View Full Version : Glass over carvel point of clarification...
05-11-2005, 03:41 PM
I was actually thinking about this this morning. I just came into a classic Novi-shaped open skiff (think downeast picnic launch), carvel planked cedar over oak. To get it back into the water would require replacing at least two planks and recaulking. I would much rather reef out all the old caulk, pay the seams with something like Sikaflex, soak the planks with a few coats of unthickened epoxy, then lay a few layers of 6 or a couple of layers of 10 ounce glass over the hull. I would then like to flip the hull, spall the hull with cross beams to hold it's shape, remove the intermediate frames, coat the entire inside with epoxy, fair the inside, and reinstall intermediate frames over the epoxied/painted interior, then apply oiled ceiling strips over the frames. My speculation was that the Sikaflex would allow a little cross grain expansion and might stave off crushed fibers/cupping. Would ANYONE here support this decision?
05-11-2005, 04:03 PM
Sounds like an awful number of manhours to ruin a nice classic that probably only needs a couple planks, a few new fasteners, some cotton and some paint.
1) Epoxy doesn't stick to seam compound...enough working of those seams over time and you'll have a nice, unrepairable mess telegraphing through... and attendant large lines of fabric weakness just waiting to split on impact at the exact spot where glue won't stick.
2) You'll likely never get all those fasteners out without a lot of damage, an unreasonable amount of time, and the resulting holes so large that future repairs will be problematic.
3) Old wood always has minor fungus and damage you'll just seal in, hastening its demise. Epoxy breaths much slower than paint.
4) If the planking is flat sawn...much of the Eastern cedars are...and the boat is as large as I think it is...then they may flat-out crack on you. Old wood is more athletic...yet more brittle, too...than new wood.
5) Sometime later in its life that epoxy barrier will be penetrated, letting in water that can't get out fast enough to save that old wood from the fungus habitat that'll also get in.
6) Some day the boat will require repair....something your plan doesn't facilitate. Feathering in a cold-molded-style patch won't work over that seam compound.
7) You can fix the boat conventionally in a tenth of the manhours you are describing.
Carvel boats are easily and relatively cheaply repaired over the course of a life that can exceed a century or more, with care. Your boat will be difficult and expensive to repair and I'd give it maybe 10 years before it becomes economically unrepairable.
[ 05-11-2005, 09:50 PM: Message edited by: Bob Smalser ]
"...give it maybe 10 years before it becomes economically unrepairable.
" Bob Smalser Bob, I think you are being generous in your lifespan prediction. ;)
Forrest, if you want to gain a couple of seasons of near-shore use before the chainsaw and weenie-roast party on the beach, 'glass the outside as is. If you want to preserve the boat for many years to come, do it right and repair it to original spec with original methods & materials. If it is worth restoring, it is worth restoring properly.
05-12-2005, 08:30 AM
Dump the epoxy idea and use the bane of the wooden boat forum, a flexible polyurethan product such as
Durabak www.durabak.com/ (http://www.durabak.com/)
Sanitred. www.sanitred.com (http://www.sanitred.com)
If you wish you can imbed the fiberglass in this creating a flexible matrix.
Since it is not supposed to crack or peel and expand moves with wood it should be much better than some brittle epoxy coating.
05-12-2005, 08:32 AM
Durabak now comes in a version with no rubber granules and many bright colors.
05-12-2005, 08:40 AM
Now we will just wait for the flaming responses
05-12-2005, 12:37 PM
Once upon a time at the Riverside Marina on the Duwamish River in Seattle,Washington State, there were 2 very fine new Bristol Bay Gillnetter hulls built of Port Orford Cedar, Douglas Fir and Oak framed.
Both hulls, owned by 2 brothers had been completely covered on the outside with Thiokol's rubber goo. The work as I was told had been done in an old WW II shed nearby and then the hulls were trucked to the marina where they were set up on blocks and sleepers with a nice tarp roof over them to allow interior joinerwork and mechanicals to be done.
As often happens folks plans change and the boats got very low priority and attention for a number of years. Tarps got holes in them, rainwater was allowed to pool in the hulls. By the time I saw them some 5 or 6 years had passed with this lack of care.
For sale signs were on them hanging from the ribbons of Thiokol that was peeling from the planking and Fred the owner was tearing his hair out because the brothers had moved to Alaska and left the boats there with rental bills unpaid.
This was way before most air pollution rules were in place yet Fred was afraid to just drag them back to the 'burn spot' and douse them with kero and let'em burn. With all that Thiokol on those hulls it would probably have filled all of West Seattle with choking smoke from the rubber.
I wonder if this miracle goo will react similarly?
I went to the Durabak web site but could not find any info in regard to the use of the product on WOOD.
Can the fan of this product direct me to just where the company actually states it's approval of the product on wood especially in a marine enviornment?
[ 05-12-2005, 12:53 PM: Message edited by: Dave Fleming ]
05-12-2005, 01:50 PM
They make only a reference to wood at this point.
Of course, if a wood boat is abandoned left to weather and rot, nothing will stick, all coatings will fail.
The problem as we all know with using an epoxy is it is inelastic and brittle so if the wood swells or cracks the coating can fail and when fresh water gets to the wood it rots. At least with a polyurethane you have strength with flexibility and the coating wont crack as easily, they claim it wont crack at all but every material has its limits. These polyurethanes are also absolutely 100% waterproof coatings, which I am sure some will argue that they are not.
You would of course to ensure that water cant affect the wood coat both the inside and outside of a hull. I have also found the thicker the coating the better off you are as too keeping the coatings integrity.
If someone was going to the trouble of an epoxy or polyester coating on wood, they would better served to be shown that there is an alternative that they may know nothing about, such as these polyurethane types of coatings. My only point is to make them aware that such an alternative exists. Everyone has to decide for themselves the appropriateness of any information offered for free on a message board. I seem to be one of only a few that are prepared to make such a claim, and I was hoping as time went on, more people would find out for themselves and post their experiences. Several people have privately emailed me and so far so good.
05-12-2005, 02:03 PM
Why, oh why do people insist on trying to repair a good boat in almost any way except the right way; the right way being to put her as close to original construction/appearance as possible. That project to eviscerate and encapsulate gives me the whim-whams--another good boat threatened by a trip down the tubes.
05-12-2005, 02:46 PM
...as we all know with using an epoxy is it is inelastic and brittle so if the wood swells or cracks the coating can fail and when fresh water gets to the wood it rots. At least with a polyurethane you have strength with flexibility and the coating wont crack as easily... As we all know epoxy is brittle?
Where you gettin that from?
Compared to a sealant, sure....but hardly compared to other glues.....but all those sealants are unreliable glues, if that's your purpose.
"Glue" two hunks of unfinished cedar together with the almighty 5200 sometime...stuff them under the dock float for a few weeks...and see for yourself. ;)
[ 05-12-2005, 02:46 PM: Message edited by: Bob Smalser ]
05-12-2005, 02:58 PM
Ten years? Sweet! I'm only going to rout a Hinckley Talaria cove stripe into it and sell it within two years anyway. This is gonna be perfect...
05-12-2005, 03:18 PM
Heres a link ... http://www.rotdoctor.com/poly/polymain.html
to a good amount of information on poly .I bought his version to apply to my entire topsides of my boat ,The exterior of the flybridge will be done hopefully in the next 2 weeks so I can let you know a little more about this particular product soon. I went with rot doctors over sani-tred and durabak becouse he is very quick to answer questions and give product support.
Link I meant to post :
[ 05-12-2005, 04:29 PM: Message edited by: eagletrawler ]
05-12-2005, 03:25 PM
Originally posted by forrest:
Ten years? Sweet! I'm only going to rout a Hinckley Talaria cove stripe into it and sell it within two years anyway. This is gonna be perfect...Shucks...why not sell it to somebody now sans all those manhours and get yerself a nice Bayliner? ;)
Gets frustrating, doesn't it, Bob? :rolleyes:
05-12-2005, 11:49 PM
I go with the proper restoration suggestions. I think if you check it out, you will find that it is not such a big deal to replace a couple of planks---and certainly easier than what you are talking about doing.
However, if you are determined to get epoxy into the equation, and if the planks are leaking, but otherwise sound you could consider splining. Check the threads out here.
05-13-2005, 12:57 AM
Originally posted by mmd:
Gets frustrating, doesn't it, Bob? :rolleyes: That's Ok, Mike.
The more I look at it the more I figure the proposal is so gross it has to be a joke at our expense.
Otherwise, and that Bayliner is a good matchup. ;)
[ 05-13-2005, 12:58 AM: Message edited by: Bob Smalser ]
05-13-2005, 09:41 AM
"Run, Forrest! Run!" ;)
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