any suggestions for testing epoxy?

T

tmickley

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Apr 4, 2001
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I thought I'd do some epoxy tests for handle scales and was looking for some suggestions on tests. I was thinking several dishwasher cycles would be a good test for a kitchen knife but not for a decent custom knife. Any other suggestions that could be repeatable? Maybe some one has already done some tests they'd share?

I found this thread here: http://www.bladeforums.com/forums/showthread.php?t=328948&highlight=epoxy+testing
Steve did you ever manage to get some tests devised and/or done?
 
In the dishwasher are you talking water only or heat too?
Please let me know that go. I have a seroius interest. They all soften with heat
I believe.
 
Trey giving it a sharp rap. You know hit it or drop on the floor.
Heat 3-4 hundred degrees turns epoxy grainy with no grip.

Keep us posted.
TJ
 
Hi Tracy,

I'm still getting ready for the test. I have the collection of 'glues' and my heat treated bar of ATS-34 (stainless is harder to stick to). I haven't put the samples on yet.

RE: heat

Looking at the data sheets the epoxies lose stick while hot. However, they return to their original state on re-cooling. In fact some of the industrial epoxies can double strength if cured for hundreds of hours at 300+ degrees. But they are retested at room temperature.

RE: Testing

My plan is to leave the samples in the dishwasher for a week or so. Not that I expect them to get that treatment, but I'm interested is if the heat/steam/cool cycles will make the 'glue' break down. Not that it holds the stuff together, but doesn't come apart.

After that I was going to mount the bar to the shock mount in my car for a few weeks. Again, does it hold up to vibrations and heat changes without becoming brittle and give up?

If I can find an epoxy that stays together after that, then it'll raise my confidence in its ability to last for years.

Steve
 
Another test is soaking the handle in water for different times and comparing the amount of force required to remove the handle.

When testing try to minimize variables, i.e. if using a paper plate as a palate to mix epoxy, use the same paper plates from the same package to mix all the epoxies. Use the same stir sticks from the same package when mixing the epoxies. Don't reuse the same paper plate of stir stick. One adhesive may be affected by the residue from another.

If you want samples of adhesives to test let me know.
 
For what it's worth, I have two kitchen knives that have been going through dishwasher cycles for several years now with no ill effects. One has a micarta handle the other some kind of pakkawood material. I've used standard 90 minute epoxy on everything for long enough to have included both of them.
 
Chuck, I'm going to take you up on some free samples of epoxy for sure.

I just need to get some methodology in place first. I was thinking 1" strips of stainless and stabilized wood or micarta for test scales. I'd test 5 to maybe 10 of the epoxies with the highest recomendations by the group. Certainly the Devcon 2 ton and Devcon 5 minute epoxies since they are the most widely used, Accraglass and a golf shafting epoxy from golfsmith. I'm also going to try gorilla glue. Any others I should test?
 
Have you tried an epoxy called T88 by System 3?
It has a tensile strength of 7000 PSI and Flexural strength of 11,500 PSI
it's 24 hour epoxy. I like the stuff. Good rule of thumb is the quicker the cure the weaker the epoxy. 5 minute epoxy is usually the weakest but it can also be good enough to do the job.
 
Chuck I would like to try several free samples of your Timascus. Oh wait I see it is just free epoxy :D

Actually Im glad you came on here I will email ya with an order for a few things.
 
I would like to see a test where the handle is submitted to low air pressure, probably via a vaccum chamber setup.

That one bit me last year - when they go up in an airplane (shipping).
 
I'd be most interested, if you would please, Daniel, in hearing a bit more description of what went wrong such that it was attributed to low pressure. Not being a wiseguy, but I am having a difficulty understanding this.

I've got a vacuum pump and chamber here. I would be willing to test your theory. I have Conap and West System epoxies on hand right now.
 
low pressure/humidity has affected a knife I made & shipped....as well as others I have purchased (from overseas).

I'm not accusing the epoxy of being the source of failure. On the contrary, I'm interested in ruling it out as a suspect.
 
I've heard really good comments about System 3. I think it should be included. I'll send Acuraglas, rubber toughened black super glue, liquid nails, JB Weld.

If you want to use stabilized wood I'll send that also. We have some left over wood from a factory order that should work well. If you are not set on stainless steel we will provide strips of 15N20 for the steel.

Another test would be testing the difference is strength of different thickness of adhesives. You could use shim stock to create different thickness levels in the adhesives. The same clamps need to be used each time so the clamping pressure is the same. I think this should be the first test preformed. Once the optimum thickness has been determined for each adhesive, that thickness is used for the rest of the tests.

A freeze test would be easy to do.

Can you tell I'm getting excited about the tests?!?! :D
 
Boil it in hot water for a predetermined period of time, say a week. You may want to boil it for 6-8 hours each day, while you are around for safety. Heat accellerates aging processes. Heat also causes the epoxy to break down. Do all the testing at the same temperature to get consistent results.
 
For my test I have tubes of the following:

Test stuff is in 2 classes. The first is hard epoxies
2 ton Devcon
off-brand 30 minute epoxy
Loctite e-120HP
Acraglas Gel
JB Weld
couple of 'super glues' (Don't have rubber toughened).
Gorilla Glue


The second is flexible:
GE Best Latex adhesive
Loctite Extreme Repair
Loctite ux05


Why flexible? When bonding organic and steel it might be better to have a flexible adhesive. Since we are not looking to hold things together (peening, bolts, etc are for that), we want something that holds together better than holds on. If you know what I mean. Interestingly the flexible types seem to be more heat tolerant (according to specs). We'll see.

Boil in water to age? Good Idea.

Steve

PS I'm also interested in appearance. So I plan on making small 'cavities' in the wood, but still squeeze to flush. It might be interesting to know that some epoxy holds real well if it's a consisten .010" thick, but not any use to me. So I want the wood flush around the edges, but will have a cavity so the 'glue' can work.
 
Steve or Tracy, I have one packet of West System here at home. It is about sufficient for one handle. I would be happy to send it to you.

If you need more than that, the marine supply where I got it is only a mile away. I could get some more and send it if you'd like.

Let me know. Thanks!
 
I pay $14.50 for a 1/2 pint unit if system 3 t88 at a local woodworking supply. I never mail ordered it. Not sure if you'd have to pay a haz mat charge.
I get the standard system 3 in the 3 gallon unit tbecause I also build boats.
The t 88 is super think. The stirrer will stand up in the mixing cup eliminatig the need for bulker fillers. The 2 parts pour like heinz ketsup. I've broke tongue depressors stirring it.
Most epoxy comes too thin IMO. For a filler for standard epoxy I love milled glass fiber. It's fiberglass milled down smaller than sawdust but heavier than flour. I have a tub and can send samples for anybody that wants to try it. I'll be careful sending a white powder in the mail you can be assured.
 
I have on hand to test:
Accra Glass
JB Weld
Devcon 2 ton regular and 'fast'
Gorilla glue

I need shafting epoxy, T88 System 3 and the flexible ones Steve mentions. I don't have any problem buying some or all of these but if some one has a little to send, that'd be OK too.

Mike I don't have a vacuum chamber to test with if you want a crack at that.

Chuck, you are really stepping up here and I appreciate it. I'm not sure I can see any difference between gluing up stainless or 15n20 so count on that. If you have stabilized wood, I'll use that and that will be a good test to see how that weathers a few dishwashings.


For testing methodology

A few cycles in and out of the freezer for expansion, contraction.
10 dishwashings or as many as my wife will allow to see how it handles heat and hot water.
A couple hammer blows on the flat of the handle front and back to see how it holds.
Gripping the scale with a channel lock pliars and trying to twist it off for tensile strength.
The wood would (hehe) be glued a bit off center so it could be tapped on the edge for shear strength to see if it will pop off.

Any other ideas? Keep in mind, I'm not Underwriters Lab and this isn't going to be a full time job. :rolleyes:
 
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