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How I epoxy scales on.

Posted: Mon Jun 07, 2010 4:26 pm
by snorkel
I have found drilling small dimples in the back of the scale and in the brass in addition to rough sanding with 50/60 grit provides the strongest bond. I also use acetone on the back of the scales to remove any oil in the wood and on the brass.
It has the effect of dozens of small epoxy pins and allows you to clamp a bit tighter as the epoxy will flow into the dimples instead of all being squeezed out. After the glue cures I use a simple coping saw to trim off the excess then sand to match the bolsters. I also thin out the scales before fitting, makes the fitting easier.

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Re: How I epoxy scales on.

Posted: Wed Jun 23, 2010 9:37 pm
by Miller Bro's
Why not pin them on?

Seems like a lot more work to do all that ::shrug::

Re: How I epoxy scales on.

Posted: Wed Jun 23, 2010 10:22 pm
by orvet
I am of the opinion that most any glue can & will eventually fail.
I have had scales fall off knives when I was working on them and dropped the knife.
That impact with the shearing force it can produce can cause the best glue to fail even when it is properly applied.
I rough up the liner & the handle material with 36 to 40 grit sandpaper.
I also wipe them down with 99% isopropyl alcohol, which leaves no residue or oil like some cleaners will, and it evaporates in seconds. With all that I have had scales fall off from dropping the knife or dropping the liner with the scale glued on (before assembling the knife).

I believe the best use of the glue is to seal the back of the handle material to prevent moisture damage to the handle, and to keep moisture from getting between the scale and the liner.
The pins are to hold the handle in place. I would like to think that in 99% or the knives I make the glue will hold the scales on, but I do not trust glue alone to hold on any handles. For that I trust only the pins.

Dale

Re: How I epoxy scales on.

Posted: Wed Jun 23, 2010 10:38 pm
by orvet
BTW,
For anyone who is interested in glue and how well the different brands work; I highly recommend the following thread on Knife Network: http://www.knifenetwork.com/forum/showt ... light=glue

Two knife makers spent a great deal of time, effort and expense to test a lot of different glues.
It is great reading and VERY informative!

It seems that the type of glue and how you prep makes a huge difference in the bond you get from which ever adhesive you use.
That said, I am not convinced that drilling holes in the liner & handle increases the bond enough to warrant the extra time & effort required.

Dale

Re: How I epoxy scales on.

Posted: Wed Jun 23, 2010 11:01 pm
by Miller Bro's
orvet wrote:I am of the opinion that most any glue can & will eventually fail.
I have had scales fall off knives when I was working on them and dropped the knife.
That impact with the shearing force it can produce can cause the best glue to fail even when it is properly applied.
I would like to think that in 99% or the knives I make the glue will hold the scales on, but I do not trust glue alone to hold on any handles. For that I trust only the pins.

Dale
I won`t open up another can of worms but I said this before, I don`t trust glue on anything that needs to be really secure.

Dale, I agree with your opening statement ::tu::

We have already seen new knives with shields falling off, right out of the box, never mind a few years time elapsing ::doh::

If they start glueing airplanes together instead if using rivets, I won`t be flying anymore! ::nod:: :lol:

Re: How I epoxy scales on.

Posted: Tue Aug 03, 2010 2:09 pm
by snorkel
Just a FYI, I glue and pin all my knifes, I never do pinless ones.
I like gluing them first because it makes it easier to get a tight factory fit, and I can color the epoxy with wood dust or epoxy
colorant to help hide any small imperfections as I am not perfect :-)

When you do the small dimples in the back of the scales and on the liners, it just makes the bond stronger.
after I glue, then I drill the holes for the pins and then peen them in.

Re: How I epoxy scales on.

Posted: Tue Aug 03, 2010 9:28 pm
by Darksev
I use a very similar method of pins + Glue. I've done pinless knives, but they are for show, not for carryin' round :) Nice to see the Infamous glue thread brought up again. I love that thing :D

Really glue is all about surface prep and what you intend to use it for. Alot of people swear by epoxy, I do not. Epoxy mixing is an in-exact science at best, and the final bond is rigid and IMO the shearing strength is way to dependent on surface prep. I use an expanding, waterproof poly glue made by loctite. For stabilized woods and G10 to metal bonding it's great, completely waterproof, very resistant to temperature changes and stays mildly flexible (doesn't cure "rigid"). rough up surfaces with some 50 grit, wipe down with 99% alcohol (I found that acetone can weaken acrylics and resins like those used in wood stabilization and G10's) moisten (very lightly) the most porous of the two materials put a thin layer of glue and clamp the hell out of it.

My mentality is glue holds the item in place, pins protect against shearing force. It's a joint venture. All that aside, I've taken apart a couple knives I was not happy with, and removing scales I've put on generally revolves around using a hammer and a razor blade to pop the glue joint (which usually destroys the handle material as half of it stays on the liner)

Re: How I epoxy scales on.

Posted: Tue Aug 03, 2010 9:41 pm
by snorkel
"I use an expanding, waterproof poly glue made by loctite"

Sumo Glue? I have some of that and it does work well, but oh so messy :-)

Re: How I epoxy scales on.

Posted: Wed Aug 04, 2010 12:05 am
by orvet
Darksev wrote: My mentality is glue holds the item in place, pins protect against shearing force. It's a joint venture. All that aside, I've taken apart a couple knives I was not happy with, and removing scales I've put on generally revolves around using a hammer and a razor blade to pop the glue joint (which usually destroys the handle material as half of it stays on the liner)
I agree Adam. Pins do the majority of the work of holding the handles in place.

I had to take a set of scales off a knife I had glued with Gorilla glue; the wood split along length wise at about half the thickness. I had to sand the wood off the liner.
Those polyurethane glues sure hold well!.

Dale

Re: How I epoxy scales on.

Posted: Wed Aug 04, 2010 11:34 am
by Darksev
Indeed, Sumo glue, though I think loctite may be in the process of phasing it out. They removed all references from it from their website, and took down the old sumoglue site itself. I sure hope not, it's a hell of a lot nicer to work with than gorillaglue :)

Re: How I epoxy scales on.

Posted: Wed Aug 04, 2010 3:26 pm
by snorkel
crap, I better go down to lowes and get some more just in case :-)

Your are right, it's not as messy as gorilla glue. I had to take the scales off of one I glued with gorrilla glue and I found I could split the wood with a sharp flat tip screw driver and pop the split pieces off. The poly glues hold well as long as it has some surface area, the smaller the are the less the adhesion or so it seemed in my case.