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Working with bakelite stems
Posted: Tue Jan 19, 2010 2:57 pm
by T3pipes
Can pre-formed bakelite stems be heated and shaped just like acrylic can? And are there any special considerations I should be aware of? I just got a few of these and thought it best to ask first before screwing them up really bad.
Re: Working with bakelite stems
Posted: Tue Jan 19, 2010 3:21 pm
by jeff
Yes it can. Be careful, though. Acrylic will melt when it overheats, but bakelite burns and becomes fragile. The main problem you will have is in bending. I've heard that it snaps easily, though I've never done it. Make sure you heat it sufficiently and do not force the bend. Good luck.
Like acrylic, though, it is cake to finish and requires far less sanding than ebonite. In fact, if I had a steady stock of black bakelite, I'd prefer using it to vulcanite because I find it to be far easier to work and finish.
Jeff
Re: Working with bakelite stems
Posted: Thu Jan 21, 2010 2:24 pm
by T3pipes
Any advice on epoxy for the tenon? I am using 1hr set time epoxy, let it set for 4, and it is not holding on the bakelite.
Re: Working with bakelite stems
Posted: Thu Jan 21, 2010 2:40 pm
by ToddJohnson
This probably has more to do with your mortise size versus the size of the delrin you're using. Even a thousandth or two will make a big difference. If you have any slop in your lathe at all, or the bit is even slightly oversized, or if you drilled in more than one pass, you're going to be creating a hole that's more than 312.5 thousandths. Also, the tenon should be ribbed and the interior of the mortise (I mean the mortise in the stem, of course) should be grooved to create additional friction. Also, try going to an epoxy with a shorter set time.
TJ
Re: Working with bakelite stems
Posted: Thu Jan 21, 2010 2:46 pm
by e Markle
ToddJohnson wrote: Also, the tenon should be ribbed and the interior of the mortise (I mean the mortise in the stem, of course) should be grooved to create additional friction.
Any quick way to groove the inside of that mortise? I did it with a sharp screw, but...
Re: Working with bakelite stems
Posted: Thu Jan 21, 2010 3:02 pm
by KurtHuhn
Ditto the epoxy recommendation. Lok-Tite makes an epoxy specifically formulated for plastics that has an open time of about 7 minutes. In my testing, it is a significant improvement over the typical stuff, and even over the T-88 epoxy.
Delrin, as long as you, prep both surfaces as Todd said, will be secure in the mortis. To groove the inside of the mortis in the stem, I use a silly little tool I made just for that purpose. It resembles a teensy little boring bar.
Re: Working with bakelite stems
Posted: Thu Jan 21, 2010 3:18 pm
by ToddJohnson
e Markle wrote:ToddJohnson wrote: Also, the tenon should be ribbed and the interior of the mortise (I mean the mortise in the stem, of course) should be grooved to create additional friction.
Any quick way to groove the inside of that mortise? I did it with a sharp screw, but...
Use a jigsaw blade.
TJ