[Ant]

Blykins,

Fibreglassing isnt that hard, if you are using Polyester resin, and MEKP hardener, as Mickmate said bevel back say if your work is 1/4" or thicker you might want to bevel back 3 - 3.5" . Polyester resin doesnt have a great bond strength, hence 60-80 grit sanding for it to bite to, plus be careful with cleaning, use Acetone and wipe with paper towels. If you are doing a strength repair you are far better using Epoxy resin it has 6 times or more bond strength, it is easy to work with, as long as you use the measuring pumps, but the bottom line with both products is they are better than the cheap kits available, and for myself I wouldn't introduce petroleum jelly to the mix, I would use a parting agent, and then you have to make sure it is washed and solvented off before any sanding or further repair, can be done to that area.

Another point is temperature and if you live in CA its probably not a problem, but no polyester glassing should be done lower than 15 degrees, Epoxy can be lower, as the rest of the part, or body acts as a heat sink and the secondary bond you are doing has less grip, remember the body is a primary bond as it was done basically altogether and cured together, wheras now you are doing a secondary bond and its only as strong as the bond surface your are glueing to.


Having said all that for a small area one of these kits may be just what you need, look at the chemical makeup or take it to a body shop and ask them, as if its based on epoxy or a two pot mix it will have a good bonding formula, much better than normal polyester as mentioned, but if you are doing big jobs, refer to what I mentioned in the first paragraph or look up on the Web there are many good websites on how to do glass repairs etc. One point though with these kits or epoxy, a good wet sand, paper towell off etc after it cures, as there can be a waxy residue that will make it hard to lay more over etc.