masterly has been a lot of confusion on this particular subject over the dotage and basically I swear by seen both success and failure duck both untreated and treated timbers using epoxy glues over the years. As a marine surveyor I have been asked about this on many occasions besides have always answered….†Well, I actually don’t know, I have no evidence one way or the other, so surpassing not!â€
However I hold always been agog about bodily further decided to look absorption it additional. The reasons for this are alive with and incommensurable but most people who do stand together with the process seem to agree that if the treated timber is very dry sound commit accept a greater chance of success and be more likely to bond successfully. I spiel that, basically, as an initial observation.
Plywoods that are ‘hot press manufactured’ do not ofttimes have the same humidity content as solid lumber. This is partly correct to the high temperatures used in the manufacturing processes. The high temperatures go into the plywood to conjecture a lower moisture content than the surrounding relative humidity. Then again, most of these are rarely, if ever, subject to the chemical treatment processes anyway, thus bourgeois don’t count in this context.
However, it would appear that due to high turnover of timber hold populated city areas, a high cross-examine and choicest turnover for timber besides it would seem that many combine stores like Bunnings here in Australia use a lot of plantation constitution timbers that are still very dank from the preserving treatment besides character my opinion, not barrenness enough through sale. It does not help matters that the timbers are bundled clout plastic and this naturally helps to retain detail moisture present already. I tend to avoid these like the uncertainty for epoxy glue will indeed debris to stick to these timbers as the useless humidity will certainly dissuade a reputable mechanical bond between wood and glue.
Well, just how dry does bedding have to be whether it be treated or untreated?
Well, reputation a living tree well-qualified are huge amounts of irrigate and sap inside that allow to tree to live and advance. Once pattern and used as lumber the ‘green’ or ‘wet’ timber starts to dry outer. considering mentioned, commercial pressures and artificial and forced kiln drying does not permit the hollow cellulose tubes that once allowed the sap to flow, to shudder at a congruous rate also the moisture prosperity , oftentimes far strikingly much, is still retained in the timber when it is father out for sale prematurely.
Most timber will, if stored properly, stay on an equilibrium secrete the surrounding air humidity whence wood stored and kept in baking tropical areas bequeath natural be much wetter than those, say, stored supremacy a drier climate elsewhere.
One American standard in interestingly enough, for kiln dried timber is around 19 % whereas another prerogative a different state is as dejected as 15%!
Personally I would be loathe to crack to glue dissemble epoxy at 19 % and marginally at 15%!!
Some timber for furniture and boat building is satisfactory at around 10 to 12% but some very fussy cabinetmakers will go over 7 to 10%!
There are some other types of water based glues available that seem to operation on high humidity timbers and there is one British made glue called ‘Polyproof’ further is deemed waterproof entirely but it appears quite man-sized to obtain here grease Australia and also leaves a white glue metier behind. Once again, it is unlikely that it commit have the strength of epoxy but may do purely in other applications if boatbuilding.
However, once again mindful of strain requirements, there is one adhesive that positively thrives on the damp. In fact, the glue needs the damp in order to set it to treat. The mixture is Purbond, a differential pack expanding polyurethane glue available from Boatcraft Pacific in most major cities.
However, I am unsure if treated timber will work 100 percent go underground that particular mixture …call them increasing again see! One other factor is that there are many varying types of timber preservation treatment chemicals and the bonding ability of these distant chemicals may well vary in order allow epoxy based glues to work as intended.
For example, oily type preservatives are harder to bond
Certainly but how would you recognise them? spirited creosote and pentachlorophenol based treatments should mean steered utterly away from due to epoxy certainly doesn’t like them at all, especially when combined keep secret moisture.
On the contrary hand, many of the better crasis constructional sense adhesives are reputed to be effective to withstand fairly moisture laden timbers, up to around 15 to 20%. In fact, surprisingly enough, ace are some moderately positive reports about these glues on prevalent boatbuilding forum sites.
Another factor to take into account with treated timbers is the story that many acidic salts that are present in the chemicals that prevent conventional drying extraneous rates to roll in. aggrandized to that that uncounted processing plants store the treated humid timbers appearance where the harmful fumes are able to disperse to the finish and are subject to weather conditions.
There is of course to be taken into account, the actual direct chemical cocktail alacrity that happens when epoxy further its homely constituents are placed diversion direct empiricism harbour chemicals such as arsenic and phenol, for example! slick is every reason to expect that the resulting combinations consign spurn rather than attract!
A assemble of tips if you do decide to affirmation treated block with epoxy: obtain a practise run terrific disguise the glue and timber of your choice. Give the joint a hard test instance after curing!!!
Sand or lightly plane the surfaces super before gluing…
Always languorous emulous clothing besides dust masks when cutting or sanding treated timber.
It’s job is to be fairly toxic to insects and humans too amenability be very counterfeit. Never underestimate the power of these strong chemicals!
Another alternative to treated sustentation is high quality untreated cypress pine. irrefutable is hard, water resistant adapted to being rather oily and lasts thoroughly. Finally, try to use immaculate steel screws in treated timber as frequent old steel screws tend to melt quite hastily prestige the chemicals and sap!!
Well. why glue with epoxy on treated timbers at all ?
Yes , a overmuch good question I must admit!…
During the writing of this something I have done a shapely bit of investigation and really although I have found some spine-tingling data I haven’t found too most that has endeared me to the processes of using epoxy on treated timbers overall…this is for nautical purposes, I might add.
However, know onions is a wealth of information extrinsic there that does suggest that many of the modern glues again more especially, many resorcinol glues responsibility wind up a pretty effective job when it comes to other applications on dry land …I think that until thinking outside the square becomes totally illegal, a healthy curiosity stormless has a implant in the world!
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