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My first acrylic stem- an issue

Posted: Tue May 10, 2016 7:22 pm
by DocAitch
I cut my first acrylic stem and had it looking pretty good (for me).
Then I heated it over the heat gun to bend it and a couple of things happened: 1) it took about twice as long to get to the pliant stage for bending 2) a pattern appeared on the surface of the heated parts of the stem which matched the inclusions in this piece of "tortoise shell" acrylic.
It is difficult to see this pattern, but it is also palpable.
Image
This after a gentle filing that hits the high spots
Image

Is this a common phenomenon with acrylic or is it just because of the way this particular material, "tortoise shell" is constructed?
DocAitch

Re: My first acrylic stem- an issue

Posted: Tue May 10, 2016 7:29 pm
by LatakiaLover
Just sand the surface level with 1000 or so after bending. Use backing boards, though, not just your finger.

(The perfection-chaser guys sand after bending vulcanite, too. Heating brings out zombie scratches.)

Re: My first acrylic stem- an issue

Posted: Tue May 10, 2016 8:26 pm
by DocAitch
I took it down with a #2 file, then 400, 600, 800, 1000.
It was actually kind of attractive, but it had to go.
Does this happen with acrylics in general or just with the fancy stuff like tortoise shell?Image
DocAitch

Re: My first acrylic stem- an issue

Posted: Tue May 10, 2016 9:41 pm
by LatakiaLover
Tortoise is definitely the worst, but all acrylic tends to hold pressure marks from bending.

Re: My first acrylic stem- an issue

Posted: Wed May 11, 2016 8:33 am
by caskwith
Yep this can happen with patterned rods, it can even happen on cumberland.

For me personally I find it best to shape my stem, sand to 320, bend and then sand up to 1000 and polish. I am always happier with the result, any distortion is easily removed by going over with 320 again if needed and on some shape stems I find I want to take off a little more material after bend to get the shape right, if I have only sanded to 320 I have not wasted my time if I need to go back to something coarser.

Re: My first acrylic stem- an issue

Posted: Wed May 11, 2016 8:36 am
by sandahlpipe
I've had it happen with several acrylics after bending. I always plan on a little sanding after the bend. I like the stem on this pipe!

Re: My first acrylic stem- an issue

Posted: Wed May 11, 2016 12:07 pm
by pipedreamer
I like tortoise a lot and it can be a horses ass! I always have to sand again after bending. I have yet to make one I'm happy with...

Re: My first acrylic stem- an issue

Posted: Fri May 13, 2016 8:01 am
by Sasquatch
I just never look close at my pipes after bending the stem.

Problem solved! :thumbsup:

Re: My first acrylic stem- an issue

Posted: Fri May 13, 2016 10:48 am
by DocAitch
Sasquatch wrote:I just never look close at my pipes after bending the stem.

Problem solved! :thumbsup:
This was my first experience with acrylic, guys. This surface development just caused a little consternation.
I won't look too closely in the future, thank you, Sasquatch. :notworthy: I also won't finish to 1000 and buff before bending, thank you, Chris. :doh:
DocAitch

Re: My first acrylic stem- an issue

Posted: Fri May 13, 2016 3:47 pm
by Sasquatch
It's possible you overheated it too... acrylic is really fussy. It goes from stubbornly stiff to totally liquid over about a 3 degree transition in temperature, and 3 degrees more and it'll bubble. It's no goddam fun.

Re: My first acrylic stem- an issue

Posted: Fri May 13, 2016 4:37 pm
by caskwith
Sasquatch wrote:It's possible you overheated it too... acrylic is really fussy. It goes from stubbornly stiff to totally liquid over about a 3 degree transition in temperature, and 3 degrees more and it'll bubble. It's no goddam fun.

Polyester isn't much better, except it doesn't bubble, it just turns into fudge and falls apart.

Re: My first acrylic stem- an issue

Posted: Sat May 14, 2016 10:05 pm
by Sasquatch
With the added advantage of slowly creeping back to straight over about 3 months in many cases too! Yayyy! :lol:

Re: My first acrylic stem- an issue

Posted: Sun May 15, 2016 3:26 am
by caskwith
Sasquatch wrote:With the added advantage of slowly creeping back to straight over about 3 months in many cases too! Yayyy! :lol:

Luckily not a problem I have encountered except with Ivory so I don't use it on heavy bent stems anymore.

Re: My first acrylic stem- an issue

Posted: Tue May 24, 2016 11:52 am
by mji.ipour
Well done Doc . Its good

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