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Forum topic by Karda posted 12-13-2017 10:50 PM 573 views 0 times favorited 17 replies Add to Favorites Watch
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Karda

1023 posts in 517 days


12-13-2017 10:50 PM

Hi I am rough turning a maple bowl that has developed some cracks. The wood has been drying 3 months. the center crack is long and deep the others seem to be shallow now. should I turn rough the glue or glue before turning any more. I have never done this before and need your advice thanks Mike


17 replies so far

View Gene Howe's profile

Gene Howe

10342 posts in 3391 days


#1 posted 12-13-2017 11:23 PM

They look like candidates for a two part epoxy. But, as long as you think it’s safe, I’d turn it more, first.

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

View LeeMills's profile

LeeMills

522 posts in 1264 days


#2 posted 12-13-2017 11:36 PM

Without a pic from the headstock side it is hard to tell how deep the cracks go. Judging from the bottom not very deep. It would also depend on your final shape… a gentle curve to the foot or a more straight side as you show.
I would go with thin CA and then turn more, with caution, to see what develops. A gentle curve may remove most of the bottom (lower) cracks. To me the cracks appear fairly narrow but that may not be the case.

-- We cannot solve our problems with the same thinking we used when we created them. Albert Einstein

View Bill7255's profile

Bill7255

426 posts in 2248 days


#3 posted 12-14-2017 12:22 AM

I would not turn this unless you can turn out all the cracks before you turn it around. My guess is the wood is still wet and you started turning and left it on the lathe for a while and the cracks developed. When turning wet wood you need to turn the inside and outside leaving about 10% of diameter in wall thickness and put it in a paper bag to dry for finished turning in a reasonable time. . Have you checked the moisture content?

-- Bill R

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Karda

1023 posts in 517 days


#4 posted 12-14-2017 01:17 AM

The cracks were present when I started to turn but not so noticeable until I got it rounded. here is a head stock picture. I don’t know MC I’ll check later. The crack is directly left at about 9 o clock the others are centering lines.

View Woodknack's profile

Woodknack

11475 posts in 2343 days


#5 posted 12-14-2017 01:48 AM

Limb wood? Looks like shake. Is it silver maple by chance?

-- Rick M, http://thewoodknack.blogspot.com/

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Karda

1023 posts in 517 days


#6 posted 12-14-2017 02:18 AM

Its not limb wood it is from the trunk. its not a silver maple sugar maple I think

View nixs's profile

nixs

19 posts in 375 days


#7 posted 12-14-2017 01:03 PM

I would turn the outside, fill the cracks , wrap the out side or bowl with tape or srink warp the reverse the bowl and. turn the inside. If there are cracks on inside fill and finish. Looks like elm to me.

-- Steve, SW Louisiana

View Bill7255's profile

Bill7255

426 posts in 2248 days


#8 posted 12-14-2017 04:20 PM

Is it worth it? Those are big cracks. That wood doesn’t have any special figure. Even if you are lucky enough to turn it, it will just look like a glued up bowl. At 3 months I don’t think your wood is dry and not sure if you sealed the ends. You might use it for practice, but do wrap and tape the bowl as suggested above as it poses a increased risk of coming apart.

-- Bill R

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Karda

1023 posts in 517 days


#9 posted 12-14-2017 06:18 PM

i stuck a thin metal ruler in the main crack, its about 2 inches deep. I just don’t see any save to it. I think it is better fire wood than bowl blank. Its not elm its maple I know that for sure it came from my front yard.

View LesB's profile

LesB

1673 posts in 3406 days


#10 posted 12-14-2017 06:30 PM

I work with “wild” maple a lot and I would consider those cracks too big to work with. You do not give the size of the piece of wood but I suspect it is not thoroughly dry in 3 months. I have had pieces dry for over a year and still have moisture in the center….and even start cracking when I turn it. Big pieces need the end grain sealed and left for up to 2 years in a cool dry place. Otherwise use wet turning techniques.
Cracks develop due to stress in the wood as the outer surface drys faster then the inside Wood that is wet needs to be turned all in one session or rough turned and put in a paper bag for a period of time to finish drying. One alternative is to microwave it as soon as you have it roughed out. Information on microwaving wood can be found on the internet. I do it in a brown paper bag heating the wood until it is almost too hot to hold then let it cool; repeating this process until the piece is dry. This acts as a “steam” kiln. Watch for small cracks and treat them with medium superglue between microwave sessions. Be careful not to breath any fumes that may come from the superglue as it reacts with moisture in the wood.
As far as filling with the cracks using Superglue, anything over 1/16” I would first pack as full as you can with fine sawdust then soak the sawdust with thin superglue (this soaks in quickly) then immediately top it off with medium superglue allowing as much to soak in as possible…in other words keep putting more on until no more sinks in. Then let it set over night.
You could also use epoxy but I find that a bit messy to deal with. It is better for large voids.
The smaller cracks can be filled with the just medium glue, again adding more as long as it keeps going in.
When I see cracks developing as I turn a piece I usually immediately fill them with superglue which stops their advance and when appropriate also gives me time to cut past them.
Your next problem with maple is going to be end grain tear out. When this happens I start my sanding with 60 or 80 grit sand paper until I cut past it.
Good luck

-- Les B, Oregon

View Karda's profile

Karda

1023 posts in 517 days


#11 posted 12-14-2017 08:22 PM

thanks for the drying advice, I cut it up, I did save a chunk though. I might carve it. curious thing I made a small dish from the same wood it almost finished size, turned that about a month ago and not a crack yet, I also turned a plate of the same wood within a month of cutting, no clacks yet badly warped but usable

View Lazyman's profile

Lazyman

1867 posts in 1350 days


#12 posted 12-14-2017 10:13 PM

I’ve not had good luck turning blanks that look like that and I have not had much luck using CA to repair it either. The cracks are pretty big so maybe you can get enough glue in there to hold it together. Chances are you will probably find that even if it does not explode while hollowing, the cracks will widen as it dries further. Personally, I would turn it a little smaller to see whether the cracks continue or not. If nothing else use it as practice and keep adding glue into the cracks as you go. Just make sure that you wear a face shield and clear the room as you turn it.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View OSU55's profile

OSU55

1624 posts in 1952 days


#13 posted 12-14-2017 10:47 PM

I keep the bark on wet turning stock and seal the ends, then when I’m ready – might be a week or years – cut the log into blanks and rough turn wet, leaving enough for warping (~10%) , store in brown paper bag or kraft paper in the house under climate control. I weigh it and right it down, when it stops dropping weight its ready to finish turn. How long is individually dependent on the blank. Helps prevent what happened to this blank, but it can still occur

View MrUnix's profile

MrUnix

6580 posts in 2162 days


#14 posted 12-14-2017 11:48 PM

I would have filled ‘em with epoxy and kept turning it… I’ve had blanks with much worse cracks than that. With a nicely contrasting tinted epoxy, it can really make the piece stand out from just an ordinary plain bowl.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View Karda's profile

Karda

1023 posts in 517 days


#15 posted 12-14-2017 11:57 PM

I made the decision to junk after I measured the crack, it was so deep there was nothing to save, at least I didn’t think so

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