• July 2025 Turning Challenge: Turn a Multi-axis Weed Pot! (click here for details)
  • Congratulations to Kent Reisdorph for "Sugarberry Bowl" being selected as Turning of the Week for July 14, 2025 (click here for details)
  • Welcome new registering member. Your username must be your real First and Last name (for example: John Doe). "Screen names" and "handles" are not allowed and your registration will be deleted if you don't use your real name. Also, do not use all caps nor all lower case.

Flexible CA Glue Review

Joined
Jan 14, 2020
Messages
317
Likes
122
Location
Austin, TX
Hi, I started turning rings a bit ago. Part of, or perhaps most of the process is in figuring out how I should finish them. I turned both test cases out of a piece of mesquite I had in the trash ( I love tiny projects ). As a quick aside, I'll mention that I turned another ring out of bacote and it looked pretty sweet, but that wood, I guess, is quite brittle and it didn't last too long.
The initial ring I turned I put on the same CA finish process that I use on pens. I use GluBoost CA Glue with matching accelerator. I start with about 4 coats of thin, then move to medium for about 8 or 9 coats. I then sand with those little square things that go up to 1 million grit. However, I didn't do that on these tests because I didn't really care how it looked so much as if it can survive.
My premise is that if I can wear a ring and it survives than it will survive anyone because I am an absolute brute. If I was wearing a tux ( an absurd premise I know ) and I got an urge I'd go right into the shop wearing it cuz I'm just that oblivious. So this is the ultimate ring finish test the way I see it.
So I wore this ring for about 4 days. During this time I did one day of yard work and that's about it. ( not very brutish admittedly, but it was plenty ). At the end of that weekend the ring looked like it does in these pics ( the first two ). Basically ruined.

I had heard about a "new" kind of CA that was mildly flexible, i.e. not as brittle, so I ordered some. In my research I read that it may even be a bit stronger than regular CA. I got the Mercury M20FT Flex ( thin ) and the matching accelerator. I didn't want to get both thin and medium cuz I"m cheap and didn't know if it would work.
I turned a new ring and put on 4 or 5 coats of the Flex CA thin. I don't remember why I stopped there, I guess it looked like it was building up well. Or perhaps I superglued my self to the drill press by accident. I don't remember.
I then donned the ring and have been wearing it for > 1 month. Still wearing it. And it has been through a LOT. As you can see from the pictures ( the second two ), not only is still fully intact, it still retains most of it's shine.
This strikes me as such a significant improvement that I feel compelled to write up this review. It is huge. I don't know what the down side of flex is, it's the same price as any name brand CA. And if you are using it for finish, given it requires so few coats it ends up being much cheaper. Pretty great stuff.

One question is, does one need a top coat finish. My initial thought was that you do because you may and most likely will get it wet. But then I thought about the fact that wooden bowls last for years getting soup slopped in them and then washed clean over and over. So perhaps it's not necessary. It's possible that, given the fairly thin nature of a ring, that the repeated exposure will weaken it and cause the ring to break. I don't know. That will be the next test.
 

Attachments

  • PXL_20250629_172036959.jpg
    PXL_20250629_172036959.jpg
    186.4 KB · Views: 30
  • PXL_20250629_172025126.jpg
    PXL_20250629_172025126.jpg
    173.8 KB · Views: 28
  • PXL_20250629_172120410.jpg
    PXL_20250629_172120410.jpg
    208.4 KB · Views: 28
  • PXL_20250629_172103017.jpg
    PXL_20250629_172103017.jpg
    207.6 KB · Views: 28
Interested in your results. Over a couple years ago period I turned a handful of rings and agree the most difficult part is the finish. I then wore the rings 24/7: showering, washing hands, doing shop work, digging, mechanical work, etc.

The first ones were finished with poly, if I recall they lasted about a week.

Then I tried epoxy and had very good results up to a month or two as I recall, but the epoxy process was very difficult (rotisserie etc).

The last several I used the standard CA glue like on pens, probably 10-12 coats. Even this was very difficult to apply because I could apply it over 80% of the ring (including top, both sides, and about half of the inside) but then when turning it to apply over the rest the joining glue line would show itself after a few weeks of water soaking etc.

Eventually I settled on the CA and stopped noting time etc. After a year or so of needing to replace the ring every few months I gave up and just bought a cheap silicone ring. I wore one for a year or two before experimenting with the wooden rings, and have now wore the current one for six months or more.

I’d love to turn and wear a wood ring if you perfect a finish process that lasts for years, but in the meantime have settled on silicone to protect my finger (my original gold band sits in a drawer now).
 
I'd be interested to hear how you applied the finish. I can get the inside and the outside but the sides are a mess. Here's my process.
I hot glue a flat piece to a waste block. Then I "hollow" the center. One that is sized correctly I apply the finish to the inside.
Then I take the sizing stick ( a metal rod with all the ring sizes on it creating a taper ). I put some masking tape around the area that is the size of the ring and jam it on there and mount it between centers.
I turn the ring to size then I apply the finish. The out side is easy but the sides are a mess cuz if I get too much then it builds up all unevenly.
I also don't like using the sizing stick. It's just not a very good hold. Seems like there aught to be a better way. I tried one of those expanding ones and it sucked. Wouldn't expand enough to get to the next size.
Anyway, I'll tell you how the finish holds after a couple years :), but I think you should try the flex ca I think you'll like it
 
Raif - I'll have to try the flex CA to see if it bonds better to itself.

I really like the idea of a wooden ring, but as mentioned after several experiments I've given up on it for a while: all because of finishing issues.

Attached is a pic of several rings. Some of them where the finish isn't as smooth and shiny are the epoxy finished ones. I think there might be more opportunity down the epoxy path given the strength it might add, but getting a good finish was problematic and I abandoned that.

About half in the picture are CA finished rings. Note the one standing and the slightly darker line around the inside of the ring, that is where the coats bond to themselves and where after a month or so I start getting water ingress and delamination. Maybe the flex CA will solve that issue?

My process: I've made all of mine so far out of white oak with the grain running across the ring, not perpendicular to it; I like the look that provides. I start by chucking a 6" or so piece of a little over 1" stock in a spindle turning orientation. Then turn to a dowel with dimension to equal the outside of the ring (I've found that for structural integrity and ascetics I need the ring to be ~0.1" thickness, and about 0.3" width). Next I hollow out the inside of the ring to my finger size using a micrometer with uniform sides going back to just shy of the 0.3" width and then getting thicker (kind of like a cone, you'll understand in another line or two). After the inside and outside are dimensioned, I cut the far side of the ring (0.3" from end) down through the 100mil ring thickness but not quite to the cone so there is still support. At this point I sand everything well using ~320grit if I recall.

Now for the finish. I apply several (8-10? more?) coats of CA to the ring and then wet polish up through the range of square foam micromesh pads used for pen turning. This finish application and polishing covers the complete outside of the ring, both sides, and ~half of the inside.

After finish is complete I reach in and part off the ring by extending the inside depth uniformly so that it widens that cone to meet the far side of the ring that was cut and finished. At this point I have a completed ring except that ~half of the inside doesn't have finish, and that far inside corner is sharp.

I then make a jamb chuck from the dowl, with a step to register the ring with <1/8" hold inside of the ring. Make the fit tight, and wax this jamb chuck to avoid problems from the CA you're about to apply. Then I reverse the ring and sand that inside edge that's sharp. Followed by applying a CA finish to the inside that was missed. I think I also applied more finish to the complete top of the ring as well. After polishing up I pop it off and am ready to go. Honestly it probably took as long to type this up as to make one once you get the process down. Certainly the turning is just a couple minutes, the finishing and polishing takes several more; but it's still pretty quick. The starting stock will yield several rings and they are quick so it's easiest to make more than one at a time (plus as mentioned my experience is they only last a month or so).

Not sure when I'll get around to it, but I look forward to trying the flex CA to see if that lasts better. Please let me know about your progress down this path as I'm interested in a good solution.

Thanks,
Ron
 

Attachments

  • Rings.jpg
    Rings.jpg
    223.5 KB · Views: 13
Interesting technique. I would be inclined to hollow a consistent inside size then essentially part it off leaving the edge unfinished. But if I understand correctly the issue is that the CA is not bonding to itself well and thus basically leaking.
What kind of CA do you use. I think when it comes to finishing not all CA is created the same. I haven't noticed the bonding issue, but I don't have as clear a line between the two applications as it happens basically at the bottom edge of the thin side.
When you say they only last a month, what happens? They start to get water damage? They break? The finish peels off?
I like your idea of using wax, perhaps that will reduce the difficulty getting my ring off the metal spindle I use to hold it.
As far as going down the path, I intend to keep wearing the one I got on till it ... comes off on it's own accord, so there's that. Then I also intend to experiment with just oil. In general I don't care much for high gloss or plastic-y look, so if I find they somehow survive without a top coat I may go that way.
One thing is for sure, no ring is worth trying to epoxy finish it. That just seems like it would be a real pain. Like you said it takes a hot minute to make the thing, if I had to spend hours on the finish I would go crazy.
I'll keep you posted!
Raif
 
The real test will be longevity, like 10 years from now. The longevity issue hit the journal a few years ago when museums saw that items were falling apart that had CA used in a restoration.

I have no idea why you would want a top coat, unless you want something with more UV protection. A hard coat of plastic hardly ever needs anything on top of it.
Some of these rings are giving as wedding rings @Raif Harik. Those might be the ones that need an epoxy finish.
 
Interesting, i did some testing with standard CA and found that it didnt really fail The darn wood did, it moved and pulled away from the CA. So this flexible variety is very interesting
 
When you say they only last a month, what happens? They start to get water damage? They break? The finish peels off?
I've had a couple break early on when doing mechanical work, but I don't think any broke after I established the minimum size requirements (100mil thick, 300mil wide) and started using either epoxy or CA for the finish instead of poly (these add some additional structural integrity I believe). Initially I started to notice some darkening on the sides (water ingress) which is why I developed the technique to ensure the sides were well coated (with my spindle orientation the sides are the only end grain). The last couple/few I changed out because of water ingress/CA delamination after a month or so.

The CA I used is StarBond, both thin and medium. I experimented a little with the accelerator as I *believe* that I might have better results if I don't use the accelerator...but that takes longer and I kind of lost track of monitoring if it really made a difference or not (I still think so but am not positive). When I get around to it I'll try the flexCA and let you know any results, please keep us appraised of your success as well :)
 
Just out of curiosity, is there a reason for not using the two-part metal bases that are offerred for sale?
Seems like that might solve the longevity issue - is there a reson to prefer all wood?
 
Just out of curiosity, is there a reason for not using the two-part metal bases that are offerred for sale?
Seems like that might solve the longevity issue - is there a reson to prefer all wood?
From my perspective a large part is to avoid losing a finger if I catch the ring. I leave my ring on when working on the lathe, around motors etc, and electrical work. Silicone or wood will break before my finger.
 
Just out of curiosity, is there a reason for not using the two-part metal bases that are offerred for sale?
Seems like that might solve the longevity issue - is there a reson to prefer all wood?
And from my perspective, I find rings to be too thick even with just wood so using the metal base would make it even thicker. I guess for clarity I say by thick I mean from the skin up. That's still not very clear. Whatever, those bases will make the ring too big :)
 
@Ron Solfest So now, many years later, I can give you the results of my ring's life. Well, actually it's only been a week or so :( . This morning my ring ended. The finish is still rocking but the ring is no longer ringing. That said I'm still wearing it, it is only broken in one place so it's still circular. So that's the unfortunate end to what was planned as a multi decade study of finishes.
Of course I'll turn another. I started a thread to investigate wood characteristics. Maybe my next ring will live longer.
Raif
 
So yesterday I went out to the shop and took a look at my Merc Flex CA bottle and the whole damn thing was freakin solidified. A brand new full bottle, only used once, and now it's bricked. Very frustrating. I've never had that happen before, much less this quickly. I last (and first) used it a month ago. I had the cap on and everything.
I don't know if this is a caveat of the flex ca or not. But it's pretty frustrating.
 
when I was in high school I carved a ring. Can’t remember the wood. Something relatively soft. It lasted for years before it broke. Still have the pieces somewhere.

I used linseed oil for the finish. Soaked it for several days in the stuff, so it was completely saturated. Maybe worth a try?
 
Back
Top