Seem to have lost my segmenting "touch"...

[mbellek]

So, about a month ago -- actually 2 months ago, I relocated my shop. I moved from borrowing my father-in-law's equipment, to my very own shop with my very own equipment! (yeesssss!) Just before this process began, I had discovered segmenting and was very into it, and was also very successful at it. However, other than the help of all of you (and some very very basic info from my father in law on basics of operating the lathe), I'm self-taught, so I fly by the seat of my pants a lot.

When I moved into my new shop, things were a bit slow going at first, so I haven't done segmenting in quite a long time. I just tried to make a rather simple segment the other day, and it busted within minutes of turning it! I had not even rounded it down yet! I don't get it. It was epoxied, clamped, and left to set for at least 2 days... The same thing has happened on two other occasions, and these are simple segments -- Wood-A/1/4" stripe of Wood-B/Wood-A

What are some common pitfalls of segmenting that I might be hitting? (Remember, These are hair pins that I"m making, so I'm not drilling a hole in the blank, so I don't think I'm weakening it that way)

If there is more info you need to know to help me, tell me so!

(Hope I'm not the only one thinking of woodturning on Thanksgiving!!)

 

[Russianwolf]

It may be your glue.

Epoxy is wonderful stuff for bonding one surface to another, but it is also kinda brittle in my experience. So while it may be great for gluing the tube into a blank for pen turners, it may not work as well for turning laminations. Left overs on a sheet of paper for instance can be broken like glass.

I use good old wood glue for my laminations and have never had a glue joint fail. It allows some flex in the bonded fibers, so this may be the issue that you are dealing with.

 

[mbellek]

Really?

You mean, yellow elmer's glue?

I was told that epoxy was good because it has a lot of "shear strength" -- unlike CA.

The weird thing is, I sometimes bond pieces that I've turned separately with epoxy. For example, if I try to turn tru-stone & another wood together, for some reason it has broken EVERY TIME, though not at the join. So I turn these components separately, flatten them, dowel, and bond them with epoxy.

Once, for the sake of my own knowledge, I decide to break a tru-stone/wood piece at the join. It turned out that the tru-stone gave before the epoxy did!

I was wondering if it could be like, my segments aren't perfectly square, or something like that... Does that matter? Are there factors OTHER than which adhesive I've chosen that could affect a segmented piece?

 

[Randy_]

Lots of possibilities and not enough details. A picture might help.

What kind of wood are you using?

Does the glue joint run the full length of the hair stick or are doing something fancy?

Is the glue fresh?

Epoxy has a shelf life and doesn't work as well if it has been around for a while.

 

[GaryMGg]

Melanie,
In your OP you wrote "it busted within minutes of turning" but you don't say if it broke at the joint or somewhere else.
Randy mentioned some of the problems.
Are you turning with the same tools you were using? Are they sharp enough? Are you forcing anything?
Like Mike, I use Yellow Glue for some of my glue-ups albeit I typically use medium CA for simple segments such as you're describing and don't often have failures.
Photos of the blanks in-process and after a break would probably help folks diagnose the problem(s).
HTH.

 

[Ron Mc]

Melanie,
I have done a couple segmented pens and have always used medium CA with no problem at all.
A couple questions:
What is the temperature and humidity level where you live at the moment?
You said, "and it busted within minutes of turning it! I had not even rounded it down yet!" Why are you not turning until it is round?
Can you please give me a visual? I just might be able to help you.

 

[Russianwolf]

Originally posted by mbellek
<br />Really?

You mean, yellow elmer's glue?

I was told that epoxy was good because it has a lot of "shear strength" -- unlike CA.

The weird thing is, I sometimes bond pieces that I've turned separately with epoxy. For example, if I try to turn tru-stone & another wood together, for some reason it has broken EVERY TIME, though not at the join. So I turn these components separately, flatten them, dowel, and bond them with epoxy.

Once, for the sake of my own knowledge, I decide to break a tru-stone/wood piece at the join. It turned out that the tru-stone gave before the epoxy did!

I was wondering if it could be like, my segments aren't perfectly square, or something like that... Does that matter? Are there factors OTHER than which adhesive I've chosen that could affect a segmented piece?

Yep, yellow wood glue. loc-tite in my case but any yellow wood glue will do as long as it's fresh. once opened, the older it gets the less effective the glue is. You can also use plain old elmers glue-all (white glue) as it is the same as the yellow glues but doesn't have the additives that give the color and shorten the open time that the yellow glues have. I often use it for flatwork that need alot of parts glued at one time.

 

[MesquiteMan]

There was an article in one of the woodworking magazines a while back about the various glues that we use. One point I remember specifically is that epoxy is a GREAT adhesive when you have a situation where you have a little bit of an uneven surface. It also showed that with epoxy it is quite easy to "over clamp" and squeeze out the adhesive, causing a starved glue joint. When gluing with epoxy you should use light clamp pressure. With PVA glues (carpenters glue or white glue) the more clamp force you have (within reason of course) the stronger the joint will end up.

I do not do any segmenting but have done a lot of fine woodworking with no fasteners, only glue. The only glue that I use is Titebond II. I would suggest you go that route or better yet, follow Ron's advice since he has as much or more experience in segmenting than anyone.

 

[Randy_]

Originally posted by mbellek
<br />...I just tried to make a rather simple segment the other day, <b>and it busted within minutes of turning it!</b> I had not even rounded it down yet! I don't get it. It was epoxied, clamped, and left to set for at least 2 days... The same thing has happened on two other occasions, and these are simple segments -- Wood-A/1/4" stripe of Wood-B/Wood-A...

I didn't mention it earlier; but the comment above sort of puzzles me? Were you doing something to the hairstick when it broke and if so, how was it being stressed or was it just laying on a table minding its own business?

 

[VisExp]

Like Curtis I use Titebond. If I am making something that needs water resistant properties, like a cutting board, I will use Titebond III.

Something that has not been brought up is the types of woods you were using. Some oily woods need to be wiped with mineral spirits prior to glue up.

 

[loglugger]

Melanie, the pices that are glued need to be flat so they will fit tight together.
Bob

 

[mbellek]

Randy! I meant I had JUST BEGUN turning it... lol.

 

[cbonner]

I use thick CA, clamp it nice and tight, then hit it with accelerator, let it sit for a few minutes, then move onto the next facet of the segmentation. For the glue joints, I think one likely source for issues would be how well the two pieces mate. I run it over the belt sander to get both sides nice and flat. Once I complete the glue-up, I don't give it much time before drilling. I also use polyurethane glue, which I have had good success with (the overnight set time will not work for many, but I am very happy with the results).

As for it breaking on the lathe, I would be careful about two things. First is the sharpness and type of tool. I like to use a roughing gouge, or another shallow gouge I have. Second (and probably most important) is the method in which I use it. I take very light oblique cuts, carfully avoiding dig-ins. I think using a tool in a scraping mode increases the risk of a catch and blow-out. I also cheat a bit and knock off all four corners on the bandsaw prior to the turning operation.

 

[rherrell]

I agree with the yellow glue crowd.