Builders' Forum Archives
Re: Fiberglass specs
Posted by James on Jul 20, 2006
If you're doing a glass over wood canoe there is no way you'd ever need anything as heavy as 450g/m^2. Thats roughly equivalent to 13oz/yard and if they're suggesting tissue then its probably mat rather than woven cloth. That would be used for heavy straight glass construction or glass over foam, NOT over wood. This weight won't go clear and show the wood through if you use it.
Depending on your intended use and wood thickness I would suggest the following:
Lightweight where weight is more important than durability (3-4.75mm thick wood) and reasonable care in use, but not abuse (no beaching with people or load aboard). Single layer of 4 oz (115g?)cloth will be adequate inside and out. You can add a second strip down the stems/keel to help with abrasion.
Medium weight (6mm thick wood) and heavy use/abuse running up on beaches with heavy loads etc. Single layer of 6 oz (250g) cloth outside, single layer of 4oz or 6oz inside. This is the "typical" or standard wood strip construction and is as strong as most commercial fibreglass canoes.
Heavy weight (6mm wood) and heavy use including white water with high abrasion and potential impacts... Single layer of of 6oz inside and out with a second layer of 6 oz on the outside below the waterline and up the stems. Very tough... very heavy duty, but much more weight.
In Response to: Fiberglass specs by nmhpt on Jul 15, 2006