Chopping board with curved inlays - advice needed

[Molynoox]

Hi All,

I am nearly finished with my chopping board project but I have reached the part I was worried about - it's not going to plan.
This was it two days ago but its gone backwards since then

The curved inlays are problematic, the pic above is a dry fit where I tried to pre-stress the inlays overnight by clamping them in the board. After a day they just sprung back to mostly where they were before, and some of the strips were cracking a bit.

Here is an example of one of the strips for the inlays, they are about 2mm thick:

Here is me doing an attempted glue up yesterday:

Here it is a little later after I aborted the mission:

I aborted when I went to check on it after an hour - I noticed that the board was not sitting flat because the clamping pressure was distorting it. I decided I didn't want that so pulled it apart and stripped off the glue and now I am back to where I was.

I did try steaming the strips before doing the pre-stressing so that it needed less clamping pressure but this seemed to cause the glue joints to fail on the strips.
So it solved one problem but created another.

ADVICE NEEDED
Should I have another go at steaming and if so how do I stop the glue joints failing?
Should I just have another go with same method (without steaming) but try and prevent the board from curving under pressure?
Am I doing something fundamentally wrong?

I really wanted to soften up the strips before clamping for two big reasons:
-reduce clamping pressure to avoid distortion
-to get a more snug fit between the strips and the board (even with mega pressure it didn't seem to be closing up perfectly - I think the curves are tricky in this respect)

Martin

 

[niall Y]

You are probably not steaming the inlays for long enough, for them to be fully pliable, Things take a lot more steaming than one would think. At this stage where they are completely floppy the strips will, most likely, be too hot to handle except with gloves.

Another method is to soak the inlay in hot water and bend it over a hot pipe of sorts. Instrument makers use electrically heated benders, though many improvise with hot air blowers and metal tubes and alike. If you are bending fairly thin stock using this method, you will also need a flexible metal backing strip so the inlay doesn't split it's fibres at the back of the curve and break.

You could avoid the problems associated with bending by simply using a lot thinner inlay/ veneer, and achieve the desired thickness by using multiple strips.

As you have realised, one of the downsides of steam bending wood , is that it has to dry out before gluing. PU glue can overcome this problem, as it will stick damp wood. I have used it successfully on the scarf joints of bent MDF forms, though the whole thing could easily degenerate into a wet sticky mess.

 

[--Tom--]

Could you glue up in 2 stages? Easier to get one inlay sorted and dry before doing the next.
Are you using any clamping cawls to help keep it flat - if not I’d add them to help so you are clamping in both directions

Good luck

 

[Hornbeam]

By gluing up the inlays you have made a rigid piece of 6mm (assuming all layers were 2mm) plywood. Glue up in stages using the chopping board as cauls for the curved inlay and then glue the inlay into the board. When gluing up the inlay make sure you have clingfilm covering all parts of the board otherwise everything will get stuck. You can do each inlay at a time. I would use a rigid setting glue and expect some springback.
Ian

 

[Molynoox]

You are probably not steaming the inlays for long enough, for them to be fully pliable, Things take a lot more steaming than one would think. At this stage where they are completely floppy the strips will, most likely, be too hot to handle except with gloves.

Another method is to soak the inlay in hot water and bend it over a hot pipe of sorts. Instrument makers use electrically heated benders, though many improvise with hot air blowers and metal tubes and alike. If you are bending fairly thin stock using this method, you will also need a flexible metal backing strip so the inlay doesn't split it's fibres at the back of the curve and break.

You could avoid the problems associated with bending by simply using a lot thinner inlay/ veneer, and achieve the desired thickness by using multiple strips.

As you have realised, one of the downsides of steam bending wood , is that it has to dry out before gluing. PU glue can overcome this problem, as it will stick damp wood. I have used it successfully on the scarf joints of bent MDF forms, though the whole thing could easily degenerate into a wet sticky mess.

thanks - I think I will try the 'multiple thin strips' approach you suggest, sounds like my best option right now

 

[DrDerrick]

I agree with earlier suggestions to use multiple layers. I used strips of veneers, which are each about 6mm so the 3 I used gave an inlay of about 1.8mm. Simply use as many strips as you need. Glue all sides and then clamp them into place. Ensure the strips are all longer than you need so you can tape them together at the ends to hold them together (this bit gets cut off later). The only tricky bit is ensuring that the full width of the inlay is within the board while it's all clamped, paying close attention to the bottom, as preferably it's slightly proud on both sides. Leave it all clamped up overnight to let the glue cure, then clean up and sand.

 

[Molynoox]

I agree with earlier suggestions to use multiple layers. I used strips of veneers, which are each about 6mm so the 3 I used gave an inlay of about 1.8mm. Simply use as many strips as you need. Glue all sides and then clamp them into place. Ensure the strips are all longer than you need so you can tape them together at the ends to hold them together (this bit gets cut off later). The only tricky bit is ensuring that the full width of the inlay is within the board while it's all clamped, paying close attention to the bottom, as preferably it's slightly proud on both sides. View attachment 172868View attachment 172869

thanks, this looks like best option.
the tricky part is that I have stripey inlays, so I need to line them all up too....

 

[DrDerrick]

If you mean by stripey that you're using different coloured veneers to make up the inlay - that the stripes you want go along the inlay, not across it - then no worries. Just ensure the whole inlay is glued in proud of the board on both sides, as you then plane down and/or sand down the inlay - when it's glued in place - and the stripes of the various veneers will emerge from all the gluey mess that you remove.

Looking back at the photos you posted of the inlays you want to use, they look like strips of end grain from a composite of woods glued together. Such thin strips of end grain will not steam bend, nor will they glue well. Try to keep all your glued surfaces side grain - which glues well. Remember the main reason for making chopping blocks with the end grain showing is so all the glued surfaces are side grain. Yes, as you can see, that's a problem I had when trying to inlay in the cutting boards I made - very close but not perfect.
.

 

[John Brown]

I've seen some amazing chopping boards over the years, but do they get used, or hung on the wall?
I made a spice storage box with a lid that doubled as a chopping board for my eldest stepdaughter about 10 years ago, as it made my back hurt to watch her stooping over standard height countertops (she's very tall). I found out later that she'd never used it, as she didn't want to mark it.
It was extremely basic, I hasten to add, no fancy inlays or anything..

 

[Molynoox]

I've seen some amazing chopping boards over the years, but do they get used, or hung on the wall?
I made a spice storage box with a lid that doubled as a chopping board for my eldest stepdaughter about 10 years ago, as it made my back hurt to watch her stooping over standard height countertops (she's very tall). I found out later that she'd never used it, as she didn't want to mark it.
It was extremely basic, I hasten to add, no fancy inlays or anything..

Mine will be used otherwise it's pointless.

 

[John Brown]

Mine will be used otherwise it's pointless.

Indeed. Like the bottles of wine that become so expensive that no one would ever drink them - at which point they should logically become worthless...

 

[Molynoox]

Well I am going down the route of the 'multiple thin strips' strategy and it seems to be working much better.

I have done a single glue up, with cling film on the board to protect it. I will have a look tomorrow and see how the inlay comes out

Martin