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Fiberglass Repair and Other Advice

Looking to repair the bow of my 77 minifish. The handle is solid as I can pick up the boat using it. Likewise, the fiberglass is mostly solid, except for the patch that is lifting up around the handle. I've never fiberglassed before so any advice would be welcome. On a different topic, the sail material around the grommets is fraying. Any thoughts on how to stabilize the material. Lastly, on a more trivial note, the rings that secure the sail to the booms are difficult to open. Will they break if I force them? Thanks in advance.
 

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beldar boathead

Well-Known Member
The rings are supposed to be difficult to open. I’ve opened old ones with no problem - just a lot of frustration - with no breakage as they seem to have some nylon or something flexible in the plastic. But that is no guarantee that it’ll work for you. But you can always buy new ones.
 

Weston

Active Member
The rings are supposed to be difficult to open. I’ve opened old ones with no problem - just a lot of frustration - with no breakage as they seem to have some nylon or something flexible in the plastic. But that is no guarantee that it’ll work for you. But you can always buy new ones.
I use two flat head screwdrivers to pry them open, giving equal pressure on both sides. I think one of those tools used to pry open gardeners on automobile trim would also be perfect, if you have that. They have a short two pronged end that would slide in between and also exert equal pressure on both sides of the clip.
 

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L&VW

Well-Known Member
On a different topic, the sail material around the grommets is fraying. Any thoughts on how to stabilize the material. Lastly, on a more trivial note, the rings that secure the sail to the booms are difficult to open. Will they break if I force them? Thanks in advance.
If the sail is worth saving, a tiny amount of epoxy brushed around worn grommets would keep the unraveling to a minimum. (Super-glue might be better--and easier).

Grommets at the corners should get professional attention; however, the expense should be weighed against a new sail purchase. :cool:

I've had grommets that were ready to fall out! :eek:

So I removed them--retained what sail material there was--wrapped two layers of sail-repair tape (where the old grommets had been) and punched new non-magnetic grommets back in.

Assuming a white sail! :oops:

Next time, I'd likely "face" the repair with white Gorilla tape, then cover that with the dacron sail-repair tape (above).

Grommet installation tool-kits are available cheap--but the included grommets are most often brass-plated steel. (When rusted, can stain the sail).

Real brass (or aluminum) grommets should be available at hardware stores.
 
In regards to fiberglassing, I guess my questions concerns to some degree how to properly grind off the old fiberglass, angle grinder, belt sander, random orbital sander, Dremel? How far should I grind down? Then how do I build it back up. Will the Six10 thickened epoxy hold its form or do I need something like the West Marine Rx Epoxy or the West Repair kit or something else or combo therein? I've watched some videos, but there's not much on repairing an acute angle.

Thanks for the tips on the sail. Ordered some Land N Sea repair tape to repair the grommets and some tiny holes in the sail.
 

shorefun

Member
I am a bit further along in my learning then you are at this point. Keep in mind I am just learning as I go here and this is the best advice I have found so far.

I was just doing some work on my practice hull. I have to repair a section of the keel which only had a crack. Now it has a 2" hole once I got it past the fractured stuff. I also have an area on the chine (where the hull does the 90 degree up the side) which ground out to be about 6" by 2" open area.

You need to grind back 12 to 1 for the thickness, basically 12 times the thickness of the fiberglass or so. I started with a 80 grit on a 5" random orbital. It can take off a lot, but I ended up with 80 grit flap disk on a 4" grinder to cut areas down faster then level with 80 on the RO.

That has got me to where I am trying to figure out how to make up backing pieces to do blind backing of the holes. The keel I figured out pretty easy. The side corner is bit more as it has a compound curve and I have to really fold up the paper to get it in the hole. I have to find the video where a guy was doing the same thing and try to sort out what kind of cardboard he used.

I am doing it all in laminating polyester resin per the recommendation of a long time fiberglass guy in my yacht club. The problem with epoxy is you can not do poly over it and it is more costly. The polyester might be better when on the learning curve of things. But it also depends on what you need to get done. For all the work I am doing the poly is the better choice over all.
 
I am a bit further along in my learning then you are at this point. Keep in mind I am just learning as I go here and this is the best advice I have found so far.

I was just doing some work on my practice hull. I have to repair a section of the keel which only had a crack. Now it has a 2" hole once I got it past the fractured stuff. I also have an area on the chine (where the hull does the 90 degree up the side) which ground out to be about 6" by 2" open area.

You need to grind back 12 to 1 for the thickness, basically 12 times the thickness of the fiberglass or so. I started with a 80 grit on a 5" random orbital. It can take off a lot, but I ended up with 80 grit flap disk on a 4" grinder to cut areas down faster then level with 80 on the RO.

That has got me to where I am trying to figure out how to make up backing pieces to do blind backing of the holes. The keel I figured out pretty easy. The side corner is bit more as it has a compound curve and I have to really fold up the paper to get it in the hole. I have to find the video where a guy was doing the same thing and try to sort out what kind of cardboard he used.

I am doing it all in laminating polyester resin per the recommendation of a long time fiberglass guy in my yacht club. The problem with epoxy is you can not do poly over it and it is more costly. The polyester might be better when on the learning curve of things. But it also depends on what you need to get done. For all the work I am doing the poly is the better choice over all.
Wow. Some great thoughts. That does sound like a lot of grinding. Thanks for the ratio. Hopefully, I won't have to make a hole, which leaves me a lot of negative space to free form. Yup, the form is the tricky part for sure. Perhaps, I could build it out in layers. Do you use fabric or some sort of fiberglass reinforcing? Maybe a wood form I glue to the underside of the prow, then build up.
 

shorefun

Member
I suggest you watch a few videos and look up fiberglass repair on the web.

The book 'The Fiberglass Boat Repair Manual' is also a good read.

You will need fiberglass mat and roving. You will need to somehow back the hole. This might require making a cardboard backing with strings that you lay the glass on and wet it out and pull in tight with strings until it cures.
 

L&VW

Well-Known Member
I am a bit further along in my learning then you are at this point. Keep in mind I am just learning as I go here and this is the best advice I have found so far.

I was just doing some work on my practice hull. I have to repair a section of the keel which only had a crack. Now it has a 2" hole once I got it past the fractured stuff. I also have an area on the chine (where the hull does the 90 degree up the side) which ground out to be about 6" by 2" open area.

You need to grind back 12 to 1 for the thickness, basically 12 times the thickness of the fiberglass or so. I started with a 80 grit on a 5" random orbital. It can take off a lot, but I ended up with 80 grit flap disk on a 4" grinder to cut areas down faster then level with 80 on the RO.

That has got me to where I am trying to figure out how to make up backing pieces to do blind backing of the holes. The keel I figured out pretty easy. The side corner is bit more as it has a compound curve and I have to really fold up the paper to get it in the hole. I have to find the video where a guy was doing the same thing and try to sort out what kind of cardboard he used.

I am doing it all in laminating polyester resin per the recommendation of a long time fiberglass guy in my yacht club. The problem with epoxy is you can not do poly over it and it is more costly. The polyester might be better when on the learning curve of things. But it also depends on what you need to get done. For all the work I am doing the poly is the better choice over all.
Repairing and sanding at a crack (in roving) will normally result in a 2-inch hole (or much larger). Damaged fiberglass roving keeps collapsing, as you sand away.

I used a section of a Tornado [catamaran] sail batten, wetted it, added matt, and made a wooden "bridge" over the hole. I pulled the batten up with wire, and repaired the keel from there.

Since my Sunfish keel continues to take a lot of grief from pulling up upon a wooden ramp, I ran a 4-foot strip of 4" fiberglass "tape" over the damaged area, but probably should have made it longer yet.

The top photo is damage from winter's wind tossing my Sunfish against a dock upright. The second photo was a damaged Sunfish keel—as received from a seller.
 

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L&VW

Well-Known Member
The rings are supposed to be difficult to open. I’ve opened old ones with no problem - just a lot of frustration - with no breakage as they seem to have some nylon or something flexible in the plastic. But that is no guarantee that it’ll work for you. But you can always buy new ones.
More back story:

 
Repairing and sanding at a crack (in roving) will normally result in a 2-inch hole (or much larger). Damaged fiberglass roving keeps collapsing, as you sand away.

I used a section of a Tornado [catamaran] sail batten, wetted it, added matt, and made a wooden "bridge" over the hole. I pulled the batten up with wire, and repaired the keel from there.

Since my Sunfish keel continues to take a lot of grief from pulling up upon a wooden ramp, I ran a 4-foot strip of 4" fiberglass "tape" over the damaged area, but probably should have made it longer yet.

The top photo is damage from winter's wind tossing my Sunfish against a dock upright. The second photo was a damaged Sunfish keel—as received from a seller.
Hmmm, your advice is giving my some hesitation, which is perhaps the best advice. The hull looks watertight, so it's really just bow that I'm thinking of repairing. So from the pictures do you think that as I grind back the damage, I will likely punch a hole through the fiberglass? I think the damage is largely aesthetic, do you think it will get worse? I'm pretty patient so I think I can do what needs to be done, but don't want to take the risk of compromising the hull integrity then repairing it back, if I don't have to.
 
More back story:

That makes complete sense. I'll give that a whirl. Thanks for pulling that thread.
 

L&VW

Well-Known Member
I used a section of a Tornado [catamaran] sail batten, wetted it, added matt, and made a wooden "bridge" over the hole. I pulled the batten up with wire, and repaired the keel from there.

Since my Sunfish keel continues to take a lot of grief from pulling up upon a wooden ramp, I ran a 4-foot strip of 4" fiberglass "tape" over the damaged area, but probably should have made it longer yet.

The top photo is damage from winter's wind tossing my Sunfish against a dock upright. The second photo was a damaged Sunfish keel—as received from a seller.
I found a possible "bridge" for next time. :cool: (Pic below).

It'd be easier to make a "bridge" of wood, but this happened to be handy. :)

The single piece of hardware in the picture is a "screw-eye". This can be driven into the middle of a patch to pull it against the repair target. (Using a bungee cord, wire, string, toothpicks, or twigs and parachute cord).

The tube in the same picture is a section cut from a hollow shaft of a graphite golf putter. I was wondering if this would be a good replacement for the plastic [stability] tube for early Sunfish rudders?

Probably get golf putters for free! ;)


Fullscreen capture 10182020 84212 PM.bmp.jpg
 

L&VW

Well-Known Member
Photo of Sunfish "roving"...the back side, not usually visible to the casual observer:

Fullscreen capture 642017 70619 PM.bmp.jpg

...and why you can't sand very deeply into it! :eek:
 

shorefun

Member
Why does that roving seem dry with little or no resin in it?

That is what I noticed looking at sunfish I have was that the thick strand roving did not seem saturated with resin.

Anyway just learning as I go along.
 
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