wood glues

[normanwisdom]

Easily said from behind a desk. Very different for a practitioner - "irritant" exposure every day can't be good, and if it irritates the skin it will surely be bad for the lungs. Inhalation and ingestion are very likely in a normal work condition via dust firstly (it's inevitable that some treated timber will get resawn, sanded, mishandled for whatever reason) and by transference from the skin. I know this from experience handling other peoples work

- one of the first indications of the presence of preservatives is the tingly nasty taste on the lips (you don't have to actually lick the wood to get it) and the second is the irritation in the throat (and hence the lungs). Also the treated joinery may well at some point be removed, or modified, sanded, drilled, hot-air gunned, paint stripped etc at which time preservatives will be released. Also bearing in mind that the preservative industry have a terrible reputation and would say anything - even in the bad old days of arsenic, TBT, etc, I will not have anything to do with preservatives. If my clients want it I tell them they must apply it themselves when I am well off site. My health is more important to me than the longevity of their windows/doors.

cheers Jacob.

[Chris George]

Well understood and respected as one's health is clearly a matter for a personal risk assessment. All the exposure to which I referred above would have to be subject to a COSHH assessment and appropriate PPE and other measures. Clearly, using no preservatives is safest for you and quite within your perogative but not using them will without question produce a less durable end product for the client. I do feel that you may have been influenced by what was bad practice 20 years ago in terms of active ingredients in wood preservative and that, if you are as concerned as you are about wood-preserving chemicals as they are allowed today, you should also to look equally at other activities.... bleach under the kitchen sink, most organic solvent paints, every time you fill up a car with petrol, not to mention lots of the food we gaily buy from the supermarkets!

I would also like to add that my advice is not just from behind a desk and that (if it was not clear from the tenor of my advice - I apologise) I am also a "practitioner" that my advice is based on working on site (on and off) since 1975. chris

[Chris George]

Jacob You are quite right - casein is milk based and animal glue is collagen based Both are proteins and rely on the glue action by chemical bonding with hydrogen bonds Both susceptible to biological action both prone to chemical changes on humidification In fact, casein is a better performer in wood adesion than collagen. See

glues form an elastic network with hydrogen bonds. The hydrogen bonds can be disturbed by water. Water will bond to chemical 'receptors' that would be there in the glue to hold it together and the structure can thus fail.

[normanwisdom]

Just re-reading this thread - doesn't seem to be any good reason offered for not using cascamite (or vegemite whatever it's now called). I'll buy some today.

cheers Jacob

[Andy Dingley]

Except I seem to recall that it's no longer being made!

[Peter Ashby]

This do?

Peter