Epoxy Notes (Conap K-22 Black EasyPoxy)

[staffwalker]

What do most of you guys use for epoxy? I've been using T-88 but I've had a few failures, most with delrin but one involved a ebonite cap and briar . Thought it was because the tubes I was using had gotten old so I ordered a new batch, had another failure the other day. And no I don't do anything special, just a couple of squeezes of each and mix. I use the long cure stuff but never touch a recently glued item until it has cured at least eight hours. I'm losing my faith in T-88, any recommendations?

[KurtHuhn]

T-88 has to be cured for at least 24 hours, sometimes as long as 48 depending on temperature. It's a good structured epoxy when used for it's intended purpose, but it really takes way too long to cure.

[Alan L]

I like the 5-minute stuff by the T-88 folks, but I have discovered if you leave the tubes sitting beside the coal stove too long the five minute open time becomes a 30 second open time...

On one of the knifemaking forums there was a long (as in 18 pages) thread called "glue wars" in which nearly every adhesive available was tested for the purpose of holding a flat slab of wood to a flat piece of steel. Testing included shear strength (trying to twist the wood off sideways), impact (hit it with a hammer), temperature sensitivity (freeze it and do the previous tests, heat it ditto), and finally the dreaded dishwasher test.

All cheap epoxies failed miserably. System 3 did okay, Gorilla Glue (!) did really well, West Systems did okay, Golfsmith did very well, Accraglas (regular, not gel) was second best but is considered a little too messy for pipe work by me. The best one found out of the hundred or so tested was Loctite E-120HP. This is not an over-the-counter epoxy and must be ordered from an industrial supply house like McMaster or MSC.

Remember this test was for a large wood-to-metal joint. The #1 factor in improving bond strength no matter what adhesive was proper surface prep, in this case sanding the wood to 120 and sandblasting the steel. Sandblasting the steel improved adhesion by up to 1000% over a smooth surface.

I still use the T-88 5 minute. For a wood-to-wood joint it works for me. It also does really well on lucite and ebonite, is not expensive, and takes black epoxy dye really well. This is handy for those accent rings that don't quite seal perfectly. Dye the epoxy, let cure, sand smooth, and buff. No more gap! I also like it for doing bands, because if I decide I need to redo it all I have to do is hold it over a lighter until it hits about 300 degrees and it'll pop right off. Do not try this with acrylics or ebonite, BTW...

[Sasquatch]

Proper prep does make a huge difference with almost any gluing application. I'll take cheap glue on a well-prepped surface over miracle glue on a glassy surface any day.

[ToddJohnson]

When epoxying delrin into ebonite both should be grooved. Delrin is so slick that you're not going to get a good joint by simply sticking it into a smooth mortise and gluing it. Also, the fit is so tight with the grooves that I have to use a mallet to seat the delrin. 5-minute epoxy will do a great job, and you need not jump through any ridiculous hoops, but you do have to prepare both the delrin and ebonite properly.

TJ

[buster]

Mike,

Your posts give me mild panic attacks. What are you talking about?

[staffwalker]

Todd may have hit on the problem I occasionally have. I have always deeply grooved the outside surface of the delrin, both latitudinal and longitudinal but I have never grooved the inside of the stem. Thanks, I'll start doing that.

[KurtHuhn]

Todd has mentioned something very important - both surfaces MUST be prepared very well. Alan also tangentally hit upon it. The joint between the delrin and ebonite is a mechanical one more than a chemical one, so you have to make sure that both surfaces can resist movement of the epoxy. In addition to grooves in the delrin, I also cut some reliefs at 120 degree (roughly, nobody actually measures these things) increments around the circumference. See the sticky in the stem forum for some ideas.

[bluesmk]

I had similar issues with System Three T-88, only because I wasn't careful enough to mix it 50-50. How does T-88 rate with you guys as an epoxy? I was hoping this was the cat's meow of epoxies.

Hmmm, this is what I've used for over 10 yrs, the only time it has failed me is when I was being too cheap and hanging on to something that should have been pitched.
In fact according to the company you should use less hardener. Yep, thats what I do.
A little liberal dollop, mixed with a little less liberal dollop! Here check it out:
http://www.systemthree.com/
Dan
Gabrieli Pipes

[caskwith]

What do you use to groove the inside of the mortice? I groove the delrin using a peice of hacksaw blade and i just cut lots of diagonal slashes into it then hammer it into the mortice. But im not sure how to grove the mortice. I tried using a dental pick but it didnt really seem to do much.

[bluesmk]

What do you use to groove the inside of the mortice?

Here's how I do it:

Dan
Gabrieli Pipes

[ToddJohnson]

What do you use to groove the inside of the mortice? I groove the delrin using a peice of hacksaw blade and i just cut lots of diagonal slashes into it then hammer it into the mortice. But im not sure how to grove the mortice. I tried using a dental pick but it didnt really seem to do much.

You can use the same hacksaw blade and just spin the chuck by hand (with the rod stock in it, of course) and the hacksaw blade in the mortise at an acute angle.

TJ

[Nick]

I like to tell the strength of my epoxies by adding a mixed dollup or two between my massive butt cheecks and then seeing which one holds better. I usually butt test four or five at the smae time. So far ass-masters 900T has had the strongest holding power, but it took 12 hours to cure, which was a real bummer.

[caskwith]

Two great suggestions there, thanks Dan and Todd. Im going to find a bit of scrap rod and try them both out tommorow

[geigerpipes]

What do you use to groove the inside of the mortice?

Here's how I do it:

Dan
Gabrieli Pipes

Dan that is also how I do extensions and I use these in stainless that I drill out to 4mm makes for a good bond

[Mike Messer]

Mike,

Your posts give me mild panic attacks. What are you talking about?

Just some facts about epoxy, some of its vulnerabilities, and one way to deal with them. If you will notice in several of the posts in this topic the word "failure" was mentioned. I'm trying to avoid that word, systematically, that's all. It isn't that hard to do. Sorry, about the panic attacks (I think you're kidding, though. Right?)

Geiger's threaded rod seems like a good idea, and if you can get perfect alignment and size the holes just right so that the threads cut into the wood and bamboo (or you could tap it, first, and make threads), you get a good, strong mechanical connection, and the glue just keeps it from turning. I read one of Kurt's descriptions and he said he just glued the end of the shank-bamboo connection, no glue in the holes or on the rod, right?

However, I made one pipe with a removable bamboo shank, which allows access to the smoke hole with a reamer, and also allows an optional, tip with no bamboo extension to be used. In that pipe the steel had to be glued to the bamboo, but I didn't like that pipe very much. I never smoked it, put it on a shelf.
There doesn't seem to be an ideal or perfect way to make a long bamboo. When Smoking, how do you ream a long bamboo-shank pipe? Call roto-rooter? I use a guitar string (a big wound E string).