Eooxy Failure-Help Please

One new addition:

In my experience, if (unmixed/ uncured) epoxy reaches freezing tempatures, it is junk.
 
The freezing thing is an excellent point! Prior to having a heated shop, I was constantly throwing out all sorts of adhesives, finishes, etc. that had gotten "frost bitten". My next phase was an old mini fridge, with a light bulb inside to keep things from freezing, but it quickly became "stuffed". There is just so much stuff in a knifemaker's shop that freezing will ruin, that I can't image not having a heated shop.....at least not here in Montana!
 
My shop is wood heated, so it is impractical to keep it heated all the time...so,

I have full sized (old and dead) fridge for the same reason. The freezer portion has a low watt bulb in it to protect stuff from freezing...the fridge portion serves as a "hotbox" to cure my slabs and scales and has a higher wattage bulb in it.

I store the bulk of my resins in the house and carry it out he shop after warming up.
 
bladsmth said:
Another trick is to make a mechanical spacer as part of the joint.Some makers have used a piece of 4 oz. polyester or fiberglass. Used with a West System epoxy it makes a super strong joint.

Mix them with a scale if you want to make sure the ratio is really exact.

Stacy
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Stacy,

I don't understand the part about using 4oz. polyester or fiberglass... or maybe I'm being dim. Would you be willing to yap about it a little more, please?

Brownell's AcraGlass instructions define the correct mixture of resin/catalyst as 4:1 by volume, specifically noting the wrong mix will result from measuring by weight. A person could weigh the proportional volumes and get a corresponding weight proportion... that could be helpful for small quantity uses where a person needs less than 1t. : 1/4t., or 1/2t. : 1/8t.

Mike
 
Check Jantz Supply, I think they are now carrying "Mini Corbys" Tehy are not in my catalogue but some one told me they are .125.
 
Acetone is NOT a good cleaner as the final step in a glue up. It leaves an oily residue that will weaken an adhesive bond. I use alcohol as a final cleaner. If it's good enough for my liver, it's good enough to clean a knife handle.

Surface preparation may be the single biggest factor affecting adhesive success. "Crummy" glues significantly outlasted "best of class" glues when they had a good surface prep vs. a bad one with the best of the glues.

Sheering force resistance is generally the Archilles heel of most adhesives we use. A knife dropped at just the right angle will pop a scale off easily if it is not pinned.

Ed maybe Brownell's best sales man. Acra glass is fantastic adhesive and is perfect for glueing up knives. When I finished the glue wars testing, I threw away $50 in unopened, brand new Devcon II packages it did so poorly.

As for Corby's, I will have two more sizes soon, a mini and a micro. They are just getting finished up at the machinists now. I'll post something in the for sale. I'm excited about these. I am also going to have step drill bits made to match all of the corbys I carry.
 
The poly/glass cloth is placed on the scale which has had resin spread on it. The tang has a light coat of resin on it ,too. The fabric provides a very thin, but even space between the scale and the tang. You can clamp the heck out of it and it won't go to resin starvation.The joint looks like a regular glue joint when the resin is cured and sanded. Works particularly well with tinted resin.

Stacy
 
bladsmth said:
Grinding a slight hollow in the tang and scale will make a reservoir of epoxy that will prevent joint starvation.Drilling the handle like swiss cheese does a similar function, making "epoxy rivets".
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Just make sure the void spaces are small (ie. lots of small holes in the tangs, or multiple small hollows in the scale). Epoxy shrinks when it dries, and if you have a large volume of it there will be a residual tensile stress on the bonding surfaces. If you have a lot of void space, a solid filler (like microspheres) will reduce shrinkage.
 
For the past year I've been using 2 part epoxy from Golfsmith. Acraglas and others might be better, but as far as 2 part epoxies go, epoxies designed for golf club construction are designed to withstand shear forces. I'm looking into another epoxy used in the aerocraft industry that is being used more and more by golf club builders, called Epibond. Unlike other epoxies, it supposedly will not break down at high temperatures (like in the trunk of your car in summer).
 
bladsmth said:
The poly/glass cloth is placed on the scale which has had resin spread on it. The tang has a light coat of resin on it ,too. The fabric provides a very thin, but even space between the scale and the tang. You can clamp the heck out of it and it won't go to resin starvation.The joint looks like a regular glue joint when the resin is cured and sanded. Works particularly well with tinted resin.

Stacy
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I'm clear now, Stacy... thank you.

Mike
 
I agree with Tracy on not using acetone to clean. While acetone Will dissolve most any oil or wax, it dries so quickly that it leaves whatever is dissolved behind, making a nice uniform coating of whatever is dissolved in it...
What ever you degrease with has to be used in sufficient quantity to not only dissolve oils, but also flush the area clean of the resultant solvent/oil mixture.
This is akin to rinsing the soap off dishes - you can't rinse with soapy water...
Grain alcohol is great for this, and isn't too toxic.
If you can get 99% Isopropanol, it will work too, but the 70% stuff will Not.
 
fod said:
Mickley has 1/4" shoulder (the smallest I know of) corbys:
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Yeah I'll probably just get some of those. I need a couple for a rehandle project anyway.
tmickley said:
As for Corby's, I will have two more sizes soon, a mini and a micro. They are just getting finished up at the machinists now. I'll post something in the for sale. I'm excited about these. I am also going to have step drill bits made to match all of the corbys I carry.
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Aha! Now we're talking. Keep us posted, Tracy!!
 
tmickley said:
As for Corby's, I will have two more sizes soon, a mini and a micro. They are just getting finished up at the machinists now. I'll post something in the for sale. I'm excited about these. I am also going to have step drill bits made to match all of the corbys I carry.
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Geeeezzz Tracey whats the hold up, it has been over a month since we talked about those. Just kidding. :) That is great news though, can't wait to see them. After talking to you about them I tried a few from Jantz, did not really like them to much.
 
tmickley said:
Acetone is NOT a good cleaner as the final step in a glue up. It leaves an oily residue that will weaken an adhesive bond. I use alcohol as a final cleaner. If it's good enough for my liver, it's good enough to clean a knife handle.

Surface preparation may be the single biggest factor affecting adhesive success. "Crummy" glues significantly outlasted "best of class" glues when they had a good surface prep vs. a bad one with the best of the glues.
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Tracy,

I'm wondering if you know how electrical contact spray works as a metal cleaner. It does not have oils in it and is used in a flushing manner... or, that is the way I've used it for surface prep for both gluing and damascus etching?

Another thing... are oils heavier than acetone? Like acetone would float on oil? I'm wondering if a bath in acetone would clean oil off and drop them to the bottom of the pan.

Mike
 
something that I have not seen mentioned here or else where on the glue wars . I found that Devcon awhile back changed there product some . There is the 2 ton clear industrial strength , mfg. # 14310 . This is different from the stuff the hardware stores sell . The 14310 carries a fire hazard material label where as the hardware store stuff does not and is 1/2 the cost and is junk IMO .
 
Mike Krall said:
Another thing... are oils heavier than acetone? Like acetone would float on oil? I'm wondering if a bath in acetone would clean oil off and drop them to the bottom of the pan.
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I think you would just end up with a tank full of gooey acetone and a similarly-gooey blade. I suspect the acetone would "mix" with the oil and not separate or precipitate as you would hope. I could be wrong, though.

The good thing about acetone is, it's an excellent solvent. That is, it dissolves many things very readily. It also happens to be pretty volatile (it evaporates quickly at room temperature), and can leave behind some of the "goo" it just dissolved. I use acetone on a cotton shop-rag to clean off fresh epoxy from a ricasso or tang, but that's about it. Even then, I use a "new" part of the rag and fresh acetone every couple passes, and finish off with either alcohol or dish-soap/water.

Keep in mind the MSDS sheet on acetone:

ACETONE
Synonyms: Dimethylketone; 2-propanone; dimethylketal
Chemical Formula: (CH3)2CO

Health Rating: 2 - Moderate
Flammability Rating: 3 - Severe (Flammable)
Reactivity Rating: 0 - None
Contact Rating: 3 - Severe
Lab Protective Equip: GOGGLES & SHIELD; LAB COAT & APRON; VENT HOOD; PROPER GLOVES; CLASS B EXTINGUISHER
Storage Color Code: Red (Flammable)
 
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I use acetone but only when 90% Isopropol(sp?) alcohol doesn't clean things up. Acetone is pretty toxic stuff as far as I am concerned. Fitz can jump in here any time and tell us all the science of the stuff. It dissolves nearly everything. The problem is it soaks right into your skin, carrying what ever it dissolved right along with it. I try to always wear gloves when using it. Here is a test. Wipe on glass and let it dry. Do the same with 90% rubbing alcohol. See the oily residue acetone leaves. Alcohol just leaves with you with a hangover.

Proper surface prep is more important than the glue - or at least as iimportant. In doing research during the glue wars tests, I found every manufacture used standard metal coupon blanks that had all been sand blasted for testing. These are companies with a very high motivation for the absolute best outcome of their adhesive. They all used sand blasted coupons for their tests for bonding to metal.

If anyone has ever seen the years old knife making video done by Ron Lovelass, he talked about sandblasting his knife tangs. He called a sandblasted tang something like surgically sterile prepared surface or something like that. It isn't of course but he really thought it was important.
 
When I was first playing with knives in high school, before the internet or I know there were knifemaking books out there I had a couple handles shear off like yours, even had a couple of full tangs flex enough even with pins glued in to break the bond.

Now I don't consider epoxy anything but a seal. On pined knives I pien them, it doesn't take much to upset the ends and they look like pins when ground flush. Or loveless bolts. A big thing is I do mostly hidden tange knives, which when done rite I believe are stronger than full tange. I use accureglass just to be sure, but even with out epoxy the handles wouldn't come off. If nothing else steel and wood have differant expansion and contraction rates due to temp.
 
Thanks for all the help with my question re. epoxy.

I have decided to go with Locktite E-120HP. The irony is I had some on hand but thought it was only good for non-porous material. There seems to be a date on the stuff I have which I bought 3 +/- years ago. The date is 2008/08. I wonder if this is an expiration date?? Anyone know?? Just to be safe I will order frersh stuff from McMaster Carr.

Again-Thanks for the help I will visit often.

John in Wyoming
 
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