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Help Please about stem bending

Posted: Thu Jan 17, 2008 6:50 am
by Bob Oakley
I have just bent my first stem. It is a Lucite stem (pre-made) that I put on a slightly bent dublin pipe. When I bent the stem, it bent in an angular shape (elbow shape) not a curved shape. I bent it to an angle about 25-30 degrees. Sorry, no pictures yet. The stem looks good on the pipe although it may be too much of an angle. My questions:

1. Is this angular bend a "design" flaw in the pipe? A pipe cleaner passes and I do not detect air flow interuption.

2. Did the stem bend at an angle because I bent it too soon - before it was properly heated?

3. If I re-bend, do I bend back to straight then bend it rounded?

Thank you for any information you can give me.

Posted: Thu Jan 17, 2008 7:19 am
by Bob Oakley
I was just able to get computer working and got this picture of the pipe and stem. Hope this illustrates better than words.

Image

Re: Help Please about stem bending

Posted: Thu Jan 17, 2008 8:28 am
by pierredekat
1. From a purely "design" standpoint, the general consensus is that the bit should be parallel with the top of the pipe. But there is some flexibility in that rule.

And for me, anyway, I think this pipe would look a whole lot better with a straight, or nearly straight, stem, since the shank is so straight, and more or less parallel with the top of the pipe.

But beauty is in the eye of the beholder, and if you like it, that's all that really matters.

2. Possibly, if you heated the stem over a candle, or some other narrow heat source. But if the stem was heated more evenly, it could be that you didn't bend evenly. Like when I do it, I use a potholder and bend along the face of my thumbs.

But it's not that simple, either. Because sometimes you have to tweak things a little. Depending on the thickness of the stem and its temperature, sometimes you have to apply a slight amount of extra pressure in the thicker sections.

And even in the best-case scenario, more often than not, you still have to wait until the stem cools and really true things up with files and sandpaper.

3. Honestly, do you have another stem to work with? Because I have a real sneaking suspicion that this one has a stress crack that, one day, will just fall apart unexpectedly. Unless it was just really melted good in that one area when you bent it, anyway.

Posted: Thu Jan 17, 2008 8:35 am
by KurtHuhn
It's only a design flaw if you didn't mean to do it that way. :)

The abrupt bends tend to come from heating a very localized area and bending at just that area. What did you use to heat the stem?

Ask 12 pipe makers how to bend a stem, and you'll get 12 different responses. What I normally do is set the heat gun upright on the workbench and wave the stem over it, rotating every couple seconds so that one side or the other doesn't burn. I heat pretty much the entire stem and use my entire hand to form the stem to the shape I want. Fingers on top, thumb on bottom, and create a curve over the length of the entire stem.

Posted: Thu Jan 17, 2008 10:46 am
by kkendall
It's not that unusual for lucite to do that, especially if the stem was heated a little more in that area.

The stem WILL straighten out with heat and you can try again. Try to heat the whole last half of the stem a little more evenly - keeping in mind that the center section will need a bit more heating because of the cross sectional area that needs to be heated compared to the section behind the button.

Another thing you can do when the stem is softening up and ready to bend, use a bottle of Corona out of the fridge and lay your stem across the surface of the bottle to make the radius. (or whatever bottle has the diameter you want). You will get a more consistent radius and this also helps the stem to cool and set in place a little quicker.

BTW - Nice looking pipe!

Re: Help Please about stem bending

Posted: Thu Jan 17, 2008 1:52 pm
by Tyler
pierredekat wrote:1. From a purely "design" standpoint, the general consensus is that the bit should be parallel with the top of the pipe. But there is some flexibility in that rule.
I'd take issue with this a bit. I don't think there is a consensus. I also think that many fine pipes are ruined by the bend of the stem. IMO, many many pipemakers tend to over bend stems. Parallel is often too far.

As for the issue at hand, heating a stem is a bit tricky to avoid the kink. Basically you need to evenly heat the stem over its whole length which translates into much more heating near the shank where the stem is thickest. What you see with your stem is typical. The thin area got hot and pliable, the thick area did not, so the stem "turned a corner" where it was too cool to be pliable.

Tyler

Posted: Thu Jan 17, 2008 3:15 pm
by hazmat
Bob.. this is completely off-topic, but I noticed you list location as Erie, PA. That's my hometown!!! I'm now in Harrisburg but make it back up there a couple times a year to catch some of those chrome rockets you've got swimming 'round the lake.

Matt

Posted: Thu Jan 17, 2008 4:03 pm
by Frank
The heating part has been covered, so I won't go into that. As for the bending, I bend the stem over a large diameter wooden dowel, clamped in my bench vise.
kkendal's idea of a cold beer bottle sounds interesting. I think I'll give it a try.

Posted: Thu Jan 17, 2008 4:20 pm
by hazmat
Frank wrote:The heating part has been covered, so I won't go into that. As for the bending, I bend the stem over a large diameter wooden dowel, clamped in my bench vise.
kkendal's idea of a cold beer bottle sounds interesting. I think I'll give it a try.
You just want a reason to drink a beer :lol:

Posted: Thu Jan 17, 2008 8:40 pm
by Bob Oakley
Thank you all for your help. I think I will re-bend the stem with the technique that you all talked about. I will also keep the bend very slight and rounded. Maybe use a scotch bottle instead of a Corona bottle. :lol:

Posted: Fri Jan 18, 2008 12:10 am
by KurtHuhn
hazmat wrote:You just want a reason to drink a beer :lol:
Real pipe makers don't need a reason. :twisted:

Posted: Fri Jan 18, 2008 12:11 am
by KurtHuhn
Bob Oakley wrote:Maybe use a scotch bottle instead of a Corona bottle. :lol:
And that works for me, too. :D