Possible chemical reaction when applying CA

[PilotC150]

I'm a new turner (just got my lathe at the beginning of January), and have recently started trying a CA finish. I've done about seven pens/pencils and a few other things. For the first handful I used Hut Crystal Coat (https://www.rockler.com/crystal-coat) which gives a really nice satin finish.

I've done a couple pens now with a CA finish and I absolutely love it! My process is:

• Turn blank (about 2000 rpm)
• sand wood up to 600 grit (1000 - 1500 rpm)
• One coat of Stick Fast thin CA (turn by hand)
• Multiple coats of Stick Fast medium CA (200-250 rpm)
• Sand with micromesh from 1500 to 12000 git (1000-1500 rpm)
• Polish and buff

I now know (from reading here today) that I should wait some time before polishing, and probably make a couple other changes to how I apply the finish. But for the pen I made yesterday, I got a beautiful, glassy finish on it. The problem I'm having is when I'm applying the first coat of thin CA. There appears to be some sort of chemical reaction between the CA and the paper towel I'm using and after only a few seconds there's a smoke or vapor of some sort coming off the paper towel. It doesn't happen while putting on the medium coats, though.

What could be causing this? And maybe just as importantly, what should I be using to apply the CA? Should I be using a different brand of CA? I got the Stick Fast from Rockler, in the lathe aisle, so I assumed that would work well enough. And for the pen I did yesterday it did a spectacular job, but I'm worried about the vapors coming off the glue.

 

[KenB259]

That's why most people, including , myself that apply with a paper towel use the blue ones. That reaction is very minimal with the blue towels.

 

[PilotC150]

That's why most people, including , myself that apply with a paper towel use the blue ones. That reaction is very minimal with the blue towels.

Well it's good to know it's not something crazy I'm doing wrong. I'll have to pick up some of the blue ones. I just happened to be out of them right now so I used my regular ones.

Thanks for the quick reply!

 

[jttheclockman]

First welcome to the site. You are asking the million dollar question that gets askes many times over. But to make it short yes CA will react to paper towels of any kind. Many people have gone to using various methods such a plastic baggies, foam, and other things. Need to do some searching here for many threads on finishing with CA. It will make your head spin. Good luck and stay safe.

 

[Dalecamino]

It is a normal reaction. The paper towel has some activator in it that causes the smoky vapor you're seeing. It gets really HOT. My medium CA does the same thing, but takes a little longer. Just let things cool down before going to the next coat. You're doing fine!

 

[mmayo]

Be sure the blue ones are blue with no greenish cast. The greenish ones are no bueno.

 

[wouldentu2?]

Try this, available wherever they sell kids art stuff. No reaction to CA, no absorption and lays it out smooth. 1100 rpm and only thin is what I use. Work back and forth till happy with coat or it just begins to drag. When I am done with a coat there is no CA on the foam.

 

[magpens]

Hi Chris !! . Warm welcome to IAP !!

You seem to be progressing at quite a rapid pace !! . Well done, and keep posting your work and your methods ! . All of us are still learning !!

 

[Fred Bruche]

What I have experienced is that certain woods (some ebonies for example) seem to activate the CA polymerization, and a faster reaction leads to more heat in a short amount of time, thus more smoke/vapors.

 

[JBidinger]

Be careful with that. I managed to get some pretty serious burns from thin CA kicking off on a paper towel that had become stuck to my fingers. :-(

It's good to know that the blue towels don't do it as much. I'll try that.

 

[Monty]

Be aware that not all blue towels will work. I used to by my towels at the Blue Box Store. A few years back they changed from the blue Scott towels to another brand. That brand would smoke when CA was applied. Since that time I make sure I only use Scott blue towels. Just recently I noticed that Scott has changed the texture of their blue towels. I have not had to buy any recently so I don't know if this change will affect the CA or not.

 

[target64]

Just a point to consider. You might want a metal trash can with lid, to dispose of your waste material.

 

[tomas]

My $0.02 worth. IMHO, there is no need for CA with acrylic blanks. However, I wet sand with Micro Mesh on all blanks. To apply CA, I have been using Brawny paper towels since I started 12 years ago. I have tried the craft foam but without much success. For my pens I use Abranet up through 600, I then wipe the blank with DNA (denatured alcohol) and then wet sand with MM up through all 9 grits. I get the MM with the foam backing and store them in a 16oz storage container full of water.

Tomas

 

[PilotC150]

My $0.02 worth. IMHO, there is no need for CA with acrylic blanks. However, I wet sand with Micro Mesh on all blanks. To apply CA, I have been using Brawny paper towels since I started 12 years ago. I have tried the craft foam but without much success. For my pens I use Abranet up through 600, I then wipe the blank with DNA (denatured alcohol) and then wet sand with MM up through all 9 grits. I get the MM with the foam backing and store them in a 16oz storage container full of water.

Tomas

For the record, the pen that I posted the picture of (in the first post) isn't acrylic. It's a dyed Box Elder burl. https://www.woodturnerscatalog.com/...abilized-Dyed-Box-Elder-Burl-Pen-Blanks?c=286

They're gorgeous blanks that look even better when they get the glossy finish from CA.

With acrylics, I don't use sandpaper or Abranet since they're pretty smooth straight from turning, but I do wet sand with MM up through grits to 12,000. I've only done a couple acrylics so far, but that's what I've done so far.

 

[papawsprettypens]

For the record, the pen that I posted the picture of (in the first post) isn't acrylic. It's a dyed Box Elder burl. https://www.woodturnerscatalog.com/...abilized-Dyed-Box-Elder-Burl-Pen-Blanks?c=286

They're gorgeous blanks that look even better when they get the glossy finish from CA.

With acrylics, I don't use sandpaper or Abranet since they're pretty smooth straight from turning, but I do wet sand with MM up through grits to 12,000. I've only done a couple acrylics so far, but that's what I've done so far.

I love the CA finish, but I've started having issues with customers complaining (and me replacing) that the finish is "cracking". Is anyone else having this issue. They are daily use pens that go from indoors to outdoors during the course of the day. I am now afraid of using the CA finish on my pens now. Anyone else having this issue? Or solution?

 

[penicillin]

I use craft foam, too. One ~ 9 x 12 inch (2 mm thick) sheet will do a lot of pens. I paid 88 cents a sheet at Walmart.

 

[randyrls]

Chris; What you are seeing is STEAM. Yep; when CA reacts quickly it can get so hot that water in the CA will flash into steam. The cellulose in paper towel causes it. It can burn you. As many have said, use craft foam. It goes by many names. It doesn't react with the CA and it is closed cell so CA will not come through the foam.

 

[JBidinger]

Try this, available wherever they sell kids art stuff. No reaction to CA, no absorption and lays it out smooth. 1100 rpm and only thin is what I use. Work back and forth till happy with coat or it just begins to drag. When I am done with a coat there is no CA on the foam.
View attachment 299506

I can confirm this stuff works great. After I had an incident with severely burned fingers from CA I have been looking for a different way to apply CA that works for me. The baggy over the finger didn't work well for me but using this craft foam is a lot like using a paper towel but without any of the smoke and absorbed CA.

 

[mmayo]

Please wear gloves when applying CA, I do too. I use quarts of CA yearly and get sellable objects. I never sand until after all the CA is applied and has cured. It doesn't crack ever.

I use a metal pail to hold all CA covered Blue Scott towels. Craft foam did not give me the results I needed. For the last several days I've been using 1/2" square blue towels to get finish in rings and not the mandrel. I've been pleased.