Threading Liquid Diamonds Epoxy

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H

hokie

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Hi everyone!
I am looking to cast parts for my kitless pens instead of turning raw material to size in order to save a bit of time. I was attracted to liquid diamonds due to its ease of use and apparent ease of turning. However, I'm wondering if anyone else has encountered the threading issue I'm trying to address with liquid diamonds.

After curing for a few days, my casts are nice and hard, unable to be dented with a fingernail, not even close. When I turn my tenon down to size and thread with a die, the threads appear quite rough and the black color goes near white/light gray. The delrin I usually use stays smooth and black after threading, so I'm not sure how to either prevent the phenomenon or fix it after threading.

Here is a picture of what I'm talking about...


If it needs polishing, what is the best way to polish without damaging the threads? If I need to change my casting or threading approach, I'm all ears!

Thanks in advance!
 
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I have the same issue when threading dark color Acrylics. I wonder if threading while it's still relatively soft might help, Delrin is a soft plastic.

I polish my acrylic threads with plastic polish using the cap working it on and off the body. I use Brasso for metal threads.


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I have been struggling with that myself so I won't be of much help.
Applying PlastX with a toothbrush somewhat helps some, but doesn't give a perfect result.
I have also noticed that dark colors (i.e. black or such) are much more prone to showing the kind of badly polished look you encountered, so I'm experimenting with other colors or having visible threads in that range of color (see the last kitless pen I posted). I have also gotten other items (pads, compounds,...) but haven't had a chance to test them.
One simple thing I'm planning to test is using Renaissance wax on these threads, it can't hurt :)
 
Last edited:
Curly said:
What are you using for thread lube? Try some cooking oil if you were doing it dry.
Click to expand...

I don't use any lube because I just assumed the softness of the plastic wouldn't require it. I tried adding "Back to Black" automotive spray that gets applied to faded black plastic panels on vehicles to darken them and it worked at first, but the effect faded within a day.
I am sure an oil of some sort would work to keep the material dark at first, but I am just not sure about its longevity.
 
Fred Bruche said:
I have been struggling with that myself so I won't be of much help.
Applying PlastX with a toothbrush somewhat helps some, but doesn't give a perfect result.
I have also noticed that dark colors (i.e. black or such) are much more prone to showing the kind of badly polished look you encountered, so I'm experimenting with other colors or having visible threads in that range of color (see the last kitless pen I posted). I have also gotten other items (pads, compounds,...) but haven't had a chance to test them.
One simple thing I'm planning to test is using Renaissance wax on these threads, it can't hurt :)
Click to expand...

Glad to know I am not alone! I am hoping to find a long term solution because I'd like to give a pen to someone and not have the fit an finish fade over time (or at least to a minimal extent). I'll keep experimenting.
 
More4dan said:
I have the same issue when threading dark color Acrylics. I wonder if threading while it's still relatively soft might help, Delrin is a soft plastic.

I polish my acrylic threads with plastic polish using the cap working it on and off the body. I use Brasso for metal threads.
Click to expand...

Like I responded to Fred, I'm glad to know it might not be operator error! I like the idea of using the cap to polish, I might just need to make a cap with close enough tolerances, I suppose. I tried using fine string with plastic polish on another piece and it was such a chore. Tiny buffing wheels just done get deep in the threads either.

I am intrigued by the thought of threading at just the right point in curing, but that sounds stressful! I wonder if I could demold, chuck, turn, and thread while relatively soft and not cause any issues. Hmmmm.
 
There's a fancy plastic polishing method I've read about that seems promising, namely "vapor polishing". I saw a couple of videos where they used acetone to do that, but I have not tried it or even sure it would work for epoxy.
 
Curly's suggestion of using a light oil like vegetable oil is a good one .

I have never threaded the material you are threading, but I have threaded plenty of acrylics.

You definitely need a lubricant, IMHO. . I use WD-40, which works well.

There is another thing ... heat. . When you are threading you are stressing the material a great deal. . Stressing generates heat, and heat can discolor plastics.

It would be a good experiment to try a lubricant AND try threading more slowly than at present.
 
magpens said:
There is another thing ... heat. . When you are threading you are stressing the material a great deal. . Stressing generates heat, and heat can discolor plastics.
Click to expand...

I actually tried heat! I used a propane torch to lightly kiss the threads as it spun, but instead of melting, I got puffs of smoke and it just started to stink. No visual change worth mentioning.

I will definitely try the threading lube, but I have to admit I'm skeptical because I just can't wrap my head around how the cutting action at the deepest part of the cut is going to result in any different of a finish than if I just applied oil after the cut is made. I need to just trust those with a bit more experience, obviously. I'll let everyone know how it goes!
 
Fred Bruche said:
There's a fancy plastic polishing method I've read about that seems promising, namely "vapor polishing". I saw a couple of videos where they used acetone to do that, but I have not tried it or even sure it would work for epoxy.
Click to expand...

I would love if something like an acetone vapor could do the job. Great idea. I'll do some research, experimenting, and report back!
 
Fred Bruche said:
There's a fancy plastic polishing method I've read about that seems promising, namely "vapor polishing". I saw a couple of videos where they used acetone to do that, but I have not tried it or even sure it would work for epoxy.
Click to expand...
Acrylic can be flame or chemical vapor polished. See http://www.penturners.org/forum/f19/how-chemical-polishing-inside-demonstrator-pens-148238/ for an example of polishing acrylic with Methylene Chloride (a.k.a Dimethyl Chloride). These methods do not necessarily work with other plastics.

I've had good success cutting and tapping threads in opaque Alumilite (Alumilite White and RC-3 Black). Acetyl (Delrin) is another easily threaded material (often used in commercial pen kits). Others also thread Acrylic, Cebloplast, Flexigran, and Ebonite. Polyester and some epoxies do not cut as cleanly.

See http://www.penturners.org/forum/f56/making-fountain-pen-section-tutorial-88966/ for some helpful hints.

I hope that helps,
Eric
 
greetings
Acetone vapor is used to polish cellulose acetate screwdriver handles and other cellulose objects. Acetone can be used but it gets smelly.
 
I don't have a lot of experience here but I polished the threads turned with alumilite on the beall buffing wheel. Used huts ultra and lightly buffed the threads -a blue pen I turned came out nicely doing this
 
Thanks everyone for the suggestions!
I just tried acetone and it didn't seem to work much if at all. Even dipping the piece directly into the liquid didn't seem to have an effect. I'll give the other options a shot soon.
 
Hokie I just came across you thread and thought I would share some insight. If you have already remedied your problem then great, I would love to hear the solution. If not then this is my insight.
Looking at your picture at the beginning of you thread it appears that instead of cutting threads you are braking threads. What I mean by that is looking closely at the surface of the cuts intead of a clean cut it is thousands of small chips. The reason you are noticing the color change is the light is reflecting in all microscopic cracks that where created from the fracturing of the resin. This is caused by only a couple of things. One your die is not as sharp as it needs to be or you need lubrication on the cut.
Based on your follow posts I would say it's the later. Peter and Mal would be correct with there advice for lubrication. I would also say although most epoxy resins are very chemical resistant I would stay away from the WD-40 as the solvents in it could have an adverse affect. The lubrication is not only there to help with heat dissipation but, more importantly in your case to actually assist in the cutting of the material. The lubrication helps the remove slight binding and gauling of the die and ease it through the material. The menuscual binding and gauling of the die causes it to lock in place and as you continue to feed it forward it will jump forward causing the fracturing rather than cuting. You would not see these issues when working with a material like delrin because delrin is a fairly slick material for all purposes it is self lubricating. That is one of the many reasons it is so widely used in the machining world.
As for solution's after the fact there are a couple of this to consider. Looking at the suggestion that have been made. First trying a chemical solution I don't think you will have to much luck as epoxy is quite chemical resistant. That kind of process works on materials that are susceptible to solvents like PVC and ABS. Second heat, will will most likely not get much help here either. Once again it is the propertys of the material epoxy is fairly stable with heat and once you get it hot enough it burns rather than melt. Heat is best on plastics the will melt before they burn like polycarbonate and HDPE. Lastly polish this is the one that is most promising but it won't work on its own.
I would start with a quick coat of thin CA to fill the cracks and chips then chase the threads once more followed by polishing.
 
John Eldeen said:
Hokie I just came across you thread and thought I would share some insight. If you have already remedied your problem then great, I would love to hear the solution. If not then this is my insight.
Looking at your picture at the beginning of you thread it appears that instead of cutting threads you are braking threads. What I mean by that is looking closely at the surface of the cuts intead of a clean cut it is thousands of small chips. The reason you are noticing the color change is the light is reflecting in all microscopic cracks that where created from the fracturing of the resin. This is caused by only a couple of things. One your die is not as sharp as it needs to be or you need lubrication on the cut.
Based on your follow posts I would say it's the later. Peter and Mal would be correct with there advice for lubrication. I would also say although most epoxy resins are very chemical resistant I would stay away from the WD-40 as the solvents in it could have an adverse affect. The lubrication is not only there to help with heat dissipation but, more importantly in your case to actually assist in the cutting of the material. The lubrication helps the remove slight binding and gauling of the die and ease it through the material. The menuscual binding and gauling of the die causes it to lock in place and as you continue to feed it forward it will jump forward causing the fracturing rather than cuting. You would not see these issues when working with a material like delrin because delrin is a fairly slick material for all purposes it is self lubricating. That is one of the many reasons it is so widely used in the machining world.
As for solution's after the fact there are a couple of this to consider. Looking at the suggestion that have been made. First trying a chemical solution I don't think you will have to much luck as epoxy is quite chemical resistant. That kind of process works on materials that are susceptible to solvents like PVC and ABS. Second heat, will will most likely not get much help here either. Once again it is the propertys of the material epoxy is fairly stable with heat and once you get it hot enough it burns rather than melt. Heat is best on plastics the will melt before they burn like polycarbonate and HDPE. Lastly polish this is the one that is most promising but it won't work on its own.
I would start with a quick coat of thin CA to fill the cracks and chips then chase the threads once more followed by polishing.
Click to expand...

Thanks John! Sadly, Once I started having this problem, I stopped pursuing the epoxy threading effort, but not before I tried a few of the suggestions in the thread. First, the die is practically band new, so I'm confident that isn't the primary factor. I next tried threading when the epoxy was slightly softer, but it was just too sticky. I then tried lubricant, specifically mineral oil. Unless I was doing something wrong, I just wasn't getting any better results to be honest.

I wish you posted earlier, because you predicted some of my other troubles as well! Dunking the threads in solvents like acetone did squat and heating the threads on the lathe with a propane torch caused issues as you imagined. As a last resort I tried applying thin CA. While the "whiteness" went away, the roughness still showed through and even keeping the CA from gunking up in the fine threads was a challenge too.

I've conceded I need to try a different material like Allumilite. I understand it threads beautifully. It just takes a bit more in the way of tools and techniques to get cured properly. I had high hopes for the Liquid Diamonds because folks like Chad Schimmel (in this video @ 8:40) indicates he wants to try threading it. The fact that he updated his description to announce he was carrying it made me think it did everything under the sun, including threading. I guess not :/
 
hokie said:
Thanks John! Sadly, Once I started having this problem, I stopped pursuing the epoxy threading effort, but not before I tried a few of the suggestions in the thread. First, the die is practically band new, so I'm confident that isn't the primary factor. I next tried threading when the epoxy was slightly softer, but it was just too sticky. I then tried lubricant, specifically mineral oil. Unless I was doing something wrong, I just wasn't getting any better results to be honest.

I wish you posted earlier, because you predicted some of my other troubles as well! Dunking the threads in solvents like acetone did squat and heating the threads on the lathe with a propane torch caused issues as you imagined. As a last resort I tried applying thin CA. While the "whiteness" went away, the roughness still showed through and even keeping the CA from gunking up in the fine threads was a challenge too.

I've conceded I need to try a different material like Allumilite. I understand it threads beautifully. It just takes a bit more in the way of tools and techniques to get cured properly. I had high hopes for the Liquid Diamonds because folks like Chad Schimmel (in this video @ 8:40) indicates he wants to try threading it. The fact that he updated his description to announce he was carrying it made me think it did everything under the sun, including threading. I guess not :/
Click to expand...
Sorry to hear that it never do work out for you but best of luck to you on your current endeavors đź‘Ť
 
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