CA question

[vacca rabite]

On all the pens I have made with CA, save one, the glue has not made a clean break at the body of the blank, and I am left with a white line at the ends of the blank.

This pic was for another experiment (failed overall) but shows the issue I am having. How the heck do I fix this in the future.

Tonight I ruined an otherwise really nice body with this issue, and it is ****ing me off. HELP!

Zach

 

[Woodswood]

I have found when I only apply 3 coats it's not as bad, but have not completely found a solution yet, let me know if you do.

Nathan

 

[BSea]

Do you leave the bushings on to apply the CA? I'm guessing you use a mandrel. If you do, try removing the bushings and putting some wax on the bushings before applying the CA. Or If you have 60° centers, you can apply the CA between centers without bushings. This is the way I do it, and I've put over 20 coats of CA on a blank without a problem.

 

[Xander]

Newbie here and I've only done one CA finish (more on that in an other post, just let me say that I learned a LOT doing that pen) so I don't know all the answerts but...

Do you remove your blanks and put just a smear of vaseline on the bushings so the CA does not stick? Then put blanks back on mandrel and apply CA.

Also, before removing the finished blanks run a very sharp blade between the blank and the bushing. I found an exacto knife works.

Like I said, i'm no expert so please obtain more advice.

 

[Woodswood]

What is a 60 degree center?

 

[leehljp]

I use Turning Between Centers as mentioned above. But before I got there, I had the same problem and here is how I solved it most of the time. I have a set of mini chisels that I use for some small bowls similar to these:
Set of 8 Benjamin's Best HSS Micro Detailing Anniversary Set at Penn State Industries

I used the diamond and small parting tool to cut the CA down to the bushing just at the bushing/blank joint. This made separating them easier. This worked except when I was using oily woods such as ebonies, cocobolo and the like. I often had trouble with lifting and the "white" showing (because it lifted) when separating. Since I did quite a bit of those woods, and had the lifting of the CA a little too often to suit me, I changed to TBC and haven't had any problems since. That was back in '07 or '08.

 

[BSea]

What is a 60 degree center?

60 Degree Live center that goes in the tailstock. You probably have this for your mandrel.

60 degree dead center for the head stock.

 

[leehljp]

What is a 60 degree center?

60° centers are the live center on the tail stock ends that go into mandrels. Most lathes come with a center for turning wood. The mandrel is metal and the dimple in the end is made for metal lathe centers. The wood centers tend to wallow around inside the mandrels.

That is what a 60° center is.

Now Part 2 to that. In the last three or 4 years JohnnyCNC has made bushings with 60° cups in it for using in Turning Between Centers (not using a mandrel). In this case, 60° centers are needed on the tail stock end (use with LIVE center) and head stock end (Use with dead center).

However, if one has the bushings for mandrel use, these can be used with just about any live center. Contrary to what most people will tell you, you do NOT have to use 60° centers for standard bushings to turn without a mandrels (TBC).

AS a reference to this, here is the first dead center that I made and used and posted here back in '08 and it was NOT 60°.
IAP Home - Photos - Imported Photo from leehljp

IF you use custom bushings and they are MUCH better than commercial ones, you WILL need 60° live and dead centers.

 

[Pens By Scott]

Also, Delrin bushings might be another solution, CA doesn't stick to Delrin. Check with Hans at Bushings, he's a member here (hewunch)

 

[ALA]

I have the same problem with the glue coming loose near the edges. I just did a Cigar pen that turned out pretty good except for this problem, TBC is sounding better all the time!

 

[Woodswood]

Will I have to replace all of my bushing if I change over to this TBC?

 

[BSea]

Will I have to replace all of my bushing if I change over to this TBC?

No, you can use your old bushings until they need replacing. once you get the TBC down, you really don't even need bushings. Just a set of calipers. Not that I'm recommending that, but when I get a kit that I'm just trying out, I don't buy bushings until I know it's a kit I'll make more often.

 

[vacca rabite]

When ditching the mandrel for centers, how do you know you are actually on center? Will the blank and bushings self center?

Zach

 

[BSea]

When ditching the mandrel for centers, how do you know you are actually on center? Will the blank and bushings self center?

Zach

That's right. The centers go into the tubes or bushings, and there you go. As long as your tailstock is in line, you should be good to go.

 

[vacca rabite]

I'll have to try it. Turn the blank on bushings and finish just on the tube. Ditching the mandrel would be nice. Less setup. And hopefully no CA lifting and annoyed me when a nice kit and blank are screwed by an unclean CA break.

 

[Mike8850]

I still use bushings when I finish with CA but my last step is scoring with a sharp X-acto knife.
I do this with the lathe off.
Mike

 

[leehljp]

I'll have to try it. Turn the blank on bushings and finish just on the tube. Ditching the mandrel would be nice. Less setup. And hopefully no CA lifting and annoyed me when a nice kit and blank are screwed by an unclean CA break.

You are perceptive. You would be surprised at how many times over past few years that people with the mandrel problems of different kinds could not "see" the "less setup". From many, questions came back as I have to buy more (dead center, more bushings etc - while at the same time they will spend much more on a new mandrel than a dead center. Other replies were it is too complicated to imagine while in fact it is much more simple requiring far fewer steps, and less dropped bushings , and easier checking on the work.

This last step is a bonus on the TBC. How many times do we want to take a blank off and check it very closely but refrain because of the steps of unscrewing the mandrel, taking the bushing off, afraid of a misalignment when remounting - so we don't. It is one step with TBC. Much less complicated.

Less complication, more simple, less things to go wrong, less parts involved! Cheaper too than extra mandrels. The real hang up is Three-fold -
1. Some enjoy the ability to do BOTH parts of a two part pen at the same time. (Nothing really gained except for seeing them together.)
2. It is a little daunting with all of the investment to get started and learn the pen making process for most. To immediately have to "re-adjust" our thinking, it is hard to let go of what we have just learned. (Stockholm syndrome taking effect on a minor scale.)
3. Trusting the big catalog makers recommendations / I'm a beginner, not a cutting edge person yet. All of the big catalog and large companies have and sell these items (mandrels) so it MUST be the BEST way. / TBC is for advanced users, I am not there yet.

Give it a try. It is not for advanced users only. More focus can be to making that pen instead of the complicated mechanics of mandrels.

ONE WARNING: The lifting "can" still happen, but it is much easier to "score" the edge of the finished blank on TBC than with bushings. There is a greater sizing difference on the end of the TBC blank/center than with blank/bushing on a mandrel. But with over CA'ing, it can still happen, just the percentages are GREATLY reduced.

 

[Seer]

You can always try these from Johnny as well.
http://penturnersproducts.com/index.php?main_page=index&cPath=2_15

 

[Carl Fisher]

I don't remember the last pen I finished while still on the mandrel or with bushings. I still use an adjustable mandrel for most turning but will finish between centers with just the 60-degree centers right into the brass tubes. The quality if our finished pens has improved so much with just that simple change.

If there is enough ca build up across the gap of the tube and center, I take a modified old kitchen knife that has been ground into a parting tool of sorts and part the joint. Then clean up by hand with sand paper on a flat surface. Very easy.

 

[vacca rabite]

just ordered a dead center from John Gooden. looking forward to dumping the mandrel.

Zach

 

[raar25]

I use a set of delrin bushings that I hand made on the mandrel which aproximates 60 deg centers. The bushings fit inside the brass tube while still on the mandrel. I have since almost eliminated the breakage at the end of the blank. Just keep in mind you may have to occassionally trim off excess CA. When you do this make sure you use inward strokes with your sharp razor knife.

 

[leehljp]

Just keep in mind you may have to occassionally trim off excess CA. When you do this make sure you use inward strokes with your sharp razor knife.

I use a pen mill SANDER rather than a bladed pen mill to trim or even a knife for that matter. A sanding mill is much safer at getting the excess off. I have never ruined a blank with a Sanding pen mill but have with knife or bladed pen mill.

 

[BSea]

I use a pen mill SANDER rather than a bladed pen mill to trim or even a knife for that matter. A sanding mill is much safer at getting the excess off. I have never ruined a blank with a Sanding pen mill but have with knife or bladed pen mill.

I agree 100%. A sanding mill is quick easy, and best of all exact.

 

[EricJS]

You can always try these from Johnny as well.
MAGIC FOR FINISHING : Penturners Products!

Take a look at these Eliminator Bushings as well. These are cone-shaped bushings that slide onto the mandrel. These will give you the same results as between centers, but you can finish both upper and lower at the same time.

These were a life saver for me.:wink:

 

[Wood Butcher]

It kinda looks like the CA has seperated from the blank upon removal of the bushings. I have experience this on occasion and have solved the problen by turning between centers BUT...that doesn't solve the issue with the faulty blank. I have found that if I carefully apply a small amount of thin CA to a piece of waxpaper and then place the end of the blank in the CA the seperation goes away. Your results may vary.
WB

 

[tbird1957]

You can make your own dead center. Delrin is idea choice. Here is a simple dead center I made with delrin. Also shown is a set bushings I made for center turning on a mandrel. Both very simple to make. I use the dead center all the time. I use it for applying CA, polishing, sanding, etc. I also use it to sand the brass tubes, very quick and easy. I never have a problem with the CA. As stated before in this thread, CA will not stick to Delrin.