Epoxy help

[Huntsman Knife Co. LLC.]

Hey guys,

Ive used the search function and read several threads but I still need some help with picking epoxy.

Right now I am using Loctite 5 minute epoxy on my handles and usually micarta or steel pins. I really like the fast setup time because when I work its usually in 6+ hour increments. I like to be able to get a knife handle done in a singe session start to finish.

However Im worried the Loctite 5 min epoxy isn't strong enough or resistant enough to heat and moisture. I want to make sure that my handles never come off my knives and can handle a lifetime of use.

I tend to do alot of laminated handles and Im very concerned about delaminations.

Is the Loctite 5 minute epoxy, or any 5 minute epoxy strong enough for a laminated knife handle? If not, whats the best epoxy out there for laminated handles? Should I be concerned about delamination with the handles Ive completed? Here are some handles that Ive done recently and this is the style I usually stick to.

 

[jonnymac44]

I also do a lot of laminate work on handles.

I'm not saying anything negative about loctite 5 min. because I haven't used it much, but I have tried out as well as tested several different epoxies and I've settled comfortably on West Systems G-Flex slow cure. Plenty of working time before it sets, super strong bond, and it handles impact shock extremely well. I don't know why anyone making knives would need a five minute epoxy anyway. If you can't afford to let a blade sit for 24 hours to fully cure then you're rushing your work too much!

The G-Flex has done really well for me for a long time now and I don't plan on changing to anything else any time soon. I do liners, multiple liners, dovetails, bolsters, stainless pins, fiberglass pins, carbon fiber pins, etc. and it works great on all of them. Give it a shot.

 

[Stacy E. Apelt - Bladesmith]

As you surely read in the threads that you found in the searches.....

5 minute epoxy should not be used for handle assembly, especially lamination. Use the slowest cure epoxy you can get, and preferably a structural epoxy.
West System and System Three both make superb resins. I use T-88 by System Three, and JonnyMac uses West System G-flex. Both will be very reliable.

BTW, Even tough 5 minute epoxy "sets" in a few minutes, it does not cure for a day...just like the slower epoxies.

Trying to save a few hours in making a knife that should last a lifetime is not good economics. All handles should sit for 24-48 hours before shaping.

 

[AVigil]

Where 5 minute epoxy will fail it when it is cold like on an early morning on the river or camping. With the cold the 5 minute stuff will just let go of the metal/micarta bond.

Since you have mechanical fastners on your handles it should not be a problem but I would keep them out of the really cold weather.

 

[Don Hanson III]

If you want fast and strong bond get Loctite 326, 324 and the activator. I have not found a stronger bond, but it might be too fast for some.

For me, 5 minute works fine on stick tang knives, but I wouldn't use it on full tangs.

 

[Remyrw]

Don, I agree, they're great but super fast. Also pretty expensive if you aren't using it up, they have the usual short shelf life and it takes quite a few knives to get through a tube if you use it right. It's not like regular epoxy, you don't want to slather it on there, a thin layer on one part, spray the activator on the other part, once the two meet you have about a minute to get things set or it's all over but the crying.
I switched to E-120HP for most knives and have been very happy. I glue up a knife and leave it for a day before doing anything else with it. As J-Mac said, there's no need to rush things. If you work in 6 hour or less stretches just time things so glue up is the last thing you do and then leave it alone. Or work on a different knife. I'm not Jonny, but even I try to glue up at least two or three knives or laminates at a time to reduce the time and materials waste. Heheh, one of these days I'll start doing laminate glue ups like his. Different materials probably, but... It's definitely the efficient way to get it done.

Personally, I avoid any consumer grade adhesives these days, at least for anything I really want to have stay bonded. The difference between consumer stuff and industrial stuff is night and day. If you want a fast set adhesive check out the commercial loctite options. There's faster stuff than the E-120HP, but be aware that you're giving up a lot too. Usually temp range and shock resistance. For me, those are pretty important in a knife handle.

 

[Huntsman Knife Co. LLC.]

Thanks for the input!

I think I'm Going to go ahead and order some G flex from alpha on Monday and start gluing in batches.

One more question,

How important is pressure when gluing? Do you need to clamp the handle in a vice or is placing a 25lb weight on top of it and letting it dry enough?

 

[james terrio]

How important is pressure when gluing? Do you need to clamp the handle in a vice or is placing a 25lb weight on top of it and letting it dry enough?

As long as the parts are fitted snugly together, I feel you can do more damage by over-clamping and squeezing the adhesive out of the joint than by not clamping tightly enough. It's not like clamping two pieces of raw wood, where both pieces actually soak up some of the "glue". When in doubt I use small spring clamps; normally hand-tightened corby's or screws, or peened pins will keep the pieces plenty snug.

The time to make sure everything is flat and mates well is before final assembly; if you try to straighten/tighten things up with pressure, it will almost always cause problems later.

I have a different epoxy question, which I may have asked before... I'm planning a project that will involve clear polycarbonate as part of the handle. Which epoxies or CA's dry the most clear? Strength is a lesser issue since this will be a hidden tang held together by mechanical means (threaded and/or pinned pommel).

 

[Stacy E. Apelt - Bladesmith]

Any of the clear coat resins will work well. System Three Clear Coat is what I ues in similar stuatiins.

 

[amamachinist]

I have a different epoxy question, which I may have asked before... I'm planning a project that will involve clear polycarbonate as part of the handle. Which epoxies or CA's dry the most clear? Strength is a lesser issue since this will be a hidden tang held together by mechanical means (threaded and/or pinned pommel).

there is an epoxy resin that is clear as glass and and is used in restoration of valuable paintings and sculpture and glass repair. it is VERY expensive but it stays clear forever no yellowing ever.

http://www.hxtal.com/

I've used it on a glass project and it really is great. you need to measure it with a very precise scale.

anyway check it out!

 

[Hans17]

I used bondo fiberglass resin today at my first shot at making micarta. I went to 3 stores and it was the only epoxy like substance I could find.

 

[BillyJack]

I see this thread is a few years old. Are these the two go to epoxy’s still? I just read an article from West System that they improved the G-Flex formula and it is now stronger. They are saying it can withstand 150,000 psi. I don’t know if or how much stronger this is then before the upgrade.

 

[kuraki]

G-Flex, T-88 and Accraglass seem to be the most favored for bonding, with System 3 clear coat for soaking wraps or filling hidden tangs.