Finishing a window sill

jennifernil

Making a sill for a large projecting bay window, it will be about 500mm deep at the centre and 2100mm wide overall.  This is replacing one that was damaged.    It is oak  veneered MDF and has a solid oak edge.

Can we use Danish Oil as a finish on it?

Norman_Castle

Oil finishes can soak through and weaken the glue on veneered boards. I'd varnish it.

jennifernil

Thanks, I did wonder about that.

Would Osmo oil be suitable as it is OK for veneered doors?   Or does the underlying material ......MDF rather than chipboard.......make a difference?

maisie_cat

jennifernil said:

Thanks, I did wonder about that.

Would Osmo oil be suitable as it is OK for veneered doors?   Or does the underlying material ......MDF rather than chipboard.......make a difference?

Not really, the veneer on this stuff is very thin & most manufacturers specifically mention not oiling

Jeepers_Creepers

In practice, Osmo (oils in general) would most likely work, as you build it up in thin coats using a cloth - very little risk of it saturating the veneer, passing through and causing it to lift. But, folk on here are rightly not going to recommend doing this for the reasons stated.

What finish are you after? How 'dark? Solvent-based varnishes tend to add more colour, more 'mellow-yellow', whereas water-based should leave it just as tho' the wood was wet. Water-based ('quick drying') is also just nicer to use, and dries very quickly.

In either case, thin coats, well brushed out, along the grain.

Water-based also dries thinner, so will tend to leave the grain texture nicely showing.

Best if you have scrap pieces to practice and test on. If you do, then by all means give oil a bash too. In fact, if you have a small extra piece, leave it generously-oiled (more than you would in practice) and see if anything happens to it! Personally, I don't think I'd have any concerns using oil, so if this was my preferred choice of finish, I think I'd - personally - go for it. But I'm not going to suggest anyone else does so.

As for choice, blimey: https://osmouk.com/interior-products/ Then there's the usual Danish, linseeds, etc. Danish is, I think, more clear, less 'coloured', more natural. Nice to work with. But THIN coats - apply, leave for a bit, wipe off as much as you can - is the way to get a nice finish.

So you can try 'oil' if you want. But on your head be it. Don't come crying on here if... :-)

Jeepers_Creepers

Do you know the actual veneered product you have used? The manufacturer? As Maisie and others have suggested, there will be variations of quality, different adhesive methods used, etc. So worth going back to the actual maker and asking if you can.

jennifernil

Thanks!   

This is a window sill for our daughter, to replace a water damaged one (large roof leak) , and she has not yet purchased the veneered board that will be used (existing sill is veneered MDF) .    It is proving difficult to source one  that  will be a good match with the veneer on the board used for the other 3 sills in the room,  but we are working on it.  If we can speak with the manufacturer for advice, we will do so.

I was thinking of using Danish Oil purely as that is the finish I have used on all the oak skirtings and door facings that her Dad has been fitting, but they are solid oak. The oil is easy to use and gives a nice finish on the solid oak.      However, a window sill will get a bit more wear......kids toys etc.....so a satin varnish might be more suitable.

The  veneer is American White Oak, quarter cut, and the final colour should be as close to natural as possible.  The front edge of the sill will have a solid oak bullnose trim.

Testing the finish on an off-cut would not be a problem.

Jeepers_Creepers

Sounds ideal - if it hasn't yet been fitted, there will be lots of cutting, so plenty of spare pieces!

I like Danish too, as it's so easy to use and gives a lovely light satin finish - you really can't go wrong, as it's built up with such thin layers, with nothing more complex than a bit of cloth. I think you'll find it durable enough too - we have it on our dining table; it'll laugh in the face of superhero toys.

If you do try oil, the first coat will be the 'biggie' - the one that could potentially soak through and cause any issues. So that should be a light-application too in this case (ie, not pour it on and wipe away as you might on solid timber...).

I suspect the manufacturers are just being cautious about the risk, but obviously it would be a known 'risk'.

Keep us updated, please - it's a Q I've seen on here a few times.