Staining, dyeing and finishing beech wood

[vaddoc]

I must admit I very much like beech.

 

It is a very hard wood but it bends beautifully. It holds an edge, glues well, cuts well, sands well. Does not splinter. It is readily available, cheap and available in all sizes with very clean sheets - no knots or blemishes.

 

However, it swells a lot with changes in humidity and has a very distinctive grain. I like the grain for modelling but I think I am the only one...

 

In any case, I ve used beech extensively so far but never for planking. This time, I decided to plank the 2 boats I am currently building in beech. In 1:10 scale, they are quite large. Now, one hull is ready and the other is being planked so I ve been thinking how to finish the thing. I was planning to paint the hulls but it was suggested that it would be a shame to hide the planking so now some kind of clear finish is needed. And here lies the rub.

 

Both the pear and beech wood I ve used are steamed and have a pink hue. The hull is sanded to 400 grit and it really cries for some colour enhancing and finish. The second photo shows the hull against coloured wood - it needs something doing.

Beech wood is notorious for resisting any finish. The wood has areas with very large open pores and others that are quite the opposite. Any staining attempt will result in ugly blotchiness.

 

I tried to simply use Tung oil but the results were not good.  The photo shows how non-uniformally the oil has coloured the wood - it is the segment on the left, Tung oil straight on raw sanded wood

Now, treating the wood with sanding sealer dramatically improves things. I know most people use Shellac, I personally never liked it - I find methylated spirits too toxic. I ve been using a water based sanding sealer which I think is excellent (Decoart-Americana multi purpose sealer). The bottom wood sample was sanded to 400 grit, had a coat of sealer, sanded with 400 grit and then had Tung oil. Much better colour uniformity.

So Tung oil needs sealing first. What about changing the colour though?

 

I decided to try Van Dyke crystals. I ve never used the stuff. I applied it directly to sanded wood. Fantastic colour but also dramatic grain inversion, the growth rings really stand out.

Now, the next photo is really interesting. The two upper strips have been coated in different strengths dye. The third was first sealed with sanding sealer, then dyed. Fantastic result! The last is just plain beech wood.

This was the only time I succeeded dyeing beech wood. All my subsequent attempts were disastrous. Did not matter how many coats of sealer, what grit of sand paper, every time was a massive failure. Photos bellow

There is no room for error finishing a hull, especially with a dye which cannot be sanded off. So Van Dyke crystals cannot be considered due to poor reliability and repeatability.

 

Next I tried stains. I had some left over samples of Osmo stains. I had found out from previous experience, that straight onto wood results are not good. However, applied on sanded and sealed wood, results were excellent. In the next photo, sealed wood is on top right (3 different stains), raw wood on the bottom.

Very nice, very uniform colour. Perhaps a second coat would enhance it more. However, these stains on the pear wood keel did not look good at all and I did not wanted to treat the 2 woods separately - Too much trouble and room for error.

 

So stains are out for this project but in general: Sand the wood to 320 grit, seal the wood with decoart water based sanding sealer, sand to no more than 320 grit and use Osmo stains. You ll have a good result on this very stubborn wood.

 

So, we are back to Tung oil. I experimented using 2 coats vs 1 coat of sanding sealer and sanding to 320 vs 400 grit. The best outcome was with using one coat of sealer and sanding to 320 grit. 400 grit seamed to seal the wood too much.

Even if something goes wrong, this thick Tung oil does not soak deep onto sealed wood and can be sanded off or stained over. In due course I ll seal the hull, Tung oil it and see what happens. I l try to post a photo in this thread.

 

I hope this will be of some help to others, especially as there is very little info on this subject on the net.

 

Best wishes

Vaddoc

[wefalck]

I gather it depends also on the direction with which the plank was cut from the tree, i.e. radial or tangential.

 

I don't remember, whether I ever tried to stain beech, but for furniture-type applications I regularly apply solvent-based(!) sanding sealer, rub it down with 320 or 400 grit, apply another thin coat and then rub it down with steel-wool (or scrape it for flat surfaces), which results in a smooth satin finish with a light honey colour.

 

Methylated spirit is only toxic, when you drink it !

[vaddoc]

I had an interesting message from @Jaager, so I ll add a few more thoughts.

 

It seems that Beech which is plentiful this side of the pond, is not as easy to find or as inexpensive in America. I was not aware of this.

 

Now, methylated spirits is ethanol with nasty chemicals added so it cannot be drunk. Jaager suggested that Shellac could be diluted in isopropyl alcohol, this never crossed my mind. For a sealer, I still prefer water based products. As a finish though, it worth a try to see how beech wood likes Shellac. IPA should be more pleasant to work with.

 

Tung oil, as a finish, needs initially to be diluted with mineral spirits. However, I only use it to change the colour of the wood so no need to dilute.

In regards to sealing the wood prior to staining, my research so far shows that wood conditioners, recommended prior to staining difficult woods, are essentially varnishes or some type of sealers to close the very large open pores and prevent blotchiness. Indeed, my results on beech were impressive-sealing the wood prior to staining works well.

 

I ll get some shellac and see how this works.

 

[wefalck]

Just a few additional thoughts:

 

In principle alcohol (ethanol) is something dead cheap, but in many countries qualities fit for human consumption is heavily taxed. In Germany a litre of 96% was something like 50€, but the actual production costs are in the cent range. I seem to remember that in the US one could get it in a liquor store for a fraction of that price, but is information 30 years old.

 

I am not sure what alcohol is used in them, but ready-made shellac solutions do not have an offensive smell (but I am actually quite tolerant towards the smell of organic solvents). Perhaps they use just plain ethanol, as the shellac solution would be unfit for human consumption, of course. So this could be solution to the problem, rather than mixing it up yourself.

 

Sanding sealers used to be nitrocellulose lacquers in a mixture of organic solvents with pumice powder added. I gather these days they are acrylic emulsions in a mixture of water and alcohol(s). Water however, has less good wetting propoerties with respect to wood than organic solvents. Therefore, the modern sanding sealers do not penetrate wood as well, as did the old ones.

 

The effect of such varnishes or lacquers, with or without pumice fillers, is that they fill the pores in the wood, obviously. Light then is not reflected from the surface of the wood, but sort of channelled into the pores from which it is not reflected anymore (or less). This makes the wood appear darker with 'depth' in the sheen.

 

Beech-wood is very common over here in Europe and used for all sorts of purposes, where you need a harder wood than e.g. pine, but do not want (or cannot afford) to use tropical hardwood. However, as all woods growing in temperate climates, it has growth rings with different properties. When cut tangentially (which it normally is) the growth rings will take on dyes quite differently, so it may look patchy after dying. A tinted varnish (stain) over a clear sealer is probably a better option.