Yellowish flecks appearing in wood as I sand

[Pij]

Hi

I am sanding an old table top because of bad water damage in one place.
I am using an orbital sander. As I started to remove wood, yellowish flecks began to appear, as you can see in the photos below. When I kept sendingsanding, some of the flecks would disappear but then new ones appeared in other places.

Does anyone have an idea of what could be causing the problem and more importantly, what I can do about its? The problem isn't too obvious on bare wood but I am sure it will be obvious when I apply a finish. I have just wiped the surface with a damp cloth to illustrate the problem.

The table has sentimental value because it was made by my grandfather in the 1940s. My mother remembers when she was a child, the table was painted pink and in the bathroom as a washstand.

My grandfather was a keen woodworker, I am a more reluctant one but I would love to restore the tabletop.

I'll be grateful for any help

 

[Jacob]

It's probably grain filler applied first before the stain, french polish, etc.
Sanding old furniture is usually best avoided- too destructive. Sometimes a good wash down is all it needs (followed by wax polish etc). Otherwise a cautious strip with Nitromors is fairly safe.

 

[Pij]

Not sure those photos are showing, so:

 

[Pij]

It's probably grain filler applied first before the stain, french polish, etc.
Sanding old furniture is usually best avoided- too destructive. Sometimes a good wash down is all it needs (followed by wax polish etc). Otherwise a cautious strip with Nitromors is fairly safe.

Thanks for the reply. If it were filler, wouldn't it be visible on the original surface, or just below? I had sanded off quite a bit before it started appearing.

Also, given that I seem to have gone down the wrong road here, is there anything I can now do? Thanks

 

[MikeG.]

I suspect Jacob probably has it right, but if not, could the table have been waxed? If so, your sander might be pushing dried wax into nooks and crannies in the wood surface.

 

[sunnybob]

acetone is the recommended way to strip old wood surfaces, as said above, youre just pushing the old finish further and further into the wood. But it can be dangerous to use, so extreme caution is advised

 

[HJC1972]

Well I’m a furniture restorer.....

Here’s my tuppence worth:

I must have refinished over a hundred teak tables in the past twenty five years. I have seen this a few times and I’ve never quite figured out for sure what it is. I’m almosy certain that it isn’t grain filler. Teak, traditionally at least, was nearly always oiled. To my mind this is still the best way to re-finish what is a naturally oily timber. Grain filler was rarely used on teak, as it is nearly always finished open grain, much the same as oak and other large pore timbers.

As i previously mentioned, I’ve never quite figured out what the cause is but I suspect that what the “yellow”that can be seen in the grain is actually the ply, chip-board, or, on an earlier piece, pine/oak substrate showing through, where there has been some minor grain tear out caused by the cabinet scraper.

Regardless, I’ve never much worried about it, as a light stain and umpteen coats of oil, and, if needs be, a slightly darker wax afterwards is usually enough to kill the problem.

 

[Nigel Burden]

I have the same on a 1970s Jentique table that was lightly sanded a few years ago. It doesn't look like filler, and appears in one place on the edge. The table has been treated with three coats of teak oil, but the yellowing is still visible. I am aware that this is probably a veneered table, but it doesn't look as if the sanding has gone through the veneer.

Nigel.

 

[Sheffield Tony]

If that top is not solid, someone has done a darn fine job of faking it !

Could it be old finishes in the open grain of the wood, or even a natural material like oxidised oils or resin in the wood ?

 

[HJC1972]

I’m not certain, you never can be from a photo, but I’d have a fiver on it being veneered.

It has a cross banding veneer, which does not always mean it’s veneered but is usually a good indication that it is.

 

[HJC1972]

Oh, and for what it’s worth, I don’t recall ever having seen the yellow fleck in the grain on any solid teak that I’ve refinished. Which only adds to my reasoning on grain tear out being the cause.

 

[Sheffield Tony]

Hard to tell from pictures, and I'm only looking at them on my phone, but in zooming in on the first picture it looks a lot like delaminating veneer, but the end grain on the edges of the top looks pretty convincing in places too ?

 

[HJC1972]

I can’t see a photo that shows the end grain, I must admit. But if there is one that somehow is not showing on my Ipad then perhaps it is solid teak.

The grain pattern does look like a rotary cut, pretty much the same as you get on Danish, G-plan and Nathan furniture from the 50s right through to the 70’s.

 

[Sgian Dubh]

.. perhaps it is solid teak.

It is. The image is clear enough on my monitor to see that the grain on the flat surface transfers to the edge moulding without a break.

As to the yellow bits, I'm not sure, but I suspect the pink paint applied at some earlier point may have something to with it, although that colour obviously is not yellow. Generally, a bit of a mystery. Slainte.

 

[mrpercysnodgrass]

Your table top as Sgian Dubh said is definitely solid. It is interesting to note that the edge moulding that you have not stripped has a black grain, which is good news because whatever is in the grain can be turned black again. I think your whiteish flecks can be one of two things, plaster of paris grain filler or some sort of mineral deposit that would have been present throughout the tree. I have come across mineral deposits in a few different species of timber including teak and cuban mahogany. If it is plaster of paris some warm linseed oil should colour it back up, warm the oil in a glass jar set into a saucepan of simmering water then apply the oil with a scotch pad ( a sponge scourer will be fine ) and scrub it into the grain, leave for five minutes then wipe off any oil left on the surface with kitchen roll. If that does not work leave the oil to dry. The next stage will be to use a grain filler. I think the best one to use will be Jenkins Repro Mahogany No 4 nitrofiller. It will both fill the grain and stain it close to the edge moulding. The nitrofiller is rubbed into the grain and the excess wiped off, you can then adjust the colour as necessary and apply whatever finish you fancy.
Hope this helps. keep us posted.

 

[Pij]

I wasn't expecting so much expert and detailed feedback — thanks to everyone who took the trouble to reply. And it does look like this is a tricky issue so I have gone back to take a closer look and now provide some more information including some high resolution photos with some of the end grain.

Veneer versus solid wood: initially, I thought I had sanded through the veneer to a different wood below, but the underside of the tabletop looks identical. Note that there are no flecks in the underside, though I haven't sanded this as deeply, and the flecks didn't start appearing in the top before I had sanded down quite deeply (unfortunately, the water damage went very deep because a vase had been left on it for a couple of weeks with water trapped underneath).

Photos that might help:

Finish: initially I did use a cabinet scraper ends of the first layer that came off looked like varnish (though I don't know if old oil would look similar).

Paint/filler: whatever the flecks are, they are definitely trapped particles within the open grain. Looking closely, it does appear yellowish to me, so it might not be the previous pink paint (though perhaps that would have discoloured — the paint went on in the 1940s!)

Just to reiterate is, flecks did not appear until I had sanded off quite a lot of wood, which makes me wonder whether or not that could explain filler or paint residue.

As for the new filler/linseed oil treatment, that does seem to be the one thing I could do, thank you. Are there any other options — I will otherwise assume this is the best way to go.

Wood: it looks like people are agreed that this is teak?

The table shelf looks like it might be a different wood, photo in case that is relevant

Sorry this is a long post and thanks again for all the help.

 

[Pij]

I think your whiteish flecks can be one of two things, plaster of paris grain filler or some sort of mineral deposit that would have been present throughout the tree..... If it is plaster of paris some warm linseed oil should colour it back up, warm the oil in a glass jar set into a saucepan of simmering water then apply the oil with a scotch pad ( a sponge scourer will be fine ) and scrub it into the grain, leave for five minutes then wipe off any oil left on the surface with kitchen roll. If that does not work leave the oil to dry.

The next stage will be to use a grain filler. I think the best one to use will be Jenkins Repro Mahogany No 4 nitrofiller. It will both fill the grain and stain it close to the edge moulding. The nitrofiller is rubbed into the grain and the excess wiped off, you can then adjust the colour as necessary and apply whatever finish you fancy.
Hope this helps. keep us posted.

Thanks for the advice - this had to go on the back burner for a while. I tried the linseed oil, but no luck, as you can see.

Should I assume that this is the end of the road and I should accept the flecks and move on?

Also, I only used linseed oil on a small area - should I try to remove from that area, or apply to the whole top before proceeding to using the grain filler?

Thanks

 

[yetloh]

It could be silica deposits in the wood. I have had this very extensively in a couple of (probably) Cuban mahogany table leaves that I recyled. In my case, I was very pleased to dicover that the deposits became invisible when I applied a couple of coats ot shellac. This may be worth a try as it is easily scraped away if unsuccessful.

Jim

 

[Pij]

Thanks