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Vibratory bowl finishing - ebonite and acrylics/resins

latheman78

Hot Rolled
Joined
May 28, 2022
Location
Southern Ca Mtns.
Presand as you were doing. Try dry crushed corn cob (available at pet stores) in your vibratory polisher. Squeeze in a tube of tooth paste for the polishing magic. Add just a few drops of water. You want it on the dry side not wet. Let it go overnight.
Toothpaste? What brand, there are many types with various ingredients.
 

Zeuserdoo

Aluminum
Joined
Aug 31, 2015
Location
The Moridor
Try some from the dollar store on an old piece of bed sheet and rub the pen part for a few seconds. If there is enough abrasive in the toothpase, you will see a shine coming up pretty fast.
I have heard of using cheap toothpaste to remove scratches from acrylic, sounds like it's worth a try for a $1 tube of paste.
 

NewtonPens

Plastic
Joined
Jan 6, 2016
I actually made pens for a guy who collected money off a Kickstarter ages ago. He used some space age write upside down and on oily surfaces cartridge. They were ball point fixed (if that is proper nomenclature) with a screw on cap. I kept a few and gave a few away. They had a loop on the screw cap so you could hang it around your neck. Utterly shocked it didn't catch on. They were thick metal and short, probably best used as weapon
like putting a roll of quarters in your hand while punching someone.

Do note their was some sarcasm in there.

That sounds pretty cool. Can you upload a pic here? The way the market is, if you don't show your face at shows, especially the bigger ones (DC, San Fran, LA) the people who would spread your name the most won't get to meet you and know you, and then talk about how cool you are and how interesting your pens are. There's LOTS of metal pens from several different makers, and the designs are pretty similar between a few of them. The thing that really makes them each work (I think) is that the owners/makers get out to shows and meet people. A good blog post can be worth a LOT in advertising.
 
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NewtonPens

Plastic
Joined
Jan 6, 2016
Try some from the dollar store on an old piece of bed sheet and rub the pen part for a few seconds. If there is enough abrasive in the toothpase, you will see a shine coming up pretty fast.

Will try that if other things don't work out, thanks.

I just sent each of my 3 materials to Kramer and they're going to test tumble in different medias with different polishing compounds to see what happens. I'll hear back from them in a few weeks.

And right NOW I have each tumbler going with play sand and different polishing pastes from autozone. The sand bag was busted open and practically free, so this isn't going to cost me too much.

The wood chips/polish + shipping from Kramer will be over $300. Ouch. They have some other stuff, too. Some kind of preloaded media that looks interesting.
They also have some stuff called Bright Nut XA - https://www.kramerindustriesonline.com/product/premium-treated-tumbling-media/
that's supposed to do well with plastics as well.

I'll post pics tomorrow afternoon with results from the play sand.
 

sfriedberg

Diamond
Joined
Oct 14, 2010
Location
Oregon, USA
I just sent each of my 3 materials to Kramer and they're going to test tumble
This is a very valuable service, and I suspect most of the tumbler equipment and media people will do it if you have specific parts and ask nicely. They have all the stuff on-hand to experiment with, and frequently have some people with a lot of diverse experience. Obviously, they want to sell more machines and media, and people are more likely to spend money if they have proof in hand of the results of a specific process.
 

NewtonPens

Plastic
Joined
Jan 6, 2016
This is a very valuable service, and I suspect most of the tumbler equipment and media people will do it if you have specific parts and ask nicely. They have all the stuff on-hand to experiment with, and frequently have some people with a lot of diverse experience. Obviously, they want to sell more machines and media, and people are more likely to spend money if they have proof in hand of the results of a specific process.
Yeah if they show me I can spend $300 and get what I want, I'm happy to do it. It's the spending big money without knowing what will happen that I don't want to do.
Update - the sand is just leaving a nice matte finish on the parts. There's a big difference between the two polishes I chose though, so that's cool.
 

NewtonPens

Plastic
Joined
Jan 6, 2016
I'm going out today and will buy some corncob bedding on the way home. The sawdust left a nice matte finish.
 

NewtonPens

Plastic
Joined
Jan 6, 2016
So been running corncob bedding overnight, 14 or so hours so far - and VERY little difference from a matte finish. Will add a bit more polish to the bowls over the course of the day to see which one does better. The bedding might not be great though - it's mostly crumbled and turned to dust in there.
We'll see after some more time.
 

sfriedberg

Diamond
Joined
Oct 14, 2010
Location
Oregon, USA
For the ebonite, you might want to try some different hard media in the 1st pass. Maybe an extended run with a finer grit, or add an intermediate pass with a finer grit after the first pass. It sounds like too much surface rougness might be surviving to the final organic media+polishing compound pass.
 

magicmaker

Hot Rolled
Joined
Oct 7, 2006
Location
Tucson, AZ
So been running corncob bedding overnight, 14 or so hours so far - and VERY little difference from a matte finish. Will add a bit more polish to the bowls over the course of the day to see which one does better. The bedding might not be great though - it's mostly crumbled and turned to dust in there.
We'll see after some more time.
If your corncob is roo soft, add crushed walnut shells.
 

latheman78

Hot Rolled
Joined
May 28, 2022
Location
Southern Ca Mtns.
I hate to keep signing the praises of an HF product:

https://www.harborfreight.com/18-lb-vibratory-bowl-with-liquid-drain-hose-96923.html

Even stranger they are comparing it to a model far inferior. The only thing that could be it's downfall is the motor and that can be replaced with a better one. It even gets better action
than the Thumler UV-18 I had, I am wondering if the small HF vibe bowl is the size of the UV-18.

I think Newton has that 5# model, do you mind checking how much water it would hold?

I really don't think walnut would polish plastic without additives, but like I said I mostly polish metals.
 

NewtonPens

Plastic
Joined
Jan 6, 2016
Yeah I have the 5lb bowl from HF. Seems to work as well as my Burr King, but a lot louder.
I might just be using the wrong additives, but the walnut shell I ran the other day only gave it a moderate shine.
Not near enough to a mirror or almost mirror polish that I get with the buffing wheels.
 

latheman78

Hot Rolled
Joined
May 28, 2022
Location
Southern Ca Mtns.
If I am just using media my HF large model is so loud, I can't stand to be in the shop when it is running. It is as bad as running hex stock in a steel tube barfeeder without a liner.
 

surplusjohn

Diamond
Joined
Apr 11, 2002
Location
Syracuse, NY USA
As a final finish . Think about a dry tumble with wax balls. I have seen Hardwood parts tumbled with wax and they came out looking like someone fussed with them for an hour
 

NewtonPens

Plastic
Joined
Jan 6, 2016
I've never thought about waxing the parts. Not sure if that would be a good idea with fountain pens that get handled a lot.
 

magicmaker

Hot Rolled
Joined
Oct 7, 2006
Location
Tucson, AZ
I ran crushed walnut shells on its own and didn't see much shine. Would walnut plus corncob be any better?

Thanks
The pumice in the toothpaste does the polishing. The crushed walnut is the carrier. If the corn cobs turned to mush, things were too wet. Add only a few drops of water.
 

BoxcarPete

Stainless
Joined
Nov 30, 2018
Location
Michigan, USA
I've never thought about waxing the parts. Not sure if that would be a good idea with fountain pens that get handled a lot.

I haven't ever used wax, but I polished most of my pens on a 2x72 using a felt belt charged with white rouge. Gets them shiny enough for me, but whatever the binder is in the white rouge gets on the pen, and it's enough to mess with ink flow until it wears off. Had me scratching my head for days before I figured it out, and it was at least another week of regular handling before it worked right.

Something to keep in mind when you choose your polish, that it doesn't have some kind of semi-persistent hydrophobic component.
 

NewtonPens

Plastic
Joined
Jan 6, 2016
The pumice in the toothpaste does the polishing. The crushed walnut is the carrier. If the corn cobs turned to mush, things were too wet. Add only a few drops of water.
The corncob turned to dust without any water at all. I'm guessing it was just cheap stuff in no way meant for this. It was all compressed into little cylinders, and after half a day it was all dust. :/
 








 
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