Adhesive Question

[Raymond Fries]

I am a beginner at turning. I bought one of these back scratchers for a gift:

http://www.packardwoodworks.com/Merc...Category_Code=

I turned a purpleheart but handle only used a different profile. The hole in the handle is 7/16" diameter and 4 1/2" deep. It is a snug fit for the scratcher.

Would it be better to use epoxy or CA glue. I do not want to put to much adhesive in there and cause a problem.

Is it better to put a little adhesive in the hole away from the top to avoid it coming out. The handle is finished and do not want to mess it up.

Thanks

[Don Orr]

Personally I don't like or use CA glue if I can avoid it. Epoxy is an excellent choice for this project. If the fit is snug as you say then placing the glue down in the hole a little should work just fine. Epoxy will also give you enough working time to get the scratcher all the way into the handle before it sets. Post a photo of the finished piece-we love pictures!

[John K Jordan]

Raymond,

I far prefer epoxy over CA and use it on all handles. CA has been known to get brittle and have problems with age. Also, some wood species, such as Cocobolo, can cause CA to set up VERY quickly - I remember one that set up so fast I couldn't even get the shaft inserted all the way. (Ruined that one.) Also, epoxy squeeze-out is easier to clean up than CA.

I like to use quality 1-hour epoxy instead of the fast-setting stuff. Zero problem with setting up too quickly - the parts can be taken apart and redone several times if needed.

I do two things when using epoxy on a shaft like that. One, the epoxy can seal around the shaft and cause air pressure to build up inside the hole as the shaft is inserted. This feels like a strong spring and can make it difficult to seat the shaft it completely. To minimize that I scratch a healthy groove or two down the inside of the hole (or on the shaft itself, at least on the part that will be hidden) to give the pressure someway to escape. Two, for a smooth metal shaft I rough up the shaft with a grinder, Dremel, or shaft to give the glue something to grip to.

I like to put a little epoxy into the hole with a thin spatula or something and also smear some on the shaft. It doesn't take much! Any glue put in the hole will be pushed towards the bottom and any put on the shaft will be squeegeed out the top. I twist back and forth as I insert the shaft to distribute the glue. Some will squeeze out at the opening so I keep pieces of paper towel to wipe them up immediately. A little wax on the wood around the hole will let any squeeze-out to be removed cleanly.

If air pressure does build up as I insert the shaft I press it down hard and hold the two pieces together under pressure from a clamp or vise or weight until the glue sets up. (I get this ready before I start, just in case.) Even with a lot of springy force from the air it will eventually dissipate through the wood but even if it doesn't it's no problem after the epoxy is set up. Note that you can also put epoxy in the hole only on one side and push the shaft straight in - this may let air escape on the opposite side and when seated, the shaft can be rotated to distribute the glue. (BTW, the fit doesn't need to be too snug. The epoxy will easily fill any looseness and the connection will still be very strong.

One other thing I like to do - I mix small quantities of epoxy on a piece of aluminum HVAC tape on my lathe bed or workbench. I find it easier to mix that way, doesn't waste a mixing container, and cleanup is instant. It addition, by testing the residue on the tape with my thumbnail I can judge when the epoxy is almost and completely set.

If new to this and if you have a piece of scrap rod you might even practice with a hole in a piece of scrap wood to get the feel of it.

BTW, if you ever need to remove a epoxied handle heating the metal with a torch will soften the glue and the handle can be twisted. That's commonly used to remove lathe tools from wooden handles.

JKJ

[Brice Rogers]

When I'm mixing epoxy, I use the thin wooden coffee stirring sticks that places like Starbucks "provides" for woodturners like me. I also use them to apply epoxy inside of a hole plus on the shaft, like John mentioned. Popsicle sticks, while available at art stores and while great for mixing epoxy, are generally a little too big to get into shaft holes.

To avoid the "hydraulic lock" situation, I too will make a slot in either the handle or the part going into the hole. I have also, on some occasions drilled a small hole from the outside of the handle into the hole. I hide the 1/16" hole by putting it in the center of burned groove. I guess that alternatively I could simply wipe it off or could stuff some fine sawdust into the hole after the epoxy oozes out.

[Raymond Fries]

Awesome tips guys. Thanks. Glad epoxy is the way to go. I avoid CA glue just because it has a evil smell.

The trapped air is excellent to know about as this is my first handle and probably would have encountered that problem. The fit is so snug now that there is that there is alot of resistance about two inches down so I have not pushed the scratcher all the way home. Looks like I need to make the hole slightly larger with the scoring mentioned. I like the idea of roughing the metal. What I have is smooth.

I will post a picture here when finished.

[John K Jordan]

...The fit is so snug now that there is that there is alot of resistance about two inches down so I have not pushed the scratcher all the way home. Looks like I need to make the hole slightly larger with the scoring mentioned. ...

One way to enlarge the hole slightly is to get (or turn) a wooden dowel that will fit loosely into the hole. Cut a saw kerf an inch or two down the middle on one end. Put a piece of coarse sandpaper in the slot and wrap a bit loosely around the dowel so it will still fit easily into the hole. Put the dowel in a portable drill or drill press, gently twist it to put it in the bottom of the hole, then spin it the dowel and sandpaper while moving it up and down. (Don't let it pop out of the hole and mess up the wood there.)

Some other ways I've used to slightly enlarge a hole:
- drilled a tiny bit oversized with a drill bit, perhaps a metric bit.
- used a round file and worked my way around the hole.
- used the same drill bit as for making the hole and just moved it up and down while spinning - can "ream" out the hole just a little.
- found a metal rod the same diameter as the hole and peened some notches around the bottom with a cold chisel to make an impromptu reamer/burnisher. (works well)

If you scratch up the actual shaft you will be using near the bottom (maybe even cut or file some straight grooves in it) you might hold it tightly in a vise or something and twist the handle on and off by hand until it slides on easily.

I suspect a fit a little looser than a little tighter might even work better since it would allow a bit more room for the epoxy.

BTW, I faced an interesting problem recently when I went to epoxy a polished carbide burnishing rod (I got from Reed Grey) into an osage orange handle. Carbide is difficult to scratch up! I used a diamond bit in a Dremel.

burnisher_IMG_6767.jpg

JKJ

[Raymond Fries]

Thanks again for a of the tips guys. They made my project a success. Here is the finished scratcher:

Scratcher.jpg

[Don Orr]

Nicely done, thanks for following up.