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sturina
5th August 2011, 04:13 PM
Ok, have been working on this red ash bowl. Unfortunately as I turned I have discovered a few cracks which I have stabilised with epoxy and wood dust. Unfotunately I didnt find this one until too late and it expanded (it is about 3cm long). Will the same trick with some expoxy and sandings work to hold it together or am I better off just removing the whole top 3cm (though I am not keen as I love the shape).

Sorry the photos arent great but used my phone.

Tips and suggestions please

wheelinround
5th August 2011, 05:38 PM
epoxy and coffee grinds even all the way to the top will look good :2tsup::2tsup:

joe greiner
5th August 2011, 08:27 PM
What he said. For best mechanical purchase, enlarge the crack with a miniature dovetail bit in a Dremel to create an undercut.

If you're considering removal of the top 3cm, I assume it's still mounted. Pack the epoxy and coffee "mortar" proud of both surfaces, and turn flush and sand. The appearance will approximate small-scale terrazzo, because of the varying density/color of the ground coffee.

Cheers,
Joe

dr4g0nfly
5th August 2011, 10:28 PM
A more drastic solution I've used in the past to cut out and hide cracks would be to take an Arbortec (or just an angle grinder) to the rim and deeper around/ removing the crack giving a rough rim area, scorch that back with a gas torch and finish as if it was a lightning struck bit of wood.

Drastic but dramatic.

orraloon
5th August 2011, 10:44 PM
There are all sorts of ways to either fill a crack or make a feature of it but life is easier with no crack in the first place. If you leave in the center of the log it almost always starts a crack.Check out how this guy cuts blanks from a log.
Wood turning lathe tips:techniques: woodturning instruction (http://aroundthewoods.com/)
Regards
John

Skew ChiDAMN!!
5th August 2011, 10:46 PM
As Joe said, enlarge the crack if you'll be filling with epoxy. Provided you let the epoxy cure properly, it should be safe to spin up.

For this "type" of crack, which fades away to a hairline fracture I like to also place a drop of CA right at the start of the crack. The idea being that if the epoxy lets go, the crack won't drastically extend further. (By "lets go," I don't mean with a BANG and parts spraying across the room! I mean for the odd occasion when it simply doesn't adhere properly and you hear that telltale tic-tic-tic sound which says "Stop the lathe! Quick!" :;)

I honestly don't know whether the drop of CA makes any real difference but I have plenty of it, a drop won't hurt the bank and it makes me feel a bit happier. Which is always an important factor in turning. :U

If I'm still feeling a tad insecure, I'll occasionally also build up the inside with a thinnish smear of epoxy; enough to make me feel comfortable finishing the outside but not enough to cause an imbalance that'll flex the rim significantly. Then wrap the outside in duct tape and turn down the inside.

Oh... and throttling back on the RPM to less than my usual Ludicrous Speed tends to increase the survival odds, too.