metal bushing bleeds onto the pen

[anna]

I've been making some pens for practice and also trying to get the finishing down pat. I noticed, though, that for some wood species, some discoloration happens where the wood butts against the bushings, and that occurs during sanding. I think metal filings are sanded off the bushings and into the wood. Looks really ugly, too.

I was wondering how do I prevent this from happening. One idea I have is to seal the wood before sanding with higher grits. I'm thinking of using CA, maybe? I really don't know if that'll work. If it does, should I get the thin version or can I just use the gap-filling version which I currently have?

Are there other ways to get around this bleed through problem? I thought softer woods are more susceptible to this, but I've done a couple of spalted something or other (probably maple, and it felt pretty soft) and there were no bleed throughs that are apparent at all.

 

[leehljp]

There are several ways and several combinations of ways.
1. Sand from the center of the blank outward, use thin strips of sandpaper and don't use the same section twice as it will introduce the metallic dust to the center of the blank.
2. With experience, you will probably soon learn how to line the edge of a strip of sandpaper up with the edge of the blank and pull rather than carrying the sandpaper all the way over on top of the bushing.
3. CA will help some but learning to do the above will be the best in the long run.
4. Make your own bushings out of delrin.

I used to take flexible but thick nylon type of washers for use as bushings between the bushings and the shoulder of the blank. This extra shoulder helped until I learned to do techniques 1 and 2 above. Take some flexible plastic type of storage bowls, drill some holes the size of the smaller part of the bushing and then cut them out in washer form - about 1/8 inch or 3 mm larger than the hole. These extra spaces will help keep the sandpaper away from the bushings.

 

[johncrane]

If you have a air compressor and a air blowing nozzle simply blow off all the dust and debris from the blank after each sanding grit.only draw back is a increase in your power bill.

 

[angboy]

Originally posted by johncrane
<br />If you have a air compressor and a air blowing nozzle simply blow off all the dust and debris from the blank after each sanding grit.only draw back is a increase in your power bill.

I must be impaired when it comes to doing this. I keep reading on here about people using that canned air or air compressor to get rid of things like this or other dust, etc., but for some reason when I try it, nothing gets blown out. Does anyone else have this problem or am I the only one who can't seem to get this trick to work?

 

[wdcav1952]

Angela,

The compressor should be plugged in to build up air pressure prior to attempting this method. [][}]

Seriously, if you are trying the "canned air" it usually does not have sufficient pressure to accomplish the task IMHO.

 

[gerryr]

That was mean, Cav, but I'm jealous you beat me to it.[}]

Angela, if you're using an air compressor, you can adjust the pressure at the nozzle. I have mine set for 60psi and it works great.

 

[Rifleman1776]

Using a dead center for the drive (headstock) and a live center at the tail stock, you can eliminate mandrel and bushings for final sanding and finishing. Just be cautious not to sand the ends down too far. Do a search for 'no mandrel' turning for a full explanation of this technique.

 

[anna]

After each grit, I normally stop the lathe, sand along the grain, then use a slightly damp paper towel (with alcohol) to wipe off the dust. That's when a pen takes me two hours to do. I didn't quite follow that procedure last night when I got the metal bleed through (it was late and I was getting sleepy and tired). Don't know if it was just coincidence, though.

I do have a compressor, but I have never even plugged it in yet. Maybe it's time to try it out finally.

I will work on my technique as Hank prescribed. It all sounds like common sense after someone else points it out to you. I'll also have to research the "no mandrel" turning. At this point, I'm thinking that I can make some of the plastic bushings Hank suggested, and just before sanding I can remove the metal bushings and replace them with the plastic ones. Oh, and I did try to use calipers to get to my final diameters instead of relying on the bushings, but that made the pen turning take forever, too.

I have so far to go before I really learn all these things. Not to mention the unpredictability of the CA/BLO finishing method. At least for me, anyway.

 

[Jerryconn]

Something else that you can do is coat the bushings (only on the larger diameter, not the part of the bushing that fits in the tubes) with a thin coat of medium or thick CA. Let it dry them put them back on the mandrel and sand. This way you are sanding off the thin CA coating and not the metal.

 

[Jeff-in-Indiana]

I do a combination of a couple of the mentioned techniques .. I made bushings from corian and old slimline tube pieces, and turn the ends at an acute angle so when used in place of the regular bushings, it auto-centers the blank, and gives me some "air space" at the ends of the blanks, so I can pull the paper away before it contacts anything .. and if it DOES hit the corian, I do not care, that will not be a staining-source for the wood ... plus you do not slowly reduce the size of your bushings by sanding ... Good Luck!

 

[angboy]

Originally posted by wdcav1952
<br />Angela,

The compressor should be plugged in to build up air pressure prior to attempting this method. [][}]

Seriously, if you are trying the "canned air" it usually does not have sufficient pressure to accomplish the task IMHO.

Originally posted by gerryr
<br />That was mean, Cav, but I'm jealous you beat me to it.[}]

Angela, if you're using an air compressor, you can adjust the pressure at the nozzle. I have mine set for 60psi and it works great.

Oh, you guys are mean... You see, I was trying to be environmentally conscious and save energy[)]... OK, maybe not... maybe I'll have to call dad and have him explain this whole "plugged in" concept to me... yet another shop technique I have to master, oh does the learning ever stop...[:X][:X]

 

[angboy]

Originally posted by dishripjlt
<br />I do a combination of a couple of the mentioned techniques .. I made bushings from corian and old slimline tube pieces, and turn the ends at an acute angle so when used in place of the regular bushings, it auto-centers the blank, and gives me some "air space" at the ends of the blanks, so I can pull the paper away before it contacts anything .. and if it DOES hit the corian, I do not care, that will not be a staining-source for the wood ... plus you do not slowly reduce the size of your bushings by sanding ... Good Luck!

And I'm almost afraid to ask, but Jeff, what do you mean by an acute angle? I'm having a hard time picturing which way the angle would go? Do you have any pictures of the bushings you've made that you could share?

 

[doddman70]

another possibility you might consider is your pen mill. I'm not sure how you square your blanks but early on in my pen turning i was having the same problem. i was squaring the ends with my pen mill in my drill press i used to cut my blanks real long and so there was a lot to mill down i noticed a lot of smoke coming from the blank while milling and when i took the blank out i noticed the burn mark from the mill i turned the blank and after i had the black lines on the next one i trimmed the blank on the band saw before milling and i sharpened the mill no burn marks and no black lines after turning and sanding. ever since i make sure my mill is sharp and trim the blanks as close to the brass as possible before milling no black lines since.

Shane

 

[RussFairfield]

Much of what we see as stain comes from the sandpaper and not the bushings. The adhesive holding the abrasive to the paper backing starts to melt at a very low emperature and then carries the sanding dust and grit into the open pores of the wood.

The solution is sanding at slower lathe speeds. Don't let the sandpaper get hot.

See if that doesn't help.

 

[weidnd]

Anna,
I had the same problems, especially with the lighter woods like maple. Like you, I used a combination of techniques that have virtually eliminated the problem.
1. Low speed and great caution near the ends (Russ's video helped there)
2. A thick coat of thin CA after the first grit to seal open grain
3. Clean between each grit with denatured alcohol - (thank you John at Woodcraft)
4. Reapply CA if I sanded far enough down to "open" the grain again.

Like you I found this added time to the process. However, I have found that while the art and joy are in the turning, the magic happens in the sanding.

Dan

 

[leehljp]

Originally posted by Rifleman1776
<br />Using a dead center for the drive (headstock) and a live center at the tail stock, you can eliminate mandrel and bushings for final sanding and finishing. Just be cautious not to sand the ends down too far. Do a search for 'no mandrel' turning for a full explanation of this technique.

I have been meaning to give this a try for a problem that I have been having. Today, I made a dead center and used it in a 2 MT drill chuck. Worked well.

I have been having CA trouble with oily blanks such as ebony woods. The CA would tend to separate from the wood in a spot or two at the ends upon taking it from the bushing. Even with the bushing waxed or even delrin spacers.

So I made the "no mandrel" dead center and the CA went on just fine on a piece of ebony.

This will probably be my default method from now on. Love it!

 

[Jeff-in-Indiana]

Originally posted by angboy
<br />

Originally posted by dishripjlt
<br />I do a combination of a couple of the mentioned techniques .. I made bushings from corian and old slimline tube pieces, and turn the ends at an acute angle so when used in place of the regular bushings, it auto-centers the blank, and gives me some "air space" at the ends of the blanks, so I can pull the paper away before it contacts anything .. and if it DOES hit the corian, I do not care, that will not be a staining-source for the wood ... plus you do not slowly reduce the size of your bushings by sanding ... Good Luck!

And I'm almost afraid to ask, but Jeff, what do you mean by an acute angle? I'm having a hard time picturing which way the angle would go? Do you have any pictures of the bushings you've made that you could share?

here is a terrible rendering of what I am saying .. although this is "prettier" than the real bushings .. haha


The black part is the bushing-material (Corian, polyresin, soft wood)
The gold part is the mandrel itself (it was going to be the tubes inside the bushing, but I did not "enclose" it in color (D'oh!)
The wood part is the blank "riding high" on the bushings which are centered on the tubes inside the blank.

This gives you access to the ends/edges of the blank, and some air-space to allow "riding off the end of the blank" with the sandpaper / finishing cloth / MicroMesh