Good information about surface prep for adhesion.

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Ryan J

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Jul 14, 2014
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I came across this video just now that I thought you guys might find informative. Great information for epoxy surface preperation. The water break test at around 5 minutes in is also something I'd never heard of. I know a lot you are very scientific, as am I, on your approach to getting the most out of every step of the knife making process. Anyway, here's the link. https://youtu.be/HiL6uPNlqRw
Apparently, the best substance (relatively safe substance) for removing all oil residue from a surface to prepare it for adhesion is plain old comet. Better even than 99.9 percent pure acetone. It's all in the video.

A thread on here I read the other day lead to this research. Glue Wars 2. Also very informative. Surface prep was discussed there as well. If you haven't read it here's a link to the thread: http://www.bladeforums.com/forums/showthread.php/337504-Glue-Wars-2
Hope you enjoy
 
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Awesome video, very informative and it was interesting to learn the mechanics of why some techniques work while others fail. Best part for me was the titanium streaks on ceramic, we have a sink in a small bathroom that's a mess of them from the clips on my crk's, and it drives my wife crazy! Tried cleaning it before to no avail, but I'm gonna give this a shot soon...
 
Interesting how comet works and worked where some other substances failed. Would bleach then be a good cleaner to prep knife handles?
 
I just purchased this new epoxy made specifically for knife handles. Still in the mail so I have no experience, but a check of their website shows a somewhat backward explanation than what is often mentioned here.
http://bladebond.com/Technical data.html
It says that you clean the blade first with acetone or denatured alcohol twice and then you grind the blade to increase surface area, not the other way around.
 
All of my research has turned up the same. Mechanical abrasion, usually the preferred method is sandblasting, then blow off with clean air and apply epoxy. Everything else compromised the adhesion, to one degree or another, with pure denatured alcohol being the least to compromise. The engineer I spoke with at 3M, where I get my top secret weapon for high strength, was one of the first people to tell me not to use solvents.

Funny you should mention BladeBond right now. I've been testing their stuff for several weeks, and so far I'm impressed. BladeBond Ultra has exactly the thick consistency I prefer, and in the bashing and beating tests I've done has been most impressive. It's going to replace my normal epoxy for standard handles, which at the moment is West Systems G-Flex. G-Flex performs quite well, but this stuff is at least as good, and an order of magnitude less messy, which means I waste less. Seems like a lame complaint of the stuff, but I find it way too runny. Great for patching my Kevlar canoe, though. Neither of them replace my secret weapon, but BladeBond Ultra will probably be used more than anything in my shop, as it is literally fifteen times less expensive than the secret weapon!!!
 
Thanks for posting that, I'd like to try bladebond but have been waiting to hear some "field" results. Does it have any color to it when cured?
 
I don't notice any color to it, as my seams are pretty tight, but when mixed it's a milky white. No more or less obtrusive than any of the other epoxies I've tried.
 
The water break test has been used for a long time by electroplaters.
Alcohol is most definitely a solvent.
 
eyeeatingfish said:
Would bleach then be a good cleaner to prep knife handles?
Click to expand...

Yikes... that sounds like a very bad idea.

What you need to keep in mind is, there are many different "kinds" of "bleach". And they are all a lot more , shall we say, interesting, than you might suspect. The stuff in Comet is not the same as the stuff in Clorox.

What they all have in common is, they're "oxidizers". Short answer, combined with normal atmosphere and steel, they can rust it today. Not tomorrow, to-freaking-day. :)

Sodium hypochlorite (clorox/household liquid bleach for laundry, disinfecting, etc) is a fairly unstable and fairly-reactive compound. That's why it has to be watered-down so much to be safe to use around the home. (Usually about 3%... municipal water-treatment facilities and swimming pools usually buy it at no more than 15%, and then dilute even further. Full disclosure: I'm not a trained chemist; I only know this because I used to work in a plant that got in tanker-loads of "liquid chlorine bleach" at 20-25% weekly, and then immediately diluted it way down for industrial purposes.)

The easiest way to "patina", "age" and yes, "pit" almost any hardened steel (if you want it to look like it's been in use and experienced environmental corrosion for a few decades), is to leave it in a jar of Clorox for few hours. Go ahead, try it. ;)

I won't even guess how badly that would react with/foul up whatever adhesive we might use if it wasn't fully cleaned away and neutralized, but the short answer is this: I'm pretty sure Clorox would be a terrible idea for adhesive/tang prep.
 
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