Fiberglass Work
- Thread starter Bob J.
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You can use polyester resin and fiberglass matt or cloth. It comes in a tape format (on a roll in different widths) which makes cutting for tabbing easy. Polyster resin is cheaper than epoxy. Everybody is epoxy crazy and think they need to use that to fix anything and everything. While epoxy is better suited for some projects, it is not necessary to use on all projects. Your boat was made with polyester resin (isothalic is better than orthothalic) and so you can do repairs and projects as you have detailed very successfully with polyester resins and save a little money for something else.
Polyester bonds very well with green polyester but doesn't stick that well to cured polyester. Epoxy does a much better job. I would use biaxial roving like 1708 which has epoxy compatible mat on one side. Be sure to place foam at the edges of the bulkhead to avoid hard spots. This way the tabbing takes the load evenly.
I used polyester resin and 6 inch wide 10 oz glass tape and used continuous length from bottom of the bulkhead right up to the cabin roof. Just remember to take a wire brush and scruff the hull surface where the new tape/resin will go and wash it with acetone.
The picture is the structural bulkhead and is covered by 1/4 birch for a finish.
The tape is a bit difficult to see I guess.
Happy sailing,
Brina
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I used about 75 gallons of polyester resin when I rebuilt Bietzpadlin. In ten years of sailing there has not been a single bond failure any where on the boat. If you want better than plain polyester then go with vinylester which has the bonding charactaristics of epoxy and the cure times of a polyester. Alternate layers of mat and woven are as strong as you can get and far more than you actually need.
Polyester resin with mat and woven roving with do great for your job. Vinylester might do a little better but is unnescceary. Epoxy, not so good. Most epoxies have a different temperature swell and swink rate from polyester which can tear apart the "stronger" bond with time and temperature change.
Two other points, always put a layer of mat under woven roving to assure good glass contact and forget the wire brush. You need to abrade the surface with at least 80 grit or better. You do not have to go deep but you should scuff the entire area thoroughly to get good adhesion.
FYI I do this for a living and have for a number of years
Two other points, always put a layer of mat under woven roving to assure good glass contact and forget the wire brush. You need to abrade the surface with at least 80 grit or better. You do not have to go deep but you should scuff the entire area thoroughly to get good adhesion.
FYI I do this for a living and have for a number of years
An Abrasive Idea...
Speaking of "scuffing" the surface to give the new resin some tooth......
I used to believe that 80 grit was rough. This always took a while.
Then a pro boat builder pointed me towards 16 grit on an angle disk grinder. Put your intake hose for your shop vac right there adjacent to the out-fly from the disk. Put on your bunny suit anyway.
Change disks often.
Works great.
Unlike others here I always use West System epoxy and Bi-Ax. Others will have good solutions that work for them just fine. It's a case of there being more than one "right answer."
Have Fun!
:cry:
And do wear a mask....
LB
Speaking of "scuffing" the surface to give the new resin some tooth......
I used to believe that 80 grit was rough. This always took a while.
Then a pro boat builder pointed me towards 16 grit on an angle disk grinder. Put your intake hose for your shop vac right there adjacent to the out-fly from the disk. Put on your bunny suit anyway.
Change disks often.
Works great.
Unlike others here I always use West System epoxy and Bi-Ax. Others will have good solutions that work for them just fine. It's a case of there being more than one "right answer."
Have Fun!
:cry:
And do wear a mask....
LB
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