bending stems and delrin tenons

For discussion of fitting and shaping stems, doing inlays, and any other stem-related topic.
Post Reply
Doug535
Posts: 271
Joined: Sun Nov 26, 2017 3:49 pm
Location: Independence, Missouri

bending stems and delrin tenons

Post by Doug535 »

Ok, so I took George's suggestion on the last author attempt and tried to re-bend the stem more and further back. I now have a tenon that flops around like a sausage in a street corner girl, and the stem face is no where near flush anymore. WTF did I do wrong? Did I not heat it up enough?/too much? It was apparently hot enough to melt my epoxy but still took a fair amount of force to get it to start a bend. Wrong epoxy? (I use a standard 5min epoxy) I use my parting tool to cut 2 grooves in the tenon and use my dremel to cut lines inside the mortise. Or is it possibly a culmination of more things than one?
LatakiaLover
Posts: 3120
Joined: Sun Sep 02, 2007 4:29 am
Location: Kansas City, USA
Contact:

Re: bending stems and delrin tenons

Post by LatakiaLover »

Stem bending is not just the "heat and apply pressure" thing that most people would guess. Doing it really well is quite difficult, in fact, and takes a LOT of experience and practice to get right every time.

You obviously heated the material enough that the glue softened. (which usually means around 180 degrees unless high heat glues are used)

There's no need for high heat glue, though, if you shield the shank/tenon joint from direct heat by shielding it while heating, and then support the base of the stem by holding it instead of the shank when applying bend-pressure.

If you don't have a pair of leather gloves, it's time to get some. They take all the "scary" out of handling hot objects and getting accidentally scorched by the heat source.
UFOs must be real. There's no other explanation for cats.
User avatar
Sasquatch
Posts: 5147
Joined: Tue Jan 13, 2009 1:46 am

Re: bending stems and delrin tenons

Post by Sasquatch »

acrylic or ebonite stem?

Either way, yes, obviously you heated something up too much in the wrong spot and you need to focus your heat more and/or protect the tenon from heat. 1.5" of wet pipecleaner in there helps too.
ALL YOUR PIPE ARE BELONG TO US!
User avatar
Sasquatch
Posts: 5147
Joined: Tue Jan 13, 2009 1:46 am

Re: bending stems and delrin tenons

Post by Sasquatch »

What are you heating with?
ALL YOUR PIPE ARE BELONG TO US!
Doug535
Posts: 271
Joined: Sun Nov 26, 2017 3:49 pm
Location: Independence, Missouri

Re: bending stems and delrin tenons

Post by Doug535 »

Sasquatch wrote:What are you heating with?
I'm heating with a heat gun. As far back as George suggested I start my bend I heated it as close to that area as possible. At almost 7/8 thick at that spot it took quite a bit to get it to even start to bend. By then, when I started to bend the tenon just went with it.
And I'm using ebonite.
User avatar
Sasquatch
Posts: 5147
Joined: Tue Jan 13, 2009 1:46 am

Re: bending stems and delrin tenons

Post by Sasquatch »

At 7/8" thick it ain't gonna bend. Bend the part that will bend, and make a few corrections to the line afterward by hand, ie, file it to the desired shape.

Fat stuff requires lots of cheating.
ALL YOUR PIPE ARE BELONG TO US!
Doug535
Posts: 271
Joined: Sun Nov 26, 2017 3:49 pm
Location: Independence, Missouri

Re: bending stems and delrin tenons

Post by Doug535 »

Duly noted. I may go back and make another stem for it at a later date, I've got to move forward towards making a correct author.
wdteipen
Posts: 2817
Joined: Sat Mar 29, 2008 1:05 pm

Re: bending stems and delrin tenons

Post by wdteipen »

To correct this problem, don't use Delrin. :D

Seriously, Delrin has a much lower melting point and is a real pain with bending thick stems. The heat travels through the airway and begins heating the pipe from the inside as well as the outside to it's real tricky to keep the tenon from overheating. I've found the trick to be heating the stem very slowly.
Wayne Teipen
Teipen Handmade Briar Pipes
http://www.teipenpipes.com
Post Reply