Dear Joan,

I found David Chatterley’s article on epoxy resins in the last Bulletin very interesting and informative. I would like to add a little information based on my experience, which may be helpful.

• Regarding surface coating and the statement that epoxy is brittle: epoxies do vary in this regard between manufacturers, but even if water penetrates to the wood beneath it should not spread between timber and coating causing delamination as happens using polyester resins. The effect remains localised due to the strong bond on adjacent fibres.

• I personally have found glass tape to be virtually invisible under epoxy. However, glass tapes intended for polyester lamination may have a specific dressing which can cause visibility problems when used with epoxy.

• Epoxy resin cannot be used for coating timber by itself as it suffers from degradation if exposed to ultra-violet light. A varnish which is opaque to u-v light must be used — or paint.

• Cleaning up — it is not generally known that epoxy softens if exposed to a temperature somewhat above that of boiling water. A hot air gun, normally used for paint stripping, is a useful tool, when used in conjunction with a paint scraper. As wood is a good insulator there should be no risk to the integrity of an adjacent joint if common sense is employed. I have certainly not had any trouble in this way. It is because of this softening that sanding belts clog up due to the heat generated. To minimise this effect if belt sanders are used they should be run at low speed and kept moving over the surface.

• When sheathing with glass cloth I have found that applying resin on top of the draped cloth using a plastic squeegee is much the best way. One generally has much more time than one thinks; however I keep a quantity of slow hardener in stock for this type of job in case the weather is warm. PB