Does oiling both faces really make a difference?

UKworkshop.co.uk

Help Support UKworkshop.co.uk:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
I've always wondered how making spindleback chairs from green wood don't fall apart when brought inside?
Or do they?

And if the greens have their way cutting down trees will end along with woodworking.
We will all be forced to grow willow. Planted in a container area underneath the home and up through the floor boards.
Instructions will be given how to weave basic furniture, beds,chairs, tables .........a living home.
 
As a green party voter since 1985, i know that 👆 is wrong













no instructions will be given, unless you want to give a bunch of the unhippiest money loving hippies up at findhorn all your dough
 
Though I have been a green voter since 1985, never voted for anyone else 🤫
 
Here's something else to think about: a table top seems to dry out more on the topside, especially if exposed to the sun, than the shaded underside, and so the edges are likely to cup upwards. I've done some tops cut from full width slabs and I've made sure that the growth rings are curved side down: if dried uniformly this will tend to result in edges cupping downwards, so counteracts the differential drying of top and bottom. I'm wondering if in extreme cases it would also be worth leaving the bottom unfinished.
 
@JoshD i think you have unfortunately got yourself mixed up. The reason for cupping is that the radial stresses within a tree are basically trying to get the growth rings of a processed piece of wood to straighten out flat. Therefore, if you have a board laid as you describe ie the growth rings look like a U, then as they equalise the edges will be forced down and you eventually will have a hump in the middle. The obverse being the case when the growth rings are orientated like an n. hence why we try to have 1/4 cut straight grain blanks for planes etc.

I may be misreading what you've written, if so apologies .
 
@JoshD i think you have unfortunately got yourself mixed up. The reason for cupping is that the radial stresses within a tree are basically trying to get the growth rings of a processed piece of wood to straighten out flat. Therefore, if you have a board laid as you describe ie the growth rings look like a U, then as they equalise the edges will be forced down and you eventually will have a hump in the middle. The obverse being the case when the growth rings are orientated like an n. hence why we try to have 1/4 cut straight grain blanks for planes etc.

I may be misreading what you've written, if so apologies .
confused now, do smiles get happier or sadder as they dry (if you follow my thinking)
 
@Droogs, take a completely flat-grain board: this could be a slab cut far from the pith of an enormous tree or a jointed board with alternating "smiles" and "frowns". If it dried uniformly it wouldn't cup at all. But my point is that a table in the sun doesn't dry uniformly: I have a table cut from walnut slab where the top is 6.9-7.4% on the top side and 7.6-8.0% on the bottom side. I'd expect this differential to cause "smile" cupping in my theoretical perfectly flat-grain board---so to offset this I should use a board with a moderate "smile" ring pattern. If I get this right the smile cupping from the moisture differential will be offset by the frown cupping that arises from a smile ring sructure. Make sense?
 
I m still a Danish oil person after all these years.
I believe that oiling all round seals the wood and protects from moisture ingress. Oil solids or micro balloons?
I know myself that that is probably incorrect but to date I have never experienced an explosion from anything I've made where the base timber could have held moisture.
But, I do rough plane then bring the wood inside, placed underneath beds to aclimatise for long periods of time.
I use Ronseal poly on table surfaces protection on top of Danish oil, again after a longish drying out time between the two applications. Only on the show face.
Genuine interest why should you put poly over Danish oil? I thought they were different bases???


Cheers James
 
I worked in the shop fitting industry and latterly in the manufacturing side of the business where it was essential to always balance panels whether they were being covered with laminate or veneer on the finishing side of things it is good practice to at least seal the back side of panels / items as it can save warping problems later on
 
As i read what you've said Richard, is that they way a table top is looked after in terms of cleaning/care etc has a much more influential impact than the rings natural tendency to try to flatten as in a free standing board/plank. This being due to the locking in position of the the parts in a piece of furniture. Am I interpreting correctly then that groth ring orientation then is basically immeterial in the tops construction?
 
Genuine interest why should you put poly over Danish oil? I thought they were different bases???


Cheers James

Hello James.
Im not saying you have to apply poly to ever job you do, but in my experience its a surface finish that gives better protection that just Danish oil alone.
20210213_132648.jpg

This is water damage on oak with just a danish oil finish.
By applying a couple of coats of waterbased poly it protects the surface better and also gives a harder finish protecting from knocks and bumps.
There has been a lot of discussion over the years about this subject.
So long as the danish oil is left to really dry out before then application of poly there is no reason not to use it.
Except maybe its another process that takes time and some argue you may as well forget the danish oil and just varnish. Then you lose the depth of colour danish oil gives to your piece.

Here is my wifes cactus table...dont laugh!
These have been sitting on this table in full sun with a south facing aspect for eight years.
You can see there is very little yellowing of the surrounding area and virtually no colour change.20210213_132541.jpg20210213_132534.jpg
At the end of the day you do learn by your mistakes and try to rectify them or remind yourself next time Ill try something different.
I hope this has answered your question although as I said not everyone will agree.
Regards
 
Here's something else to think about: a table top seems to dry out more on the topside, especially if exposed to the sun, than the shaded underside, and so the edges are likely to cup upwards. I've done some tops cut from full width slabs and I've made sure that the growth rings are curved side down: if dried uniformly this will tend to result in edges cupping downwards, so counteracts the differential drying of top and bottom. I'm wondering if in extreme cases it would also be worth leaving the bottom unfinished.

Apart from a few trestle tables, most solid wood table tops that I've seen weren't finished on both sides.
(Anecdotal evidence, I know, but still...)
I'd say the two main reasons a table top deforms in some way is that the stock wasn't seasoned properly
to start with, the other is central heating.
Exposure to long periods of direct sunlight can cause problems also. Best to avoid such jobs altogether.
As for growth ring orientation, alternating the smiles was once considered prudent. Many people on the internet and in WW
publications are reporting that orienting the grain for looks should be the priority, regardless of the 'smiles'.
I've tried both ways, didn't see any difference. Maybe it was luck.
 
I've always wondered how making spindleback chairs from green wood don't fall apart when brought inside?
Or do they?
I seem to remember reading somewhere that as the seat dries out, it grips the spindles tighter, and that the ends of the spindles were often slightly bulbous to take further advantage of this.
 
has anyone actually done any control studies of this? It seems such a basic of finishing wood I am surprised there isn’t a concrete answer to this.

does osmo actually seal the wood preventing moisture being absorbed (Or excreted) over a long period? Would a piece of wood oiled on all sides absorb moisture if submerged in water?
 
I had a birch worktop in my futility room. I only oiled (Osmo) the top, and it cupped noticeably.
I appreciate that it's but one anecdote, and that the plural of anecdote is not data, blah blah blah....
Next time I'll saw it in half, and oil only the underside of one half. Promise...
 
Back
Top