Hi all,
Is it easier to break epoxy bond on 5" of 1/4" threaded rod or smooth 1/4" rod used to turn a rod just to shape butt cap.

Herb

Honestly as long as you coat either mandrel with paraffin I don't think that you will have any trouble to include birch bark handles. I would suspect the smoother may be a better option as most of the threaded rod flexes pretty easily and the smooth drill rod is much more suited for mandrels.

Tom

Herb

Both work as the idea is to use a barrier, such as mandrel wax or paraffin, between the rod or mandrel to prevent the epoxy from fully bonding to the rod or mandrel.

I now prefer to wok with a mandrel, which is generally closer to dead on straight than threaded rod, but have previously used threaded rod. Frankly, I think release from a mandrel is easier. However, it could be that I did not properly prepare the threaded rod.

Thanks guys

Tom
I did notice that the un-threaded rod is stiffer

I will go with that .9
Herb

The threaded rod (all thread) is a much softer metal, and especially the 1/4" will flex pretty severely under pressure. I have used both in a few diameters, and now use the all thread only for gluing up and not for turning.

Threaded rod (all thread) is a soft steel which in it self makes it flex easily under pressure. When you cut threads into it reduces the effective diameter. A 1/4" threaded rod is about the same as 3/16" smooth rod. Smooth rod from a hardware store is better but not necessarily straight the best is drill rod. It is hard and straight and less likely to flex under pressure. I use all thread for glue ups. I wrap in Teflon tape and use paraffin on top of that. All my turning mandrels are drill rod

I only use all threaded rods for both glue ups and turning. Since the threaded rods are softer than the unthreaded rods, I like to use a threaded rod that is very close to the finished inside of the blank.

I never put anything on the rods before gluing up. But, for most of the glue ups that I do especially with cork, I use Titebond III for the glue. Titebond III is an air dry glue so tends not to cure well in a non vented space. As a result, I glue up a grip and let it sit over night for 10-15 hours. Then, I remove the threaded rod. When the threaded rod is removed when using Titebond III for glue, the glue is generally soft on the inside of the grip.
So, after I remove the threaded rod, I will run the threaded rod up and down the grip a half dozen times to clear out any excess glue. Then, I lay the grip down and let it dry for another day. After removing the threaded rod, I put a nut on the threads and use a variable speed drill to run the nut up and down the rod a dozen times to clean any glue out of the threads.

Before gluing up any cork grips, I ream and or drill out the center of each cork ring, so each cork ring is a pretty close match to the location where that ring will be on the blank when finished. That way, after every thing is glued up and turned, there is very little reaming required for a perfect fit on the blank.

Any time that I need to remove a threaded rod from a grip, I use a variable speed drill with reverse to just back the threaded rod out of the grip by basically unscrewing the threaded rod from the grip.

Take care

The easiest way I have found for removing glued up grips from a mandrel (I prefer a smoothmandrel) is to drill a hole in your workbench, place one end of your mandrel in the hole and tap the top with a hammer until the mandrel loosens. Then continue tapping until the mandrel is flush with the cork then use a slightly smaller rod (old sawed off screwdriver) to tap the mandrel on througth the grip. I use old broken "bell hanger" drill bits (14" to 18") for my glue up mandrels.

Rog

Wax toilet seals are a good lube for preventing the bonding of epoxy to the mandrels. But careful application of the epoxy can keep almost all or all of it out of the threads of threaded rod. If you drill out the rings to better match the OD of the blank, like Roger does, it is harder to keep the glue out of the threads. But less reaming. A tradeoff.

I drill my rings to 5/16 ID and use 5/16 threaded rod for both gluing and turning, and it is strong and straight enough. Less reaming than 1/4 ID, more than Roger's method. Less reaming means less chance of losing concentricity in the reaming.

Lots of methods here that are working for builders. Find what works for you and do that.