Scales - glue joint failures

[Xunil]

Recently, in a couple of threads, issues with handle scales were mentioned.

Here are two knives of three knives that I currently own where the scales have lifted from the tang, separating from it:

The third knife is not pictured but is made by a very good and well known UK maker.

One of the above is made by me (and it's not exactly my first time to dance ) while the other is from a very good American maker.

None of the knives have been kept in the same environment (one in the house, one in the cottage, one in a large shed), all three are different ages and the only common denominator I can see is the handle material, which is stabilised Box Elder Burl on all three.

I can only vouch for the knife I made, where both the tang and the insides of the scales were thoroughly cleaned prior to glue up and 'keyed' on a 40 grit belt. Neither the knife nor the scales were ever worked to the point where they were hot and none of the knives have been subject to extremes of heat, cold or damp.

All three knives show no serious shrinkage or expansion of the scales in relation to the spine. At the most you can barely feel a fingernail catch on the edge of the scale/spine on two of the three knives.

Strange.

Maybe I'm just lucky...



I know at least one other knifemaker who has encountered this. Has anyone else ?

 

[Robbi]

touch wood, not so far, but i'm going to check now !

that's really weird, is there any chance that the same make of glue was used on all 3 ?

 

[shaggystu]

just out of curiousity, and i appreciate that it may be very difficult to tell, but has the glue come away from the scale or the tang? could it possibly be that box elder burl doesn't take glue so well?

stuart

 

[Xunil]

touch wood, not so far ...

No pun intended...



I doubt it can be the glue but even if we all used the same brand, it would have been from different lots/batches.

I use Devcon 2-ton epoxy on mine and I've glued up more knives than I care to remember with it, which have all held together without incident.

Interestingly the other maker I have been discussing this with also reported the issue with Box Elder and didn't mention any other materials.

Box Elder - my anti-glue Nemesis ...

 

[Xunil]

I'll get the loupe out tomorrow and take a closer look.

My theory is that the Box Elder is being processed in such a way that the stabilisation does not, in fact, make it dimensionally stable.

I cut a couple of Box Elder blocks a few weeks ago into scales and left them, and sure enough they have arched slightly.

Not much point in a stabilised material that isn't stable. The clue is in the name...

 

[Samon]

All I have in the 'workshop' is the 'no nails' multi purpose glue..is this any good for rehandling my first project? if it's not, can you advise me in the right direction of an affordable glue?!

 

[Xunil]

Any good two part SLOW set epoxy resin is usually a sound choice.

The rapid set stuff generates enough heat to force material warpage, and it can also be more brittle once set.

The slow set stuff generates no noticeable heat and once it's on it (usually) stays on. Apart from on my three knives...

 

[Trunks]

In total i have made three knives and have owned a total of four custom blades; the only one i had where the scales separated from the tang was stabilized birch burl, bought from Brisa.

At the time i just assumed the wood had "settled" a little. I just forced some more epoxy in and tightened it up again.

I did wonder though if i had applied an uneven pressure when locking the knife/scales in the vice to start with, or exerted too much pressure - thus squeezing out too much epoxy - thus not having a strong enough bond to hold the scales in place. In reality i think it was a combination of all three factors.

P.s. I have had no trouble with the other materials i have used. Same epoxy & techniques etc - just different scale material.

Hope this helps

 

[Siberianfury]

this is exactly why i prefer a well made stick tang

 

[Xunil]

That's what is really weird here - I build/assemble my own knives with gentle finger pressure and a couple of elastic bands or large plastic clips (like big clothes pegs) to hold the assembly together so there is no risk of a dry joint from excess pressure at all. Guess why I do it that way...



I keep coming back to the handle material - I've even tried it with bolts instead of pins and the ends still lifted slightly, so the addition of an active mechanical joint (posh name for a bolt) made no positive difference. I don't think I'll be having my timber stabilised by this company again. That said, I have stuff from four or five years ago that is as sound as a pound from the same source.

Another reason why I prefer hidden tang knives...

*sigh*

 

[Samon]

So, is there a decent affordable glue for my needs?

 

[Robbi]

it's the economic climate mate, they're cutting down slightly on the stabalising time to save electric bills expence !

 

[Robbi]

Samon, 2 part araldite would do you mate

 

[Samon]

http://www.amazon.co.uk/Araldite-Ra...ef=sr_1_2?ie=UTF8&s=diy&qid=1301440121&sr=8-2

This is the stuff, yes?

 

[Robbi]

that's the stuff mate, but get the normal one, not the rapid if you can.

 

[Xunil]

it's the economic climate mate, they're cutting down slightly on the stabalising time to save electric bills expence !

Aha !

The fiendish cunning caused by the current economic downturn has encouraged the surreptitious release to market of non-stable stabilised timber products.

All the added costs. Non of the benefits.

The swines...

 

[wattsy]

i've got a knife with the same handle material and the same problem from a well known uk maker too

 

[sapper1]

Even though The handle is stabilised the material will still shrink,that seems to be a common thing with lots of stabilised handles.I find with an unstabilised handle the material breathes and will absorb enough moisture to stop the handles lifting.
Having said that I have a knife with stabilised handles that do shrink and expand with the weather but they haven't lifted.

 

[Hoodoo]

No pun intended...



I doubt it can be the glue but even if we all used the same brand, it would have been from different lots/batches.

I use Devcon 2-ton epoxy on mine and I've glued up more knives than I care to remember with it, which have all held together without incident.

Interestingly the other maker I have been discussing this with also reported the issue with Box Elder and didn't mention any other materials.

Box Elder - my anti-glue Nemesis ...

Some years back a knife maker (Rod Garcia) told me that Devcon and many other epoxies were not the greatest although Devcon is probably the most popular and I've used it myself without a problem. This led to a big debate on one of the knifemaker forums. I used to have the link to that discussion but I'd be hard pressed to find it now but I will look. I believe at that time the most favored epoxy was made by 3M, based on some significant testing. I was never able to find this epoxy in the stores. I think you have to buy it in a large container through an industrial supplier. I think 3M makes cheaper epoxies but this was their high dollar line iirc.

 

[Hoodoo]

Hmmm, easier to find than I thought. Here is the epoxy Rod recommended.

http://www.ellsworth.com/display/productdetail.html?productid=1225&Tab=Products