I’m trying my hand at a segmented bowl. To be clear, its rings cut from slab, reassembled into a bowl blank…so, still segmented but maybe not in the traditional tetrahedron sense.
Anyway, I started to turn it, 24 hours after final glue up and it came apart at one of the seams. My inclination is that I simply did t use enough glue, so I’ve reassembled it with more titebond and it’s setting up now.
I’m using the lathe as a press to hold all the layers together during glue up (one layer at a time).
Anyone else had this happen? Am I missing something more fundamental than ‘more glue’. Any tips would be appreciated.
Ryan/// ~sigh~ I blew up another bowl. Moke told me "I made the inside bigger than the outside".
to glue up rings or segment, the faces being glued should be flat as possible. And a far amount of glue is needed. In the few segments I have done, I used a hose clamp to hold everything together for each ring created, and let it set for a few days. Then sand the faces flat prior to gluing the rings together, a disk sander works well for this. You can use the pressure of the lathe to hold the rings in place as the glue dries. Again, I wait a few days to allow the glue to cure. Hope that helps Ryan
Thanks. I used the tape trick for the one true segmented section of it, but I’ve lost two rings during my process (the true segment seems to be holding quite well). The rings were pretty flat, as they were cut from a panel glue up that I did (and ran through the planer on both sides to make it all smooth), however, I did run the last failed ring across the flat master sander before I re-glued it. I’m thinking it’s a combination of not enough glue, and the lathe probably doesn’t provide as much concentrated pressure to the joints (especially as the blank gets wider) despite the use of Cole jaws as a backing plate. I’m sure a press or a bunch of clamps would provide more. I was trying to use the lathe as it provides near perfect centering the way I had is set up. But without any experience I don’t know if it’s a freak accident or I’m doing stuff wrong. Maybe that’s just not going to work.
Ryan/// ~sigh~ I blew up another bowl. Moke told me "I made the inside bigger than the outside".
Ryan, something else I have done is; I took a couple of large square pieces of 3/4" plywood say 16" square, and used threaded rod at the corners, creating a clamp for gluing up rings. I laid out the circles so I could get everything centered. when yu tighten it down you will see the corners start to bend together with the pressure.
I do my glue-ups for this sort of thing with the chuck on the skinny end of the bowl-to-be, the wide end sitting on a piece of cardboard on the floor, and a gallon of linseed oil on top of the chuck. Never had a problem with things coming apart, but if the joint looks glue starved, I’ll tug on it a bit and re-flatten and re-glue if it comes apart.
I flatten the wide end of each layer on the lathe, and the skinny end of the next layer on the stack is flat from when I made it.
You can see some voids and soft spots in there. On this one I wrapped the whole thing in blue tape and poured on a little more epoxy to fill the voids before attempting to turn it.
Might not be the “right” way, but it’s worked for me.
Good deal Dave, thanks for the info! I think the glue joints were starved. We’ll see how it turns in a couple days I guess. First time failures are ok with me, I chalk them up as learning for sure!
Ryan/// ~sigh~ I blew up another bowl. Moke told me "I made the inside bigger than the outside".
Well, I blew up the last of the three joints on that bowl that I was worried about. Perfect score! Also glue starved. I’ve glued it back up, but things are getting thin and I’m starting to have alignment issues. I’m hoping I can still make it work, since it’s attractive and I can see it finished in my mind’s eye. Learning points for me all around…we’ll see how it comes together next week when I get off shift!
Ryan/// ~sigh~ I blew up another bowl. Moke told me "I made the inside bigger than the outside".
