03-25-2017, 01:01 PM
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With the design settled, I packed the handle and knot up and shipped it off to my friend.  We'd work together through email to pick materials and fine tune things to put together the final wood handle...and since we both have day jobs...I needed to figure out something to keep me occupied until he could work on the handles.  While I did a lot of tweaking and scaling to get the more substantial handle I was looking for, I kept going back to the original design...it was much smaller, but I really liked it, and it would accommodate a 22mm knot. Not being a wood turner, the next step was to figure out how I could make a handle myself...and probably more critical, how I could make one that matched the shape of my design!  Here is a hint...

[Image: Qf2DqvU.jpg]

23 1,938
 03-25-2017, 04:06 PM
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Casting the handles seemed like my best bet.  I settled on resin and cement as materials for the casting. Silicone was used to make the molds...one mold a proof of concept, the other the final mold.

Some shots of the mold making...

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silicone poured around the 3D print (the print is anchored to the bottom of the mold with a dot or two of hot glue...)

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the silicone mold removed from the foam core box mold...

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and the 3D printed blank removed from the silicone mold...

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23 1,938
 03-25-2017, 04:18 PM
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The first mold I made was a proof of concept mold...just to see if it worked.  And it did!  The 3D print I used had not been cleaned up at all so the mold itself was rough.  I then cast a cement handle, again a proof of concept, to make sure the material would work in the mold and that I'd be able to remove it without breaking...

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and the first handle out of the mold...

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It was pretty rough, but it worked!  All the blemishes, as well as the layers of the 3D printing process, showed in the final result...which was fine for this first attempt.

23 1,938
 03-25-2017, 04:23 PM
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A few more tests, this time in clear and colored resin, decided me on moving forward with cement as the casting material.  I was concerned that the resin would require too much finishing to get to a presentable look, whereas the cement had a naturalness that lent itself to minor levels of finishing...this is assuming that the blank for the mold, and the mold itself, was as smooth as possible...more on that later.

[Image: uEaV5Lb.jpg]

23 1,938
 03-26-2017, 06:47 AM
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With the casting material finalized, I used epoxy, primary and sand paper to smooth out the 3D print.  I then poured a new silicone mold over the cleaned up, and now smooth print.

[Image: VTqjanu.jpg]

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23 1,938
 03-26-2017, 06:57 AM
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With the final mold complete, I began casting handles and experimenting with mixing ratios for the cement.  When de-molded, the handles need very little finish work -  I light sanding on the bottom and a very very light overall sanding...

It took some time before I could figure out how to make the concave bottom of the handle...and then it dawned on me...ping pong balls!  I cut a ping pong ball in half, weighted it with cement, and use it as a "cork" after pouring the cement.  It caps off the top of the mold and forms the concave bottom.

[Image: LxF87Pk.jpg]

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cast with and without ping pong ball form...

[Image: q1kqVgN.jpg]

[Image: U4PKOcG.jpg]

23 1,938
 03-26-2017, 07:12 AM
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I picked the best of the castings and put together my brush...I experimented with different lofts and ended up with 50mm.  Two quarters and some silicone shim and fix the knot in place temporarily.  I am thinking of moving the knot down to 47mm to make it a touch more scrubby.  When I am satisfied with the final loft, I'll epoxy it in place.  But for now, there seems to be no reason...the silicone seems to be working fine.  The handle, strangely enough, has a leathery feel to it.  It's quite nice in the hand.  When first exposed to water, it had a bit of a splotchy appearance as it dried, but after the first use, the handle has a very consistent look and finish -- making me think that some of the crazy finish experiments I've been working on (not detailed here!) are for not.

The final assembly...

[Image: 0pI0cNC.jpg]

[Image: OmNqos1.jpg]

[Image: m7F6VRl.jpg]

[Image: dnd0kpn.jpg]

23 1,938
 03-26-2017, 07:20 AM
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...and some pics of the final brush...

[Image: ardYvaJ.jpg]

[Image: Xxzrya7.jpg]

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[Image: UizjyY7.jpg]

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23 1,938
 03-26-2017, 07:43 AM
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Very cool read. Great to see things like this on the forum...

3 104
 03-26-2017, 09:27 AM
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Thanks Mike!

23 1,938
 03-26-2017, 10:02 AM
  • Rufus
  • Senior Member
  • Greater Toronto Area
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Very nice.  I wish I had your talent.

8 1,014
 03-26-2017, 02:57 PM
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Thanks @Rufus.

23 1,938
 03-26-2017, 08:04 PM
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A very concrete example of how to make a unique brush. Thank you Smile

3 5,466
 03-27-2017, 05:54 AM
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Ha! That's a good one!

23 1,938
 03-28-2017, 12:57 AM
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Mighty impressive Tom!

4 1,038
 03-28-2017, 02:20 AM
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Thanks for posting this-just fascinating!

29 831
 03-28-2017, 02:46 AM
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You have impressive talent Tom.  Thanks for putting in the huge amount of time and effort I know this thread required.  It's been fascinating to follow.

52 7,704
 03-28-2017, 02:54 AM
  • German
  • Simpson 2 Band Aficionado
  • USA
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Thanks for sharing this story.

43 2,020
 03-28-2017, 03:14 AM
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Fascinating for sure.

Great job!

11 1,597
 03-28-2017, 08:29 AM
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This has been a joy to follow.

1 119
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