Scale adhesives

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bluerush55

Joined
Mar 6, 2008
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Whats the best adhesives for scales? IM wanting to places some wooden scales and bone scales! Thanks I hope I have done this right IM new to posting and being on this site!
Thanks Don G.
 
Welcome to BF! :)

I think it's basically an epoxy, but I wonder if anyone's tried Gorilla Glue......
 
I've thought about Gorilla glue too. The only thing that concerns me is how it expands when it dries... might not be a big deal. Anyone have any experience using it?
 
fivefold said:
I've thought about Gorilla glue too. The only thing that concerns me is how it expands when it dries... might not be a big deal. Anyone have any experience using it?
Click to expand...

I've used it, just not for scales. If I was going to do some permanently (I'm a big fan of removable scales), I'd probably use that. Just wet a bit, draw a bead, and clamp for a day.

Gorilla glue was designed for dissimilar materials, and metal/bone is pretty dissimilar. :)
 
I have used gorilla glue for scales, it works well. You will need to scrape the foam off of the spine and scales after the glue is set. Most folks just use a two-part epoxy to seal their scales, some use CA. I wouldn't suggest using any glue to hold scales onto a knife without a mechanical fastener. If you're talking about bonding wood and bone together, I think that gorilla glue or the rubberized gorilla superglue would both work well.
 
The thing about CA (superglue) is that it's not water resistant, so it will degrade over time. That and it's very temperature sensitive. Anything over ~200 F and it's starts to break back down.
 
Epoxys are good, but not the 5 minute stuff. The slower the better.

There are other products that are showing good promise - such as Loctite depend - but good slow cure epoxy - or Brownells acraglass - are excellent performers. Roughing the surface - excellent unwarped fit, cleaning beforehand and mixing the epoxy far beyond what you think is necessary - all go a long way.

Rob!
 
I used some Elmers PE glue to glue up some scales last night, Same as gorilla but different brand. The only thing bad about it is that if there is a gap anywhere, it will fill with the foam from the expanding glue.
 
Rob please explain why not to use 3 mon epoxy . I just used it on a handle. But the other one i used 20 min epoxy.
 
Slower curing epoxies generally have better characteristics for a knife maker (tougher, stronger, etc.). The fast cures are convenient but at the sacrifice of some strength.

--nathan
 
the loctice adhesives with the spray activator work REALLY well, but have a learning curve.

Gorilla Glue works fantastically. the expension is not a problem, it's an odd glue in that you want the TIGHTEST clamping and smoothest fit you can get. the GG doesn't have a lot of strength for gap filling, but I've used it on quite a few knives with less oily wood handles and as long as you remember the water, clamp tight, and wait overnight, it's solid. Back in the Glue Wars, it held up better than a lot of stuff.

2 part slow cure epoxy works well for me, too. The 5 minute stuff is really 90 second stuff in the summer here, so it's pointless to even try. No fanciness needed, just get the regular clear 30 or 60 minute epoxy at the hardware store. You can find better and worse ones, but I've never had any problem. Never bought eopxy at the dollar store or harbor freight, though :D

I'm currently testing out my first CA glue up. I can't believe it doesn't work given the track records of some of the makers who use it. SO I'll give it a shot. I gather surface prep and fit are pretty important in this, too.
 
I use Loctite 324 and 325 to adhere my stone, bone and ivory scales. This stuff cures aerobically, so the stuff on the outside won't be dried up... just wipe off excess and clean with "Goof Off". This stuff is awesome. It’s expensive, but considering the fact that the can of activator is enough to last for at least 100 knives and you don’t' waste any epoxy mix in and measuring. You tend to use a lot less. The stuff pays for itself all the way.

Speedbonder 324
High impact applications
Amber Color
Gap fill to 0.040”
Viscosity 17,000 (higher is thicker)
Shear 3,000
Temp range -65f to 300f
Cure speed fixture 5 min
Full – 24 hours
Activator 7075
Comments: good gap fill and temp range. Has a higher sheer rate than 325 but lower flexibility for thermal cycling. If you aren’t running your knife through constant temperature changes, this is the better choice over 325.

Speedbonder 325
Severe environment
Transparent dark brown color
Gap fill 0.040”
Viscosity 20,000 (higher is thicker)
Shear 2,200
Temp range -65f to 300f
Cure Speed fixture 5 min
Full 24 hours
Activator 7075
Comments: This is used to bond metals that move slightly due to temperature changes. It takes thermal cycles very well since it is slightly flexible. It is slightly thicker than 324 so it is easier to apply. The color of epoxy seems to bother people. If you have a large glue seam you can see, you should work on closer tolerances more and worry about adhesive color less.

Speedbonder 326
Fast fixturing
Transparent dark brown color
Gap fill 0.020”
Viscosity 18,000 (higher is thicker)
Shear 3,500
Temp range -65f to 250f
Cure Speed fixture 1 min
Full 24 hours
Activator 7075
Comments: Great shear strength. This stuff is for speed. It sets in under a minute. If you are into fast production times, this is the one for you. It is used in the jewelry trade to hold expensive stones so it’s great adhesive. You just have to move fast.

Depend 330
Rough or porous surface general purpose
Transparent dark brown color
Gap fill 0.030”
Viscosity 67,000 (higher is thicker)
Shear 3,300
Temp range -65f to 250f
Cure Speed fixture 5 min
Full 24 hours
Activator 7387 or 7380
Comments: This glue is made for all around use. It will stick to (slightly) dirty surfaces and porous surfaces.

All of these adhesives are Acrylic 2 step, no mix structural adhesives. They require a tight space and activator to kick off. They are anaerobic meaning they do not cure in the presence of oxygen. These are fantastic adhesives but no adhesive will over come poor surface preparation. Many cleaners leave a residue that causes exceptionally high failure rates in adhesives. I use pure alcohol that I buy from Home Depot for cleaning. I use a #0 file to roughen the liners where they meet the bolsters and a 36 grit dremel "drum" wheel for the rest of the liner surface. I prep the metal surface just before gluing the scales and wear nytril gloves to do all of the handling after cleaning.
 
Josh K said:
The thing about CA (superglue) is that it's not water resistant, so it will degrade over time. That and it's very temperature sensitive. Anything over ~200 F and it's starts to break back down.
Click to expand...

This is not true of any and all CA glues. Most superglue breaks down at similar or higher temperatures than epoxy and many are available that won't break down easily in water. Starbond is an example of this and has been used for many many years by Scott Slobodian as a lacquer alternative on saya. The gorilla super glue I mentioned before is also water resistant.

Not all CA is the same, neither are all epoxies. JB Weld is a great high-temp epoxy, but devcon 2-ton can easily be removed with a little heat.
 
Thanks everyone for replying. Should I rough up the brass liner and how?
If I have posted this in the wrong place please forgive me. I tried searching this but could't find this topic and I know with all these knife makers it's been covered. I need the book BladeForums for Dummies lol
Don G
 
The best way to prepare the surface is by blasting, if that method is available. If not, rough it with some sandpaper. Either way, I would clean with alcohol before gluing.
 
Maybe I'm a bit obsessive...

For epoxy prep I rough with 60 grit on the tang and scales. just a quick pass, I've already cleaned them up to 220 minimum for fit.

I dont' worry too much about the wood, I do all the sanding at once (I finish the scales on the knife) and there's nothing to clean on the wood side.

On the metal, because of the oils, baked on oils, etchants and buffer compounds and all I wash in HOT water with a good desgreasing soap (I use Oasis, it's really good and is fertilizer once it's down the drain) then I rinse for a timer count of 2 minutes. then i rub down with blue paper towel and alcohol.

not a lot of difference for gorilla glue except I finsh out at a smooth 120 grit and work the scales wet for the glue up.
 
There's at least 1 knife supply company that sells a, by their description, "superglue on steroids" that is kick butt for knives. I used it on my 1st knife and it's worked well so far.

I found the exact same, including packaging, product at hobby lobby in the model building section for $2 - $5 per bottle. It comes in super thin which has done a great job on finishing micarta. Besides the 1st knife the whole bottle has gone that direction.
 
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