Advice on Restoring 1970 Fiberglass Canoe

I have an old neglected fiberglass canoe and I am currently investigating whether or not I can repair it. I have a standard set of DIY experience so I likely can handle my way through this with some advice on steps and materials, with passable quality.

Google keeps sending me to similar threads in this forum so there must be some knowledgeable people around.

 

Yes repair !!!
Its a good old boat and with some grinding and careful glassing you could have a really nice boat again . Will be a little heavyer naturaly but still good . The chopped strand and 18 oz woven roving day when you could make anything at all . Id start with the outside first . Take you time and carefully grind the whole outer surface and get rid of thepaint or red gel coat . The gunwhale round the top , is it possible to get it off or not ?? If not do a neat scrap and clean job in the wood and restore it at the same time . The outside id do with woven Kevlar and epoxy The same epoxy could be used to recoat the wooden Gunwhale . all at the same time !. Take the kevlar over the keel and finish it there then wen you do the other side overlap so the keel ends up with 2 layes of kevlar cloth over it .I would also yes peel ply over the top of the resin ! When it is all hard the peel ply gets ripped off and givs a good surface to gently sand and prime and paint with a two pot uretane paint . . The inside needs the same sort of treatment and grind backand get rid of all the flaking Gelcoat but do not grind into the glass scuff the surface yes to get a good bond for the epoxy coat inside!! Kevlar had excilent wear resistance and epoxy is best resin can buy so combined with the urethane 2 part paint will last for long time .
Its best to get shot of all the gelcoat on the outsdie as its extra weight and the gel is the weak place for the epoxy to bond to . Get to the glass below but not through it !!!.

 

I think that I would take a slightly different tact if I were working your refurb.

From your photos, it appears that the gel coat that is still on the exterior of your canoe is still nicely bonded to the substrate. If not, then remove the poorly bonded portions. I would abrade the exterior with an orbital sander and a 50-80 grit sand paper. Depending on how involved you want to get, you can remove the gunnels (PITA) if you want to deal with reinstalling them or just leave them be and work around them.

If you need to make any repairs to the hull (nicks, gouges, etc), apply thickened epoxy to the prepared area, sand and fair.

The sanding you'll be doing is just removing any loose or poorly bonded material and to provide "bite" for the next step. After the first round of sanding go over the exterior again with a finer, 120-180 grit, sand paper. Once done with this, clean the exterior of the hull. Mask off any areas that you don't want epoxy to adhere to. Apply 3 coats of marine epoxy over the entire exterior surface to build up a protective coating over any exposed fiberglass. There are many good epoxy products on the market. Apply the epoxy with a foam roller for the best build and consistent thickness. Once the first coat has gotten tacky, apply the second coat and repeat for the third coat. If you reapply before the epoxy reaches full cure, you can avoid sanding in between coats. I you plan you day right, you can do it all in a day.

Let the build coats harden sand with 80-120 grit and finish 180-220 grit. You should have a good substrate now for a decent marine finish. You can get a decent finish with the roll and tip technique and a good marine topsides paint. Since you will most likely "dry sail" the canoe, a topsides paint will work fine. I have even used exterior gloss latex and a roller and gotten decent results. It all depends on what you want for a finished product.

On the inside, I would remove any loose gelcoat, hit it with the aggressive grit all over the inside to provide bite again for the next steps. I'd use unthicken epoxy and coat all of the areas where the gel coat is missing or cracked. Let it go tacky again and start working those areas with epoxy thickened with silica and micro balloons. There are other options for thickening. The silica is structural, but hard to sand once set while the micro balloons are non-structural, but will improve workability of the cured epoxy. Smooth the repairs and do the epoxy triple-coat and paint and you should be good to go.

This method is a little more user friendly and involves a few less dollars. If you have not worked with epoxy before, it is an excellent introduction to the process. I you do mismix a batch, you only have that coat to remove, you have fewer concerns as the surfaces you are working are essentially non-permiable and you've not ruined any cloth. It may be possible that there are areas that need a cloth treatment, but I didn't see anything jump out at me in your photos.

If there are any areas where you have cracked gel coat that you epoxied and filled, there is the likelyhood of those cracks reappearing. A complete removal of the gel coat in those areas should negate any possibility of those cracks returning. You could also glass those areas instead if you felt the gel coat, otherwise, was in good condition and firmly bonded. The risk of the crack reforming is further reduced, over epoxy and filling, but still a possibility.

Good luck on your rebuild.

 

It sounds like something I can tinker around with this summer and have a reliable old boat to keep at a cottage.

Both detailed posts are greatly appreciated. Time to get sanding!

 

Wow LP, amazing...

LP, I loved this quote. I am sort of in the same situation but am a complete newbie to this hobby. I fish a lot, don't make much, and have wanted a boat to find better spots on the river. I found a 13' fiberglass canoe that had blistered gel coat because of a nearby brush fire and a small gouge on the bottom of the boat. Also, the gel coat is practically completely faded on the bottom almost to where I can feel the fiberglass layer. Should I attempt the same overhaul you recommended previously or do you have any other suggestions. I will have pictures but just wanted to touch base with you because your post has been the most informative for the situation I currently have.

I would appreciate any future advice you can send my way.

Sincerely,

Aaron

 

Thanks for your gracious request Aaron.

From your description, the same plan could/should apply. The blisters will need to be sanded and filled and faired with thickened epoxy. It sounds like the gelcoat is beyond salvage so painting is in the offing. There are some less expensive marine paints on the market that will offer better performance than a latex product. It sounds like you plan to use your canoe regularly so a more durable product is recommended.

I'll keep an ear to the ground if you have questions.

 

Blisters...

LP,

Thanks so much for the speedy reply. I now have confidence knowing there's advice just around the internet corner. I started to sand down the canoe last night with my orbital sander and 80 grit paper. I want to take a picture so you can get a better idea of the shape of the canoe, but I am confused at the technique I should use on the bubbling. It isn't like its a bubble every inch or two, they are practically lining the sides of the boat. Like I said, the gel coat is gone on the bottom. I can litereally grab some of the bubbling and tear it off. It almost seems it's fiber, but I was hoping what was ripping was still gel coat that had the impression from the fiber layer underneath.

My question is how to tackle the sides. Should I cut out the bubbles? I have the epoxy filler that was recommended at the marine store, along with everything else I needed. Should I cut a small hole in each bubble and fill with the resin then sand down after hard? I just felt like when I sanded one of the bubbles all the way until it was gone that I went to far, almost into the fibers. Will this matter since I am reapplying epoxy? I definitely want to take your advice on the paint but would love to feel confident in what I am sanding is correct.

Sorry for the lengthy response, just hoping to form a picture in your head so it would be easier for you to steer me in the right direction.

Thanks so much again man, I really do appreciate it. Pics to follow!

 

An informative thread; thanks all around.

I have an old 'Snowbird' centerboard cat, built in the 50's. One internet site I found years ago claimed they were the first production fiberglass boats in the country; I don't know if that's true or not. But I'll pretty well guarantee they used the hull of a wooden Snowbird for a plug to make their production mold.....

Anyway, restoring it is on my to-do list when I retire in a couple of years. The centerboard trunk seems to have been built of interior plywood and glassed over, and it's shot; the whole thing will have to be cut out and replaced Also, the gel coat on the deck is crazed. It isn't lifting, but it's spider-webbed with cracks.

Reading this thread gives me a lot more confidence in my ability to put the boat back in the water without driving myself crazy.

 

My best guess is that the blistering is in the gelcoat. I only have limited experience on glass boats. When you sand the blisters fair to the hull, do you open them up at all? Or, do you still a layer of gelcoat over the blister. Ideally, sanding them fair will open them up, though you may still have a pit to deal with. Additionally, when I say "fair", I mean down to the level of the exterior of the canoe, not until all evidence of the blister is gone. The key is to removing the blistering with the least possible effort and the least amount of your valuable time.

If sanding fair doesn't open up the blisters, I see two or three possible avenues.

The first is to take a drill bit about the size of the average blister and drill into every blister. Not through the hull, but through the blister layer only. Time consuming and a real pain if there are many blisters. Afterwards, sand everthing fair, wet with unthickened epoxy and fill the remaining pits with thickened epoxy. The unthickened epoxy will flow into the voids better than the thickened epoxy. Sand and fair as needed when cured and then apply the sealing coats of epoxy.

A different approach would to sand deep enough to open up the blisters and fill and fair as before, but try to rebuilt some thickness with the thickened epoxy. This too is can be labor intensive if your not adept at filling consistent layers like this. As an alternative to layering with thickened epoxy, you could regain some lost thickness, if needed, by applying a layer of glass, especially if the blistering was localized and you don't have to cover large areas.

A third approach would be to sand the hull smooth, fill any holes and just throw a layer of glass over the blistered area regardless of whether all of the blisters has been sanded out. This would possibly leave some voids in the substrait that may or may not come back to remind you they are there, but may be the fastest method to get your boat to the water though not technically the best method.

Use of fiberglass will add cost to the repair and will most likely use a bit more epoxy to fill the weave and fair the edges.

If sanding fair doesn't open up the blisters, I think I would lean towards the first method if there isn't a horrendous number of blisters to open up.