Epoxy user issues

[Sean Yaw]

For instance, on this last knife I just built I used my file guide with both liners clamped in. I glued on the larger bottom pieces to both liners and just clamped while in the guide. Once cured I removed and individually glued on the micarta bolster piece and clamped I also added a clam to both ends to keep the joint secure. If you do a g10 similar divider same principal. Hope that makes sense.

It does. Thank you.

 

[AVigil]

I use to use Speed Bonder 324 but gave up on it when joints would not cure. I believe it had been exposed to heat in storage or it was old stock. After the 3 bottle I switched.

I discovered JB Weld Clear Weld, which can be purchased at big box stores. It works very well, very strong and flexible.

I have used Bob Smith products such as Maxi cure. It is strong and works OK but it has no impact strength and is very brittle can release if dropped, don't ask me how I know that

Currently I am using Gorilla Glue Hi Impact super glue. It is very strong, great impact strength, not brittle and gives enough time to get things right. I rough both surface with deep scratches with 50 Grit, apply the glue to one side and put on the other side and slide it back a fourth a couple of times. Then hold with finger pressure, insuring a flatness until it sets so the part will no longer slide. Then I put on a couple of spring clamps and let it cure.

I always time my glue up to let it cure fully and even with super glue that is 24 hours often.

To get a scale off I have to take a torch to the liner to get it off, nothing else will do it.

 

[Signalprick]

I use to use Speed Bonder 324 but gave up on it when joints would not cure. I believe it had been exposed to heat in storage or it was old stock. After the 3 bottle I switched.

I discovered JB Weld Clear Weld, which can be purchased at big box stores. It works very well, very strong and flexible.

I have used Bob Smith products such as Maxi cure. It is strong and works OK but it has no impact strength and is very brittle can release if dropped, don't ask me how I know that

Currently I am using Gorilla Glue Hi Impact super glue. It is very strong, great impact strength, not brittle and gives enough time to get things right. I rough both surface with deep scratches with 50 Grit, apply the glue to one side and put on the other side and slide it back a fourth a couple of times. Then hold with finger pressure, insuring a flatness until it sets so the part will no longer slide. Then I put on a couple of spring clamps and let it cure.

I always time my glue up to let it cure fully and even with super glue that is 24 hours often.

To get a scale off I have to take a torch to the liner to get it off, nothing else will do it.

Thank you for mentioning the "slide around" technique Adam. I do the same and it really helps create a stronger bond.

 

[Horsewright]

I use to use Speed Bonder 324 but gave up on it when joints would not cure. I believe it had been exposed to heat in storage or it was old stock. After the 3 bottle I switched.

I discovered JB Weld Clear Weld, which can be purchased at big box stores. It works very well, very strong and flexible.

I have used Bob Smith products such as Maxi cure. It is strong and works OK but it has no impact strength and is very brittle can release if dropped, don't ask me how I know that

Currently I am using Gorilla Glue Hi Impact super glue. It is very strong, great impact strength, not brittle and gives enough time to get things right. I rough both surface with deep scratches with 50 Grit, apply the glue to one side and put on the other side and slide it back a fourth a couple of times. Then hold with finger pressure, insuring a flatness until it sets so the part will no longer slide. Then I put on a couple of spring clamps and let it cure.

I always time my glue up to let it cure fully and even with super glue that is 24 hours often.

To get a scale off I have to take a torch to the liner to get it off, nothing else will do it.

I switched to the Gorilla Glue Superglue that Adam mentions years ago. I’ve done thousands of knives with it. I use it on all bolstered knife handles and the regular clear Gorilla Glue on non bolstered knives. Absolutely true the handle material will let go before the bond does.

 

[Sean Yaw]

I switched to the Gorilla Glue Superglue that Adam mentions years ago. I’ve done thousands of knives with it. I use it on all bolstered knife handles and the regular clear Gorilla Glue on non bolstered knives. Absolutely true the handle material will let go before the bond does.

Just so I am clear (see what I did there?) on the products you are referring to, is this the "regular clear Gorilla Glue"?

Clear Gorilla Glue | Gorilla Glue

Clear Gorilla Glue is an incredibly strong glue that's easy to use. This clear glue is ideal for indoor and outdoor projects and bonds virtually everything.

www.gorillatough.com

And is this the "Gorilla Glue Hi Impact super glue"?

Gorilla Super Glue | Gorilla Glue

Gorilla Super Glue is the go-to adhesive for a variety of household projects. This clear glue dries in 10-45 seconds and stands up to wear and tear.

www.gorillatough.com

And why do you use different glue depending on whether or not there are bolsters?

 

[Horsewright]

Yes and yes. The clear doesn't foam up like the regular or white Gorilla Glue. Ya bet.

 

[ErikMB]

Just reading this thread... thanks so much for asking and answering these questions.

I just switched to a new type of epoxy and it has not been working well. I was trying to figure out if I don't put in enough hardener, don't stir it enough, don't wait long enough, or what. I had not thought of it sitting on the shelf in the heat for too long. I just mail-ordered it so who knows how long it's been where.

Also, glad to know that the Gorilla glue I was using is good stuff. I was worried things would fall apart after a while.

 

[john april]

i think you might be heating up your scale/liner during shaping and thinning more than you realize and the bond is letting go. i have done it many times myself. it seems the thinner the liner the faster the heat travels across it. with your present technique, have you tried to pull apart a liner /scale to check the bond? if it seems like a good bond when trying to pull it apart, but fails later, makes me think heat. i always use a mechanical fastener ( domed pins or corbys) so for me, the epoxy is just a sealant so no liquid can set between the scale and liner, or the liner and tang so no corrosion can start in there. i think that is important. try cutting closer to your final profile with the saw so there is less to shape and sand away, and get very close to your final scribe line with a coarse sharp belt before moving up to a finer grit. the finer the grit, the more friction, and it gets hot faster faster.

 

[ErikMB]

Good point. I do let my stuff get really hot when grinding or belt sanding. I had not thought of that. Thanks. That's very useful.

The times I was thinking of though were after glueing on the scales and clamping them for 24+ hours. These times are still a mystery....

 

[Natlek]

Good point. I do let my stuff get really hot when grinding or belt sanding. I had not thought of that. Thanks. That's very useful.

The times I was thinking of though were after glueing on the scales and clamping them for 24+ hours. These times are still a mystery....

Ambient temperature in you shop .......................is ?

 

[AVigil]

Good point. I do let my stuff get really hot when grinding or belt sanding. I had not thought of that. Thanks. That's very useful.

The times I was thinking of though were after glueing on the scales and clamping them for 24+ hours. These times are still a mystery....

Never let it get hot once it is glued. Constant dunking to keep it cool. Heat will break glue bonds faster then you realize.

 

[ErikMB]

I just fixed something for exactly that reason... sigh... back at the computer, now, supposed to be working...

If heat melts the glue, does that glue return to a cured state after it cools? Especially clear Gorilla glue and typical epoxy?

 

[ErikMB]

Ambient temperature in you shop .......................is ?

I set up a workbench in the backyard. The garage is filled with my wife's stuff... sigh... ;-)

I'm in the Bay Area of California. Daytime temperature maxes out around 86 but is usually more like 75 during the day, now.

 

[Natlek]

I set up a workbench in the backyard. The garage is filled with my wife's stuff... sigh... ;-)

I'm in the Bay Area of California. Daytime temperature maxes out around 86 but is usually more like 75 during the day, now.

OK , that is more then enough so epoxy can properly cure

 

[JoeBusic]

All is well said here and I'll just add a ultimate guide to epoxy bonds. Key is thick layers. If one wants, coloring the epoxy will give added esthetics.
So:
1. basic cleaning, no need to make an effort
2. sand with anything bellow 320 grit. Fresh sanding will remove all dirt and reveal fresh steel and other material
3. apply a thin coat of epoxy with a small painting brush on all surfaces. For a handle it's usually 4 surfaces.
4. use a lighter or any other small flame apparatus and lightly flame the surfaces one by one. It will accelerate hardening but before that it will lower the viscosity which will make it penetrate well in the tiny scratches from sanding. It will level the coat also.
5. repeat at least 2x. More will give a thicker coat. No need to rush, epoxy will achieve a chemical bond even if it's hard but not cured yet. No need to wait either as the hardening is accelerated.
6. when ready to assemble apply a thin coat but no flaming this time.
7. fit, adjust, clamp with whatever force seems fit. Hardened layers will not escape. If the clamp is not strong, the fresh layer will fill the small possible gaps or pockets.
8. go get a drink or two. I made this with 10 min epoxy. 5 min epoxy was too fast. 30 min epoxy is probably the optimal.

Hammering will destroy the material but not the bond. It's not just strong it's tough also as epoxy breaks after 3% deformation. Thicker layer, bigger the 3% is. To remove, heat and/or sand.

My 5c

 

[Bill DeShivs]

I just fixed something for exactly that reason... sigh... back at the computer, now, supposed to be working...

If heat melts the glue, does that glue return to a cured state after it cools? Especially clear Gorilla glue and typical epoxy?

No. Once the bond is overheated, it's ruined.

 

[john april]

like adam suggested, dip it in water like you would a blade to keep it cool. i put ice cubes in my water bucket too

 

[Horsewright]

Besides debonding your glue, excess heat can warp some of your natural handle materials. Ask me how I know. The only time I wear gloves at this stage is when its so cold I have too, which probably ain't gonna happen to you up there. I want to feel the heat so I know when to dunk. I too will use ice cubes in the summer. Winter time around here don't need to, water wants to freeze up on its ownself.

 

[Horsewright]

Glue up time. Yesterday afternoon had a group of 21 bolstered knives ready for the first part of glue up here ya go. I'd cut and processed and drilled all bolstered material that morning and put the bolsters on around noon. Early afternoon had flattened and fitted all handle materials and spacers to each individual knife. Here ready for glueing in late afternoon. Each knife has a number on the taped blade that corresponds with the handle material. I glue on all the right side handle materials first and then the next day will trim, profile, drill the right side and then glue on the left side. I glue on the right side first because...I glue on the right side first. These are the non bolstered knives in this batch they will be attended to later:

All 21 with their handle materials and spacers ready to go:

Use up old glue bottles first:

Reinforcements standing by:

Second (left side) all laid out and ready to go for the next day:

Glueing:

Spacer in and flush forward and down:

Clamped and confirmed forward and down:

The more complicated spacers the same thing flush forward and down:

Life is so much easier when ya just squeeze the glue out of a bottle where ya want it. Especially working on multiples at the same time. All glued and clamped. That table has glued up a few knives in its time:

I do give the tops (spacer area) a quick spritz of accelerator after they are all on the table. This is to keep the spacers from sliding about if the table gets knocked or bumped while drying. In the summer I will often carry it outside to dry in the sun or in the winter it will go inside the house to dry overnight. I found that quick little spritz will save ya aggravation later from a slipped spacer.

Aye, end of a productive day, time for a wee dram. Woodford Rye:

 

[Sean Yaw]

You have more knives on that table than I have made so far! It is very helpful to see this type of information in visual form. Thank you for taking the time to take those pictures.