re-coring or filling... is filling possible?

[centerline]

I have been following the post about recoring the cabintop from the inside and it got me to thinking.....
the boat i just bought has a soft spot around the forward cabintop stanchion on the left side.... and it seems to run rearward a bit...
I am wondering what would be the best method to firm it up.... I have a constant duty vacuum pump and I was wondering if i removed all of the deck hardware and then drilled a 1/2" hole in the deck near the forward end and then built an adaptor plate that i could screw down and seal around that 1/2" hole, do you think I could pull a vacuum on it for a couple of weeks and dry it out? if the air could come in around the deck hardware holes and pass thru the rotted core to the vacuum pump it should carry the moisture with it. and eventually dry it out, wouldnt it? even a constant, live vacuum without air passing thru will remove moisture due to the extreme lower atmospheric pressure.... so the air passing thru may or may not help the drying of it......

but if it could do that, it seems like it should be possible to build a catch tank that would hook in line between the vac pump and the custom made adaptor plate, and then tape over the holes where the deck hardware was attached so that it could actually pull a vacuum on the space. then epoxy could be introduced to one or more of the deck fitting holes so as to suck the resin in to the empty core and pull it thru until it reaches the catch tank.... (the catch tank is only there to protect the vac pump) then remove the vacuum and let the skins return to their normal shape as the epoxy settles in..... remove all the pieces and parts and tape over the holes and let it cure......

have you ever watched how a seal-a-meal or food saver pump works?, it looks like the process should work the same way for filling an empty core space.
the liquid seems to seek out the vacated air space to the sides as well as moving forward filling the entire void the as the vacuum does its work....

has anyone tried this process?

my other thought is to empty the boat of everything movable or in the way, and then roll it over and support it upside down...... then cut the panels out of the inside and do a conventional recore..... it would still be a lot of work but it seems cleaner and easier than doing it upside down or cutting the outter panels out...... but then I have to deal with the interior liner also..... a fill job from the top seems like it would be the easiest to me....

 

[Joe]

I used "captain Tolley's creepingcrack cure" for a small deck area appox. 12"x12"........ if your damage is just limited to the area around the stanchion base..... this stuff is way easier that what you propose.

 

[centerline]

I used "captain Tolley's creepingcrack cure" for a small deck area appox. 12"x12"........ if your damage is just limited to the area around the stanchion base..... this stuff is way easier that what you propose.

I have what i would suppose amounts to 5-8 sq ft of soft deck.... I can still walk on it fine but it feels spongy.... I have used capt. tolleys formula also, but are you sure you can use it to fill this much of a void.... it seems like an awful thin product to me.... i have never put the stuff in a paper bowl to see how it sets up in bulk form, or how much shrinkage it has after drying, and is it waterPROOF after it dries?

and what i propose might seem a bit complicated, but I dont think it really is... dry the rotted core and push or suck in epoxy resin..... if the resin was pushed in, I think it would be channeled to the nearest exit because of the resulting air pressure elsewhere in the void, but if it was sucked in, it would be sucked into, and filling the voids left by the removal of the air under vacuum... due to its viscosity it would not travel fast but spread out sideways as it filled the cavity, and as it filled, it would make its way forward to the source of the vacuum. It most definitely would want to follow the air out, but as the air would be leaving the entire space, I think it would be sucked into all areas where the air is being removed from. side to side for the entire length of the void. I just dont see why it wouldnt work..... if i could only get the rotted core dried out.
but It would depend on how much space is available for the epoxy to travel through..... even though the core is soft and rotted, it may be dense enough that the epoxy would plug itself up trying to get thru it all....

just think, if the process would work how much easier it would be to do an entire deck.... a couple days rather than a few weeks.

 

[NYSail]

Captain Tullys wont help you.... This stuff is good in right application, but it is a band aid. Also, be careful with the stuff as it turns color and is unsightly.

 

[sandpiper10471]

Centreline - I like your thinking a lot. I have often dreamed of a simple solution such as yours. The idea of using vacuum pressure to infuse the resin is similar to the process some builders use when laying up a hull. Problem with a restoration such as yours is that there will still remain a certain amount of non-structural wood between the skins. Secondly, I doubt you could get it to dry out sufficiently. Thirdly, you are looking at a vast amount of thickened epoxy. That stuff when contained can build a dangerous amount of heat. The price of the epoxy could be offset by efficiency of time. I am sure these three concerns can be addressed individually and I don't want to stop this great thinking process you have initiated. Let's see what others have to say.

 

[Joe]

I have what i would suppose amounts to 5-8 sq ft of soft deck....

Well that's major.... I thought you were talking about a small area around a stanchion base.

My capt tolley fix was more involved than simply squirting the stuff in a few cracks.... I drilled a number of quarter inch holes in a grid pattern over the infected area. I covered the area to keep it dry, but not air tight, and let the section dry for a week. Then I squirted the penetetrating epoxy into the holes to help seal the damaged wood.... the holes were then filled with normal epoxy.... I then covered the holes with gel coat.

My main purpose was to stabilize the core after repairing an old crack in the deck caused by a falling object.... and it was limited to a pretty small area compared to your project.

My point in all this is suggesting you could use the vacuum process in conjuntion with perforating the deck..... I just can't see how the wood can be dried out through a single hole. You can inject epoxy into the perforations after the wood's dry, paint the area... or resurface with a product like kiwi grip. Just a thought.

 

[Merlin Clark]

You can use an oscillating multitool to make a fine cut around the bad section, lift and save the skin, then recore that section and replace the skin in a matter of hours, rather than waiting weeks to pull the water out. If you can match the color of the gelcoat with a gelcoat repair kit, it should be unnoticable.
I'd use marine or exterior fir plywood or a man made core material rather than balsa. Why replace something that rots easily with the same when better materials are available?
The man made products are lighter but more $$.

 

[Joe]

You can use an oscillating multitool to make a fine cut around the bad section, lift and save the skin, then recore that section and replace the skin in a matter of hours, rather than waiting weeks to pull the water out. If you can match the color of the gelcoat with a gelcoat repair kit, it should be unnoticable.
I'd use marine or exterior fir plywood or a man made core material rather than balsa. Why replace something that rots easily with the same when better materials are available?
The man made products are lighter but more $$.

I think that's the way I would go..... it seems to a much more acceptable method of dealing with the repair. Although the multi tool would work well in tight corners.... for long runs, a small, battery powered circular saw would work faster and cleaner. The downside to the circular saw woud be the width of the material removed in the cut.

 

[sandpiper10471]

I rebuild a lot of decks. At the moment, I am on my third of the summer. My preferred choice of tools for cutting out the top skin is a four inch diamond blade on an angle grinder. Fast, small kerf and easy to cut a straight line. The corners I cut with my Fein.
I far prefer to put new glass on the deck as opposed to reusing the original skin. Firstly, that skin will likely not come off in one nice untorn piece. Then you are in to rebuilding that skin. Also, most decks were laid up with chopperguns and the skin is not necessarily uniformly thick. Then you are still into fairing and long boarding to get a fair surface. However, sometimes it is appropriate to use that skin, especially if you are trying to save a unique nonskid pattern that would be hard to copy.
My preferred core material is balsa. It is easy to work, is light, is relatively economical and has the highest compressive strength by far of any core material. Every recore I have done has been solely due to poorly mounted fittings. Doesn't matter what core material you use, you MUST keep the water out. Read Maine Sail's musings on potting and bedding.