refiberglassing

[bojangles]

hey
I am doing up a small boat which has only one layer of fiberglass mat. Its really old and a bunch of it needs patching anyway. My question is, do I sand down to wood, or can I just re-fiberglass on top of the old stuff. Also what is the most common fiberglassing format? I was thinking cloth,then a layer of mat, or roven woving or something.
You're imput would be appreciated
thanks

[dereksireci]

In order to get a good bond the surface of the old glass can be ground then cleaned with acetone just prior to applying new glass. What type fabric to use depends on your budget and the loads that it will see in service. Fabrics have different strength properties depending on the fabric orientation and type of weave. Way short answer but I hope it gets you started.

djs

[fiberglass jack]

I would remove all the old glass you say there is one layer which wont take much to grind the reason i say this is that the glass may have delaminated and you will be wasting your time just glassing over the old glass make sure you seal the wood before you glass i would use epoxy as the resin but polyester will work its been used a lot in the past but everyone on this form is in love with epoxy if money is no object epoxy,