CHIPS AHOY! need advice

[BeeAMaker]

SUCCESS!

Thanks to everyones advice and tips I think I got it. I didn't sand or polish that blank yet, I used my round carbide as a skew chisel then went over it with some #0000 steel whole, very smooth and way less chipping. (I think temp might have something to do with it also, see below)

I want to give a big shout out to Ed from Exotic Blanks for taking the time to look at my technique. I will be taking what I learned to the next maker meetings in the upcoming weeks. With my new found confidence, I believe I can save at least 2 of the 3 blanks.

Now to change the subject, but I think it is related as I believe this has something to do with Temperature.

I noticed the brass tube is proud of the blank, but only on one end. This is true with all my plastic blanks I have glued up and squared. I square them on a disk sander so the ends should be flush. Here are a couple pics.

And like I said, this is only on one end, so I am thinking maybe I don't have enough adhesive at this end, allowing the brass to expand - or the plastic to shrink beyond each other. Thoughts? These are all "esters" material as well I had one allumilite one that had been turned and one wood blank that i had turned that were OK. I think it is a temp issue, but if they are glued properly, (and the glue holds) they should expand and contract together.

Thoughts?

 

[jttheclockman]

No on the temperature thing. What glue are you using and how are you storing to let dry??? That I would blame on creep. You should have glue on all sections of the tube when inserting into blank and then spin it while inserting. If you have a temp thing going on. acrylic and metal do not expand and contract at the same rate. You would have much bigger problems than you have now and are we talking subzero temps and then desert temps. Also if you are gluing in cold temps than that is a problem in itself.

Is the other side flush with the blank??? If it was acrylic shrinking why did the other side not shrink?? If no glue is the cause then this is a first I ever seen. Put it in the sun and see if it expands back

 

[mecompco]

My shop is kept at 50* during the winter, I've never seen anything like that. I HAVE seen tubes slide around a bit after glueing (5 minute epoxy), so I'm always on the lookout for that. Once their dried and squared, they are all good.

In thinking back, I have had a couple of tubes slide after during assembly. I had painted both tube and blank with silver spray paint. My hypothesis is that the silver paint is so slick that the epoxy didn't adhere properly (scuffed tubes and all). Never had it happen with any other paint.

Anyway, trim that back up and use it. There are a few pens that are really touchy about tube length, but I don't think that little bit will hurt (well, unless it does). I've done it a number of times, but as always, YMMV.

Regards,
Michael

 

[jttheclockman]

After a second look. They look way too perfect for the amount of tube exposed. need more info. The 2 things that pop into my head are poor alignment with a barrel trimmer. The cutter is cutting more blank than tube. Second if sanding, what are you using to sand? If you are using a sanding disc of any kind and using velcro backed sand paper the acrylic will sand faster than the metal when you push in on the sandpaper. It has a plush feel to it and thus it will push past the blank and sand more blank off than tube. Are you sure did this not look like this when you got done prepping the blank. Just does not make sense to be that perfect and exact on 2 blanks.

 

[BeeAMaker]

Well I have to agree it doesn't make much sense.

I use 15min epoxy from PSI
https://www.pennstateind.com/store/PKGLUE2.html

I coat the tubes and slide them in and out, twisting as I go.
I let dry in my office (where temp is more stable) and then trim the next day.
I use this,
https://www.turnerswarehouse.com/products/pen-blank-squaring-jig
To square the blank on the disk sander flush to the brass, until the brass is shinny.
The ends were flush at this time. The sanding pad is solid - if it were soft, the end would rounded, not 2 different levels.

As I stated, this is only on one end, the other end is flush so the tube hasn't moved. I have a Wood blank, and a Alumilite blank that is still flush on both ends. Although these are stored in my office, the office heat goes to 63 during the weekend. This discovery was on Saturday. The blanks were prepared and flushed this past Monday. I don't have time right now, but later I will look up the data sheets on these plastics to see what their temp coefficient is. I also want to note that it has been colder the past couple days than it has been when I prepared them. It is warming up again too, today it is supposed to reach almost 60 and Mon and Tue will be in the mid 60's I will wait and see if the tube is still exposed on these warmer days.

I have done a lot of brass inserts on Corian tops, I have cut it flush one day, only to come into the shop the next day and see that it is almost a 1/16 to short. It will be interesting to see where these tubes are at mid next week.

 

[jttheclockman]

My shop is in the basement and I never turn the heat on in there. So the temp is around 60 degrees but could drop depending on outdoor temps. Never had anything like that happen. I have seen this on wood projects, not wood pens. But that is expected and compensated for when building. wood moves.

One side and that perfect and same amount is weird to say the least.

 

[BeeAMaker]

After doing some digging, and still waiting for an opinion from the chemist in our maker group, I found this;

"Polyesters as thermoplastics may change shape after the application of heat. While combustible at high temperatures, polyesters tend to shrink away from flames and self-extinguish upon ignition. Polyester fibers have high tenacity and E-modulus as well as low water absorption and minimal shrinkage in comparison with other industrial fibers."

So here is a theory for you, Could I be over heating the plastic while buffing/sanding, thus causing the end to "shrink back" from the tube? I have extra tubes and cut of blanks, I'm gong to test that theory as soon as I can.

I'll re-square the blank before assembly, no biggie there. I'm just trying to figure out what is causing it.

 

[jttheclockman]

Why not both sides. I can see extra heat when sanding the ends but after you are done it will cool off and you really are not heating that much or at least I hope you aren't.

 

[CREID]

You need to look at your end squaring procedure. If you were heating it up enough to cause shrinkage, you would notice other distortion.

 

[BeeAMaker]

You need to look at your end squaring procedure. If you were heating it up enough to cause shrinkage, you would notice other distortion.

Not when I'm squaring it - that part is fine. This happened long after that. I'm thinking when sanding/polishing. I'm setting up some test to see if I can duplicate it.

 

[jttheclockman]

You need to look at your end squaring procedure. If you were heating it up enough to cause shrinkage, you would notice other distortion.

Not when I'm squaring it - that part is fine. This happened long after that. I'm thinking when sanding/polishing. I'm setting up some test to see if I can duplicate it.

I just can not see how you can create that kind of heat sanding or polishing. It would have to be hot to the touch. I always wet sand MM and hardly ever use sandpaper and if i do it is touch and move on. This material you are using must be very touchy. I have never read anything like this on here. Maybe i missed a thread and maybe some can do a search for this.

 

[Liljim9747]

Chipping

I have started using 80 grip sand paper to work the edges.I seem to loose less blanks this way.

 

[CREID]

You need to look at your end squaring procedure. If you were heating it up enough to cause shrinkage, you would notice other distortion.

Not when I'm squaring it - that part is fine. This happened long after that. I'm thinking when sanding/polishing. I'm setting up some test to see if I can duplicate it.

I just can not see how you can create that kind of heat sanding or polishing. It would have to be hot to the touch. I always wet sand MM and hardly ever use sandpaper and if i do it is touch and move on. This material you are using must be very touchy. I have never read anything like this on here. Maybe i missed a thread and maybe some can do a search for this.

I have to agree, if that much heat is being generated, something is wrong. More than likely the tube protruding from the blank is from either poor end squaring or glue failure and the tube slipping.

 

[BeeAMaker]

You need to look at your end squaring procedure. If you were heating it up enough to cause shrinkage, you would notice other distortion.

Not when I'm squaring it - that part is fine. This happened long after that. I'm thinking when sanding/polishing. I'm setting up some test to see if I can duplicate it.

I just can not see how you can create that kind of heat sanding or polishing. It would have to be hot to the touch. I always wet sand MM and hardly ever use sandpaper and if i do it is touch and move on. This material you are using must be very touchy. I have never read anything like this on here. Maybe i missed a thread and maybe some can do a search for this.

I'm just as baffled, but the best I can come up with at the moment. I should be able to test this tomorrow. I'll take pictures or video with every step. Maybe I can spot the cause, or if nothing else, eliminate others.

 

[Scissortail Pens]

If you're looking to a chemist for this, you're overthinking this by leaps and bounds. I mean it's not right, nor is it wrong. Molecular chemistry does have a role in this, but at the same time it doesn't. And it shouldn't. This isn't rocket surgery. Stop trying to make it harder than it is and by all means, quit over thinking it. If it's carbide you're using, just rotate the tool you're using to about 30 to 45 degrees and use it as a skew, you'll get the hang of it, promise. You can continue to make it more complicated than it really is and the only thing that will get you, is to stop working on what you're wanting to work on.

 

[BeeAMaker]

If you're looking to a chemist for this, you're overthinking this by leaps and bounds. I mean it's not right, nor is it wrong. Molecular chemistry does have a role in this, but at the same time it doesn't. And it shouldn't. This isn't rocket surgery. Stop trying to make it harder than it is and by all means, quit over thinking it. If it's carbide you're using, just rotate the tool you're using to about 30 to 45 degrees and use it as a skew, you'll get the hang of it, promise. You can continue to make it more complicated than it really is and the only thing that will get you, is to stop working on what you're wanting to work on.

Yes I have already solved the chipping issue - like you suggested, I started using the carbide as a skew - works well thanks. I even saved 2 of the 3 blanks.

We are on to a different issue where the brass tube is protruding further than the plastic, pictures a few post back. Any ideas there?

 

[thewishman]

That has happened to me a few times. I just sand the tube flush again and move on.

 

[Scissortail Pens]

If you're looking to a chemist for this, you're overthinking this by leaps and bounds. I mean it's not right, nor is it wrong. Molecular chemistry does have a role in this, but at the same time it doesn't. And it shouldn't. This isn't rocket surgery. Stop trying to make it harder than it is and by all means, quit over thinking it. If it's carbide you're using, just rotate the tool you're using to about 30 to 45 degrees and use it as a skew, you'll get the hang of it, promise. You can continue to make it more complicated than it really is and the only thing that will get you, is to stop working on what you're wanting to work on.

Yes I have already solved the chipping issue - like you suggested, I started using the carbide as a skew - works well thanks. I even saved 2 of the 3 blanks.

We are on to a different issue where the brass tube is protruding further than the plastic, pictures a few post back. Any ideas there?

I'm sorry Glenn. My post was uncalled for. I'm a little mad at the world at the moment. I went in last Thursday for a 12 minute operation to straighten out the lens in my left eye and walked out 4 hours later blind in that eye. While I'm trying to use that as an excuse, there's no excuse for me saying that to you. I'm sorry and I apologize to you and to anyone else that had to read this drivel that I posted. I hope you figure out what's causing your issue.

 

[BeeAMaker]

If you're looking to a chemist for this, you're overthinking this by leaps and bounds. I mean it's not right, nor is it wrong. Molecular chemistry does have a role in this, but at the same time it doesn't. And it shouldn't. This isn't rocket surgery. Stop trying to make it harder than it is and by all means, quit over thinking it. If it's carbide you're using, just rotate the tool you're using to about 30 to 45 degrees and use it as a skew, you'll get the hang of it, promise. You can continue to make it more complicated than it really is and the only thing that will get you, is to stop working on what you're wanting to work on.

Yes I have already solved the chipping issue - like you suggested, I started using the carbide as a skew - works well thanks. I even saved 2 of the 3 blanks.

We are on to a different issue where the brass tube is protruding further than the plastic, pictures a few post back. Any ideas there?

I'm sorry Glenn. My post was uncalled for. I'm a little mad at the world at the moment. I went in last Thursday for a 12 minute operation to straighten out the lens in my left eye and walked out 4 hours later blind in that eye. While I'm trying to use that as an excuse, there's no excuse for me saying that to you. I'm sorry and I apologize to you and to anyone else that had to read this drivel that I posted. I hope you figure out what's causing your issue.

No worries, sorry to hear about your eye. I probably should have started a new thread about the Tube issue anyways. I kind of hijacked my own thread lol.

 

[Charlie_W]

Glenn, Just to clear things up for me, is your material shrinkage occurring after the blank/tube is glued and squared?......and before it goes to the lathe?...is this right? Or is this after you have turned and finished the blank?

When you say you are turning between centers, does this mean using between centers bushings or truly between centers....the blank being held between a 60 degree dead center and a 60 degree live tail center?

How much pressure are you exerting on the pen blank while turning between centers?

Is there any heat transfer from bad bearings in either the headstock or a live center that is getting hot and transferring that heat to the pen blank/tube?

Possibly try flipping your blank end for end between the turning and sanding processes.

Just some thoughts.....hope something here helps in some way to alleviate your problem.

Good luck and please report your findings.

 

[BeeAMaker]

Glenn, Just to clear things up for me, is your material shrinkage occurring after the blank/tube is glued and squared?......and before it goes to the lathe?...is this right? Or is this after you have turned and finished the blank?

It happens after turning and sanding, but before polishing. I have not polished either tube. I also have not seen happen to acrylic or wood.

When you say you are turning between centers, does this mean using between centers bushings or truly between centers....the blank being held between a 60 degree dead center and a 60 degree live tail center?

Between Center bushings.
https://www.pennstateind.com/store/PKMBCM2.html

How much pressure are you exerting on the pen blank while turning between centers?

Very little, as light as possible, however I think it happens when sanding. My RPMs are around 1K while sanding. To high perhaps?
If we can start a fire by spinning a stick in the palm of our hands, I can imagine what types of temperature build up we can get at 1K or higher. I try to keep my paper/pads moving at all times and not hold in one spot. I wet sand with the pads. I wish I had a Thermal camera.

Is there any heat transfer from bad bearings in either the headstock or a live center that is getting hot and transferring that heat to the pen blank/tube?

I would hope I don't have a bad bearing already, It's only 2 months old. But I had this concern as well. It;s a bit of a story, but basically I never went much above 1800 RMP, not until i started having the chipping issues with polyester and Acrylester did I start cranking it to 2500 - 3000. Now at that speed my head stock will get warm to the touch and the heat does transfer to the head stock center. I can't remember which way the stock was in the lathe but I usually put the butt at the Head stock and the nib end to the tail stock. The shrinkage is at the nib end.

I also wonder if maybe I "forgot" to turn the RMP down before sanding. I wasn't use to the RPMs being that high when turning so I might not have thought about it. I don't think sanding with 600 grit at 3000 rpm would be very "cool".

Possibly try flipping your blank end for end between the turning and sanding processes.

Just some thoughts.....hope something here helps in some way to alleviate your problem.

Good luck and please report your findings.

I will!, thanks for the suggestions.

 

[BeeAMaker]

There are many factors at play here, so this might get long. But for those that are curious I'll give you the short answer first.

#0000 Steel Wool. - Not a good thing for Polyester blanks. - Let me explain.

First off I want to state that I have worked with Acrylic for the past 30 years. I can cut it, drill it, sand it, polish it, flame treat it, and just about any thing else. So working with the Acrylic blanks (or what they call "Acrylic") was like second nature, no problems what so ever. When I am done truning it, I sand it from 240 - 320 - 400 - 600 then #0000 steel wool then Novas #3, #2, then Jewelers rouge on a 20K RPM buffing wheel. Work very good - On Acrylic.

Mistake Number 1: Assuming these 3 blanks were Acrylic. When I purchased them there was no indication what material they were - Or I simply missed it. So I turned these blanks like I would acrylic. That is when I had the first problem, chipping. I started this thread asking for advice not realizing these blanks were polyester. After getting great advice from all you guys I figured out how to turn them better with little to no chipping.

Mistake Number 2: Once I had saved the blanks, I sanded them just like I would the Acrylic, even though by now I knew they were polyester. Which would be OK except for one thing, Polyester is much more susceptible to heat, and it holds heat much longer than other types, Acrylic is much more forgiving. To make matter worse, I am almost certain I forgot to turn down the speed before sanding. Polyester has a much lower melting point than Acrylic so sanding at to high of a speed becomes much more of a problem, but more importantly it becomes much more of a problem with #0000 SW. Because you can't tell how much heat is building up. It doesn't get hot on your finger like sandpaper would.

Mistake Number 3: Not paying attention. when I got to the 400g and the 600g papers, I recall thinking it was odd that I was gumming up the paper so quickly. This was the polyester powder melting into the sand paper. I also remember getting little "balls" stuck to the blank. But I ignored the obvious sign of over heating (I was still stuck in Acrylic mode). When I use SW, I ball a small piece up on the end of my finger so it don't get wound up on the lathe. The SW builds heat very quickly however I can not feel that heat because it is insulated buy a ball of SW. I did not realize it was getting too hot and this is where the shrinkage occurs.

To sum up I spent last night and this evening proving this all to myself. Sorry, I did not take pics or video as I didn't have the time I thought I might. so I concentrated on where I felt the problem was, the sanding process. I could re-create the problem when I used the Steel Wool at to high of an RPM. In fact, at one point I was purposely trying to over heat the blank with the SW, it didn't take long and I discolored the material, basically I burned it. and I was unable to sand it out after words. Although I didn't try, I'm sure one could get the same results with Sandpaper or microns as well.

Here is a picture of the discoloration.

Tonight I continued to play with it and got my sanding process down without all the heat. Even with the SW. Basically, go slow, I kept the RPMs blow 1200. It sands nice and the SW does not build up so much heat. If you are wondering why I use SW, it is because it allows me to go from 600g right to polish. I have done tons of Corian counter tops and I can sand down to about 400 grit, #0000SW and then polish and skip all the microns. Works good for me.

Here is the blank I saved tonight, (sorry it;s kind of blurry)

I will approach unknown materials more carefully from now on. I also intend to compile this information and others into a tidy Quick Tip video to hopefully help other newbies. This all might be a bit OCD-ish but I learned a lot about polyesters and Acrylesters ( which by the way are someplace between Acrylic and polyester) I was not previously aware of. Besides being more brittle, Polyester is also a very soft material. I think it's important to understand the dynamics of the material.

Now, thanks to everyone here I can now confidently turn and sand Acrylester and Polyesters. It will only get better from here.

Hopefully this information helps others.

 

[jttheclockman]

Are you using real steel wool??? If so I suggest dump it and get some nonwoven synthetic if you truely in need of steel wool which I believe you do not. You are running the risk of getting this in the motor or if you have a VS controller in there too. Do not want to breathe steel wool either. No good things can come from using it on pen blanks. Just a suggestion and a warning.

I hope you figured your problem out. I am still not buying it but you did the experimenting. Maybe I never got my blanks hot enough ever to have what you had happen. If and it is a big if because many times I go right to the wet dry paper and start at 1200, I have to sand at all I start with 400 grit and go to 600. Then wet dry till 2000 and then MM If you have to start lower then you need to practice your with your tools more. I inserted my opinion here and that all this is, my opinion.

Good luck.



www.amazon.com/Non-Woven-Assorted-A...&qid=1489038927&sr=1-4&keywords=non+woven+pad

 

[BeeAMaker]

I forgot to ask, at what RPMs do you guys do your sanding, MM, and then Polish?