# There must be a trick...



## Fred Bruche (Mar 31, 2018)

.. but I can't figure it out. And the search doesn't seem to pull an answer. So here it is. Is there a trick to evenly polish threads on "plastic" material? What I have tried (toothbrush, cotton rag, blue workshop towel) can't seem to reach the "valleys". Tried with a few plastic polish compounds to no avail.
 If it makes a difference, I am working with galalith. 
Thank you for any help!


----------



## magpens (Mar 31, 2018)

Fred, I am interested in the answers you may get so I am piggy-backing (subscribing) on your thread !

Hope you don't mind ... LOL


----------



## lorbay (Mar 31, 2018)

When I need to get my threads super shiny I use flame polishing. I use a very small tip in a propane torch. Make sure you get some practice on a few pieces first, there is a sweet spot, like fast but not too fast.
Lin


----------



## Curly (Apr 1, 2018)

I don’t think the flame polishing is a good idea on the vintage materials. Best usually is to cut the threads as clean as you can to start with. A lubricant like cooking oil helps but not a petroleum based one. Petroleum oils and solvents can be detrimental to plastics. You might try some of the non-waxed flosses to hold the polish. Either single strands is several held together but not twisted. That’s all I can suggest.


----------



## More4dan (Apr 1, 2018)

I’ve used polish on the threads using the cap to polish the body by threading it on and off. For metal threads I’ve used Braso the same way.  


Sent from my iPad using Penturners.org mobile app


----------



## magpens (Apr 1, 2018)

Curly, I find your comments very helpful as always.  But why not twisted together ?


----------



## Curly (Apr 1, 2018)

If you twist it it would be like string and not get to the bottom where loose strands pulled tight would conform to the V form of the thread. That's my theory and I'm sticking to it.


----------



## magpens (Apr 1, 2018)

Sounds perfectly reasonable ... I get what you meant now. .... to take advantage of the smallest fibre diameter possible.


----------



## Terredax (Apr 1, 2018)

My answer involves a way to spin a buff wheel. If you have a motor off of something else, or a method of attaching to your lathe, or even a drill could work (just take longer), just mount a string buff and buff the threads without any pressure on the wheel. Let the ends of the wheel just touch the material.
Don't linger, it will heat up and melt or distort the threads.

A string buff is designed to stay cool, and to reach complex shapes without cutting the details. They work great on plastics.

I would use two compounds, which requires two individual wheels. One wheel, one compound. Never apply different compounds to the same wheel.


----------



## Fred Bruche (Apr 1, 2018)

Thank you everybody for the suggestions!!
That piece might have been doomed from the beginning, I used WD40 as the lubricant :frown: not sure but I won't do it again. 
John thank you for the buffing wheel idea. I don't have one for the lathe but I have some with my Dremel tool. I had only one string wheel on hand and gave it a try. That's probably the most promising thing I have used and I could see it do the trick. It didn't completely work though, but it could well be because I futzed with that piece for a while already and might have ruined it. On my way to remaking it right now  And I can use the doomed piece to try the other suggestions!!


----------



## Pierre--- (Apr 2, 2018)

I used a hairy buffing wheel, you know, this kind of hippie stuff saturated with plastic polishing compound. It did not really polish satisfactorily the bottom of the threads, but I was close. Then, for a smooth screwing, I used a silicone lubricant spray, and the whole threading was looking great. It seams to stay attractive over time.


----------



## MikeinSC (May 13, 2018)

I'm curious, why the desire to polish down to the root of the thread? 

On a side note, I highly discourage the use of anything food related as a source of lubricant. Especially cooking spray. It can gum up equipment that is meant to slide. If you don't believe me, ask anyone that does restaurant equipment repair what it can do.


----------



## jnpenworks (May 19, 2019)

MikeinSC said:


> I'm curious, why the desire to polish down to the root of the thread?
> 
> On a side note, I highly discourage the use of anything food related as a source of lubricant. Especially cooking spray. It can gum up equipment that is meant to slide. If you don't believe me, ask anyone that does restaurant equipment repair what it can do.



Excellent point. Just noticed that on my tools this weekend ‍


—
Jason Miller
Sent from my iPhone using Penturners.org mobile app


----------



## jnpenworks (May 19, 2019)

More4dan said:


> I’ve used polish on the threads using the cap to polish the body by threading it on and off. For metal threads I’ve used Braso the same way.
> 
> 
> Sent from my iPad using Penturners.org mobile app



Does that seem to work pretty well? I’ve also seen some people use just a small Dremel and rotary brush to do that. What do you use as polish? Something like One Step? Thanks!


—
Jason Miller
Sent from my iPhone using Penturners.org mobile app


----------



## More4dan (May 19, 2019)

jnpenworks said:


> Does that seem to work pretty well? I’ve also seen some people use just a small Dremel and rotary brush to do that. What do you use as polish? Something like One Step? Thanks!
> 
> 
> —
> ...



I use Meguiare’s Crystal Craze #9 auto polish. Used as a finish polish for new paint jobs to remove any swirls from clear coat polishing. I also use it as a final polish for resins and CA finishes. 

Danny









						Meguiar's M9 Mirror Glaze Swirl Remover 16oz
					

Shop for Meguiar's M9 Mirror Glaze Swirl Remover 16oz with confidence at AutoZone.com. Parts are just part of what we do. Get yours online today and pick up in store.



					www.autozone.com
				





Sent from my iPad using Penturners.org mobile app


----------

