Glueing/laminating for turning - any recommendations?

[Warb]

I have received a request to make some "yarn bowls" that are deeper than any of the blanks I have "in stock". They are required by Christmas, so I can't cut green blanks and dry them, and buying deep blanks is expensive, so I'm thinking I'll laminate 3 pieces of 2" stock to make a suitable blank. I've never done this before, so I'm looking for hints'n'tips! My current plan is to run the stock through a drum sander (80 grit) to make sure it's flat, then glue (I believe I have Gorilla Glue and Titebond 1, possibly also 2, in the shed), and clamp. I've read that I should allow at least 24 hours for the glue to bond fully. The bowls won't be used for liquids or foods, so that isn't an issue with choice of glue. The timber to be used is American oak, though it is possible that some bowls may be a New Guinea Rosewood/American Oak/Vic ash sandwich.

One slight complication is that the yarn bowls have a slot cut in one side, so the finished product does not have complete "rings" - there is a break in the glue line, cut in after turning. Will this cause any problems?

Is there anything else I should be aware of? Will 80 grit on the drum sander give a good joint (strength and appearance) or do I need to go to 120 grit on the drum or even a R.O.S.?

Any input is much appreciated!

[Peter White]

Titebond original would be my choice I do a lot of segment turning.Flattening with a drum sander is fine need multiple passes
to ensure flatness and check with a good straightedge holding up to a light source to ensure no light shows between straightedge
and segment.The slot you cut for yarn should not be a great concern.

[Skew ChiDAMN!!]

Are you talking about gluing pieces that are wide enough for the depth of the bowl 'side-by-side' to give you the width of the bowl... or stacking boards of a suitable size for the bowl diameter on top of each other to build up the depth?

If the latter, you can simply rough turn the base and dress the mating face square on the lathe. Dismount, mount the 'middle' section and proffer up the base so you can transfer the position of the mating face over then dress that section flat. At this point one can save some time in hollowing out - and also save some timber for another project - by using a jigsaw to core out the middle.

Drawing up a cross-section of the bowl before starting can be very useful to ensure you leave enough thickness in the blank wall to achieve the planned curvature in the finished product. It can be quite frustrating otherwise. :rolleyes:

Glue the base and middle together - I often do this on the lathe, using the tailstock as a clamp - then rough turn the middle section.

This process can be repeated as many times as you like until you have the depth desired.

It's also good practice at remounting pieces. ;)

[Warb]

Are you talking about gluing pieces that are wide enough for the depth of the bowl 'side-by-side' to give you the width of the bowl... or stacking boards of a suitable size for the bowl diameter on top of each other to build up the depth?

If the latter, you can simply rough turn the base and dress the mating face square on the lathe. Dismount, mount the 'middle' section and proffer up the base so you can transfer the position of the mating face over then dress that section flat. At this point one can save some time in hollowing out - and also save some timber for another project - by using a jigsaw to core out the middle.

I was indeed thinking about stacking them (horizontal "stripes"), but using the lathe to create the mating faces had not occured to me. I certainly like the idea of saving the "cores" for other projects - I really dislike turning perfectly good timber into shavings unnecessarily!

[ian]

You may have already started this project build, but if not, have you considered using coloured epoxy resin to glue up blanks of the required thickness?

I can't quite visualise what you intend, but 10mm of the coloured epoxy would both glue the material together and provide an interesting colour contrast.

[Warb]

You may have already started this project build, but if not, have you considered using coloured epoxy resin to glue up blanks of the required thickness?

Thanks for the suggestion, and in fact the epoxy arrived this week! This was going to be the Mark II version - I hadn't quite worked out the details so I was concentrating on the Mark I (just plain laminating!), but haven't had time because I've been caught up working on the farm......

The bowls will be around 6" diameter, 5" to 6" deep. My original plan was simply to laminate 3 or 4 x 40mm boards to give the required depth (as horizontal stripes in the finished product). I usually make bowls and platters that are turned from a single piece of timber; in this case I don't have the required 6" deep blanks on hand, but I do have a bunch of American oak, Vic Ash and New Guinea Rosewood board offcuts........ So the Mk I version was to be straight lamination.

For the Mk II I was contemplating epoxy layers, but as yet I haven't figured out the details and I've never tried this before! If I laminate full circles of timber there will be a lot of epoxy wasted filling the "middles" which will then simply be removed on the lathe. The next plan was to cut out rings of timbers (as Skew suggested), figure out a way to space them correctly, and then use a plastic bowl or similar to fill the void in the centre and save epoxy wastage. But that's as far as I've got with the plan. I spent my youth making fibreglass canoes, but haven't (as yet) combined resins with timber for wood turning, so there's some learning to be done!

[ian]

To save on the amount of epoxy needed, you could use a moulding medium like putty or clay or plasticine to make an inner and outer dam on one layer, fill the resulting void with coloured epoxy and repeat for the subsequent layers of wood.
when turning the resulting construction you would cut off the dams revealing the epoxy stripes.

[Warb]

To save on the amount of epoxy needed, you could use a moulding medium like putty or clay or plasticine to make an inner and outer dam on one layer, fill the resulting void with coloured epoxy and repeat for the subsequent layers of wood. when turning the resulting construction you would cut off the dams revealing the epoxy stripes.

My first thought when I read this was "yeah, right", but then it occurred to me that fresh new plasticine probably isn't the same as the rock-hard lumps that I remember from my childhood - some of that old stuff would hold an edge to rival any Japanese knife! :)

I've also got lots of leftover sections of PVC pipe, so I could possibly hot-glue inner and outer PVC rings between the timber rings to contain the epoxy?

What's the technique to get 100% bubble free rings? Make a sealed system (top timber ring, dams, lower timber sandwich) and fill through a hole with the system on it's side? Or make the dams fractionally wider than the top timber and "float" the top ring (wet the surface first?) on the epoxy?

I've just redesigned the entire MkII in my head.....again......

[Warb]

I've just been reading about casting epoxy and avoiding bubbles by using a pressure pot, and I realised that I have a paint pressure pot that I acquired some time ago and have never found a use for... I have now!