Timber kitchen benchtop joints

[Naushikaa]

Hi there,

Came here after reading an old thread on burnishing timber, which is what I'd like to do for the kitchen benchtop. Very useful info but now for my own question I couldn't find an answer to....

On the advice that the timber may warp, I'll burnish both sides, but what should I do to the joining faces? Burnish before connecting? Or not burnish and seal with a varnish? I imagine I should avoid getting any oil on the connecting edges if I'm to varnish?

What about around cuts such as for the sink?

Thanks so much!
And if anyone around the Gold Coast is selling an orbital sander for this job, please get in touch!
Cheers.

[Naushikaa]

Anyone out there that can help? What product should I use to seal the sink cutout? And should I do this before burnishing to avoid getting the oil on it? thanks.

[Chief Tiff]

Hi Naushikaa and welcome to the forum!

You don’t need to burnish the underneath, just let the oil soak in. Same for the sink cut outs and edge joints; just saturate with the oil and leave them to air dry. If your joins are tight and square with zero gaps oil alone is enough. If you have gaps and fill them with varnish they will give you problems down the track when the timber moves due to the passing seasons.

Out of interest what timber are you using and how are you making the edge joints; straight 45 degree mitres or Mason’s Mitres? The 45’s are wasteful of timber but both sides of the joint move together; Mason’s Mitres look more professional but the two surfaces have grain running at 90 degrees to each other so one edge will try to move over time.

[Naushikaa]

Hi Naushikaa and welcome to the forum!

You don’t need to burnish the underneath, just let the oil soak in. Same for the sink cut outs and edge joints; just saturate with the oil and leave them to air dry. If your joins are tight and square with zero gaps oil alone is enough. If you have gaps and fill them with varnish they will give you problems down the track when the timber moves due to the passing seasons.

Out of interest what timber are you using and how are you making the edge joints; straight 45 degree mitres or Mason’s Mitres? The 45’s are wasteful of timber but both sides of the joint move together; Mason’s Mitres look more professional but the two surfaces have grain running at 90 degrees to each other so one edge will try to move over time.

Thanks so much for your response!

We were planning on doing Mason's Mitre... BUT plans went very pear shaped today... For complicated reasons, we've decided to go an IKEA kitchen, and the solid timber bench they have is only in a light coloured oak. As far as my research today went, staining it a darker colour and burnishing doesn't work. Apparently you just end up sanding off the stain colour.

SOOOOOO.. since IKEA benches are wider than standard in Australia (and the price of custom timber is just too much for us), we're now thinking of getting their "thick veneer" benchtop product. It's 3mm veneer, apparently good to sand and repair, oil as usual. Inside is particleboard/chipboard.

Any further tips on this new situation? Can we seal the chipboard at the cuts with the oil like with the solid timber you think?

Cheers

[Chief Tiff]

This makes your plans easier; that material won’t move with humidity but it will react to heavy moisture; even though the core will be moisture resistant. The cut edges will need sealing with varnish (oil, not water based); thinned down to a watery consistency so it will be sucked into the core. You will also be fine using a Mason’s Mitre for the join. You’ll still need to duplicate the finish on the underside if it is also veneered; but as before burnishing won’t be required.

Regarding staining; unless it is supplied pre-finished you should be free to apply whatever colour stain you want. You sand everything down to 400 grit first, then apply the stain and de-nib with 600 grit before adding the oil and burnishing. At 600 grit the amount of wood being removed during the de-nibbing is negligible. If you’re looking for an affordable ROS either the AEG or the cheap Makita from Bunnies will do the job; I’ve used them both for burnishing my Redgum benchtops. And The Sandpaper Man (forum sponsor) can supply the abrasives you’ll need; top quality and value for money. 400, 600, 800 and 1200 grits are what I use along with Organoil hard burnishing oil.

Important; do a test piece first! You’re the one shelling out for this; you don’t want to be paying twice if my advice turns out to be moo-poo.

[Beardy]

I have used those IKEA benchtops and they are fine. Finished with Tung oil they are holding up 4 years down the track with plenty of use no worries

[Naushikaa]

This makes your plans easier;

I like the sound of that!

The cut edges will need sealing with varnish (oil, not water based); thinned down to a watery consistency so it will be sucked into the core.

What is the best thinner to use here? Mineral turps, "low odour" turps, white spirit?

You’ll still need to duplicate the finish on the underside if it is also veneered; but as before burnishing won’t be required.

The bottom is not a wood veneer, it's laminated or something. Hope that doesn't cause an issue.

Thanks for all the staining tips in the case of the solid timber top.

I have used those IKEA benchtops and they are fine. Finished with Tung oil they are holding up 4 years down the track with plenty of use no worries

Great to hear! Was worried about the veneer lifting from the chipboard. Do you have joins in your installation though?

[Chief Tiff]

What is the best thinner to use here? Mineral turps, "low odour" turps, white spirit

Hopefully the varnish you choose will state what thinner is required; it’ll more than likely be mineral turps. White spirit is more used for cleaning than thinning.

[Beardy]

The bench I did was 1200 wide so I have joined two panels together with no issues and it is beside a sink

[Naushikaa]

The bench I did was 1200 wide so I have joined two panels together with no issues and it is beside a sink

Good work! I freak out at the idea of joining laminate or this thick veneer stuff. Really want it to come up nicely.
So you applied the tung oil to the open chipboard ends as well as the veneer the same?

[Naushikaa]

So finally at he "doing" stage! My thought is though, what is best to use as the joining glue if the chipboard is sealed with the thinned down varnish? I thought the typical PVA glue used (also provided in our benchtop joining kit from Bunnings) doesn't stick to varnished surfaces well.

[rwbuild]

Rapid clear silicon, been doing it for 40 yrs, never failed yet

[elanjacobs]

+1 for silicon

[Beardy]

My preference has moved from silicone to a Polyurethane like Sikaflex 11FC. Mainly because any excess can be removed from timber and it won’t effect any finishes you plan to use like silicone does