Alder bowl - where did that amazing colour go?

[howlingbaboon]

Last night I attempted to finish the first bowl that I ever turned from green (fully dry now). After I originally turned it, to my surprise, it turned a wonderful colour with a mixture of reds, oranges, pinks and yellows with all kinds of tiger stripes, spots and blotches. Especially seen as it was my first bowl (actually 2nd now I come to think of it the first was a natural edge), I thought I'd hit the jackpot and have been looking forward to seeing these colours and patterns in the finished piece.  Even though it didn't look it, I found it surprisingly oval during final turning but I also found that, as the surface wood was removed, the colour and patterns vanished (obviously the grain remained but these other patterned were different from the grain, like another layer).

I didn't have the energy to finish sanding yet but am wondering if this colour will return. Was the colour a result of some sort of oxidation seen as I was only on the surface? In which case, If I delay applying the finish (was planning on Danish oil, Rustin's?), could my colours return again. Or maybe the oil will bring them out?

Here's a pic with the nearly finished bowl besides a very similar rough turn from the same batch. As always, I value and appreciate your advice! :-)
Cheers
Dave

[Les Symonds]

Alder loves to grow in marshy ground, so its cells often have all manner of muck and minerals stored in them, and its timber produces curiously high levels of sugary-proteins. When a green piece of timber is pre-turned and left to dry, the moisture rises to the surface bringing a lot of these deposits with it, staining the surface, but when it is re-worked all the superficial deposits are turned away......having said that. this does seem to be an extreme case. Amazing degree of colour change.
Les

[howlingbaboon]

ah so that means the colour could be gone for good...

[Les Symonds]

ah so that means the colour could be gone for good...

I think that's probably the case!

[seventhdevil]

as a general rule the colour of the wood will be what colour it is when turned green and not the colour the wood goes whilst drying.

there are exceptions like purpleheart that change due to UV light but they are rare.

[howlingbaboon]

Gutted! Would there have been any way to preserve that colour then? Like if I had finished it green and just let it be oval maybe? I guess that still would have involved sanding so that could have removed the coloured surface anyway...

[seventhdevil]

if it's colour you are after then i suggest you use a more exiting timber to start with...

though in saying that alder is a perfect canvas for colour if you are into that sort of thing.

[Eddie Perkins]

Could it have gone to Aldershot 

Try an oil finish, it may pull out some colour.  Danish oil works well.

[howlingbaboon]

My first 4 bowls were Alder which I salvaged from my friend's firewood pile with the promise of turning one for her. If only she knew how much time it will have taken me The colour show of each of them was amazing and I will be sad to lose it.  I just turn what I get from the local tree surgeons.  I quite enjoy the pot luck!   Just got a good haul of Beech (not spalted but temped to put it back in the woods for a while!)  which seems very nice to turn. I've been fortunate to get a nice variety so far. (apart from the 1st lot which was Euk which is still taking up far too much room in my garage!)

[edbanger]

The best thing to do with Alder is let it spalt then you get the colour

Ed

[BrianH]

if you want to spalt your projects try sealing a green rough-turning in a plastic bag together with either a piece of its own bark or a handful of grass clippings (I seem to get I different result from each so presume they carry a different species of rot spores) it'll spalt quicker than burying it in the woods.
All the best
Brian

[howlingbaboon]

Ok, that's good advice. I might try the spalting on some of this Beech. I turned some lovely spalted Beech a few weeks back. It was the log I was going to try and make a djembe drum from which I never got round to due to ill health. The spalted was a nice surprise.

Do some woods oval more than others while drying then? I'm guessing thicker walls mean more ovaling? This last one never seemed to want to get round again and I was getting worried that if I took any more off the outside that I wouldn't be able to round out the inside. I guess I'm worried as I turned the spalted beech bowls (from our old garden tree so sentimental and intended as gift for my parents and the neighbours) much thinner so am hoping they will oval less or I could be in trouble.

[seventhdevil]

yes some timbers shrink alot more than others whereas some you hardly get any movement at all. catalpa is a very stable timber but the most movement i've had from a clean bit of timber was a bit of whitebeam as i lost 30mm on the width of only a 12" bowl.

[Mark Hobster]

With luck the finished bowl with oxidise a little but not to the level before truing up,  if you really like those colours then turn to finish thickness and wet sand while still green,  with the idea of only truing up the foot when dry so it doesnt wobble and hand applying and hand buffing any finish,  you might have to lightly polish the whole thing with high grit paper just to take any raised grain down or de nib,  or lightly with 0000 wire wool,  remove dust before applying a finish,  this way you will keep the staining albeit with an out of round bowl..  Not such a bad thing

[Mark Hobster]

About warping,  end grain bowls warp a lot less,  some woods warp a lot more,  worse one I have done for warping so far is Lime,  that went like a rugby ball and at 10" wide a 1" wall thickness for drying was actually just perfect for a thin rim without taking the height down