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-   -   Testing for the ultimate adhesive (http://www.knifenetwork.com/forum/showthread.php?t=27463)

tmickley 03-14-2005 07:57 PM

After 1 cycle of heat at one hours at 150F, then freezing, then heat for 1 hour at 175, then freezing, we have two more failures tonight.
The 3M spray adhesive (held out way longer than I ever thought it could) and the rubberized super glue. I think the rubberized super glue holds better at room temp, at freezer temp it seemed to be quite a bit harder at freezer temp and it just seemed to 'shatter off' when tapped. The tap is 3 solid whacks with the big hammer on the edge of the wood trying to shear it off the metal. The remaining adhesives are holding much better than I thought they would with the whacks they are getting. I'm going to do one more heat, freeze and whack cycle and then move on to some other kind of destructive test.

SteveS 03-14-2005 08:24 PM

OK Just finished the dish washer test - no easy failures. My current samples (sorry if it's getting confusing, but deal with it :) )

ATS-34 60HRC cleaned with Simple Green/brake cleaner
1. Loctite Extrem
2. E-120HP
3. Acra Glas
4. West Systems (failed)
5. U-05fl
6. DEVCON (failed)
7. JB Weld (Failed)
8. 2nd West Systems (failed)

Redo ATS-34 60hrc no cleaning (freshly abraded with 50 grit)
6. DEVCON
7. JB Weld (failed after dishwasher)
8. Gorilla

Mildsteel test: Simple Green/brake cleaner
9. E-120HP
10. JB Weld

Again after the redo and the dishwasher test everything is still holding but the JB Weld/simple green combination.

This is VERY interesting to me. JBWeld on stainless cleaned with Simple Green/brake cleaner failed right away. JBWeld on stainless that was not cleaned is just fine. JBWeld on mild steel cleaned with simple green/brake cleaner failed.

This tells me directly that there is a problem with the cleaning method. I've never had a problem with brake cleaner, but never used Simple Green before. I had a number of failures that shouldn't have been (this test and the one before) all of them I used simple green to de-grease.

Does that tell you something!!!!????

Steve

Texasjack, thanks for the information that is extremely useful.

fitzo 03-14-2005 08:34 PM

This is interesting, Steve. Simple Green is touted by the manufacturer as leaving "no residues". That and it's environmentally-friendly attributes are considered its selling points. I used it for years to clean my motorcycle that was loaded with chrome, and I never saw that dullness of soap film. On the other hand, I have unsoftened Lake Michigan water, which has enough minerals dissolved in it to make concrete, and it rinses soaps off wonderfully. Out of curiosity, do you use softened water to rinse the soap off, or is it hard water?

Thanks for the effort, guys! Steve, I feel bad that I recommended the Simple Green, and apologize if I have wasted your time and effort.

tmickley 03-14-2005 09:48 PM

Steve, the only cleaner I use is rubbing alchohol and that is rare. I only use cleaner (alcohol) when I can't give the surface a fresh grind to clean off anything stuck on there. I figure there isn't a much cleaner surface than a freshly ground piece of metal.

I glued up a couple more things today. One I used was called PC-7, a 2 part paste epoxy. It comes in a little cans like 1/2 pints of paint or that wood putty used to come in. The colors look like and mix up to the color of JB Weld but with the thickness of plumbers putty except it is a lot tackier. This stuff is very thick and looks like it would go on like laying a welding bead. I knew right away it was not appropriate for handles or even sealing bolsters since it is too thick and would not squeeze out. It is very interesting stuff and I was immediately looking around for *something* to use it on. I settled for glueing up a few test pieces of metal, 1 set sand blasted, 1 set roughed up with fresh 36 grit, 1 set just as it came. I hope to test which surface prep will provide more tooth, the sand blasted or the 36 grit, the plain will give me some idea to compare to. When you need to epoxy something together with a mechanical lock that is the consistancy of thick toothpaste, this is the stuff. If epoxy can be cool, this is cool beans. Won't work worth a #### for knives, but it looks fun to use on something.

Omega 03-14-2005 09:56 PM

ive been reading this thread for awhile now and i just cant see jb weld every failing, i used it to fix a carbarator and its still holding. it has to be the cleaning agent


bill

SteveS 03-14-2005 10:45 PM

Bingo - the acraglas popped off. Yup that was washed with Simple Green. The only things that held are U-05FL, e-120hp, and xtreme.

Don't feel bad Fitzo. Who would have known? It might not be the simple green, exactly. But all my results point to it.

Dang, but I did go thru a lot.

I'm sitting here looking at this bar, hammering away on the pieces set without cleaner using the angle iron sans JB Weld. This is very different results.

I think now I'm going to have to grind everything off and start a-fresh.

Still, I hope we all learned something here. Something valuable. And that my friend Fitzo is worth the effort.

Fitzo, I used the RO water from my home filter system. Most of the just is gone. It's still not distilled, but close.

Tracy, I like the idea of straight from the grinder, but that's not always practical for me. Hmmmm, must be an answer.

Steve

justice 03-15-2005 12:25 AM

i may be wrong but i would think that acetone is the best thing for degresing and cleaning the surface to be glued.
dish soap and hot water might be good. dish soap gets some realy greasy stuff clean.

but i think grinding the surface or sanding then a fast light wipe down with some alcohol or acetone is the best way.

sometimes i just scratch the surface up with a file in a random patern insted of grinding/sanding it. sanding/grinding seems to leave a uniform patern. and i think that a random one might work better

or how about drilling holes half way though or all the way through(plus normal ruffing upand cleaning) the metal to give the epoxy more surface area to grab. mabey even taping these holes so the epoxy forms perminent screws inbetween the two glued surfaces.

just some thaughts.
keep up the good work guys!! every day im chomping at the bit for more info from this thred
...justin

tmickley 03-16-2005 04:34 PM

http://www.mickleyknives.com/assets/.../onebroken.jpg
One broken to failure piece, one not yet tested. Three of these were constructed using PC-7 epoxy (which is amazing stuff) to test what affect (or is that effect? I can never keep those two straight) surface preparation has on a joint quality. One set had no surface prep, one was sand blasted and another was roughed up using a fresh, sharp 36 grit belt.

http://www.mickleyknives.com/assets/...oadtesting.jpg
Here you see the load test. I added 25lb bags of lead shot. Here is a picture at 50lbs where the metal is actually bending under the load and the joint is still holding strong. The size of this joint is maybe 1&1/2" square. I was really impressed with this PC-7 stuff. Maybe all the others would have held just as well. I may do a couple more tests to see but I was still impressed. All three held 75lbs, all three failed as I added another 25lb bag so I never was able to accurately measure, by weight, how much each surface held but we can still draw some valid conclusions I think.

http://www.mickleyknives.com/assets/...oadresults.jpg

The joint to the left is 36 grit, the middle sand blasted surfaces and to the right no surface prep at all. Starting from right note one piece ended up with most of the epoxy and the other piece had maybe 50% of the surface with epoxy residue. In all three cases, the epoxy failed, not the material, but in the test pair on the right, the adhesion partially failed by not sticking well to the metal. The left pair shows fairly even epoxy failure with 10% or so adhesion failure. The center test shows very even expoxy failure with no adhesion failure visible. The residue coverage was very even on both pieces. The conclusion we can draw is that sand blasting a surface is clearly the best method of surface preparation followed closely by a good, even ?scratched up? surface from a new, sharp 36 grit belt. I?ve been using a 36 grit belt but going forward I will be using the sand blaster to surface prep any where I can for better adhesion performance.

McAhron 03-16-2005 10:27 PM

A good way to check for residues is to take the simple green or any other cleaners and mix it according to the instructions and spray a piece of cleaned glass,wait for it to dry and look at it from an angle to see if there is residue.I have tried cleaning windows with simple green and i can tell you it leaves a residue that has to be be polished off with a dry cloth afterwards ,or if left on its own streaks your windows.Acetone isnt good for surface preperation either because it is common for the acetone to have some levels of varnish and other impurities such as kerosene.Alcohol if its the 99.99 stuff works very well but many of the ones sold are only around 70%.I would have to say i think your both right that the best preperation is newly abraded metal that hasnt even had time to oxidize.I realy appreciate folks like you two who take time out of their busy schedules to benifit all of us.Thank you and i look forward to the final results.

p.s no pine rosin? :)

peregrine 03-17-2005 08:10 AM

Not to muddy the water but...
 
This info is great! Just a thought, after the tests are complete, I am now wondering how the holding power of silver solder would fair similarly (in your joint steel on steel tests), since "you are only as strong as your weakest link."
Just a thought.
Roger

SteveS 03-17-2005 12:19 PM

Tracy,

I was thinking about the forces in your last test. That PC-7 stuff is amazing!

Steve

Frank J Warner 03-17-2005 01:09 PM

This is a great thread and experiment! Hats off to Steve and Tracy for all the hard work and expense.

Two points, if I may:

First, any two surfaces you glue together must have sufficient tooth. Often, an 80-grit swipe isn't enough. It's helpful to put gouges and nicks in unobtrusive areas using whatever methods work best (edge of a grinding wheel, gouges, etc.).

Second, I have not seen a commercial degreaser worth its weight in water. Simple Green and brake cleaner are okay but ALWAYS leave an oily residue behind.

I use a deglazing solvent sold to print shops. They use it to recondition the surfaces of printing blankets and ink rollers on printing presses, among other things. Basically, it's pure trichloroethylene, and will suck the oils right out of your skin (you won't leave fingerprints!), and leaves absolutely no residue behind. It's available from A. B. Dick for around $40 per gallon, part # 83-9-105533. Great stuff if you can find it.

-Frank

SteveS 03-17-2005 01:38 PM

Thanks Frank!

I was wondering where to get that stuff. The closest I could find is lectra-clean. The only chemical it lists is: tetrachloroethylene

I suppose 5 is better than 3. (hahahaha, heck if I know what difference it makes.)

When I get a chance I'm gonna clear off my test bar and start over using sand blasting.

Steve

PS I'm with you on the gouges. For an actual construction technique I believe a shallow hollow grind down center of the tang would work well. That way you'd have a few thousands for the epoxy to settle in.

Steve

TexasJack 03-17-2005 05:28 PM

Trichloroethylene is listed as an ozone depleting chemical (like Freon) by the USEPA and it's manufacture and uses are tightly restricted. It's also a listed Hazardous Air Pollutant. Like all chlorinated solvents, it doesn't decompose well. It can hang around the shop longer than you think and increase the exposure risk.

A good alternative is acetone. It's cheap, has low toxicity, and will dissolve just about any hydrocarbons - including epoxy. It is flammable, so some care is needed.

One thing to watch with degreasing - as the solvent volatizes, the surface gets cold. You can get condensation on the blade that will then interfere with the glue.

Stuff like Simple Green and citrus solvents work good for some applications, but they are all surfactants and will tend to leave some residue.

DaveL 03-19-2005 11:23 AM

Like many, I am sure there are surprises in store for us. I have never been disapointed with Acra-glas but when it "popped off" it was a total surprise to me. I have read some of the same about JB weld too. I have used Loctite 330 with good success and all of this is to say that when the ultimate glue shows up, will you do a compete listing? I think we all want to know the best, the circumstances, if any, that caused failure for the other favorites and general recomendations if you have them. This is the most awesome thread running anywhere!


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