Minimum no. of CA coats needed - International Association of Penturners
     International Association of Penturners
Pens for Service Members
 
Support The IAP

Go Back   International Association of Penturners > Community Forums > Finishing
  Forgot Password
Register FAQ Members List Search Today's Posts Mark Forums Read
Finishing It ain't a pen till it's FINISHED!


Logged on members can hide ads!

Welcome to penturners.org!

You've found the home of The International Association of Penturners. You are currently viewing our site as a guest, which gives you limited access to view discussions, photos, and library articles.

Consider joining our community today. You'll have full access to all of our content, be able to enter our contests, find local chapters near you, and post your questions and share your experience with our members all over the world.

Membership is completely free!!

If you have any problems with the registration process or your account login, please contact us.

Reply
 
LinkBack Thread Tools Display Modes
Old 07-07-2018, 08:02 AM   #1 (permalink)
 
Join Date: Feb 2009
Location: Melbourne, AUSTRALIA
Posts: 245
Photos: 0

Default Minimum no. of CA coats needed

I was reading through some of the old posts and came across this one which claims that a reasonable finish can be obtained with as little as 3 or 4 coats of thin CA. I tried a few times to replicate the result but while I managed to get what I thought was a good finish, there would always be a small patch or 2 where I sanded through even though I used a light touch with my sanding. Has anyone here ever been able to get consistent results with as little as 3 or 4 coats of thin CA? Original post CA Finish - the new way! - International Association of Penturners
Tiger is offline   Reply With Quote Top
Old 07-07-2018, 08:25 AM   #2 (permalink)
 
TonyL's Avatar
 
Join Date: Mar 2014
Location: Alpharetta, GA
Posts: 5,497
Photos: 6

Default

I have not - but wish I could (and achieve a high-gloss finish with the appearance of depth). This is by no means a recommendation: I apply 2 coats of thin followed by 8 to 10 coats of medium using a paper towel or craft foam. I start sanding around 400 grit. I am sure that there is plenty of room for improvement.
__________________
Am I not destroying my enemies when I make friends of them? Abraham Lincoln

Peace,

Tony

Member of Local IAP Georgia Chapter meets quarterly in Roswell, GA
TonyL is offline   Reply With Quote Top
Old 07-07-2018, 08:48 AM   #3 (permalink)
Member Liaison
 
leehljp's Avatar
 
Join Date: Feb 2005
Location: Tunica, MS,
Posts: 6,089
Photos: 46

Default

Tiger,

I am going a different direction than the fewest number of coats on this post. "Sand Through" in spots is often indicative of what we often refer to as "Out of Round" which is not necessarily the "correct" term, but more or less the common use term.

If you have calipers, measure the diameter of the pen and then rotate the blank about 45 and measure again and then again at 90 from the original measurement. Then do this in the middle and again at the other end of the turned blank. This will show if there are high spots and low spots.

If you have low and high spots, "sand through" will occur on minimally coated blanks.

The reasons for OOR can be several:
1. bushings on occasion have the hole bored off center by .01mm or so;
2. if using a mandrel, the mandrel can flex if too much pressure is applied with sanding or turning tool;
3. using the wrong tail stock live center (must have a 60 live center with a mandrel.) The wrong tail stock will cause wobble and OOR.
4. too much pressure in sanding - combined with soft wood sanding quickly while hard grain side does not.
5. pulling the tail stock up too tight (you don't want to leave it loose,) but too tight will force a mandrel to flex or wobble.

Since 4 of these deal with mandrel problems, many turners switched to Turning Between Centers, often referred to as TBC, which does not use mandrels.

The blank should be perfectly round when measured with calipers before applying CA or other finish. This does not deal with the CA application referenced in your link, but the work that should be done prior to the application of CA, particularly if you want to use the least amount of CA needed.

BTW, you didn't say why you wanted to use the minimal amount, but using the least amount is dependent upon each individual turners habits. I use less by not applying with paper towel. PT will absorb up to 90% of the CA while putting 10% on the blank. Some people use the small parts bags that pen parts come in; put that on your finger and apply a drop on the bag and rub it onto the slow turning blank. Smooth the CA flow down the blank. There are other applicators that do the same and do not absorb into the paper towel. For me, I get a more even and consistent flow of CA on the blank with a plastic or foam applicator than I do with paper towel. I still use PT on occasion just because, but most of the time it is with a plastic or foam applicator.
__________________
Hank Lee

Experience is what you get when you don't get what you wanted!

Last edited by leehljp; 07-07-2018 at 09:06 AM.
Likes: (1)
leehljp is offline   Reply With Quote Top
Advertisement
Old 07-07-2018, 10:17 AM   #4 (permalink)
 
jttheclockman's Avatar
 
Join Date: Feb 2005
Location: NJ, USA.
Photos: 83

Default

Oh the best thing about this post is the link and seeing all those names that use to visit here. Some not with us any more but it sure good to see those again. Brings back memories.

Finishing is a subjective topic and everyone has developed their own method. Rudy Vey who use to live right down the street from me started that thread and it was his method. As I mentioned in that thread I had gone to a couple of his shows and seen first hand his success with this. I also stated at that time I was new at pen turning and would eventually develop my own method which I have. I found about 2 to 3 coats of thin CA followed by 3 to 4 coats of med is sufficient for me. I now have a feel of how much I have to undercut the dimetions to build back up with CA to get to where I want to be.

My suggestions is read all the threads but strife for your own method and stick with it. Comes easier the more you do it. No right or wrong way.
__________________
John T.
Likes: (1)
jttheclockman is offline   Reply With Quote Top
Old 07-07-2018, 11:01 AM   #5 (permalink)
 
Warren White's Avatar
 
Join Date: Aug 2014
Location: Livermore, CA
Posts: 356
Photos: 0

Default For what it's worth....

....my procedure is 3 coats of thin, followed by 3 coats of medium, followed by another 3 coats of thin. The purpose of the first three is to allow penetration of any deep grain; the three coats of medium keeps me from sanding through, and the last three coats of thin gives me a more even finish to sand. All coats are put on while the lathe is turning at a slow speed.

I apply the thin directly (and carefully) on the blank with a paper towel under the blank and wipe it off back and forth to even it out. The medium is applied with a drop on a paper towel then on the blank. I use accelerator on the medium (3 very quick shots at a time), and only if needed to the thin.

When I have sanded through (and I have a couple of times), I attributed it to being too aggressive in sanding with the first couple of grits of micro mesh. Easy does it with them, and a a low speed. Once I don't sense any abrasive action with the micro mesh, I turn the speed up.

I hope this helps. It is frustrating to have to reapply the finish.
Likes: (2)
Warren White is offline   Reply With Quote Top
Old 07-07-2018, 11:08 AM   #6 (permalink)
 
lorbay's Avatar
 
Join Date: Jul 2009
Location: BC. Canada
Posts: 3,042
Photos: 134

Default

10 coats of thin for me. In 2 min or less.
Lin
__________________
"If you come to a fork in the road Take It."
Yogi Berra.
Likes: (2)
lorbay is online now   Reply With Quote Top
Old 07-07-2018, 11:50 AM   #7 (permalink)
 
DavidD's Avatar
 
Join Date: Oct 2017
Location: Colorado
Posts: 163
Photos: 1

Default

Clearly, there's no right or wrong answer, and much depends of techniques and products.

I use Titebond Medium and apply six coats using blue shop towels. Sometimes I mistakenly only apply three (I do three coats at a time and then remove to sand buildup from ends) and these often still build enough to withstand wetsand and polishing.
DavidD is offline   Reply With Quote Top
Old 07-07-2018, 12:54 PM   #8 (permalink)
 
Join Date: Mar 2017
Location: Houston, Texas
Photos: 12

Default

Early on I used BSI thin and medium. Recently I started using Mercury Flex thin. The flex is much softer and I have been struggling with sanding through. I have modified my technique with the flex so I am not nearly as frustrated, but will probably switch back to BSI for most of my pens. It was surprising to me how techniques that worked quite good with one brand totally failed with the other...
__________________
--Sam
Dehn0045 is offline   Reply With Quote Top
Old 07-07-2018, 02:33 PM   #9 (permalink)
 
Join Date: Jun 2018
Location: Columbia,SC
Posts: 96
Photos: 0

Default

3 thin, 3 medium unless I'm not happy with it. I have sanded it all off and started over.
__________________
* The above post most likely has not been proof read nor grammatically correct. Spelling, ehh, 50/50 with spellcheck*

Have a Blessed Day, ivel
ivel is offline   Reply With Quote Top
Old 07-07-2018, 07:24 PM   #10 (permalink)
 
Join Date: Feb 2009
Location: Melbourne, AUSTRALIA
Posts: 245
Photos: 0

Default

Thanks for your thoughts and Hank I appreciate your detailed reply. I am returning to pen turning after a short absence and this weekend I received an urgent request for a particular pen. As it’s the weekend I was not able to get any medium/thick CA or my choice of sandpaper so I was a little short on supplies. So armed with a couple of skews and some old micro mesh and thin CA I did my best. I read through some of the old posts and found the one cited so gave it a go. Now I should point out that I turn b/w centres, use digital calipers and use craft foam to get as much CA on the blank as possible. I’ve not had consistent results with mandrel, bought bushings etc. I find that I can quickly turn the blanks to size but it’s the finish or the pursuit of the perfect finish that is time consuming for me. Hank I think you’re right that there is some OOR and I love your suggestion of multiple caliper readings but if I have cleaned out the Morse taper and the dead centre and live centre meet I’m not sure where the OOR could be coming from. I have always had an admiration for those that can quickly and repeatedly produce pens, if I had that skill I would have made a lot more.
I should also say that my experience matches some of the responses here namely I need at least a couple of medium coats to prevent sanding through, other thing that is useful is if I have ridges and obvious high spots with my CA finish a finely sharpened skew with a light touch removes them quickly without having to exhaust one’s sandpaper stock.

Last edited by Tiger; 07-07-2018 at 07:27 PM. Reason: Add a sentence.
Likes: (3)
Tiger is offline   Reply With Quote Top
Related Content
Logged on members can hide ads
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


All times are GMT -5. The time now is 02:03 AM.

Powered by vBulletin® Version 3.7.6
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0

Content Copyright © 2003-2018 by Penturners.org, LLC; All Rights Reserved
Terms Of Service   Acceptable Use Policy