the CA liner/scale bond.

If you look around some very accomplished long time knifemakers use CA for the liners and scale materials.

BTW anyone looking for a great epoxy, that is very strong and easy locally available take a look at JB Weld Clear Weld epoxy available at Home Depot. This stuff sets up within minutes and at full cure is very strong, 3500 psi tensile strength, and is not brittle. JB Weld knows their stuff
 
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