Re glassing our decks

[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

[deltaten]

Matt;

My plan, and one recommended by most experienced glassers, is to;

remove glass at "dead" s[pots
dig out bad ply
grind back glass to 12:1 or as closeas possible fora goodscarf join
thoroughlywet out hole and fitted replacem. piece w/epoxy resin.
fair surface
apply two layers (or more?)of 1708 bi-axial cloth, tobuild back to original height of deck
fair w/epoxy filler to smooth enuff
paint w/ two-part or spray w/gel coat
apply anti-skid paint. Awl-Grip water-based seems to be giving gooodresults??!
go sailing

HTH,
Paul

[GILow]

Sounds so lovely and simple when put that way.

What's the thinking on epoxy resin vs vinylester vs polyester?

Particularly given that I plan to remove all of the existing fibreglass first. My understanding is that epoxy is better for bonding to existing fibreglass, but I may have that backwards. Either way, I am assuming that there will be little, if any, bonding to existing fibreglass, perhaps with the exception of bonding to the hull sides under the toe rail.

Matt

[deltaten]

"all the fiberglass"?? the entire deck??
I might then be tempted to go w/polyester. Don't know from vinyl ester. Since yer boat is probably from the. factory poly; and yer doing the entire deck, poly it is.
There are pros &cons for each system... Figure your tolerance for each set of issues and costs; then decide.
Poly is generally cheaper resin, faster to set; but trickier in heat, can end up brittle (IMHO) and between laminations process can be difficult.
Epoxy is most times more $$, usually slower to set and has it's own .lamination issues; in my experience less than poly.

I have heard tell of a fella using poly for large, field applications; then tying it in with epoxy once set and cured well.
What will work best for you is entirely your decision.

I have a source here for epoxy at near poly prices; so it's a no-brainer for me

YMM(km)V

HTH,
Paul

[GILow]

I wish I had a source for good pricing on epoxy but the best I could find doubled the cost of the job. Problem is the deck is very large for a boat of this length and none of it is good enough that I won't regret fixing it right from the start. Have looked at that final bonding layer of epoxy around the edges though. Still trying to figure out which order of application works. I gather if you are going to combine the two then it would be epoxy last?

Matt


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[robwilk37]

epoxy has much better bond strength, especially to wood, than the other options. id say the above is accepted protocol with the exception of the 1708. the CSM portion of the combi cloth will just waste resin so a straight biax gets the job done and is easier to fair. peal ply is also your friend and will speed fairing.

google kiwi-grip, some good reviews so far.

[deltaten]

agreed, rob. I,m doing smaller sections and filling 1/4" core Areas with the 1708, so I want the build up.. in matt,s case, a full lay up schedule would prolly be best.

matt,
yes; but depending on how the lam is set up, perhaps not necessary.. a lot would depend on attach ment point enginering. you * might* wanna have some sorta FRP engineer (?) schedule the layup. big job ( overall) for a DIY project!

[GILow]

Glad to get that clarification on the 1708. Could not quite understand the numbering but it sounds like the 08 refers to the weight of underlayer of the material?

Another source of confusion is that here in Oz the suppliers are quoting in GSM for the fibreglass weights whereas most online articles refer to ounces. I think I should be looking at two layers of 450 gsm or maybe 600 gsm biaxial cloth.

Yes big job for a DYIer and not one i particularly relish but probably one I will end up doing myself. Labour cost would at least double if not triple things. So far I have done ok from a lot of reading and asking questions then not rushing things. Well at least the boat has not sunk yet which is promising.

Matt


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[ssanzone]

Okay... a few things...

1. if you are removing all of the current glass, use laminating resin. it will save you 19 fortunes.
NOTE: if you are only cutting out the compromised areas, use epoxy
2. after cutting out the wood core, use foam (Divinycell or similar). It is REALLY easy to work with.
3. The amount of filling, fairing and sanding (time) required to get your deck smooth will be calculated in multiples on 100 (meaning a really really really really long time.
4. kiwigrip nonskid is all varieties of amazing and will save you a bazillion hours of the aforementioned time.
NOTE: I am very happy with my synthetic teak decks which I partially selected when I realized I had 200+ hours into fairing the deck and it was not even close to perfect (enough) for paint

If you have pictures and / or specific questions, let us know as a lot of us have been through this.

My last bit of advice is pull every bit of hardware off your deck before you start. You DONT want to do this twice so... if there is a screw in your deck... remove it, inspect, repair and then replace.

gl.

-steve

[Valmika]

Something you may want to check out I have heard the an epoxy resin degrades much quicker from UV. If you were to paint on top of your decks to block the UV I think you would be alright. The advantages in strength are a tempting factor

[ssanzone]

Originally Posted by GILow

Yes big job for a DYIer and not one i particularly relish but probably one I will end up doing myself. Labour cost would at least double if not triple things. So far I have done ok from a lot of reading and asking questions then not rushing things. Well at least the boat has not sunk yet which is promising.

Matt


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I do not agree... it is a lot of work but it is not overly complex as you are working on large-ish flat areas.

Your biggest challenge will be not making a mess (of yourself).

-steve

[Terra Nova]

I would use biaxial with mat and epoxy resin. One layer would probably be enough, if the structure is sound.

[zboss]

There is a really great set of videos on youtube by "Boatworks Today". He did 3 or 4 hours of instructional videos on laying mat and CSM and discusses the various reasons he uses one or another resin.

https://www.youtube.com/watch?v=JAtjHjJhBV0

[Cadence]

I didn't read all of the posts. The one common thread was don't get cheap, use epoxy don't try polyester.

[Jim Cate]

G'Day Matt,

Man, you are a glutton for punishment! I admire your ambition, but not the state of your knees post job...

I have no advice about the glassing part of your project, but for the finish paint, have a look at Acrylmeric Sportscote :
Acrylmeric Sportscote

It is a similar product to Kiwigrip, but its industrial heritage means that it is MUCH less expensive. A fifteen liter pail cost us about 180 Aud a couple of years ago, and was about twice what we needed for our deck.

Good points:

The very best non-skid surface that I have ever experienced on a boat deck... bar none, both wet and dry.

Easy to apply.

The non-glossy nature of the surface means that you will not need a perfectly fair finish to look good... will save some wear and tear on you and your knees.

Bad points:

It is hard to keep clean (as is Kiwigrip or any other similar product). This fact is enough to keep Minaret from using such things, and I greatly respect his opinions, but I have more tolerance for such issues. It just works so well...

Good luck,

Jim