# Help: which material for an ink window?



## Pierre--- (Jun 29, 2018)

Hi everyone, 

I tried to make an eyedropper with ink window. I used PMMA (Plexiglas), but no matter how careful I was with drilling and turning, after polishing it was rather a leaking cracked ice than a clear ink-proof window. 

So, what you guys use for ink windows? I heard of "clear acrylic", which seems unknown to our regular providers, so where do you get yours?
Thanks for your answer.


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## duncsuss (Jun 29, 2018)

Pierre--- said:


> Hi everyone,
> 
> I tried to make an eyedropper with ink window. I used PMMA (Plexiglas), but no matter how careful I was with drilling and turning, after polishing it was rather a leaking cracked ice than a clear ink-proof window.
> 
> ...




I use the same thing you used (in the USA it normally goes under the DuPont name "Lucite") but try to get "cast" rather than "extruded". I was told there are often internal stresses introduced by the extrusion process that can cause cracks when the material is drilled, turned, etc.


Somebody told me it's possible to improve the working quality of extruded rods by putting them in hot water (a bit like annealing metals), but I don't know how long for or exactly how hot the water should be.


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## Curly (Jun 29, 2018)

I remembering seeing the boiled extruded rod stuff a few years ago but I have no idea where. If memory serves and it often doesn't, :roll eyes: You need to put something on the bottom of a cooking pot to keep the blanks from touching the bottom of the pot, small towel perhaps and boil the rod for at least 20 minutes. Once it cools down again you can turn it. I'll get around to trying it someday. 

If the cracking inside the blank looks like a bunch of interconnected cracks, kind of like a partially broken windshield, it is called crazing. Plexiglass does it from prolonged exposure to the sun, accelerated by ammonia cleaners. It will also do it when drilling with petroleum based products like solvent (Varsol, mineral spirits) and kerosene. If you used a cutting oil or lubricant meant for metal that will do it too. The post about segmenting running now has a picture of a blank I made that crazed inside that I think was from the CA glue but I may have used WD-40 or some other oil to lubricate the drill, I don't remember and can't say for sure.

http://www.penturners.org/forum/f17...w-up-blank-while-drilling-131424/#post1759483


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## Penultimate (Jun 29, 2018)

I bought acrylic tubing, I don't remember if it was cast or extruded, from eBay. It worked well for me. 


Sent from my iPad using Penturners.org mobile app


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## Pierre--- (Jul 1, 2018)

Cast or extruded PMMA makes a lot of difference indeed. I know what to use now. Thanks for your help!


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## penboard (Jul 20, 2018)

*PMMA for inkwindows*

I bought some wonderful stuff from Delvies plastic years ago. 
no problems at all for recreating inkwindows on new pens, 
or build a whole new piston filler barrel. 
and yes, it needs to be cast acrilic.


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## PenPal (Jul 20, 2018)

Pierre--- said:


> Hi everyone,
> 
> I tried to make an eyedropper with ink window. I used PMMA (Plexiglas), but no matter how careful I was with drilling and turning, after polishing it was rather a leaking cracked ice than a clear ink-proof window.
> 
> ...



Hi mate a while back I bought a number of pens from China direct so I could use the parts ,many were clear. Glued a threaded piece in the cartridge. No Idea where I ordered but Google was my friend,cheap as chips and may fill your requirement.

Kind regards Peter. PS JINHAO ON E BAY FOR STARTERS (free freight).


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## jalbert (Jul 21, 2018)

This:
Unpolished Cast Acrylic Rod - Clear, Colors, Pearls and Fluorescents - Delvie's Plastics Inc.


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## duncsuss (Jul 22, 2018)

I've used both Delvies unpolished (the link John provided) and US Plastic Corp, who sell polished rod at a very competitive price. Which is cheaper seems to come down to who is charging least for shipping.


(It makes no difference to me whether the rod is polished or unpolished, since I'm going to be turning it down to size anyway.)



https://www.usplastic.com/catalog/item.aspx?itemid=24197&catid=440




Duncan


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## CrimsonKeel (Jul 24, 2018)

Could someone cast you a clear resin window?  ive cast some clear PE blanks before.


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