Advice on Fiberglass Repair

[roscoe23]

Hello Sailnet! I'm a proud new owner of a '77 Seafarer 22. My brother and I have been fixing minor things and doing some sailing, and we are now ready to tackle the biggest challenge: a nice hole on the starboard side from what looks to be a long time at a poor mooring.

Attached is a picture of the area to be repaired. I was hoping to get some advice on how to handle the separation in the hull below the hole. It's flimsy about 8-12" below the hole.

Should I just fill it in with expoxy and clamp it together somehow (how)? Or should I sand off at least part of the outer layer and cover it with new cloth (seems like a better plan, but more work). Also need to figure out how to work around the hardware on the deck and keep the shape of the toe rail.

I've purchased fiberglass mat and cloth and West Systems epoxy. I've read the fiberglass manual from west systems and various things online. We have done some repairs on our old cat before, but this will be more extensive than our previous experience.

Any advice or suggestions on how to approach this would be much appreciated.

Thanks!
Tyler

Here's the pictures:

i54.tinypic.com/314rts9.jpg
i51.tinypic.com/1j26op.jpg

[paul323]

The photos help, but it's tough to give advice without seeing it in person; however, I would sand off the gelcoat around the effected areas. Use acetone to clean the area. I would then use a lightweight material, such as thin ply or even cardboard, to span the hole and give it some shape - something the new 'glass mats can lie against. It could be glued or screwed inside the hole...then I would add the layers of fiberglass matting, in sets of 3, then letting harden, then the next set (so thing's don't overheat and deform), building up to just above flush (so it can be sanded flush).

You may also want to visit your library and get some of Don Casey's books, such as This Old Boat.

I know it looks a bit intimidating, but fiberglass is awesome stuff, easy to handle, and as long as you make sure the patch is 3-4x bigger than the original hole, it will be as strong - or stronger - than before. Sand it down and only you will know....

[roscoe23]

Thanks paul! Adding a thin support as a base sounds like a good idea.

Should I work much from the inside? The guy at West Marine suggested I do most of the work from the inside, but I don't think that makes a lot of sense given the nature of the hole. There is pretty easy access from the inside, yet it will require working with the contour of the toe rail (somewhat narrow).

How would that work with the supporting piece - would I put it in the middle for shape and lay glass on both the inside and outside, working both sides up until high enough to sand down?

[paul323]

Hmmm..there are so many ways to do this...note that fiberglass does not stick certain plastics (or wax). Your supplier can sell you plastic sheets, or I sometimes use the plastic found in retail "boxes". This plastic comes in very handy as the fiberglass touching it will set totally glass-smooth so when you peel the plastic off no sanding needed. If you use this plastic - perhaps with a bit of wood behind to make it more rigid - as a form, it can easily be peeled off when dry and reused. It will allow you to make more complex shapes.

In many cases I would agree with the WM guy, and start from the inside; that makes sense if you have a puncture hole; just tape the plastic on the outside of the hole, build up the layers on the inside, remove the plastic, your pretty well done. But in your case I think some more artistic rebuilding of the rail will be needed. As the damage is pretty severe, you may want to have the matting overlapping the hole on the inside and outside.

So an option would be to set up the plastic on the inside, and build up the layers on the outside; maybe using more plastic and a wooden form (thin ply) to help your final layers on the outside to follow a nice, smooth. matching curve along the rail. Then remove the plastic from the inside, and put a couple of layers of mat inside to reinforce it both ways. Perhaps a bit overkill?

BTW, Grinding is essential; people recommend a 12-1 ratio for a really solid repair, so put on the dust mask! And remember when applying that the cloth should we "wetted" with the epoxy (please tell me you are using epoxy...) not soaked. Too much epoxy is bad - but equally you don't want the fibers dry! You could buy a fancy roller, but I just use a scraper to make sure the resin penetrates all the fibers, and remove excess resin.

Hope this helps...thinking it through first is probably 75% of the work!

[mitiempo]

Most fiberglass mat is not compatible with epoxy. If the mat you purchased is not specifically labeled as epoxy compatible it isn't.

The binders holding the mat together will dissolve in the styrene of polyester but in epoxy they will not.

Cloth is fine as it doesn't have binders, being woven instead.

[TQA]

First the good news. Your repair is in a non critical area so stop worrying.

The better news comes next. This is an easy repair.

Start from the inside. Grind away about 3/4 of the thickness at a bevel of at least 5 to 1 more is better [ Casey says 12 to 1] Lay on cloth layers with thickened epoxy. [ NOT MAT] Build up till you have the required thickness. If you can, tape on a piece of flexible material coated with a release agent to hold everything in place till it 'kicks'.

Repeat from the outside. Now you will want to use that flexible material coated with a release agent possibly with a layer of 'peel ply' to get the shape but no biggy if you cant, it just means more sanding.

Scarf in a new rail section.

Epoxy is not UV resistant so paint your repair.

Go sail the sucker.

[roscoe23]

Thanks guys for the advice and encouragement.

So an option would be to set up the plastic on the inside, and build up the layers on the outside; maybe using more plastic and a wooden form (thin ply) to help your final layers on the outside to follow a nice, smooth. matching curve along the rail. Then remove the plastic from the inside, and put a couple of layers of mat inside to reinforce it both ways. Perhaps a bit overkill?

That sounds good. I've bought 80 grit 5" disks to use with a sander. Will this be sufficient for grinding?

Most fiberglass mat is not compatible with epoxy. If the mat you purchased is not specifically labeled as epoxy compatible it isn't.

This is alarming - I need to check what I have.

[mitiempo]

Mat doesn't reinforce the repair. The glass in mat is all short pieces - it builds thickness but doesn't add strength. In construction of a boat all the mat does is fill the spaces between layers of roving. I wouldn't use mat and never do myself.

[shogan50]

You might check out a book called "Advanced Composite Techniques", subtitled, "Lightweight Moldless Techniques for the Aircraft Homebuilder", by Zeke Smith.

[mitiempo]

The best how-to is here: Fiberglass Boat Repair and Restoration
At the top of the page is a link to the entire downloadable manual. Easy to understand with many illustrations. Works with any brand of epoxy, just mix each to the proper proportions.