Hey Gang
I have been doing my research and saving my boat bucks, and now I am ready to go purchase my supplies to finish replaceing the core of the cockpit floor. I already have the core material( Exotic Wood of Annapolis sold me a 1/4 sheet of 3/8 marine ply, for $15.00 ). The question I have is this. Does anyone know from experience how many layers of 6oz. cloth will it take to make the top skin slightly less thick than the original. The repair manual states" The combined thickness of the layers should be slightly thinner than the original panel to allow for shaping and fairing". I am not confident that I will be able to tell because you can't really get down and look at it along a flat perspective.
Since this is not a repair you can stop in the middle of to go get more supplies, I am trying to do the repair in my head first to make sure I did not forget anything. I ran into a problem when I got to this stage. I am not hooked on 6oz cloth either I just need a place of reference to start, also 6oz seems to always be available at the store.
So to summarize: If anyone can tell me what combination of, and how much cloth they have used for this repair I would be grateful.
Will Wheatley
Suzi Q
CD25
willwheatley@starpower.net
Cockpit floor repair. How Many Layers?
Moderator: Jim Walsh
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Ron Musk
Re: Cockpit floor repair. How Many Layers?
Will,Will W. wrote: Hey Gang
I have been doing my research and saving my boat bucks, and now I am ready to go purchase my supplies to finish replaceing the core of the cockpit floor. I already have the core material( Exotic Wood of Annapolis sold me a 1/4 sheet of 3/8 marine ply, for $15.00 ). The question I have is this. Does anyone know from experience how many layers of 6oz. cloth will it take to make the top skin slightly less thick than the original. The repair manual states" The combined thickness of the layers should be slightly thinner than the original panel to allow for shaping and fairing". I am not confident that I will be able to tell because you can't really get down and look at it along a flat perspective.
Since this is not a repair you can stop in the middle of to go get more supplies, I am trying to do the repair in my head first to make sure I did not forget anything. I ran into a problem when I got to this stage. I am not hooked on 6oz cloth either I just need a place of reference to start, also 6oz seems to always be available at the store.
So to summarize: If anyone can tell me what combination of, and how much cloth they have used for this repair I would be grateful.
Will Wheatley
Suzi Q
CD25
I'm not sure how many layers of 6 0z. cloth you will need.I can tell you how we repaired the cockpit floor on our 30fter.We cut the top layer of fiberglass approx. 3/4" inside the gutter perimeter and pulled it off.(its 1/8-3/16 thick).Remove the balsa core being careful not to damage the fiberglass mat layer below.Fit your 3/8" ply and taper all the edges so it will slide under that 3/4" left all around.You will need to grind a taper on this remaining edge of fiberglass.Also rough up the surface of the bottom glass you will stick the plywood to.We used a biaxial nonwoven fiberglass cloth,8 oz. I think and a couple of layers with the weave alternated.This stuff is very strong.Wet out the bottom layer of fiberglass mat and ply bottom and edges with epoxy then mix a thickened batch a bit looser than mayo and use it to butter the bottom and edges of the ply,be sure you get good coverage all around and stick it down,put some weight on it and let it set-up.When it has set wet out the top of the ply and lay your 1st layer of cloth cut so it just overlaps onto the tapered original fiberglass edge you ground.Succeeding layers should overlap a little more.It is important to have everything cut and ready to go before mixing any glue,you don't want to get ahead of yourself or you can create a real mess in a hurry. Build the layers up until slightly below the original sole height.You can then fair it to finish with West 410 microlight or similar.
You may want to experiment with a small mockup of glass layers glued to a piece of ply to get the thickness close,stay a bit under rather than going thicker.It is really not a difficlt job if you take your time and organize everything before hand.I have heard that a yard will charge a couple of grand or more to do this repair--if that gives you any incentive ! Good luck.
Ron Musk
s/v R&R
CD30 c
ccerre@rcn.com
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SteveZ
Re: Cockpit floor repair. How Many Layers?
In 1999, I submitted the below post to the cd bb after I repaired my cockpit sole. Perhaps it might help you...
Just thought I'd update everyone on my work to repair the cockpit sole of my CD and provide information to anyone else contemplating a similar job. As I mentioned in previous posts, I had some water intrusion into the cockpit sole. The sources of the problem were failed sealant around the deck fill and around the area where the rudder post emerges through the sole. The test holes that I drilled showed that the area that was actually rotted (as shown by black or dark brown balsa core) was fairly limited, but about 25% of the area of the sole had saturated or,in most areas, damp core.
For structural repairs, I confined all my work to the tan nonskid area. I used the system suggested by Gudgeon bros. (West system epoxy) and drilled 1/4 holes into the top skin of the panel. Each hole was beveled with a countersink. Using a circular saw, I also cut off a portion of the fiberglass skin (about 1.5 sq. ft) to remove rotted and saturated core. Unfortunately, the fiberglass in the skin was damaged when I pried it off, so I elected to replace it. The total area I cut out was probably overkill, but it ensured that all balsa that was compromised by rot was removed. I used a heat lamp over the area to help dry remaining areas of the (damp) core that were drilled. Due to extensive crazing in the cockpit sole, I removed the all of the gelcoat from the nonskid area with a belt sander. New 3/8 inch balsa core (purchased from Defender) was laid in with epoxy thickened with silica and the holes were filled. The replacement skin was laminated with 6 layers of 12 oz fiberglass fabric and West epoxy.
Cosmetic repairs. I faired in the topside with epoxy thickened with low density filler, followed by 2 layers of 6 oz fiberglass over the entire nonskid area to tie everything together and provide a smooth surface for gelcoat. I experimented with several methods for reproducing the nonskid texture. I found that the method that works best was to add a small amount of colloidal silica to thicken the gelcoat (obtained from GCPI; thanks Dana!), and then apply it by using a foam sponge (the cells in the sponge need to be very fine, similar those of a foam brush). When patting the gelcoat onto the panel with the sponge be careful not overwork the area or the peaks can become too sharp. With a little practice, the result is very close to the original nonskid texture. The last step was to spray PVA over the repair with a Preval spray canister to allow the gelcoat to cure. Because I replaced the all of the gelcoat over all of the tan nonskid area I did not have to worry about blending the repair into the surrounding area.
The total repair cost including epoxy, fiberglass, balsa, gelcoat, protective clothing, masks, sandpaper, etc. was about $400, but I am very happy with the results. West System Epoxy technical advisors were extremely responsive to my questions about making the repair and techniques for re-gelcoating over epoxy.
Just thought I'd update everyone on my work to repair the cockpit sole of my CD and provide information to anyone else contemplating a similar job. As I mentioned in previous posts, I had some water intrusion into the cockpit sole. The sources of the problem were failed sealant around the deck fill and around the area where the rudder post emerges through the sole. The test holes that I drilled showed that the area that was actually rotted (as shown by black or dark brown balsa core) was fairly limited, but about 25% of the area of the sole had saturated or,in most areas, damp core.
For structural repairs, I confined all my work to the tan nonskid area. I used the system suggested by Gudgeon bros. (West system epoxy) and drilled 1/4 holes into the top skin of the panel. Each hole was beveled with a countersink. Using a circular saw, I also cut off a portion of the fiberglass skin (about 1.5 sq. ft) to remove rotted and saturated core. Unfortunately, the fiberglass in the skin was damaged when I pried it off, so I elected to replace it. The total area I cut out was probably overkill, but it ensured that all balsa that was compromised by rot was removed. I used a heat lamp over the area to help dry remaining areas of the (damp) core that were drilled. Due to extensive crazing in the cockpit sole, I removed the all of the gelcoat from the nonskid area with a belt sander. New 3/8 inch balsa core (purchased from Defender) was laid in with epoxy thickened with silica and the holes were filled. The replacement skin was laminated with 6 layers of 12 oz fiberglass fabric and West epoxy.
Cosmetic repairs. I faired in the topside with epoxy thickened with low density filler, followed by 2 layers of 6 oz fiberglass over the entire nonskid area to tie everything together and provide a smooth surface for gelcoat. I experimented with several methods for reproducing the nonskid texture. I found that the method that works best was to add a small amount of colloidal silica to thicken the gelcoat (obtained from GCPI; thanks Dana!), and then apply it by using a foam sponge (the cells in the sponge need to be very fine, similar those of a foam brush). When patting the gelcoat onto the panel with the sponge be careful not overwork the area or the peaks can become too sharp. With a little practice, the result is very close to the original nonskid texture. The last step was to spray PVA over the repair with a Preval spray canister to allow the gelcoat to cure. Because I replaced the all of the gelcoat over all of the tan nonskid area I did not have to worry about blending the repair into the surrounding area.
The total repair cost including epoxy, fiberglass, balsa, gelcoat, protective clothing, masks, sandpaper, etc. was about $400, but I am very happy with the results. West System Epoxy technical advisors were extremely responsive to my questions about making the repair and techniques for re-gelcoating over epoxy.
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John R.
Re: Cockpit floor repair. How Many Layers?
I can't tell you how many layers you will need but I can say I wouldn't use cloth except for the very last layer. I would make the first layer biaxial (for maximum strength) and then additional layers would be mat with a final layer of cloth. Biaxial will build thickness the fastest and mat will allow thinner layer build ups if needed, cloth can be a real pain to work with because it unravels easily and can easily distort when working with precut shapes. Make sure you use epi-sized fiberglass when working with the epoxy, it will wet out far better then regular fiberglass. If you decide to use polyester resin or vinylester resin rather than epoxy use regular fiberglass and not epi-size.
Have fun.
Have fun.
Will W. wrote: Hey Gang
I have been doing my research and saving my boat bucks, and now I am ready to go purchase my supplies to finish replaceing the core of the cockpit floor. I already have the core material( Exotic Wood of Annapolis sold me a 1/4 sheet of 3/8 marine ply, for $15.00 ). The question I have is this. Does anyone know from experience how many layers of 6oz. cloth will it take to make the top skin slightly less thick than the original. The repair manual states" The combined thickness of the layers should be slightly thinner than the original panel to allow for shaping and fairing". I am not confident that I will be able to tell because you can't really get down and look at it along a flat perspective.
Since this is not a repair you can stop in the middle of to go get more supplies, I am trying to do the repair in my head first to make sure I did not forget anything. I ran into a problem when I got to this stage. I am not hooked on 6oz cloth either I just need a place of reference to start, also 6oz seems to always be available at the store.
So to summarize: If anyone can tell me what combination of, and how much cloth they have used for this repair I would be grateful.
Will Wheatley
Suzi Q
CD25