Poly on Osmo?

[memzey]

Hi gang,

I've just made a small coffee table from cheap pine and am considering what finishes to use. I like Osmo and have some to hand but also like the durability of poly based varnish. What I'm wondering is whether I can give the frame and top a couple of coats of Osmo and then give the top a coat or two of thinned poly to add durability? Has anyone else done this?

 

[Phil Pascoe]

Why not just the poly? What do you hope to gain from the Osmo?

 

[memzey]

I like the look Osmo gives, I'm just not sure it's durable enough for a table top. I don't think poly gives the same depth etc. which is why I'm asking whether it would work if applied on top of the hard wax oil.

 

[Phil Pascoe]

I'd think it would throw it off because it has a wax content. There's an easy way of finding out, though - try it on something unimportant. I don't whether there would be any advantage in using Danish under Poly - it works OK, it might be worth an experiment.

 

[ED65]

I like the look Osmo gives, I'm just not sure it's durable enough for a table top.

Not a fan, but if a soap finish is durable enough for tables and even on floors then I think Osmo should be!

But it does of course depend on what you're looking for. If you need a proper level of protection from water (spill and ignore it) then I think poly is the right call.

I don't think poly gives the same depth etc.

If you want to maximise depth under a varnish use linseed oil, unlikely you'll find anything that'll give greater depth than that and you won't have any concerns about the poly bonding properly.

 

[MrDavidRoberts]

Hi gang,

I've just made a small coffee table from cheap pine and am considering what finishes to use. I like Osmo and have some to hand but also like the durability of poly based varnish. What I'm wondering is whether I can give the frame and top a couple of coats of Osmo and then give the top a coat or two of thinned poly to add durability? Has anyone else done this?

I have got JUST the osmo and Fiddes alternative on so many things including a dining table/ benches/ stairs I built and wherever else I want a nice look - It has been surprisingly excellent.
Where as in the varnish I have on other stairs only after a year has started to give problems and doesn't looks nowhere as nice as the osmo.

 

[memzey]

All good feedback thanks guys. I have BLO as well as Raw linseed oil on my finishing supplies shelf. I'd prefer to use BLO - I don't suppose it will make much difference which I choose would it? If the poly bonds to one I would expect it to bond to the other right?

 

[Beau]

For pine I would just use the Polyurethane.

 

[profchris]

The rule in lutherie is soft finish over hard, never the other way round. With hard over soft, say poly over oil, the hard finish is likely to crack through wood movement.

Furniture would be finished thicker so this might not be an issue, but ...

Also I'd worry about adhesion between the two dissimilar layers. I guess the question is whether you're happy to strip and refinish if it doesn't work.

The alternative as a base layer to pop the grain is shellac. Nice and hard and pretty much everything adheres to it (poly for certain).

 

[ED65]

All good feedback thanks guys. I have BLO as well as Raw linseed oil on my finishing supplies shelf. I'd prefer to use BLO - I don't suppose it will make much difference which I choose would it?

If you had a long time to finish this off it wouldn't matter which, but BLO will 'dry' much faster than raw oil that hasn't been further processed.

You can usually overcoat wood that has had BLO rubbed in the next day quite safely, although people who are more cautious will wait longer to be sure it's more fully cured before the varnish goes on (which is probably a good idea in colder workshops).

The rule in lutherie is soft finish over hard, never the other way round. With hard over soft, say poly over oil, the hard finish is likely to crack through wood movement.

That doesn't really apply to oiled wood (oiled with a pure oil, not an oil & wax mix) because it's not on the surface.

Not to divert the thread but once you begin to delve into that 'rule' in detail it's clear it isn't a hard-and-fast one in practice. Prime example is varnish over shellac, which works great of course, but is actually a violation of the rule if you're fussy about how you define hard and soft.

 

[woodbloke65]

I like the look Osmo gives, I'm just not sure it's durable enough for a table top.

I've used Osmo PolyX since it first arrived here and it's my 'go to' finish for almost everything. It's actually very durable because it's a flooring product as well as being used on furniture. The golden rule with it is to only use two very thin coats and de-nib between each with some worn 320g paper...once bone dry (best left overnight) it will also take a beeswax polish really well. I apply the wax with a grey Webrax pad and polish with a duster. If in any doubt, make up a sample (say 300 x 300mm), apply the Osmo and see what sort of abuse it will take - Rob

 

[ED65]

There are different kinds of durability and levels of same.

I like a straight oiled finish on hardwoods, super-easy to apply, love how it looks and it can be surprising how tough the finish is. For most furniture in a typical home I think it provides sufficient protection, but it's not really properly durable in all the ways that count so less suited to tabletops. For a "really durable surface" what it comes down to for me is whether you can leave water standing on the surface and basically ignore it until it has evaporated (or if it's red wine, no staining at all of the underlying wood).

If you're really demanding good durability means you can have a hot coffee mug with a damp underside sitting on the surface for 10 minutes without a dark stain forming on the wood or getting a round pale mark.

Regardless of whether the PolyX can do this (I've read user complaints that strongly suggest it can't, although one must leave room for some user error possibly being a factor) the fact remains that it's quite an expensive finish and the cheapest varnishes going can at least stand up to the first requirement above 8)

 

[gasman]

I'm in agreement about Oslo or Fiddes hardwaxoil. They both give a good finish and are my go-to for almost everything - tables, chairs, etc etc. I second everything that Rob Woodbloke said - but would just add my ha'penyworth. I usually use 3 coats - all of them really thin. I only rub down with worn 320 if there are irregularities - but if the coat is very uniform, and you get the timing just right - then when the coat is just dry - ie not tacky to the touch - then you can polish the surface with a fine duster and it will polish up to a beautiful sheen
Kind regards
Mark

 

[memzey]

All good stuff to know, thanks everyone. I've been applying BLO for the last two evenings which is looking good. I aim to apply a final coat tonight and then two coats of thinned poly varnish rubbed in over the next couple of days. I'll post a pic if anyone is interested but it's nothing to write home about, it was made by me after all!

 

[ED65]

As you're going to poly over the top I honestly don't think you should bother with another coat of the BLO. These days many who are doing a straight oil finish only apply three coats, with poly going on you won't notice any visual improvement with another coat. In fact often the second coat doesn't do enough that you'd really notice, although I habitually apply a second coat myself.

 

[memzey]

Thanks Ed. I think I'll see what it looks like tonight and decide if an extra coat of oil will be worth it.

 

[woodbloke65]

I'm in agreement about Oslo or Fiddes hardwaxoil. They both give a good finish and are my go-to for almost everything - tables, chairs, etc etc. I second everything that Rob Woodbloke said - but would just add my ha'penyworth. I usually use 3 coats - all of them really thin. I only rub down with worn 320 if there are irregularities - but if the coat is very uniform, and you get the timing just right - then when the coat is just dry - ie not tacky to the touch - then you can polish the surface with a fine duster and it will polish up to a beautiful sheen
Kind regards
Mark

Agreed, and if you polish with a grey Webrax (which includes a very fine 1500g abrasive I believe) and a decent beeswax polish (I use the organic Swedish stuff from CHT) burnishing with a soft duster, the finish is fabulous - Rob