Overturning and building up CA?

[JasonM]

Ive seen several threads mention purposefully turning a bit past the bushing in order to build back up with CA to get to the target diameter.

For those doing this, roughly how thick are you building up with the CA?

I ask because I'm still learning/experimenting with CA and don't know it I have a good grasp on how much of the diameter ends up being finish.

 

[Justturnin]

I turn about 0.10mm below the finished size and build back about 0.10mm above so i have about 0.2mm of ca. then i sand the excess off to get a glass finish with no ridges or dips. once done i will have a 0.10mm thick finish whoch means more to me than 20 coats without knowing what was removed during polishing.

 

[JasonM]

Thanks, Chris. Great explanation.

 

[GeorgeP]

I turn about 0.10mm below the finished size and build back about 0.10mm above so i have about 0.2mm of ca. then i sand the excess off to get a glass finish with no ridges or dips. once done i will have a 0.10mm thick finish whoch means more to me than 20 coats without knowing what was removed during polishing.

Hi,

I'm very new to this and I am quite confused by the various types of CA. Are you using the thin or the thick type for finishing? Can someone highlight the types of use to the type of CA?

 

[glen r]

George, I usually start with thin CA to seal the blank and fill any small voids that may exist. I use medium CA after about 5 to 10 coats of thin and usually do about the same number of medium making sure that I dont get any ridges in the finish. I don't use thick for finishing. Once I am happy with what I see I let the blank sit for at least 24 hours before I start any sanding. I wet sand with MM to 12,000. Like others have stated, turn to a little less than the bushings and then build up the CA to the diameter that you need.

This is the way I do it but its not to only way to get a good finish. It comes down to what works for you. It takes a while to get to what you are happy with but it will happen and it will likely be different from what many others are doing.

 

[Justturnin]

George, I usually start with thin CA to seal the blank and fill any small voids that may exist. I use medium CA after about 5 to 10 coats of thin and usually do about the same number of medium making sure that I dont get any ridges in the finish. I don't use thick for finishing. Once I am happy with what I see I let the blank sit for at least 24 hours before I start any sanding. I wet sand with MM to 12,000. Like others have stated, turn to a little less than the bushings and then build up the CA to the diameter that you need.

This is the way I do it but its not to only way to get a good finish. It comes down to what works for you. It takes a while to get to what you are happy with but it will happen and it will likely be different from what many others are doing.

Close enough to how I do it that I will leave it at that. Practice with the Med though because if you put it on too thick you can get some gnarly ridges.

 

[GeorgeP]

Thanks Glen

 

[Tom D]

I have been doing this for a while. To me the thickness of the CA depends on the look I am trying to acheve. If you have a really figured blank and want to show a lot of depth you want a thick CA finish. You also have to take into concideration the thicker the CA the more work you are getting your self into.

 

[IPD_Mr]

Here is something that should help fit this to your finishes. Over the next ten or so pens that you make, take measurements of the ends and middle of the blank to get a starting figure. Now do your normal finish. This will give you an average of how thick your finish is throught the blank. Example:

Blank Before Finish:
Left Center Right
.475 .492 .478

Blank After Finish:
Left Center Right
.481 .496 .481

This is a great way to also tell where you are heavy handed and where you are not. This example would show that you are either heavy handed when it comes to MM on the right side, you are using more preasure when applying CA or a combination of both. At any rate doing this over ten or so blanks will give you a great base on learning how thick of a finish you actually apply. Other factors that will effect you is the temperature when you are applying the finish, how long you let the CA cure before starting to use MM and your mood when you are sanding and applying the finish. You would be surprised at how much pressure that you use when mad or frustrated as compared to a normal relaxed state.