Finishing Birch plywood

Jeremy Nako · 5 Feb 2021

I've built a small desk using Birch ply for the top.

I've tried a number of finishes on scrap wood, and I don't like any of them.

Osmo Polyx leaves quite a rough texture (for a desk top), waxing looks like unfinished Birch ply. A coat of shellac leaves a nice smooth finish to the touch, but it still looks unfinished.

Staining comes out very blotchy (I've read that Birch needs to be 'sealed' before staining, but any help with how / what to do is gratefully received !

Help !

Any photo examples would be fantastic, but some general advice would also very welcome.

TheTiddles · 8 Feb 2021

If you want a fast, hard, durable finish on ply, it’s varnish.

Rustins quick drying (from toolstation) does really well and can be applied in just a few hours

Aidan

Rorton · 8 Feb 2021

Its not furniture but the only thing in birch ply I can find that I used Osmo on, but I finished my router fence and table saw insert in PolyX and its smooth to the touch.

18mm Birch ply

How are you applying it? I use a non abrasive pad to apply it (thinly!) then after 10 or 15 mins, use a fresh piece of the pad to remove any excess so its nearly dry looking, then let it cure in a warm spot for 8 hrs, then do the same again. Have done lots of walnut and oak including a 2.4m solid walnut desktop and its been really smooth, not rough.

Sometimes you could go to it a few hours after and then 'burnish' it with the same dry white non abrasive pad

petermillard · 9 Feb 2021

I’ve had good results with a water-based flooring lacquer - easy to apply with a foam roller, dries fast, with a silky smooth finish that’s hard wearing. I like Junckers Strong, but I’m sure others will do the job just as well.

With Birch ply I’ve always found the first coat of any finish to raise the grain significantly, especially with a water-based lacquer - first de-nibbimg feels like you’re sanding the finish off completely, but the 2nd and 3rd coats go on much better. HTH P

chris.gid · 9 Feb 2021

I use Holzol furniture or floor oil on most of my projects. Finish really brings out the grwin of the ply without making it too dark (if I want it to look unfinished try Screwfix floor varnish, but you notice the finish on the wood rather than soaking in).

Here's a desk I made earlier in year and is holding up very well.

It's the same finish that was used on the parquet floor.

I sand down to 320grit, apply the oil with a clean cheap kitchen cloth or paper towel so the surface is damp but not much visible sitting on the top, dry, denib with 320grit if rough or brown paper if smooth, reapply, dry and denib with brown paper again.

I've only really worked with birch ply and solid ash, you do get a nicer finish with ash probably because there is a lot more depth of wood to soak into, my guess is that any finish hits the glue after the to ply and doesn't go any further so that top layer gets more saturated than s piece of solid wood would do.