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Fly or die
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Discussion Starter · #1 ·
I'm doing a deck that is 56 1/2 wide and 3 foot long. I now have a single piece of 1 1/2 chop mat on it and it is still very flimsy any ideas beside adding a second bulk head? Maybe more glass? Trying to keep weight down ::)
 

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BBA Counselor
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You need to add some support strips going from the bulkhead to the transom and then glass on both sides before it will stiffen up. Once it's all tied in to the sides, transom, supports and bulkhead it will help keep it from flexing. I'd also add another layer or 2 of the mat, 1.5oz is super light, I also perfer cloth to mat as it will be stronger. I'd want at least 6oz of cloth on the bottom and 9oz plus on the topsides for puncture resistance.
 

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Just clarify; you have 1 1/2 oz mat laminated to both sides of the nidacore?
I used 12 cloth on my decks and they were flimsy until both sides were laminated. I think you need more glasss also.
I saw some post online with folks using 18oz roven but that might not be needed if it is supported well. I would think you need at least 10oz on each side. My decks are supported where the is no more than one square foot of span and it doesn't flex under my 235lb with the12oz. Hope this helps.
 

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If you dont want to add another bulkhead, then you can "top hat" the bottom section which is basically glassing in another stip of core on the bottom. I would add a layer of 1708 on both sides before top hatting the bottom. It will stiffen up tremendously.

look here:
http://www.bertram31.com/proj/tips/core.htm
 

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Fly or die
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Discussion Starter · #5 ·
I only have 1 side glasses as of right now since the gange plan was to have that stuff and flip it over and it would stay perfectly level to glass the top was my theory which so far is invalid with only one piece of ounce and half mat so I will add a few more layers and also add a couple strips of nidacore in that and let it dry since I am trying to stay away from a second bulkhead
 

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Fly or die
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Discussion Starter · #6 ·
Sorry that was kind of confusing looking back at that. I have 1 side that's is glasses te other side is not. I wanted to face glass side down and set unglassed side up to the sky and they glass it into the boat should I put the nida core cross beams horizontally from port to starboard or vertically transom to bow? I know you said transom to bulk head but what if I glass the pieces in before I put it in the boat? And I was thinking 3 to 4 inch wide strips by 3 feet if I got vertically and then glass the edges of the transom when I crawl under the deck and secure it

Sort if it's confusing I an clarify if need be
 

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Fly or die
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Discussion Starter · #7 ·
One more thing should I put in the bulk head first? drill the face hole where I want it then add the vertical strips of nidacore glassed into the bulk head then add te top deck on top of the already completely glassed strips?
 

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The plascore will be super flimsy if you only have one layer of 1.5oz. On one side. It won't stiffen up without a few layers on both sides. I'm telling you, do two layers of that mat on one side and a layer of fab-mat from Higgs on the other. Mine does not flex at all.

I bonded some pieces of 1/2" divinycell on the sides of the hull level with the bottom of the deck so I could then bond the deck to that where there was no bulk head. You are going to need more structure than 1 bulk I think.
 

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No composite structure is going to be stiff until there is glass on both sides. 1.5oz csm is not going to be enough glass on each side. if you just want to use CSM, then you are going to need at least 4 layers. I wouldn't suggest that though as yo uneed some real meat on there to spread puncture type loads. do all the underside glass work first, as glassing upside down sucks to say the lease. read the entire link I sent and let that sink in. there is tons of good info on Bertram31.com
 

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Fly or die
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Discussion Starter · #10 ·
definitely trying not to have another bulkhead but we will see. im going to play with it tonight after class. damn rain and humidity threw me a hard curve ball to the knees so I couldn't glass front top deck :mad:
 

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Fly or die
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Discussion Starter · #11 ·
can not for the life of me figure out the bulk head I guess when I turned the contour gauge I have to line it up with the angle I put it on when I measure in the boat I then have to transfer that to the cardboard cut out. that's why it is off at the top or maybe just hold it straight up and down next time.... glad it was on card board not 100 dollar piece of nidacore
 

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The trick is to use several pieces of cardboard or luan....instead of one large one. Then secure them together so they don't move once they are cut and you are happy. The contour gauge is ok for some small tricky parts like your oddly shaped corner there, but it's not well suited for the larger areas. Try using a compass set at an inch or 2 instead to trace the hull sides onto your template.
 

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Light, Strong, Cheap. Pick Two.
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No composite structure is going to be stiff until there is glass on both sides. 1.5oz csm is not going to be enough glass on each side. if you just want to use CSM, then you are going to need at least 4 layers. I wouldn't suggest that though as yo uneed some real meat on there to spread puncture type loads. do all the underside glass work first, as glassing upside down sucks to say the lease. read the entire link I sent and let that sink in. there is tons of good info on Bertram31.com

Yes. The decks in my Fowl River 16 Build were 60" wide x 5' long. I cored them with 1/2" divynal and put one layer of 1.5oz csm and one 24 oz woven roving on each side ane they are solid as a rock.
 

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Fly or die
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Discussion Starter · #15 ·
Thank you cwright I will do that then I need to find some woven roven and I don't not know what divynal is? I am glass the decks as the under side right now I heard already it was a royal pain in the ass I can only imagine! But I'm on the hunt for some roven woven now and more cagisal to mix with resin and fill in some of the honey combs. Hoping to knock a lot out this weekend progress pic in a minute, doesn't look like much but for a first timer I think I did alright.

5 foot front deck 3 foot back deck and I'm going to inset the rear bulkhead a inch 1/2 or 2 to protect my nav switches thanks for all the help guys very appreciated!
 

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Fly or die
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Discussion Starter · #16 ·
oh divynal is like nidacore sorry :D you put 1 piece on top of the woven roven correct so it has a nicer finish? also when I sand it, what should I use as a filler to make it even? and I wanted to aw grip it I guess? but have no idea my "boat guy" bailed on my. funny how you can never get favors returned when you need them... :mad:
 

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Divinylcell is foam core and completely different then nidacore. It's a better product and has strength in all directions, where nidacore really only has strength when it is in the flat horizontal position.

Basically Nidacore is used for light weight decking, but is not a great choice for bulkheads because in the vertical position the honeycomb structure has no real strength and can collapse. Which is why CW suggested you just make the bulkheads out of straight fiberglass.
 

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Light, Strong, Cheap. Pick Two.
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http://www.microskiff.com/cgi-bin/yabb2/YaBB.pl?num=1342645031/90
Check out the the decks on this page.

You can zoom in on the photo where the rear deck is sideways and see that the vertical bulkhead is about 1/4" of glass. The horozontal is cored with divynal. (divynal = high density crosslinked PVC foam)
 
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