dickb Posted September 23, 2017 Share Posted September 23, 2017 I 've made a few hidden tang knives and used various brands of Epoxy, all of which worked fine, but I don't like using it. Shelf life after opening is too short, most set up too fast for me, and assorted other real (or imagined reasons). Does anyone know what knifemakers used before epoxy was invented. Quote Link to comment Share on other sites More sharing options...
MastaStan Posted September 23, 2017 Share Posted September 23, 2017 Probably animal based glues. You can buy longer setting epoxies that buy you more time to work with....for instance 90min ones. I use these sometimes if I need a bit more time fitting together. 5mins is not always suitable lol. I've never really found shelf life a problem I use so much it never hangs around. Buy smaller tubes?!? I'm not entirely sure what else you could use. Maybe try a few hidden tangs out with no glue. Quote Link to comment Share on other sites More sharing options...
Steve Sells Posted September 23, 2017 Share Posted September 23, 2017 cutlers resin, comes from pine trees Quote Link to comment Share on other sites More sharing options...
Johnnyreb338 Posted September 23, 2017 Share Posted September 23, 2017 I use jb weld, the set time is 4-6 hrs, it's still an epoxy but very slow. The slower an epoxy takes to cure usually yealds a better bond and is much stronger. Quote Link to comment Share on other sites More sharing options...
JHCC Posted September 23, 2017 Share Posted September 23, 2017 In the art restoration studio, the women who repaired broken crystal had some specialized epoxies with curing times of 48 hours or more. Perfectly clear and strong as the dickens. Part of my job was building armatures to hold everything in proper alignment during curing. They were tricky to mix, though. The portions needed to match within 0.003 of a gram. Quote Link to comment Share on other sites More sharing options...
Frosty Posted September 23, 2017 Share Posted September 23, 2017 How old do you wish to go? Otsi's knife was glued with "I believe" tree pitch glue, lots of papers published n the "Ice man" and his gear including his blade. It might have been hide or milk glue though I don't recall. If you wish to talk about polyester or epoxy resins I have some relatively recent professional experience I'm happy to share. (By relatively recent I mean starting in the late '60s through time in the rubber plant i the '70s.) In general, there are 3 phases involved, "Breaking" or "working" time which begins when you mix the catalyst, for glue, laminating or casting resins. The first phase the resins remain unchanged liquid, paste, putty, etc. Phase 2 they start to "break" you can tell because it becomes thicker, liquids begin to gell and sometimes the smell changes. In full fledged setting phase it begins to warm. Your working time is coming to a rapid end, some types it's done, for instance you can't make a decent resin casting if it's gelling. For laminating resins you still have a LITTLE time to press or slit and lap wrinkles but if you try to lift fabric you're skating DARNED thin ice. Once broken the resin is set and you aren't going to be able to manipulate it and have it bond again. It IS however the perfect time to do gross trimming because it's not hard. You can slice it with a razor or do large stock removal with a rasp though it will plug it if you don't keep the teeth brushed out. Set time is what you see on tubes and bottles of resins and what's claimed as "Full strength" is often sales puffery but if you buy epoxy with a true full strength time of an hour or so you could probably do as well with Elmer's or hot glue. In the rubber plant we only used 4hr. epoxy to fix things like chair legs or counter tops IF we could let them set over night to cure. The FASTER the epoxy or polyester set time the weaker it is. The good stuff in the plant was 48hr. Epoxy with a 7 day cure time for full strength. 1 hr. is probably going to need 24hrs. to be sure it's fully cured. Longer won't hurt. Those are the phases of activated 2 part resins: Working time, Setting time and cure time. Polyester resins tend to stay tacky for quite a while because oxygen slows or even reverses the catalytic action necessary for the polymer molecules to do their weave their little hearts out thing. This above needing a release agent is the reason you spray the mold with wax before gell coating and laying up a component, car body, boat hull, whatever. The gell coat hides the fabric and carries color well, it usually carries a solid component like powdered limestone. Most resins don't carry dies well. Then the casters will usually lay up a fabric ply, then hit it with the chopper guns. Choppers fire shredded fiberglass cloth (sort of) AND catalyzed resin into the mold like thick paint. Working time on this kind of set up isn't a big deal, the guys with the knives, scrapers and files are mainly making sure the surfaces and edges that match the neighbor component are clean enough for the job. Epoxy isn't usually so fussy but polyesters can be REALLY picky. At home we used to use spray wax like Pledge but most are silicone now so I don't know how they'll work. If nothing else Saran Wrap works fine. Just keep the air off it and it'll set hard in just over the set time but leaving it on for the full cure time is better. Recently I've discovered its hard to find epoxy resins like I had available at the rubber plant or any paint or marine supply store. I resorted to using 2 hr. Devcon and toluol to check if it will stabilize wood for scales. That didn't work like it did when I was 20. The toluol seemed to have reversed the catalyst and it didn't set at all. Go figure, things change eh? Mixing and thinning polyester "laminating" resin with acetone appears to work just fine. As long as there is acetone in the mix it won't catalyze and set so being severely THINNED it penetrates the wood. Hopefully ALL the way through and once the acetone evaporates out the resin will set. I've already tried this on a piece of hickory left over from my hammer handle board and it's hard and you can smell the resin in the center if you touch it with a hot nail. Okay, that was a long tour through old guy memories from being a surfer and building aircraft parts. The same rules apply to any 2 part resin. Working time as stated on the container as "Setting time." Trim and clean up while it's still gelling, once it gets hard it's file and sanding time. Cure time is figure minimum 12 x setting time, 24 x is better. Your patience WILL be rewarded. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Frozenforge Posted September 23, 2017 Share Posted September 23, 2017 We have Hysol structural adhesives at work used for bonding aluminum aircraft sheetmetal structures together that replace riveting them, really strong stuff. Takes heat and patience to try and break the bond or it just tears the sheetmetal. Usually 24 hr cure and 7 days full strength. However they have a 1 year shelf life and run anywhere from $150 to $400 per quart! Quote Link to comment Share on other sites More sharing options...
Judson Yaggy Posted September 24, 2017 Share Posted September 24, 2017 Sounds like a design paradigm issue. If you don't like epoxy, try a diferent design. Barbs on the tang, rivets, screws, one piece entirely forged knife... thousands of years of knifemaking under our belts before we invented epoxy. I'm just an architectural smith, but I try to keep epoxy out of my shop, smells like cancer to me. Quote Link to comment Share on other sites More sharing options...
Frosty Posted September 24, 2017 Share Posted September 24, 2017 Oh, I tried Judson, REALLY I TRIED! I can't help myself though, I'm a weak person, I gotta ask. So, what do you think about about nail guns? Sorry man, I just couldn't resist. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Michael Cochran Posted September 24, 2017 Share Posted September 24, 2017 Frosty, the nail gun wasn't in his workshop. It was on a job site lol. I know a guy near me that uses pine pitch when assembling his knives. I haven't tried it myself but it worked for so many people before him so I don't know why it wouldn't work for anyone else. Quote Link to comment Share on other sites More sharing options...
Frosty Posted September 24, 2017 Share Posted September 24, 2017 I know, I was just messing with him a little, he'd just had a close call and I was feeling relieved enough to poke a friendly joke. Heck, I thought I was pretty restrained. My first thought was to make a crack about nails smelling like blood but I have a Paslode nail gun in my shop. Otsi's bronze knife was glued with pitch. You can cook pitch to make a better glue. At the same time there were also hide glues. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Stormcrow Posted September 24, 2017 Share Posted September 24, 2017 Never did it myself, but there are plenty of Neo-Tribal Metalsmiths (Tim Lively in Hood's Woods Volume 9 and his own Knifemaking Unplugged, both videos I highly recommend to anyone starting out bladesmithing on a budget) who have used cutler's resin made of pine pitch with a binder added. In particular, Tim used pinyon pine pitch with dried deer dung mixed in for the binder. Frosty - Otzi's knife was stone, his ax was copper. Don't know what type of glue, but I'd suspect tree pitch. Glue-up is never fun for me. If I'm doing a slab handle, the adhesive only needs to seal out moisture as the flared stainless steel tube rivets I use are stout! I've used some Loctite outdoor adhesive before, and am playing around with some other sealer. I'll take a look in the shop and see. I like it! Quote Link to comment Share on other sites More sharing options...
Frosty Posted September 24, 2017 Share Posted September 24, 2017 Yes, his ax, good catch, thanks. Have you seen the article about the x ray spectrometry they did on it? Turned out to have IIRC 7-8% tin in it so they started calling it "Red metal." I think maybe it was impurities in the smelting that added the tin and a few other trace metals, silver is common in copper ore. I think bronze was a discovery rather than an invention. Copper was being traded in ingots all over the human world and people were casting it locally. If you guilt your cupola from stones that contained tin the melt could easily be bronze. Once the alloy was discovered it wouldn't take long to figure out why one melter was producing axes, spears, knives, etc. that took 10x as long to get dull and didn't bend. I'm not a bladesmith but I've been using blades since I was 9 maybe, bought my first machete when I was 12 and my bicycle range included the Army Navy surplus store. In my experience pins are the only way to be sure the handle won't come loose so the glue becomes more of a filler so it can't wobble on the tang. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Judson Yaggy Posted September 25, 2017 Share Posted September 25, 2017 In my experience pins are the only way to be sure the handle won't come loose so the glue becomes more of a filler so it can't wobble on the tang. Yup. But thanks to the laugh you gave me above I'm going to try and make you a knife tomorrow with a bunch of bent over Paslode nails as pins. Quote Link to comment Share on other sites More sharing options...
OlvinJanoisin Posted October 17, 2017 Share Posted October 17, 2017 On 9/23/2017 at 3:17 PM, dickb said: Does anyone know what knifemakers used before epoxy was invented. Hot sulfur has been used for filling hollow bolsters and larger areas. (Now replaced by plastics) For wood handles tight hole (burned with tang) and then totally wetting handle, hitting blade tight on it and letting the rust do the job. Also birch bark tar (tökötti)... (Dunno about fish-glue, anyone knows?) And without doubt tight fitting and riveting if possible probably combined with some of above methods. That's what came up my mind... I'm not specialist, but these I have heard/read about. Quote Link to comment Share on other sites More sharing options...
OlvinJanoisin Posted October 17, 2017 Share Posted October 17, 2017 btw. for modern quick technique I have used those glue gun glues, just whittling long chips and filling the handle hole with those (not too full), and then gently pushing heated tang to hole and move it there around so that the clue will go everywhere in there... that will hold tight... and strong... (as soon you will not reheat the blade ) f.e. I made one fish hookup that way, and even trying to bend/round hook it will last...strong bond... Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted October 17, 2017 Share Posted October 17, 2017 Theophilus mentioned using sulfur for holding tangs in Divers Arts circa 1120 A.D. Quote Link to comment Share on other sites More sharing options...
JHCC Posted October 19, 2017 Share Posted October 19, 2017 Sulfur expands as it cools, locking the tang in place. Quote Link to comment Share on other sites More sharing options...
SLAG Posted October 19, 2017 Share Posted October 19, 2017 JHCC, You are right, as per usual. Let me add a little obscurata. Molten sulfur hardens into an insoluble polymerized mess that defies cleaning up. We were told not to try cleaning out the stuff from test tubes, in my under-graduate days. In other words trash the glass test tube. I do not know of any chemical that cleans it up. (dissolves it). If anyone does know, please post that information here. Thank you in advance. Pyrolysis does not count. SLAG. Quote Link to comment Share on other sites More sharing options...
4elements Posted October 19, 2017 Share Posted October 19, 2017 Hot toluene. I was going to try to extract sulphur from rocks once and that's where my research took me. It doesn't seem safe to me to heat a highly flammable liquid like that so I never followed through Quote Link to comment Share on other sites More sharing options...
OlvinJanoisin Posted October 19, 2017 Share Posted October 19, 2017 On 9/24/2017 at 3:36 AM, Judson Yaggy said: Sounds like a design paradigm issue. If you don't like epoxy, try a diferent design. Barbs on the tang, rivets, screws, one piece entirely forged knife... thousands of years of knifemaking under our belts before we invented epoxy. I'm just an architectural smith, but I try to keep epoxy out of my shop, smells like cancer to me. I totally agree with you If I see some design soaked with epoxy and it still has rivets or so on, I count these as failed or lack of skills. But certainly there are many cases where modern glues are best choice in common sense, like If you design to use hidden tang. Design matters, I also want to build and do designs which could be build in any century. Quote Link to comment Share on other sites More sharing options...
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