Fiberglass repair for 13 Sport

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Sailor536
Posts: 13
Joined: Sun Nov 27, 2016 12:10 am
Location: Grosse Pointe, Mi

Fiberglass repair for 13 Sport

Postby Sailor536 » Tue Nov 29, 2016 7:51 pm

Recently I purchased a 13-foot Boston Whaler boat with hull [stencil] number 14329. The port side has a punched-in hole about the size of your fist.

Should the damaged section be cut out before applying the fiberglass repair or should the damaged area just be pushed in a bit?

Is West System expoy with fillers a good product for this type of repair?

Thanks,

Jim
Hull damage.jpg
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13 Boston Whaler Hull 14379 - 1964

jimh
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Location: Michigan, Lower Peninsula
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Re: Fiberglass repair for 13 Sport

Postby jimh » Wed Nov 30, 2016 11:21 am

The best advice for making repairs to the hull of a Boston Whaler boat comes from Boston Whaler themselves. Please refer to

http://continuouswave.com/whaler/refere ... tions.html

For an illustrated article showing use of the recommended methods, see Taylor Clark's excellent article at

http://continuouswave.com/whaler/refere ... epair.html

Regarding use of epoxy resin for repairs to Boston Whaler boats, there are two schools of thought. Some repairers prefer to work with polyester resins, the same sort of materials used to mold the hull in its initial construction. If you are skilled in use of polyester resins and have the proper specialty resins that will actually cure if exposed to air, I am sure those resins will be sufficient for the repair.

I have made a few minor repairs to small areas of damage to my boat's hull, mostly filling old holes made by fasteners or some very minor hull damage from abrasions, and I have used WEST System epoxy resin with fillers. Epoxy resins are stronger adhesives and make better secondary bonds to already cured resin structures than polyester resins can. Use fillers with the epoxy. A repair area with undiluted epoxy will typically be much harder than the 30-year-old polyester resin of an old boat hull, and this hardness can cause an uneven fairing when sanding. Watch out for that. There are old-wives'-tales about the inability to top coat epoxy resin with gel coat resin. This can be a problem if inadequate surface preparation is used.

For some advice on using WEST System epoxy resins to repair older Boston Whaler boats, listen to Jim Watson from WEST Systems explain the method in an interview I conducted with him many years ago and preserved in a recording available from

http://continuouswave.com/whaler/radio/

You can find the interview under the West Systems subheading. In particular, listen to PART 1:

http://continuouswave.com/whaler/radio/ ... tPart1.mp3

I have successfully top coated epoxy resin repairs with gel coat resin and had no problems. I personally prefer using WEST System epoxy resin from their very handy and inexpensive repair kits. Using the pre-packaged foil containers of resin and hardener gives a perfect mixture that always cures. Generally one repair kit can accomplish a lot of repair work. I describe my own experiences in an article at

http://continuouswave.com/maintenance-logs/epoxy/

jimh
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Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
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Re: Fiberglass repair for 13 Sport

Postby jimh » Wed Nov 30, 2016 11:27 am

It is hard to judge the damage from a picture, but from the illustration above it appears the damage is confined to just the gel coat layer of the laminate. This sort of repair is described in the Boston Whaler literature (see above article for the link) as in between the categories of gel coat puncture repair and a small structural repair. Some of the gel coat looks like it is loose. This area should be sanded or lightly ground until all loose material is removed. This will probably significantly enlarge the area that will need to be covered by the repair.

Sailor536
Posts: 13
Joined: Sun Nov 27, 2016 12:10 am
Location: Grosse Pointe, Mi

Re: Fiberglass repair for 13 Sport

Postby Sailor536 » Sun Feb 05, 2017 10:51 pm

I've been sanding the hull to remove the small holes (~1/16 inch) that cover about 50% of the hull, and its been slow going sanding off the holes.

Wondering if I can move things along faster by filling the holes rather than sanding by:
- filling the holes with Total Boat Fairing compound or
- covering the entire outer hull with West System epoxy or
- painting the hull with a high fill primer. I've read that the high fill primer only fills 3 mils, and the holes in the hull are about 1/2 the depth of a credit card, which I'd estimate to be about ~15 mils.

I don't know what material was applied to the hull that caused the holes by the previous owner. The attached picture is a close up of the holes.

Thanks,

Jim
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pin holes.jpg
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13 Boston Whaler Hull 14379 - 1964

jimh
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Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
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Re: Fiberglass repair for 13 Sport

Postby jimh » Sun Feb 05, 2017 11:43 pm

Re filling those 1/16-inch-diameter holes by the hundreds: if you use an epoxy resin you should probably mix the resin with a low-density filler compound. Cured epoxy resin that is not mixed with a filler will be very hard, probably much harder than the old gel coat layer, and it would be likely that fairing to a smooth surface with un-mixed epoxy would be difficult. Using epoxy--even mixed with fillers--should give better adhesive characteristics, which might also help hold the gel coat resin layer intact better.

I have never used the fairing compound you mention, so I am not familiar with its characteristics. Since it is called a fairing compound, I would not expect it would be likely to provide much strength, whereas I would expect epoxy resin with filler to have greater strength.

You can buy a WEST System epoxy repair kit package for about $35 (perhaps a bit more at latest prices), and it will have about six packets of epoxy and a generous amount of filler. You could experiment on a portion of the hull which won't be in high visibility, and then judge how the epoxy-low-density-filler-mix works for your application. I really like working with the WEST System epoxy repair kits. The pre-measured foil packets have a very long shelf life, and your mix ratio is always right; I have never had a problem with curing, except perhaps if you mix up a batch and only need a tiny amount; the unused portion of a one-packet mix will get rather hot if allowed to cure in a large lump in the mix bowl.

The amount of area that can be repaired with one packet and some filler will be quite decent. If you find you like working with the material, you can buy it in larger packaging or just buy another repair pack or two to finish. I have some 20-year-old resin and hardener in metal cans that will still mix up and cure, although the color is now very amber instead of clear.