5 minute epoxy strength vs slow cure epoxy strength

[Ron Citerone]

I am going to re -glue a dining room chair that has a few mortise and tenons and a few dowel joint that need to be glued. I have 5 minute epoxy, but I heard it's not as strong as slow cure. Any experience with this would help before I proceed.

Thanks, ron

[ChrisA Edwards]

And, what brand of expo do you recommend for these joints?

Thanks to all.

[Frank Pratt]

Generally speaking, it is not nearly as strong & it doesn't adhere as well. Best to go spend $10 on some slow cure stuff.

[Ron Citerone]

Generally speaking, it is not nearly as strong & it doesn't adhere as well. Best to go spend $10 on some slow cure stuff.

Thanks, I have used the 5 min stuff to fill holes, but will get some slow cure for this repair.

[Mike Henderson]

I suspect the 5 minute stuff is stronger than the wood. When that back joint in a chair fails, it usually the wood that fails, not the glue - you'll see pieces of wood attached to the glue on the tenon or dowels that you pull out of the joint.

I'd say that just about all modern glues are stronger than the wood.

But it's not expensive to be safe and get the slow stuff. Just leave the chair in clamps overnight.

Mike

[Larry Frank]

What I have found with the slow cure epoxy is that they fill smaller cracks and creep into crevices much better. I used System 3 T88 which is slow cure and it really gets into every little place. The ability to get into small s p aces might make the joint or crack stronger.

[Prashun Patel]

My experience is in line with Frank’s response. Get the slow.

However, it’s not a panacea and you have to consider proper mechanical reinforcement or I believe you will fail again.

[roger wiegand]

I've never managed to break either, the wood fails first. What I have readily available in the shop now is the West system pump cans for gluing and System3 for coating. The "fast" West system takes at least 20 minutes to start to set up, the slow take a couple hours-- great for laminations. For most purposes the "fast" is plenty slow.

[Mike Cutler]

Ron
It all depends on the product. there are many, many, formulations for epoxy. If it's the stuff you get at a Home Depot, or Lowes, it should probably be able to repair a chair.
However, here is thread that would be a good read prior to the repair. You might change your mind on how you perform the repair after you read through it.

https://sawmillcreek.org/showthread.php?21822-Are-Your-Glue-Joints-Repairable&highlight=

[Jacob Reverb]

I work with epoxies a fair amount, and believe the 5-minute stuff will be stronger than the wood. If you need to thin it to get it into crevices more, you can generally thin w/ acetone up to 10% by volume.

You do want it thick enough to fill any voids and prevent a glue-starved joint. Thickeners such as fumed silica or West System 404 are your friend here.

[Stan Calow]

I use the long stuff exclusively, because I'll usually have open bottles to use up. Five minute for filling gaps or holes. There is 15-minute epoxy, just a bit harder to find. That five minutes goes by too fast for me, especially if I can't find where I put the clamp I thought I had ready.

[Wade Lippman]

I made a meat mallet out of goncalo alves and glued it with HF 5 minute. It broke immediately.
Reglued with regular JB. It has held up for 8 years now.

I can't say if HF or 5 minute is the crap, but I don't use either anymore.

[Doug Walls]

What I have readily available in the shop now is the West system pump cans for gluing I also try to keep some West System on hand, I usually buy the gallon kit & it lasts me for about a year.

I like the fact that West System has various types of filler materials so the epoxy can be modified for the application.

https://www.youtube.com/watch?v=qRCiUOpsW2U


The "fast" West system takes at least 20 minutes to start to set up, the slow take a couple hours I just use the regular slow hardener, If you want it to cure faster just add a little heat with a hair drier or heat gun. You'll be shocked at how fast it will set :eek:

Doug

[Carl Beckett]

I just use the regular slow hardener, If you want it to cure faster just add a little heat with a hair drier or heat gun. You'll be shocked at how fast it will set :eek:

Doug

I use 5min all the time. Over use it even. BUT - for a chair I would want the longer cure time of the slower setting (30min, 60min etc etc). I wouldnt over think it.

And I prefer smaller tubes where both parts squeeze out of a syringe simultaneously. Masterbond has a dispenser that has a mixing tip if you want to go that route.

For me, smaller batches stay fresh (I had a gallon of the West but its been years and still havent used it all).

HEAT definitely accelerates. But you might want the glue up time and just clamp and let it sit overnight.

[Ron Citerone]

Wow, lot of info here and the thread that was attached. I ordered slow cure from amazon and will use that. My attached garage is not 70 degrees so I may move it indoors after clamping and turn up the heat a little.

[Mike Henderson]

I also try to keep some West System on hand, I usually buy the gallon kit & it lasts me for about a year.

I like the fact that West System has various types of filler materials so the epoxy can be modified for the application.

https://www.youtube.com/watch?v=qRCiUOpsW2U

I just use the regular slow hardener, If you want it to cure faster just add a little heat with a hair drier or heat gun. You'll be shocked at how fast it will set :eek:

Doug

Epoxy is exothermic when it's curing so if you mix a fair amount of it in a container, it will get hot all by itself and harden up on you faster than you can imagine. I had that happen to me with the West Systems slow hardener. Now, what I do it put the mixed epoxy in a flat container and then put that container into another container which has ice in it. That will remove the heat and keep it from flashing off on you.

I often use epoxy when I have a very complex glue-up because of the very long open time but that first time I used a large batch of it, it flashed off on me and I had to stop and mix up another batch and put it on ice. The slow hardener is supposed to take hours to set but can go off in minutes if it gets hot.

Mike