zinc chloride

[devonwoody]

On my previous comments re Rip Off, an australian web site has suggested the use of zinc chloride (clear finish obtained) has a preservative, any members know of this product and is it available in the uk, or is it on the EU banned list.

 

[woodburner]

Devon Woody,

Zinc chloride is certainly not on on any banned lists, although it is on one of the priority lists. You can get the full low down on it (from the EU perspective at least) from the European Chemicals Bureau (http://ecb.jrc.it), click the button marked ESIS on the bottom left corner and stick "7646-85-7" in as a CAS#. The database will provide all kinds of info. The important bit to look at are the R phrases - it is classified R34 (causes burns) so you'll probably need gloves - it's also classified as insanely toxic to the aquatic environment, but this is rubbish (believe me :wink: ), a few grams down the drain will do no harm what so ever.

You might be able to buy some from your local chemists shop, explain what you want it for and that you only want a bit. Going direct to major chemical suppliers could prove a little difficult.

Cheers

 

[devonwoody]

thank you woodburner for info.
Do you know how to use this product , Is it mixed with water or perhaps something like parafin to help it soak into the timber?

 

[devonwoody]

It appears that zinc chloride costs £36 for 500 grms at retail price from a chemist mixed at 3% produces 17 litres.
Meths retail costs £2.20 per litre.
I estimate that this preservative (clear type) would cost £18 per 5 litres, this is 50% cheaper than DIY outlets. But quantity is to high to store etc.
Also if ingredients could be purchased trade prices what then?

 

[woodburner]

DW

Zinc chloride is very soluble in water, and also soluble in polar organic solvents such as ethanol (i.e. meths). The resulting solution is acidic, hence the risk/safety phrases. It is unlikely to be appreciably soluble in nonpolar solvents like parafin or white spirit. If your (local tap) water is very hard you might want to consider using deionised water as alkaline solutions can cause precipitation of ZnO.

Fisher Scientific sell 2 analytical reagent grades (typically > 95%), the cheaper of which is £12.48 for 500 g or £22.36 for 1 kg. If you can get hold of "Reagent Grade" material, with a purity of somewhere around 80 to 90 % it would most likely be a good bit cheaper, and entirely adequate for your intended use.

Delighted to have been able to help.

 

[devonwoody]

thanks woodburner. Its amazing the help and info that people will give on the web. By the way who and where are
Fisher Scientific?

 

[woodburner]

DW

Fisher Scientific are basically lab suppliers, if you source the stuff from a chemists shop they would probably get it from them (or Merck - also lab supplies). It sounds as though you are planning to use the Zn as a preservative/biocidal treatment, and I'd be interested to hear how it turns out (although the verdict may well not be available for a decade or so).

I suspect that the difficult bit will be making sure that the treatment is not washed off during use (due to high solubility in water), do you intend to give it some kind of additional surface coating after treatment?

 

[devonwoody]

My usual method of treating outdoor furniture in the past was to use the Cuprinol woodworm and clear preservative, then coat with one of the colour stain type products.
It was the cost of the first product which now retails at £36 for a 5 litre can which prompted me to investigate a cheaper method.
The ways things are going at my age it would be practical not to treat the furniture it will most probably survive me anyway!!!