# What resins will NOT hold up to no internal brass



## Carl Fisher (Oct 3, 2013)

A curiosity question about materials and their ability to hold shape without an internal support.

I'm pretty sure PR and Alumilite may have issues.  PR seems to warp in and humidity based on what I've seen just with blank storage in my shop.  A thin wall pen body I could picture warping pretty good or even becoming pliable by hand.  I'm making an assumption about Alumilite just based on how soft it is to turn, but I don't have first hand experience with an Alumilite kitless.


So what other materials should be avoided when there is no desire to use a brass tube or some sort of other structural support?


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## MesquiteMan (Oct 3, 2013)

Remember, Alumilite is actually harder than PR but has a higher tensile strength, allowing it to flex more before failure and thus turn "softer".  I have made Sierra's with no tubes before and they were fine.  I probably would not want to sit on it in my back pocket but then again, I would not want to do that even with a brass tube in it.


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## frank123 (Oct 3, 2013)

Wall thickness is the most important factor with the material used being secondary, IMO.

Alumilite -PU, I think- seems tougher than PR for the most part, but PR gives a harder surface (at least from my limited experience).  Of course, YMMV according to the brand of resin used.


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## Carl Fisher (Oct 3, 2013)

I left a pretty good wall thickness on this one.  I used PR for prototyping since I had quite a few of these blanks available.  I'm just curious if/how it will hold up over time.

My assumptions above were pure speculation and I'd be happy to be proved wrong.


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## Turned Around (Oct 3, 2013)

Carl Fisher said:


> I left a pretty good wall thickness on this one. I used PR for prototyping since I had quite a few of these blanks available. I'm just curious if/how it will hold up over time.
> 
> My assumptions above were pure speculation and I'd be happy to be proved wrong.


 
damn, I want that blank. where'd you get it?


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## Carl Fisher (Oct 3, 2013)

Garnet and Black mix that I had Jonathon mix up for me some time back.  I had a few extra in the shop and figured they would be a good test material.


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## Sandy H. (Oct 4, 2013)

I make some of the Pentel conversions that have no tubes and get pretty thin from PR.  Once they are finished, I haven't broken one yet.

I'll bring a couple to the Saturday meeting to see what you think.

Sandy.


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## BRobbins629 (Oct 4, 2013)

Most available blanks can be made without tubes.  While I have made a bunch with many different materials, folks like Brian Gray from Edison Pen Co have made thousands with PR, acrylics, celluloid, ebonite, etc.  While no material is immune to abuse there are just as many reasons to crack a tubed pen than a tubeless. One of the reasons many kit pens crack is the expansion of the brass tube when the fittings are pressed in creating stress on the material.  Tubeless pens can breathe.  I've made a few from a batch of ivory that a friend had multiple cracks with tubed kit pens and mine remain crack free.


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## Carl Fisher (Oct 4, 2013)

I'm glald to hear that I'm mistaken.  I was worried about deforming more than cracking really. 

I guess I'll move forward with PR since it's what I have the most of.  Thanks!


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