Help with using cyanoacrylate finishing wood

A

Alfazulu

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Mar 24, 2016
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Hey guys, I recently tried using some cyanoacrylate (super glue) to fill in the grain on a piece of cocobolo. I am wondering if I'm doing this correctly. Here's what I did. I rubbed a single coat on the entire handle (sanded to 800grit before the CA glue), let it dry about 2 minutes. Then, I went back to 400grit and progressively sanded up to 1200 then buffed. It came out really nice and glossy with no more grain. However, there are (barely) noticeable places where I sanded through the CA glue. So, my question is do you guys usually apply several coats of CA? If so, how many? Do you just apply several at once, or one coat, then sand, then another, or what? Do you oil the wood before CA? Finally, to what grit do you sand before putting on the CA? I think I'll go back and do another coat or two depending on what you guys say, but I'm really happy with the results. The only thing I'm not LOVING is that since I didn't oil the wood before the CA, fearing it would not stick after oil, the wood is lighter with less red tones than I had wanted.

And since a thread is so much better with pics, I'll put a few below. The one in question is the Cocobolo handled blade. Pay no attention to the micarta knife. Also, to those that recommended that I thin out/better contour these two knives in my other thread, thank you. I took your advice and they feel much better, despite me THINKING that they already felt perfect. Someone in particular told me to make them egg shaped in profile. That's what I did, and I love it. So, whoever said that was spot on.

Thanks again for all the help!

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I'm no expert at superglue finishing, but I've not had my best success with rosewood family woods. Since they are naturally so oily and dense, I've found that the glue penetrates very little and is quite easy to sand through. I have had the same issues as you, finishing by spot application of glue to sanded-through areas, then light sanding and buffing again.

Although it's true that CA finish sits on the surface mostly, the fact that it's bonded onto and soaked into the wood surface makes it better than other clear coating methods. I suspect, although I've not yet tried it, that wiping a cocobolo or blackwood handle down first with acetone, and then CA, would help the glue bond and penetrate a little more. Of course, then you'd lose more color.
 
I don't recommend CA as a finish on any oily wood ... like cocobolo.


A superglue finish is IN the wood, not On it. You flood the handle with thin CA, then let is partly set. You sand it all away until you are down to bare wood ( 400 grit is good). Some of the CA has filled the pores and soaked into the wood surface, thus slightly plasticizing it. You repeat this several times, removing the CA from the surface every time. Bruce bump uses de-bonder as a rubbing agent to thin the CA and work it into the wood before each sanding. On the last soak, you sand off the CA and then go up the grits to 2000 or higher. A light buff either on a clean wheel with a tad of matchless white polish .. of just a hand buff with a clean cotton cloth ... will make it shine like glass.
 
Although I'm not an expert knife maker, I've used CA finishes quite a bit on other hobbies. I've done it two different ways, the first way is pretty much what Stacy said and is my preferred method, Depending on the wood, I actually start the first flood at 120 grit, then sand, flood again, sand 180, flood, sand 220, etc, etc. you can stop flooding around 320 or 400, but keep sanding up to your final grit and the finish will be great.

The other method that I have seen and tried but don't really care for is taking the sanding all the way to final grit, then start adding layers, we're taking about several layers, maybe 20 coats, between layers lightly smooth out any bumps in the CA. At the end you still need to lightly sand it out but be very careful to not cut through! When done properly it's like glass, but it can be tricky this way.

CA Tip: The fumes are terrible and dangerous, if you have to work inside use your stove vent hood if you have one, suck those fumes right outside! just be sure to put a sheet of newspaper on the stove first, your significant other won't like drops of superglue on the cook top!
 
As a newbie, I read these threads with interest, I've read the Bruce Bump thread and a bunch of others but still not clear on others experience.

Do y'all prefer to flood CA, wet sand, leave slurry to dry, resand, and repeat? Or flood, let dry mostly, sand, then repeat? Wiping off residual dust in-between repeats, right?

For those tried both ways or even other ways, what difference did you see in the final finish? Thanks!
 
I thin my CA with xylene, seams to work real good, Stinky but good.
 
Just food for thought here.

There is a slightly different CA glue formulated specifically for wood finishing.
It has a slower cure and is used primarily on woodturning projects where it is applied while the piece is still on the lathe.
This method involves building up multiple coats followed by polishing the dried finish.

Woodcraft sells a kit that is used by the pen turners.


This video shows a pen turner using the kit. I would imagine the process could be adapted for knife handles.
[video=youtube;9UZLZy2v0r0]https://www.youtube.com/watch?v=9UZLZy2v0r0[/video]
 
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Mark,
I have that type, and use it on pens and other turnings. On those items, the acrylic resin is built up and polished to put a coating on the wood.

On knife handles, this type of coating finish won't last long in use. You want to impregnate the surface with the acrylic and sand back to the wood. This will completely seal the wood surface, and make it take a great polish. It is more like working stabilized wod than applying a finish.
 
Super glue works great for woods with an open pore structure, things like Purple Heart, Wenge, Bocote and figured oak.
 
Thanks for all the awesome answers, guys. It looks like I'll sand off the single layer of CA. I think it was still worthwhile just to fill all the tiny checks in the wood.
 
ive done both. filling open pores and a nice flat surface that does not pick up any buffer compound. the many layers built up makes the wood look as if under glass but i only do that finish on razor handles. i too jsut dont thing it woudl hold up on the avg knife handle
 
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