vertical casting question

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H

hooked

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Hello. I am hoping someone can point me in the right direction. I have recently been getting into kitless pens, so I have been working on making my own kitless blanks. Since I am going for 9-inch blanks, I am trying to cast vertically. I would like my blanks to fit a 20mm collet out of the mold. I have tried 3/4 PVC and 3/4 HDPE but find that both of these are oversize. Other vertical solutions I see online are larger. My PVC blanks are coming out at .810 and HDPE at .842; neither fits my 20mm collet. I notice that all of the kitless blanks I buy online fit comfortably in a 19-20mm collet.

Would anyone care to share what types of molds are being used to produce blanks that fit within a 19-20mm collet?

Thanks for any advice!
 
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JohnU said:
Turn some Alumilite rods to the length and diameter you want and cast them in silicone for your own specialty mold.
Click to expand...
Hi John,

That is an outstanding idea. Have you done any videos or tutorials on making silicone molds?
 
TDahl said:
Hi John,

That is an outstanding idea. Have you done any videos or tutorials on making silicone molds?
Click to expand...
Not yet but there are a few out there. The easiest way is to make it up side down. Glue the rods down to a nonporous material which will be the top, then make your sides about an inch taller than the rods. That will be the thickness of the bottom. If you don't have plastic for the mold box you can use wood covered with tuck tape. The "red mold maker" at Alumilite is real easy to mix and pour but it's a little costly. I've used a couple different silicone rubber types and they all come with easy instructions. Some of them will require or suggest you to pull a vacuum to remove the air bubbles from it before it cures. You can use rice to fill the mold and then dump in the mixing cup to see how much mold maker you'll need. I like to lightly spray mold release in the mold before I pour the silicone. You'll need to disassemble the box sides to remove your new mold after it cures. That stuff creates an air tight suction and won't just fall out. The silicone may be costly but you'll recover your investment in resin use when you're using less making the blanks to the exact smaller size your looking for.

Here's an example of a mold I made with wood and tuck tape.
 

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@hooked Are you using a metal lathe?

Something you might consider, is turning those .810" blanks down to a consistent diameter.
Alumilite straight out of the mold is not necessarily perfectly round. This can cause you huge issues when taking components out of a collet, then putting it back in. Yes, I know that the solution to this is to just not remove it from the collet. You will find, as you move along the Kitless path, that this is not always feasible.
Besides, you will likely find that 20mm is way larger than what you need. I would be very happy if my blanks were a consistent 18mm.
 
I do not have a metal lathe....yet.:) I was hoping not to turn all of my rods down before I use them in a collet. I like how the rods I purchase all fit in my collet and then turn them to round. I understand that I can trim them down to fit or purchase a 21mm collet as well, but as you said, it is just more material than needed and a waste of resin.

I agree that 18mm would be about perfect. The ebonite I have is all 18mm. I think making a silicone mold is a great idea and will likely go that route using my ebonite rods.
 
Leave your blanks in the mold and supported for as long as you can. Alumilite doesn't actually reach full cure for about a week. Taking them out at the two or three hour mark, can allow them to warp or deform slightly.

I haven't tried making my own molds yet. For now I'm using PTownSubbie's molds.
Make sure whatever you use to make the mold is dead straight. It would suck to have a slight warp in one of the mold rods.
Also, make sure the silicone won't stick to the ebonite.

Good luck with the venture. Let us know how it goes.
 
JohnU said:
Not yet but there are a few out there. The easiest way is to make it up side down. Glue the rods down to a nonporous material which will be the top, then make your sides about an inch taller than the rods. That will be the thickness of the bottom. If you don't have plastic for the mold box you can use wood covered with tuck tape. The "red mold maker" at Alumilite is real easy to mix and pour but it's a little costly. I've used a couple different silicone rubber types and they all come with easy instructions. Some of them will require or suggest you to pull a vacuum to remove the air bubbles from it before it cures. You can use rice to fill the mold and then dump in the mixing cup to see how much mold maker you'll need. I like to lightly spray mold release in the mold before I pour the silicone. You'll need to disassemble the box sides to remove your new mold after it cures. That stuff creates an air tight suction and won't just fall out. The silicone may be costly but you'll recover your investment in resin use when you're using less making the blanks to the exact smaller size your looking for.

Here's an example of a mold I made with wood and tuck tape.
Click to expand...
Thank you for the information!
 
When you buy Alumilite…. Pay close attention to the name. "Clear" and "Clear Slow" are urethane resins and will cure to a solid state in a few hours depending on the one you buy. "Amazing Clear" is an epoxy resin and will take 5-7 days to cure from a flexible state. Epoxy is also harder on your molds and can harm silicone molds because it's so adhesive. Too many use the company name as a resin description and it can be misleading. Good luck!
 
So... I kept this secret for a long time... Admittedly we had an edge in the market by having blanks that were perfectly suited to go in a collet out of the molds. :) These days EVERYONE is casting vertically so I'll go ahead and spill the beans... You need schedule 80 PVC not schedule 40. We used clear PVC for a long time for the long rods. We've moved on to steel molds, which also work great but are considerably more expensive.
 
McKenzie Penworks said:
So... I kept this secret for a long time... Admittedly we had an edge in the market by having blanks that were perfectly suited to go in a collet out of the molds. :) These days EVERYONE is casting vertically so I'll go ahead and spill the beans... You need schedule 80 PVC not schedule 40. We used clear PVC for a long time for the long rods. We've moved on to steel molds, which also work great but are considerably more expensive.
Click to expand...
Thank you very much!!!!! I really appreciate this information. It is your blanks that fit in my collets perfectly and why I wanted mine to do the same.
 
We targeted the fountain pen market from day 1, 4 years or so ago now I guess it was. My first feedback came from Carl Fisher and he mentioned how much he hated having to turn down blanks to fit in collets. So we played around and found the right tool for the job so that people could unwrap our blanks and immediately get to work. These days we stay in business based on reputation and quality more than the size of our blanks so figured it wouldn't hurt to share lol Have fun!
 
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