Sciencemadness Discussion Board

Hacking wood protection

Mixe - 7-7-2017 at 00:36

I have this yuuuuge newly built patio outside my house, and naturally I want to protect the wood somehow. There's this silicate-based wood protection called Sioo. It's a two-component system, and it's extremely pricy.

So naturally, I looked up the patent. It's a swedish patent filed 2012, registered in the european database as pat nr EP2003977B1. Can be found here.

It states that the first component is simply a potassium silicate solution (at 60 euros/L), and the second one is "an alcoxysilane solution". Now, the potassium silicate was easily purchased on german Ebay for practically nothing. The alkoxysilane is not as easily obtained.

In the patent it says that the silane should have three methoxy- or ethoxy groups attached to the silicate, and one branched or unbranched alkyl group in the fourth position. The alkyl group is responsible for creating a water resistant layer on the wood, and should be in the C4-C12 range. The methoxy/ethoxy groups crosslinks the silane to the silicate already deposited in the wood in the first step.

I'm at a bit of a loss to which alkoxysilane I should try to find? I have access to Sigma-Aldriches stock through a relative in the food industry business, but I really don't know which one is the right buy. Anybody?

Texium - 7-7-2017 at 05:17

Maybe isobutyltriethoxysilane?

Mixe - 7-7-2017 at 06:26

Yes, that is actually a brilliant suggestion! The price is very reasonable. Thank you!

unionised - 7-7-2017 at 15:32

or lots of other possibilities.

Lillica - 9-7-2017 at 17:19

Many outdoor protectants like that which contain silicone aren't that mysterious. Usually the silicone compounds have a single role, that is to repel water. Those shoe water protection sprays that they sell in stores is usually just an aerosolized silicone compound that coats the shoe, causing water to bead up and roll off.

In the case of wood the silicone would coat the wood, causing any water that falls on it to bead up and roll off, or simply not be able to seep into the wood.

I've seen people replicate these solutions before by taking some form of silicone oil (cheap online), mixing it in alcohol, and coating whatever it is they are trying to protect and letting it evaporate. Silicone oil are usually high molecular weight so they won't evaporate overtime.

This post isn't really a DIY guide, but if you have some chemistry understanding, you can easily replicate the solution to basically do what the store-bought products do.

Mixe - 12-7-2017 at 08:47

Yes, the functions of the silicone and alkoxsilane are well covered in the patent I linked to. The silicone itself wont provide water protection, I have tried. It needs the alkoxysilane to crosslink it into a protective layer. But the potassium silicate is applied in abundance, and penetrates the wood deeper. According to the patent, this will provide shelter from microbial growth and give the wood a nice, silvery tint over time.

Now, I tried both using the potassium silicate alone, using the potassium silicate sparsely with the alcoxysilane applied both one and two times, and adding the potassium silicate in abundance and the alcoxysilane twice. The last method proved to be the best. A good water protection was obtained, and the wood has already developed a nice tone.

Apart from knowledge of chemistry one also needs an understanding of wood and weather. I don't think silicone oil will work that well on wood. It lacks the penetrative properties and would probably end up sticky and matted over time. The whole point of this wood protection is to penetrate the wood with the first component, aided by its high pH level, and THEN solidify the silicone with component two.