CSM or Not on deck repair.

dmar11bb

Seaman Apprentice
Joined
Sep 29, 2013
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34
Well this is my first post here. I've been using the site for many years on various repairs. I am confused about something. I have read many posts on deck and stringer repair, and I am doing my first deck and transom repair on a 25 year old Center Console. A very simple question. Should I lay down CSM on the deck before my next layer of roving or cloth? I read yesterday that the CSM is a waste of time and money. I am using ply and poly resin. Should I just be using a combo fiberglass cloth?
 

jigngrub

Fleet Admiral
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Mar 19, 2011
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8,155
Re: CSM or Not on deck repair.

You can skip the lone layup of CSM if you use the 1708 biaxial cloth, the 1708 has the CSM sewn onto the back of it so you get 2 layups in one.
 

dmar11bb

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Sep 29, 2013
Messages
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Re: CSM or Not on deck repair.

Thank you for your reply. This is by far and away the best site with the best people!
 

Yacht Dr.

Vice Admiral
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Feb 26, 2005
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5,581
Re: CSM or Not on deck repair.

Hello Dmar and welcome to Iboats :) ..

Should I lay down CSM on the deck before my next layer of roving or cloth? I read yesterday that the CSM is a waste of time and money. I am using ply and poly resin. Should I just be using a combo fiberglass cloth?

While Jig is somewhat correct.. its not always the case that 1708 is a stand alone "dual layup" material. Mat is used for the initial Bonding of your glass. 1708 is mat backed ( or fronted if you like ) but it Might give you trouble when laying up over plywood alone. It only has .8 oz of mat on it..thats half of the standard 1.5 oz Mat typically used for bonding. Consider using the 1.5 oz mat when going over raw ply. Now if you have "prepped" ply that's when you could get away with using 1708 solo. I would never do this with an under the waterline repair though ;) ..

Good luck and show up some pics :)

YD.
 

ondarvr

Supreme Mariner
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Apr 6, 2005
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11,527
Re: CSM or Not on deck repair.

CSM is a waste of money when using epoxy, but not when using polyester.
 

jigngrub

Fleet Admiral
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Mar 19, 2011
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8,155
Re: CSM or Not on deck repair.

Since we're talking about glassing in a deck and not below the waterline repairs, 2 layups od 1708 biaxial will be your best build.

You could go with 2 layups of 1.5 oz. CSM and then a third layup of another 1.5 oz. CSM or 6 oz. cloth or just 2 layups of the 1708 and have 4 plies instead of only 3. I personally like the math on the 1708 better. Yes, you only get to layers of 3/4 oz. CSM... but you also get 2 layers of 17 oz. cloth which will be a very durable build with less time involved.

Apply a coat of resin to your deck and let it penetrate the wood and tack up, then lay your 1708 and wet it out and let that tack up, then the second layer of 1708 and wet it out and you're done.

... but you do realize you need to tab the decking to the hull before you glass the deck in, right?
 

dmar11bb

Seaman Apprentice
Joined
Sep 29, 2013
Messages
34
Re: CSM or Not on deck repair.

Thank you all for your replies. I am aware of the tabbing that is necessary. I was working on a lower storage area today just above the stringers that I will use for storage, and I took some pics. Will see if I can get them up tomorrow. Of course like any project, another day another question. I removed all the rotten deck where it meets the side wall and cut up the wall about 6 inches. In this area the fiberglass work lays over foam. What is the best method for tying this area back together to the plywood deck? Do I glass in wood behind the existing vertical glass work and bring that down to the deck? Help!
 

Yacht Dr.

Vice Admiral
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Messages
5,581
Re: CSM or Not on deck repair.

Its kinda hard to tell from your explanation. Are you talking about a bulkhead that rides up the sides forming the storage box?

I'll wait for the pics :)

As far as the 1708 and mat deal..well each resin is different and it will affect how the glass wets out and retains its resin saturation. So if your having problems with drainage or bubbles in your glass then just add some 1.5 oz mat before your lams ( or even on top of your 1708 ). If your not having problems then your good to go with 1708 solo. Personally I find that laying up 1.5 oz mat..then the 1708 mat side UP is the way to go for multiple consecutive lams. Mat on both sides seems to work extremely well. Whatever works best for you is the proper way :)

Dave.
 

dmar11bb

Seaman Apprentice
Joined
Sep 29, 2013
Messages
34
Re: CSM or Not on deck repair.

I cant seem to upload pics. I will keep trying
 

Woodonglass

Supreme Mariner
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Dec 29, 2009
Messages
25,924
Re: CSM or Not on deck repair.

I'd recommend a free Photobucket account to use to upload your pics
 

dmar11bb

Seaman Apprentice
Joined
Sep 29, 2013
Messages
34
Re: CSM or Not on deck repair.

I have a dropbox account but cant get that to work. Ill be back ill try photobucket
 

zool

Captain
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Aug 19, 2012
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3,432
Re: CSM or Not on deck repair.

If you look to the right of that pic in photobucket, there are 4 links under "share this photo", click on the bottom one "IMG" til it says copied, then just past it in the text here..and you get this

 

dmar11bb

Seaman Apprentice
Joined
Sep 29, 2013
Messages
34
Re: CSM or Not on deck repair.

OK So I'm interested in the method by which I connect the side wall, which is glass over foam and the new floor, which is glass over wood. How do I transition? I installed a lower storage locker floor over the stringers using sealed "fir" strips attached to the sides of the stringers set in PB mix. I sealed an glassed the bottom of the ply with resin and CSM. Now at the top I plan to tab in the sides to the stringers. This area will be purely storage. But as I replace the main deck I assume it will again rest on the side foam.? Which by the way is in great shape. So after laying down the ply (of course sealed ) how do I tie in the glass only side? Im contemplating raising the deck to make the bow a single height fishing platform. Thoughts?
 

Woodonglass

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25,924
Re: CSM or Not on deck repair.

Ok, I'm still not following where you're wanting to make this storage area. 1708 is used primarily for structural repairs. If this is a non structural feature and indeed is only for storage, then you would only need CSM and some light cloth, i.e. 6-8 oz fabric should do the trick. If you could use MS Paint to Circle the area in the pic to show us where you plan on building this box it would be quite helpful. At least it would be for me!!!:D
 

dmar11bb

Seaman Apprentice
Joined
Sep 29, 2013
Messages
34
Re: CSM or Not on deck repair.

Sorry for the confusion. The question is not where to construct the storage area as I have that part done but when i put the floor back in place, it rests on the foam. What do i build the side up with that rises up from the floor as currently it is glass over foam. I have to tie in the new side to the exiting. I will try to circle the area with MS Paint
 
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