Oldragbaggers wrote:I use Smith's CPES and according to their website, this is how they describe their product.....
"Clear Penetrating Epoxy Sealerâ„¢ (CPESâ„¢) consists of a tough, flexible resin system in a solvent blend which dissolves the sap, oil and moisture found in wood. The resin system is derived from natural wood resin and develops a chemical adhesive bond to the wood fibers themselves."
That does not sound like pure epoxy to me???? It is flexible, which epoxy is not, it is made with natural wood resin, which epoxy is not....
1) CPES is epoxy.. it also contains a number of solvents and other additives.. it's primary purpose is to penetrate rotten wood.. the solvents, thinners and other additives are included to do a number of things.. primarily, to reduce it's viscosity and allow it to penetrate and to prolong it's transition from liquid to solid.. which allows deeper penetration and the release of solvents/thinners before it reaches a gel state and traps those solvents/thinners in the resin.
2) the word "epoxy" is like the word "paint".. it is a generalization as there are literally hundreds of variations of epoxy.. some are flexible and some are not.. some contain significant portions of cellulose and some have none..
from wiki..
"These commodity epoxy manufacturers mentioned above typically do not sell epoxy resins in a form usable to smaller end users, so there is another group of companies that purchase epoxy raw materials from the major producers and then compounds (blends, modifies, or otherwise customizes) epoxy systems from these raw materials. These companies are known as "formulators". The majority of the epoxy systems sold are produced by these formulators and they comprise over 60% of the dollar value of the epoxy market. There are hundreds of ways that these formulators can modify epoxies—by adding mineral fillers (talc, silica, alumina, etc.), by adding flexibilizers, viscosity reducers, colorants, thickeners, accelerators, adhesion promoters, etc.. These modifications are made to reduce costs, to improve performance, and to improve processing convenience. As a result a typical formulator sells dozens or even thousands of formulations—each tailored to the requirements of a particular application or market."
3) wood is a composite material.. it's main component is cellulose, the fibres the cells are made from.. and lignin, the glue that binds the cells together.. the resins, oils, and waxes in wood are not part of it structural properties, they are there primarily to prevent rot and decay and to prevent insects and microbes from making a meal out of it..
4) I didn't say CPES was pure epoxy.. the quote was.." it's 'thinned down' epoxy for the price of pure epoxy.." which it is..
West Systems, System Three, Raka, Industrial Formulators and similar brands of epoxy do not have added thinners, they are resin and hardener only.. it's up to you to add thinners or other additives yourself..
by terryjones1 » Thu Dec 22, 2011 1:17 pm 
