Re glassing our decks

[GILow]

Hey guys. I really love this site. I go to bed here in Oz and wake up to find all this great advice.

A bit to take on board for me but yes, everything I have read suggests organisation is the key. Having had to shave a significant portion of my chest recently after I fibreglassed myself to our day tank I am taking comments about mess very seriously. Chest hairs don't half itch when they grow back!

Points taken about epoxy bs resins for strength, uv. This will be a painted deck which at least should deal with the Iv issues.

Jim, thank you for the deck coating link. I was going to be searching for your posts on that matter next as I had read your posts in another thread. Zboss those boat woks today links are terrific. What a clear and instructive set of videos.

Terranova your remark about one layer caught my eye. What weight of cloth would you consider adequate if done this way?

Once again thank you to all. Really good advice as expected.

Matt


Sent from my iPhone using Cruisers Sailing Forum

[Terra Nova]

This is what I would use for 1 layer.
http://www.fiberglasssite.com/servle...1708-48/Detail

[GILow]

Hey folks, one of the cloths I found is called "stitched biaxial" Sounds like a more easily handled version of biaxial. Any thoughts on this for deck covering?

Matt

[GILow]

Further question... a supplier here recommended unidirectional stitched as another alternative to biaxial if the deck was very simple and flat. He reckons it will be easier to get a smooth finish. Our deck is about as flat and simple as they come.

Is this a good idea?

Also, like TerraNova he feels one layer of 400gsm will be adequate, which, considering he is in the business of selling the materials, suggests that it will be enough. It just sounds a little light to me..?

Matt

[GILow]

Originally Posted by GILow

Also, like TerraNova he feels one layer of 400gsm will be adequate, which, considering he is in the business of selling the materials, suggests that it will be enough. It just sounds a little light to me..?
Matt

Finally found a conversion factor that seems credible, and 400gsm equates to 11oz if the numbers are to be believed. That suggest to me that it is too light if people are using 170z with an additional 8oz layer underneath as part of the cloth.

Maybe 600 gsm would be better... converts to 17.6oz using the same scale.

Matt

[robwilk37]

epoxy is preferred for its adhesion properties, not just for strength. remember the glass on the top of the deck is really just for abrasion resistance and waterproofing so if you have access to cheap uni youd be fine. and again, fairing is greatly reduced when peal ply is employed.

agree with above, its not a particularly difficult job, just messy and not terribly interesting. all sanding/grinding tools should have vac attachments. wear tyvec and a good respirator. take pics or it didn't happen...

[GILow]

This peal ply sure tweaked my interest. Thanks for the heads up from those that mentioned it, I am going to play around with some first and see how it goes. Getting a decent finish is the bit that worries me the most.

Matt

[Cadence]

Originally Posted by GILow

Hello Cruisers,

Yesterday I finally got to planning the rejuvination of our decks. They are ok, but in one or two places the fibreglass has pulled away from the plywood underneath, creating a pocket for water to pool and start wrecking things. I started by getting the scraper under a couple of the worst bits to see what I was up against, as I had some old resin and CSM I could use to temporarily patch the test areas. The glass layer came away depressingly easily at the worst bits, and revealed that of the two layers of 1/2 inch plywood underneath, the top layer was ruined in some patches, but fine in most, while the lower layer seemed very good all round. OK, no problem, much as I would expect I guess. (I'll probably get the nasty suprises elsewhere on the deck).

But, one thing that did surprise me is that the fibreglass on the deck appears to be CSM (chop strand mat). I thought it would be one of the woven cloths or dynel. I have been reading lots on this, and the general feeling I was getting was that CSM was a no-no. So, is this a bodgy job, or was there a good reason? The deck was laid in about 1980, so I guess I can hardly complain that it is starting to develop problems now.

This boat is never going to be a show-pony, my budget is not unlimited, but I would like a robust and leak proof deck for weekending and a bit of coastal cruising. There are two layers of half inch plywood over regularly spaced hardwood deckbeams with no noticable movement from the plywood or beams. The decks are open and uncluttered, with just two hatches, a couple of vents and two pulley tracks. Chain plates are independent of the deck, the deck is cut out around them and they have been sealed with a caulking compound between the deck and the chainplate fittings. This has mostly worked well.

I am not very concerned about weight, so I am happy to compromise in this area. Bonding the glass deck to the hull should be straight forward due to the construction of the toe rails which cap the hull sides and stand about two inches higher than the deck top. Also the stanchions are bolted to the hull not the deck, so there's another complication removed.

So, if you were about to tackle this job, how would you do it, as in what finish would you apply? Fibreglass cloth, CSM or dynel? I have read so many opionions, and consensus seems hard to reach. I would highly value the opinion of "C.F."rs.

For the record, I would plan to remove the entire current layer of fibreglass, as very little of it is without problems.

Matt

I read your last sentence. Good luck. Get a horse 1 1/2 disc sander and 12 grit discs, oh most important masks and a hell of a lot of fortitude. Not knowing the state of the deck. You may do better taking out bad spots filling discing the whole thing to provide some tooth and put glass on top?

I wouldn't worry about new high tech. fabrics. You aren't building a hull, just a surface. CSM would be fine.

Prior to reading the last I had said epoxy. May still be a good idea for the first layer of new ply. Thinning polyester with acidtone and soaking the plywood first works.

For what it may or not be worth.

Fiberglass lungs


Masks and the hell with clothing. The grindings will get in anyway. You may as well be comfortable. A cold shower helps.

[GILow]

I am kind of torn. On the one hand, I'd like to think the deck is still ok and that there is some adhesion and protection from the current layer of fibreglass. But on the other, I realise that any bits that are still stuck are going to be horrible to remove. Thus far I just tackled the bits that I know are really bad, so there's not much comfort to be gained from finding those bits came off easily.

I had a chat to the club, if I can prevent any crap blowing off the boat they are happy for me to do the work in the water at the work pontoon, which I would like as it is an awfully long drop from our decks to the ground when we are on the hard. I think I will be able to string up some very good sun protection using drop sheets, and if I work slowly and methodically from the bow I am hopeful that it will be a very tidy, if uncomfortable, process. Disposable suits and good masks will be the name of the game.

Now I just want to figure out the best overall weight of cloth to use.

Matt

[minaret]

Given that it was originally glassed with CSM and poly, which lasted quite some time, I would speculate that the ply provides the entire structure of the deck, and the glass is strictly a water barrier. This is not uncommon in that sort of boat, and is a repair I have done many times. I would suggest epoxy resin if your choice, slow hardener, and two layers of 10 oz WR (boat cloth), for a total weight of 20 oz, followed by an immediate application of 407/fairing compound by chemical bond. There are several advantages to this approach. Using two plies instead of one allows you to use butt joints and stagger the butts. This greatly reduces fairing. Chemical bonding your fairing both saves a step and provides superior bond. Just requires a good layup, no drips or runs.

[GILow]

Thank you Minaret. Yes, I think you describe the construction very well with your comment about it being a water barrier to the underlying plywood structure.

I am very comfortable with your suggestion of two layers of 10oz, and take the point about staggering the joins for a better finish.

I am now utterly stumped by the second marine fibreglass shop in a row telling me to use just one layer of 6oz. Can you account for this? Is this just something that comes from spending too much time around racing boat owners or maybe small fishing boats?

Matt

[chebba]

I am in the middle of recoring my deck. You can check the progress at SV Happy Trails gets a new deck and chainplates!! please, if you don't particularly like my methods, be nice.

[GILow]

Chebba, that is a really lovely boat. No complaints from me.

Actually, it really underscores one of the things about our deck repair that is a bit different to most boats. Basically, if you take your bow section, then multiply it about ten you have our foredeck, even though the boat sizes are not hugely different. There's none of the walkway down the side business to deal with on a Swanson 42 until you draw level with the deck house, which on our version is only 8 feet long, and starts at good 18 feet back from the bow. Even then the walkways are a good 3 feet wide either side of the deck house. So everything is very simple on our deck, there's just a heck of lot of area to replace, but no fiddly bits.

I think this has some impact on the choice of construction materials to be used.

Matt

[HappyMdRSailor]

Ya gotta go with the resin head here... Plus using WR v biax is going to save you a shizzitload of money on resin... Of course not saving as much as 1 layer of 6oz... Which I find rather amusing...