Posted by Brian Evans on June 08, 2003 at 00:39:36:
In Reply to: Re: Is it a must to use Fibreglass cloth contd. posted by steve on June 02, 2003 at 16:04:02:
: Ok i have decided to go with the cloth.
:I have read that when doing the seal coat, people will apply uncatylised resin to the wood and let it soak in. Then apply a catylised coat after no more soaks into the wood.
: The theory was that you could get air pockets under the fibreglass if it was to soak into the wood while drying. If you saturate the wood before hand, you could eliminate these thin spots.
: Has anyone tried this? From what i understand, the resin hardens due to a chemical reacton, so all the resin will become hard.
What you are describing is a dangerous trick, it may work with polyester resin it definitly will not work with epoxy.
With polyester resin the catylist is an initiator that starts the chain reaction of polymerisation and the resin will cure a little distance away from the point where the catylisation ends. However you can end up with resin that has kicked off but has not achieved a full cure leading later to delamination of the layup.
With epoxy systems the hardener is a component of the resin system and must be mixed in an exact ratio plus or minus a given tolerance or the stuff will not cure fully, and again painting unmixed resin on a surface first screws up that resin hardener balance resulting in under cure or no cure right where you need it the most.
Brian Evans.