Deck Delamination / Core Problems

[mbd]

OK. That seems like a good idea Ebb. More $$ epoxy $$ however. I'm sure I'll eventually get to some sort of solution once I'm in the thick of it, so to speak.

Back to the core material. I felt like I took three steps backwards today after seeing that post about the compressive strength, or lack of it with Corecell. I found the following tables on Noah's web site...

Corecell:

[mbd]

And Divinycell:

[mbd]

I don't even begin to pretend I know what I'm talking about, but I am on the A500 Column for the Corecell (and others earlier in this thread). It looks to be roughly comparable to the "H 60" in the compressive strength and modulous column ... but, I think the roughly equivalent thickness for Divinicell is the "H 80", which would make Divinycell a bit more resistent to compression, no?? Is that what you're using Ebb?

In any event, I did feel better about my purchase, if not more confused, after re-rereading about the materials. It certainly seems like it will be easy enough to get hard spots under the key areas. Now if it'll warm up so I can just do it already...

[ebb]

Holy Haddock, Mike, those number charts scare me. I pick up my foam, when I'm playing hookie, down in Santa Cruz. Fiberglass Hawaii - 1037 17th Av - 831-476-7464. But their sites are down so you can go to Monterey Bay Fiberglass (where northern California surf-boards began!)
www.fiberglasssupply.com
509-493-3464.
They all know each other and ever since clark foam committed harikari, they is all in bed together too. You know they make surfboards out of coffecups, right? So they must have that pvc foam around for integrity. It can be used with polyester or epoxy. They don't have it in 'blanks' but in sheet thicknesses like 1/2".

ASTM numbers, hmmmm: The American Society for Testing and Materials, we know from metal grades - didn't know they did foam! A good thing too!

I personally use the thumb test when the help in the store isn't looking. But, you're right, it is H80 or H100 at Monterey Fiberglass and it's probably what I get in S.C. Amazing stuff - it only looks like foam - doesn't act like foam - you can sand it to a feather edge and it still holds together! You could take a piece of it on the floor and stand on it, it's stiff and firm. Of course you could crack off a corner, or stomp dents in it, and when you cut it you use a knife....but when you work with it you know it's high end stuff!

Has an European patent, has to be imported, unbelievably expensive. Goodwin knows where to get it cheaper than anybody in the country. Airex, the too expensive closed cell foam used for matresses and cushions is the same basic stuff as the deck core. Epoxy loves it, you'll end up with a deck like a Nautor-Swan's.

Compressive strength, you say? Don't know how you compare foams, or what you compare compressive strength of foam to? But the strength of the composite deck is in the skins, not in the foam. It's the inner and outer layers that do 95% (made that up) of the tensioning and compressing. The foam keeps them a constant distance apart. My impression is that if you had an inch of foam between the skins, the deck would be even stronger. Not because of the foam but because the skins are further apart. A tube is stiffer than a rod. But because the meat in the sandwich is such incredible material it makes an incredible deck.

Didn't Mike Goodwin do his Ariel recoring with vinylester?

Mike, if I was doing it, I'd use Baltec (Defender). What the hell, now we know how to protect it. It also made an incredible deck. lasting 40 years of abuse, and it's probably cheaper than the corporate giant's dragon froth. And it's WOOD. A treat!
Who you making that too tech deck for, anyhow? Your great, great, great grand kids?

[mbd]

...go to Monterey Bay Fiberglass (where northern California surf-boards began!) www.fiberglasssupply.com
...Didn't Mike Goodwin do his Ariel recoring with vinylester?
...Who you making that too tech deck for, anyhow? Your great, great, great grand kids?

After you mentioned you use Divinycell, I Googled it and came up with the www.fiberglasssupply.com website and noticed they do not have Corecell listed as a core material...

So, I Googled Corecell. After some reading the cold sweats subsided.

Here's Mike G's Recore material and pics from earlier in this thread. (Sheesh, all this circular linking back to earlier posts is making me dizzy! Resembles how my brain feels.)

Anyway, thanks, as always for the input. How many times can we rehash what's been rehashed, right? Kind of like chewing cud I suppose - I'll have to ask a cow.

Time to put up and shut-up. As CPete has said, when I screw it up, I can always sand it down and do it again, right?

[ebb]

Mike, We have here some of the greatest posts/threads on the face of the internet! Certainly trust Mike G's get the job done atitude and methods. He's also done it a hundred times more than you or me. When you have a master like that, see how it's done, you can do your own improvisations, make it your own or add to the music.

Could treat it like watch making, make a cad drawing for your every move.
Or take up the scalpel and draw blood. Or tuna fish, as Mike called it.

Run into a problem, post it here. Lots of opinions to choose from. Some with experience to back it up. There's enough words, pictures and links on this forum to make a text book on recoring. More points made the better. Right, maybe too many choices!

It's a noble project to do for the ole gal. Really is. Fantastic!

[mbd]

Here's a real nice restoration job on a CD Typhoon. Good recore pics too... Miranda

[c_amos]

[steps into the confessional]

"Forgive me brothers for I have sinned..... I have ignored that small soft spot on the starboard side for months now....."

I read this thread yesterday, went to the boat with the circular saw set to 3/8" and ripped a 2' / 18" gash in the starboard foredeck. Was very pleased to find that I had a great deal of difficulty removing the 'lid' for both ends of the cut.

Now, Herb Tucker (prior Capt. of 226) had recored the port side with dynacell, and appears to have done a nice job. The reason I am posting is to mention one problem I came across while doing the pre-op sanding of the deck.

The seams where the original skins had been grafted together were a stress point, and had cracked...... the crack was not very visable untill I removed material around it.

A couple of 'plug tests' with a 1/4" drill bit show wet core next to the seam where he ended his repair.

I am thinking I am going to lay a section of light roving over the seams when I finish the repair I am working on now, and then probably do the same on the old repair.

Any ideas on how to get the remaining balsa core dry where it has become wet?

[Mike Goodwin]

Scrape it out and let it sit in the sun while you put a better core back in .

If it is balsa and wet , you don't want it around .
Cover the seams of the repairs with Dynel strips, stronger and more flexable than glass.

[eric (deceased)]

I need input.I never did any type of recoring.there was very minimal oil canning on the deck of the ariel I had. it was so little that I never took in mind to do such a repair----that was and is beyond the rainge of my capabilities.however as a prospective future second ariel owner I am owning up to the fact that this repair will be inevitable.I have quickly checked thru this 12 pages so far thread---but dont have the time to read it all----tell me---has any one ever replaced the wood core with only multiple layers of polyester type cloth and resin----

[Mike Goodwin]

Yep, costs more, but it takes longer to do.
Another bonus, it adds considerable weight to the fore deck, up high to counteract that heavy nasty keel .

Why poly cloth & epoxy and not glass & vinylester resin? Either way , a core is cheaper and easier to do .

[ebb]

Imco small areas like under stanchion bases that have gone bad would be great to cut open and filled with frp. Would be easier as the core transitions to solid laminate near the toe rail.

A whole deck repaired with a 1/2" thick buildup (approximate thickness of the balsa core) of frp would end up adding much too much weight to the boat. Replacing balsa with pvc foam is probably the way to go when recoring as it is arguably easier than building up layer after layer of fabric and plastic. Easier to sand and shape than the grinding on solid frp you'd probably end up doing. When recoring with foam you can use prefered epoxy rather than polyester which you may have to choose because of the many gallons you'd need.
338 had the core replaced with solid glass under the mast. But this area is only a couple square feet.
Composite decks are extremely strong and stiff for their weight, stronger and stiffer than solid, even more so in our case with the strong camber the Ariel foredeck has.
There isn't anything mysterious about using foam in doing a recore. What's mysterious is why it's so damn expensive. Less expensive endgrain balsa is still available.
Imco if balsa is protected (as it should have been by the manufacturer) it'll last forever. There are Ariels that after 40 years have not needed their decks repaired. Balsa is just fine for a whole deck recore that could last another 4 decades.

[mbd]

OK, so I'm grinding this AM - phase 2. Last week I ground the upper skins for the starboard side deck and the lower inner skin, then wiped it down with a generous amount of acetone thinking I was ready to epoxy.

This moring, I went out to give it another good grind just to make sure I had enough of the old junk off, and found the old patches of resin remaining had a kind of fluorescent green hue to them, kind of like they were wet. As I ground away at the old glass, this little brownish spot started sort of bubbling up rather than being ground away. Turns out, it's rubbery, like uncured resin or something.

[mbd]

Here it is after cutting some of it away. Not sure how extensive it is, but it seems to run underneath all the old glass - at least in this area. Could the acetone have broken down or compromised the old resin in some way?

I'm guessing the matt looking stuff is the cabin liner?

But the real question is, can I lay the epoxy and new core over this, or should I remove ALL this stuff - everywhere???

[bill@ariel231]

Mike

It looks like the head liner to me. A-231's original inner skins were alternating layers of 6oz cloth & 24oz mat. You may be able to tell for sure if that spot looks translucent from the inside on a bright day ( or what the heck, drill a 1/8th" hole it can't hurt at this point)...

when you glue up the new core, don't forget to support the inner skin in position with some sort of structure or the core may sag while you and the core are supported by just the inner skin. Not a real problem on my boat, as the side decks are small and I was careful where I stepped. one of my friends needed to take a skill saw to the deck of his boat and start again after a first attempt to core the deck left him with what looked like sea-state 2 topsides.

don't worry, it gets easier from here....

Bill