Still dunno what to do about kitchen benchtop

[Mutley2003]

Now, I dunno if this is a stupid idea or what .. I have asked about some other approaches (namely building it in situ and I got the good drum there), but now I am considering another idea.

I have a bunch of weathered eucalypt hardwood (which I asked about, re thicknessing etc), and I have cleaned up some boards with a flap disk (aka razorback) and they have come up nicely - lots of character.

These are approx 20mm thick, by 90 and 140 wide (approx, they are rough sawn) and I THINK that I can get the local sawmill (which supplies Rozelle Recycled Timber in Sydney) to dress them for me and thickness to consistent say 16mm thick and maybe 85 and 130 wide, nice and straight and flat. I hope they will do this for a reasonable price.

Now my idea is that maybe I can then glue them to a few large pieces of about 20mm (marine) ply for my U shaped kitchen benchtop. I'd like to do this on the angle (say 37 degrees to the long axis of the bench), maybe incorporate a few concentric rectangles, a sort of parquetry approach. No good reason for this, just that I'd like it to look "different" . It would be about 36mm thick, but if I have this worked out in advance (ie have the boards remilled) I can adjust bench and cabinet heights to suit - I don't suppose there is any good reason for it to be 40mm exact. The appearance of the edge is an issue, but I figure I can make a nice cover strip.

My main worry is moisture induced movement and hence cupping/warping.

In answers to my previous questions it was made very clear to me that fixing the hardwood boards to the frame as I originally proposed to do was asking for trouble.

So, am I going to have the same problem if I glue (and/or screw from beneath) these hardwood boards to a ply base? (assuming the ply base is only fixed at the ledger to the wall, and so it itself can move a bit).

Well, I dunno. I guess I don't feel comfortable with the physics of it all. If boards expand, do they do so along their length more than across their width? And isn't the point of composite boards like ply that the grain of one sheetlet runs opposite to the grain of the next, so the whole thing doesn't move? And if the ply base does not move at all, what is going to happen to my glued on boards on top .. are they going to try to move independently of the ply, and if so would that not be likely to break the glue bond?

Would it be any better if I used MDF instead of ply?



well, I dunno.

[specialist]

I wouldn't waste the effort, the few times that I have tried to join a hard oily wood like that has always ended in tears. Your best bet would be to cut them down to say around 40 wide and then glue and bolt them on the edge so that the 20mm edge is showing and make your bench like that. It's much more stable and doesn't require a backing board. About 10 years ago, this style of bench was quite popular, but has gone out in favor of a wide board appoach.. I wish I had a photo to post, but seem to have lost in the filing system. If you have any queries about how to do it, I'll draw up a quick plan.

rob

[Harry72]

16mm thick hardwood could span kitchen base cabinets, joint the edges and glue them up.
Put an edge strip around them to make them look 40mm thick.

[Mutley2003]

I wouldn't waste the effort, the few times that I have tried to join a hard oily wood like that has always ended in tears. Your best bet would be to cut them down to say around 40 wide and then glue and bolt them on the edge so that the 20mm edge is showing and make your bench like that. It's much more stable and doesn't require a backing board. About 10 years ago, this style of bench was quite popular, but has gone out in favor of a wide board appoach.. I wish I had a photo to post, but seem to have lost in the filing system. If you have any queries about how to do it, I'll draw up a quick plan.

rob

ok, I think I get you .. rip them to 40mm, turn them on the edge, glue. I have seen these .. sort of "thin stripes" of timber effect. Not quite what I was after, perhaps a bit too "busy" but maybe not depending upon the variation in the timber .. yeah, I can see it looking good.

thanks

[Mutley2003]

16mm thick hardwood could span kitchen base cabinets, joint the edges and glue them up.
Put an edge strip around them to make them look 40mm thick.

right, as in biscuit joint the 16mm planks?

I can see that working, but it is straight lines, and I wanted to see whether I could do something more fancy using boards glued onto a backing sheet .. concentric rectangles around the sink, that sort of thing

[ian]

Mutley

on and off there are threads about doing something similar to what you have in mind
From memory, the accepted wisdom is that if you want to glue timber planks to a ply or MDF substrate, the maximum thickness for the glued on plank is about 5mm — these thin "planks" called veneers are cut from a larger plank using a bandsaw.

You could lay your bench as if it were a parque floor but given the amount of moisture kitchen benches are exposed to, especially arround the sink, I would be extremely reluctant to do so


ian

[Harry72]

right, as in biscuit joint the 16mm planks?

I can see that working, but it is straight lines, and I wanted to see whether I could do something more fancy using boards glued onto a backing sheet .. concentric rectangles around the sink, that sort of thing

Yes you can use biscuits but they're not really needed, biscuits will help you align them only... theres no increase in strength.

[Amb]

Mutley

You could lay your bench as if it were a parque floor but given the amount of moisture kitchen benches are exposed to, especially arround the sink, I would be extremely reluctant to do so


ian

That's the first thing that came to my mind -you could go to a lot of trouble and get it looking realyy nice, but small gaps will open up here and there, then food, moisture, grime, mold builds up. I suppose you could give it a thick coat of hard wearing clear to seal it. But best idea is to have few joints as possible.

[Mutley2003]

ok folks, I think I get the idea.

a) veneer on a substrate is OK if it is less than about 5mm

b) BUT on a kitchen bench, where there is going to be a lot of moisture, the approach is too risky. More joints == more potential problems, particularly in this context.

So, instead of being too ambitious I need to stick to one of the tried and true methods like wide boards, or 40mm strip laminated. Not "parquet" style

OK, but at the back of my brain (such as it is) I figure it could come out looking like I could have bought it from a kitchen benchtop shop, which is maybe the smarter thing to do given my level of skill.

I appreciate the help .. I guess I will just have to weigh up the risk and reward.