Fibreglassing

[Swanrad2]

I have spotted some damage to the gelcoat of a 1979 Westerly Centaur. It has gone through to the fibreglass. I assume the resin was polyester and not epoxy so (especially with this being winter) was thinking of repairing like for like - buy some polysesyer resin and follow the same 12:1 bevall grind out process. I have never used polysester resin, any suggestions regarding suppliers (I don't need much) and major differences with fillers from Epoxy?

Cheers

 

[VicS]

I have spotted some damage to the gelcoat of a 1979 Westerly Centaur. It has gone through to the fibreglass. I assume the resin was polyester and not epoxy so (especially with this being winter) was thinking of repairing like for like - buy some polysesyer resin and follow the same 12:1 bevall grind out process. I have never used polysester resin, any suggestions regarding suppliers (I don't need much) and major differences with fillers from Epoxy?

Cheers

If it only a small area of damage to the gel-coat with little or no damage to the laminate a tube, or small tub, of gel-coat filler may be all you need.

You only need the 12;1 chamfer when repairing a hole or major damage to the laminate. Its the equivalent of a scarf joint in woodwork between the old and the new and leads to a small repair extending to a huge area!

A photo or two would help to judge what repair is needed but unless the laminate is damaged i would keep it to the minimum necessary.

 

[GrahamM376]

Agree with VicS. If no laminate damage then you just need to Dremel the cracks to get a clean edge, acetone it well to clean and then fill with gel. Cover with cling film or add MW wax so it doesn't cure sticky.

 

[neil_s]

I have a tube of 'Plastic Padding' gelcoat filler on the boat. It's ideal for small jobs and I find their 'white' is just the right shade for matching 1970's gelcoat!

 

[MM5AHO]

What others have said- if it's not to deep or wide, just use a filler as suggested.
I don't think that you need worry about polyester resin for a repair, you could use epoxy. (but not polyester on an epoxy boat)

 

[VicS]

Useful article perhaps

http://www.pbo.co.uk/expert-advice/gelcoat-repairs-make-invisible-repair-18060

but if its a white hull then you wont go wrong with the Plastic Padding gel coat filler that Neil suggests

I also keep some for dings to the superstructure but the red hull is more of a challenge!

 

[ghostlymoron]

I've also used the plastic padding gelcoat filler successfully for small non structural re pairs.
One question - do you need different hardeners for epoxy and polyester?

 

[GrahamM376]

I've also used the plastic padding gelcoat filler successfully for small non structural re pairs.
One question - do you need different hardeners for epoxy and polyester?

Yes.

 

[VicS]

I've also used the plastic padding gelcoat filler successfully for small non structural re pairs.
One question - do you need different hardeners for epoxy and polyester?

just to add to the "yes" above

Polyester resins require a " catalyst" in order to cure ... that's what's in the little tube supplied with gel-coat filler, body filler etc The proportions of the mix are not critical, within reason, but will affect the cure time

Epoxy resins cure by chemical reaction between the two components. The mixing proportions are therefore much more important, critical even. That is why the volumes of the two components, esp for small quantities are often measured with syringes or calibrated dispensing pumps on the containers.