Why Won't My Handles Stay On?

[Matthew Gregory]

Matt: you got it there i've had handles stay together and i know a ton of people who use nothing but some type of epoxy and some pins and they have never had this problem.

Great thread!

I'm surprised by all the pin and bolsters because of a comment my Father-in-law made a while back that sticks with me... he works in the aerospace industry, and one of the observations he made was that most modern planes use almost nothing but adhesives to hold them together -- rivets and bolts aren't used on the outsides due to the increase in weight, the point-source location of stresses caused my localized pressure and tension, and also the obvious differences in aerodynamic drag. He figured knives and such used bolts or pins for nothing more than aesthetic value!

BTW, Mike... great looking knife! You have an amazing talent for sculpting forms and lines -- I'm quite jealous!

 

[Dan Gray]

Dan: I hear ya i need me a mill though. they always look damn flat when i hold em on the knife or hold em together.
well atleast this one won't be coming for a sheath anytime soon. give ya some time to relax
We'll see how the epoxies and pins work and i might end up doing the "epoxy rivets" too just might be tough on this little 1/8" thick handle material. i guess in that case i can just screw em together.

Mike it can be done by hand I did it that way for a long time but it's a harder way to get dead on..using your grinder with the platen will help you I think,
if it the case,,just don't over heat them.. take the two scales once flattened put them together and hold them up to a bright light and see if you can see any light anywhere between them pinch one end together also and see if you get a spread on the other end , but on thin stuff like said pin placement will help.

don't worry about sending it later on for a sheath, I just won't be able to eat until then

Dan P: ohh you've had that stuff around long enough where i don't think you should have any worries. if not by now then i don't think its going to be anything freaky like on mine.

OK mike,, I haven't had the stuff THAT long
make sure it's dry...

 

[fitzo]

....
I'm surprised by all the pin and bolsters because of a comment my Father-in-law made a while back that sticks with me... he works in the aerospace industry, and one of the observations he made was that most modern planes use almost nothing but adhesives to hold them together -- rivets and bolts aren't used on the outsides due to the increase in weight, the point-source location of stresses caused my localized pressure and tension, and also the obvious differences in aerodynamic drag. He figured knives and such used bolts or pins for nothing more than aesthetic value!

Maybe we could do better if we could afford to spend $7million-$30million on every fighter we made, too? (Just joking around. Peace!)

Perhaps after Tracy meets with a Loctite rep he'll come back with some new wonder adhesive that will work with our materials and application capabilities in an acceptable price range.....

 

[Matthew Gregory]

Maybe we could do better if we could afford to spend $7million-$30million on every fighter we made, too? (Just joking around. Peace!)

Fitz, with you being a dollar short of God, I thought for sure you'd have enough to afford a $700 hammer! j/k

So, how many DON'T use pins or bolts, and just use adhesives? Anybody? ANd if so, what are you using?

 

[fitzo]

Fitz, with you being a dollar short of God, I thought for sure you'd have enough to afford a $700 hammer! j/k

Wrong Michael! That'd be my Archangel cousin. You know, the one with the Heavenly sword. Me, I'm on a small pension for the feebleminded.

 

[Bruce Evans]

I used to have this problem also But nobody has hit on what was causing my problem.....I cleaned and flattened with all the ways mentioned and still would have this problem with natural materials only that is....I fixed my problem in a whole different way...All my handle material is out in the shop,like most guys...at that time my shop wasent heated except when I was in there working.After completing a knife I would bring it in the house to my showcase,and after a couple of days all my pins were raised and or the scales lifted....Here is what I figured was happening,The moisture content in the air of the shop wasnt as dry as the house so even with stabilized material the handle was still drying when it came into the dryer air of the house,I figured this out when I took a few knives back out to the shop and the warppage and pinraising went back to were I finished it originally after a couple of days.If you put the handle material in the house and let it dry and only take it to the shop long enough to attach the handle then bring the knife back in,the problem went away,and when it was left in the shop everything only tightened up....my shop is heated now thus no more problem...

Now if you would forge and use hidden tangs you wont have this problem .....

Just my 2 cents worth..
Bruce

 

[tmickley]

...I'm surprised by all the pin and bolsters because of a comment my Father-in-law made a while back that sticks with me... he works in the aerospace industry, and one of the observations he made was that most modern planes use almost nothing but adhesives to hold them together -- rivets and bolts aren't used on the outsides due to the increase in weight, the point-source location of stresses caused my localized pressure and tension, and also the obvious differences in aerodynamic drag. He figured knives and such used bolts or pins for nothing more than aesthetic value!...quote]

I think that is EXACTLY part of our problem as knife makers. Entire cars are being made with adhesives. Fighter jets that have unbelievable forces of torque, sheer, temperature expansion, temperature contraction, you name it. The adhesives we have been using in our knife fabrication is at least 20 year old technology? I have an appointment with the local Loctite "Adhesives and Sealants Specialist" next Tuesday. From my testing during glue wars and some of the stuff I've used since, especially from Loctite, I think we as knife makers are way over due for a major leap in adhesives technology. I don't see any reason why we should be forced to use pins to bond scales to a full tang. Hidden tangs will need a hidden lock pin but shouldn't need a full pin either. We just need to find the right goop (a technical term) to stick it all together. I am convinced these adhesives currently exist and we need to get past using consumer level adhesives and move to specialized industrial adhesives. I'm going to push the Loctite guy to get us what we need. I hope he doesn't tell me to pisser off...

 

[leon.pugh]

Don't forget guys there are two types of bonding, mechanical & chemical. The bond to the tang is always 100 % mechanical. You must have a clean rough surface. The adhesive should have the ability to flow into the very small cervices. Good epoxys of the correct types will do that, even though they seem to thick. Warming the tang will help, as it cools it will draw the epoxy into the crevices. If the tang beads water, it is not clean. Keep these things in mind and 99% percent of the time the scales WILL STAY ATTACHED even without pins. Use them anyway, Customs knives are about quality, even one failure is to many. Even JB weld will work well if you get it CLEAN & much rougher than is required other types. Trash the Devcon, Trash the Devcon , Trash the Devcon , Trash the Devcon ,Trash the Devcon

Leon Pugh

PS: I have found if all prep work is performed well, the scales do not have to be all that flat!

 

[J.Marsillo]

I did the following experiment: cleaned a piece of plate glass and allowed to dry in air after rinsing with distilled water. It was very, very clean. Next, I laid it flat and dripped a puddle of acteone onto the surface and let it dry. There was a film from the crap coming out of the can from the hardware store. I bought another jug and had the same problems. "Home" acetone isn't that clean. 90% isopropyl alcohol from the pharmacy was cleaner. Distilled water was the best. I'd recommend wash (see that thread for soap recommendations), rinse with tap water, rinse with acetone, then follow last with distilled water and allow them to hang to dry. Hit 'em with a heat gun after to drive off any remaining moisture. Overkill, perhaps, but better than failure.

Instead of the 90% isopropyl I have been using regular dry gas (the stuff you put in your gas tank) From what I can tell it doesnt leave a residue.Then again my shop is a disaster area,dust, moisture hot,cold, wet or dry you'll find it in there
Another great thread :thumbup: and a good looking knife Grasshoppa !

 

[GibsonFan]

So, how many DON'T use pins or bolts, and just use adhesives? Anybody? ANd if so, what are you using?

My bastardized Ka-Bar has a mortised scale handle of "pakkawood"... I believe it's basically identical to the "diamondwood" sold today.

The scales were super-glued on in 1987 or '88. (I was young, my budget and knowledge were small.) There are no pins or rivets. The stick tang shows at the end of the handle. No finish or sealer was ever applied to the handle; it has held a reasonable satin finish all this time, albeit with many scratches. I have tried everything short of bashing it with a hammer, including using the butt to drive tent pegs into gravel, and it is as sturdy today as it was nearly 20 years ago. The original-style steel guard is slightly bent, and exhibits a minor amount of play... I didn't solder it to the tang, it's only held in place by the handle. It's worthwhile to note, I've never used the knife hard in really cold weather.

Having said that, for the knives I'm rehandling now, I would rather use pins without adhesive, than vice versa. I think I just plain got lucky with the Ka-Bar project. My tools and skills were extremely primitive, so I was forced to take my time on the mortises, they were/are pretty snug.

 

[David Wesner]

MDoyle , I've been using loctite 325 w/ 7075 activator and I'm having really good results.The work time that tracy listed can be adjusted easily.The first couple times I used 325 it was curing before my eyes.I even stopped using it for a while because of the fight to get assembled & clamped prior to cure. At first I was putting activator on the parts(its a spray can),I would put it on both tang & scale.Then applying 325 and assembling.Boy you had to have all your ducks in a row to beat the cure. Now what I do is put activator on one part only and 325 on the other.The parts can sit for 10 minutes like that and be as ready as when I put it on. In fact as tracy said , it requires an oxygen free environment to cure and I have put my hand in fully uncured adhesive on my glue - up bench hours after gluing up a blade. That is cool that you'll be a dealer tracy:thumbup: I'll buy from you.I think 324 & 325 are very similar in strength eh ? From what I see 324 has better shear strength & 325 is better at thermal expansion (heating-cooling-heating-cooling etc.)both are very good adhesives.Maybe you can find out a little more tracy,any info is greatly appreciated. Great thread Spangle

 

[Michael J. Spangler]

Bruce: i got enough coming at me with Mace trying to get me to forge, man you guys are relentless

Tracy: i'm with you. we're using all kinds of wacky stuff out there why can't we use a wacky super strength glue too?
i should be trying some E120 soon but i think i'm going to order the 324 this week. Good luck with you meeting. I hope it goes well

Leon: I'm going to refine my prep work from now on. better cleaning, and sure as hell not use devcon!

Thanks Joe i appreciate the compliment. If i could just finish one or two of the suckers i'd be in business

Gibson: i hear ya. always good to have reinforcements. I'm just looking for top quality glue and a really pin set-up.
I know there are glues we can rely on by themselves but i'm just looking for something to hold the slabs from seperating, and still use pins to keep it all together

David: thanks for the info on the 324 and 325 its good to hear first hand experiences.

Thanks again guys. i think this is the best post i've been involved in. some damn good info.
What do you say a poll next to see who uses what epoxy?

 

[Michael J. Spangler]

David & Tracy:
have you found there's a difference if you put the activator on the tang or the handle material? i know you guys specified activator on one and adhesive on the other, but you never said which one was which.
i was just wondering if it helps the bond at all on a specific side? or if it doesn't make a difference either way? thanks a lot guys

 

[Fox]

Am I the only one still using Conap? Blame it on the Loveless/Barney book.

FWIW - I have never had a knife come apart when assembled with Conap epoxy. I am not saying it is the best, just that it has certainly been failure free for me. I have never tapered pin holes and never peened them either. I had one customer leave a wooden handled knife in dishwater for three weeks when they went on vacation. The wood swelled and split where the pins were installed, but the epoxy bond never came loose. I have had customers drop them, leave them in the woods for days, etc., and still never had a loose handle complaint. Keep in mind that I am super anal about getting my tangs flat and ground roughly (150 grit) underneath the slabs, which are all finished at 220. I also hollow grind my full tangs and drill extra holes for weight reduction and better bonding.

I read these threads often on this board and wonder why there are so many failures? This is in no way intended as a criticism, but I still often wonder if tangs are as flat as people think or if there is contamination of some type? I agree that a change in adhesives is well past due for the knife making trade, but still wonder if changing techniques might be more helpful than a change in adhesives.

Nomex on for this one. . .:foot:

 

[fitzo]

Am I the only one still using Conap? Blame it on the Loveless/Barney book.

Up until I bought some K&G house brand last year all I ever used was Conap for 25 years. The only time it ever failed was my fault overheating the tang grinding scales to fit. It's been good stuff for me, but I cheat with peened pins and bolts.

Yeap, damn them and that book.....

 

[Fox]

Fitzo, I tried the K & G once on the recommendation of Bob Engnath. While the bond seemed superb, mixing was a pain since it was done by weight, as I recall, not equal volume. That was a number of years ago and I never figured out an easy way to mix. The other problem I had was that it finished a cream color. No matter how well a knife was assembled, I always had that thin "white" line that while not very visible, annoyed me. With Conap I have always used the clear version and never had to worry about it. Conap always seems to set perfectly with a very simple mixing procedure.

 

[fitzo]

Fox, I agree with you completely. It is a PITA to use compared to Conap, especially the way it's dispensed in salve jars.
I weighed the stuff on a gram scale, which is also a pain. Volumes aren't equal, so it's tough to eyeball.

The color, of course, presents a problem unless one buys their powdered dyes. No matter what, though, it can never be clear. I've successfully used some carbon black, but who knows how that will affect the bond strength?

I continue to like Conap very much. It would have been interesting to see how it fared in glue wars; I don't remember them testing it.

 

[tmickley]

we didn't test Conap but I wish I had. I hadn't even heard of it until we were done testing. I've talked to several golf pro's since that use it for their shafting epoxy and really like it. Golfsmith's shafting epoxy did very well also and was the most economical by a mile...

 

[fitzo]

There were simply too many adhesives out there for two guys to test. You did enough as it was. If you'd have tried to be comprehensive, let alone exhaustive, you'd still be running dishwasher cycles.

Did you know that right in your neck of the woods, Tracy, there's a company that makes Hughes 330 and Opticon, two epoxies used by jewelers? Shakudo has used them and suggested I try 330 for thin formulations, since I want something for hidden tangs.

 

[Fox]

Fitzo, the only scale I had was my O'Haus reloading scale. It was really a pain to try and spoon it out of the jars and onto something like wax paper to weigh it, all the while trying to protect the scale. I think I bought it from Bob at the Eugene show one year, but never noticed the mixing procedures until I got home; way, far away!

Tracy, I missed that glue wars thread until you guys were well down the road. I think I mentioned Conap much later in the testing, but by then you guys were nearing completion. You guys did a great job as it was.