Gluing up scales

J

jtwodogs

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Feb 1, 2009
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Was reading a thread with great interest how Stacy was explaining how he glued up scales with Corby bolts. Turned out the thread was older and Stacy closed it. But I found it very informative.

Stacy mentioned that he made small indentions in the tang with a dremel burr bit. This was to keep from extruding all the glue when you applied clamps, to keep from making a glue starved area between tang and scale.
Would the same apply if you are drilling holes in the tang for weight reduction?
 
The key with epoxy is not to squeeze it all out. You want it clamped under moderate pressure, I like the black and yellow plastic clamps ou can find at just about any hardware store. The ones with red jaws are stronger and work great too.

Indentations in the scales are good, same with "glue rivets" formed by epoxy going through holes in the tang. Make sure the scales and tang are roughed up nicely. You can even hollow grind the tang but I'd leave that for later.

I like to sandblast my tangs but that is overkill. Clean parts are what is really key. I tested G-Flex with no pins on G10/steel with a typical glue-up nd was not able to sheer the scales off with a 3# sledge. I was attempting to remove the scales without damaging the knife but it still was impressive.
 
Once the pin holes are drilled on my scales, I chamfer the holes on the inside as well, so that a pool of epoxy will collect around each pin hole.
 
I also skeletonize the tang for weight reduction and epoxy rivet purposes. I drill partial thickness holes (approx 1/16") in the scales/liners to add further "grab" into the scale by the epoxy. I make sure to outline the tang on the scale with a sharpie so I know where to drill. (If this was covered in Stacy's post sorry for the repeat)
 
Epoxy rivets from drilling lots of holes through the tang are very good for strength. Corby bolts are the ultimate in strength. You have to drill out the bolt or break the handle to get it off.

I have been considering experimenting with RTV as a sealant/adhesive for Corby bolt handles on my fillet and kitchen knives. I remember it well from my electronics days, and it was really rugged stuff. Since it bonds well to all normal handle materials as well as steel, it seems perfect for applications where a truly waterproof seal is the primary duty of the material between the tang and scales.
 
One thing is for sure, silicone makes and excellent choice for gluing granite counter tops to base cabinets, I replaced a base unit one time on a 4'x 8' slab and four guys couldn't lift hard enough to break the bond, wound up ripping the screws out of the floor, after we flipped it upside down on the carpet we had to push sharp putty knives into the silicone to get it to let loose
 
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Speaking of alternative sealants, 3M 5200 might be a good one. Once you use it the part isn't coming off without a chisel.
 
Id like to find a faster drying/ less messy/ less toxic alternative to Gflex for my knives with mechanical fasteners. With corbys or flared tubes the epoxy is just there to keep water out. It would be nice to find a better method for waterproofing under the tang.
 
Daniel Fairly Knives said:
Speaking of alternative sealants, 3M 5200 might be a good one. Once you use it the part isn't coming off without a chisel.
Click to expand...

I can speak for this stuff. 5200 is a marine sealant, is completely waterproof, and is about the toughest stuff I have ever seen when it's completely cured. Only problem is the black stuff takes about a week to even START curing, and the quick dry stuff (takes about 24 hours to cure) only comes in white. But if you have the time to wait, and are ok with the black, I highly recommend giving it a try. No way you come away disappointed.
 
Thanks for all the ideas. I will be using some of them on the next glue up. Never thought about chamfering the holes to add a little glue in those areas. I did rough up the pins in the center area to add a little more bite.
I also thought about cutting areas of the scale that correspond to tang holes but was afraid I would grind into them when contouring the handle, I probably need to do that just watch how deep I make them. As always much thanks to all who commented. Everything I have learned about knife making has come from you guys.
 
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