# False floor fiberglass layup



## firecat1981 (Nov 27, 2007)

Your stiffness will come from glass on the bottom, abrasion protection from glass on top. I would do at least a light cloth on the bottom, 6-10oz, and then the 1708 on top as a minimum. This assumes the floor is well supported by the stringers and framing.


----------



## Guest (Sep 4, 2018)

Coosa for the sole? That’s pricey lol! 1/2” depending on stringer lay out I’d go two 1708 top and bottom layed up on a table. This will give you the stiffness you need. Lay up both layers on first side at one time “this will save on resin and weight” flip board and lay up the other side the same. If you haven’t bought the biax then go with 2 layers of 18oz woven. The 08 isn’t needed or advised to be used with epoxy so if ya must use biax just use 1700 biax. I would use a biax tape @+45/-45 to tie in stringers and sole to the hull though.


----------



## Goldmine (Aug 29, 2017)

Thanks for the advice. I have not purchased the fiberglass yet. IvI'heard about the 08 CSM not dissolving/ bond when using epoxy? What do you use as a filler material then? My hull is ground down to just the gel coat and a then layer of resin with mat. I was going to do two layers of 1708 on the inside of the hull. What I removed was I believe two layers of woven and mat. The original construction used a chopper gun and polyester resin I think because the inside was not finished out clean. Should I use polyester or vinylester on the rebuild? I was wanting to do epoxy for it's sealing properties. I wasn't planning on using any wood on the rebuild.


----------



## Guest (Sep 4, 2018)

If you use epoxy then just cloth on cloth, the epoxy bridges the gap appropriately. If you ground all the woven out of the hull and just the paper thin skin coat and gel is all that is left then you are gonna have to really really support and brace that thing before glassing! If not then when the resin shrinks during curing it WILL pull it out of allignment and you will have a real mess!


----------



## Guest (Sep 4, 2018)

If it were me, I’d scrap the hull if all woven is gone. But, if I did go through with the build I’d use polyester. It is cheap, strong, pretty easy to work with once you get the hang of it. If boat is gonna be wet slipped for any period of time then Vinylester or epoxy but remember that skin is polyester also so you wouldn’t see the benifits of these really. For layup, I’d lay 1 layer 1.5oz csm followed by 1 layer of 18oz woven and roll out all air and any excess resin. Then add stringers, decks, floors, ect.


----------



## Guest (Sep 4, 2018)

Tip- if it is ground to skin coat and you do go through with rebuild... wait until the tem drops to 70-75 degrees farenheit, do glass work in early evening when it’s cooler, catalize at lowest rate your resin manufacture reccomends at that temp! This will slow the “kick off” and cure times a little helping reduce shrinkage.


----------



## yobata (Jul 14, 2015)

I read somewhere that polyester resin shrinks between 7-15%, whereas epoxy resins shrink between 2-6%.


----------



## Guest (Sep 4, 2018)

I don’t remember the rate but they all do shrink and will cause distortion if not done carefully on a rebuild! One of the reasons it’s so important to properly brace a hull when doing stringers and transoms, on top of just making sure it stays true and square.


----------



## yobata (Jul 14, 2015)




----------



## Guest (Sep 5, 2018)

Yobata, I get the feeling if we ever went fishing that we wouldn’t catch a thing due to way too much laughing! I have a hunting buddy that this happens with also. Bambi is safe when he and I go to the woods together!


----------



## yobata (Jul 14, 2015)

Boatbrains said:


> Yobata, I get the feeling if we ever went fishing that we wouldn’t catch a thing due to way too much laughing! I have a hunting buddy that this happens with also. Bambi is safe when he and I go to the woods together!


Life is way too hard not to try and laugh while you can!!


----------



## Guest (Sep 5, 2018)

yobata said:


> Life is way too hard not to try and laugh while you can!!


Agreed!


----------



## Goldmine (Aug 29, 2017)

I'm not laughing at the fact I've spent hours grinding on that hull and sounds like I screwed up.


----------



## yobata (Jul 14, 2015)

Are you sure that it's that thin? Most of the rebuilds I have seen (including mine) the hulls of this style and vintage are just built that thin to begin with. Can you measure the thickness at the rolled gunnel (assuming you sanded evenly) or at the transom?


----------



## Guest (Sep 5, 2018)

Sorry Goldmine, did not mean to get you down. I take things I read too literal sometime and reply as if. Are you positive you ground the woven out? Or maybe jist the woven that was tying in seats, decks, floor, transom, ect...? The hull will be paper thin if you ground the woven out of the laminate! The gelcoat will easily crack because the hull will flex very badly. After a closer observation of the pic showing your transom skin, it appears to be ok to me. Take a closer look and get back to us. These small boats are usually gelcoat, thin layer of chop, 1 layer 12-18oz woven then the seats and such are added. If it’s an 1/8” thick you are most likely ok.


----------



## Guest (Sep 5, 2018)

Might even be a little thinner depending on gelcoat thickness and actual layup schedule.


----------



## DuckNut (Apr 3, 2009)

"My hull is ground down to just the gel coat and a then layer of resin with mat".

From the pictures you posted I do not see where you ground all the way down to gelcoat. What I see is that you ground all of the gelcoat off and are down to clean resin and chopped strand. This is done properly for good bonding.

You're ok with where it is.


----------



## Guest (Sep 5, 2018)

Yeah DuckNut, after looking closer at pic that is what I see also! I do see a thin spot on the rolled gunnel but no way is he down to skin coat on whole boat, it would collapse. I should have looked at pics better at first before responding to just his words!


----------



## Goldmine (Aug 29, 2017)

I think the hull is going to be ok. I have not removed any fiberglass material from the sides or transom skin. The transom has been sanded just enough to get the rotten wood bonded to it free. The inside of the hull though is pretty thin. I've got pictures to show. The first picture only has the rotten sole cut out. This happend around 2012. I left about a 3 inch shelf on the sides and by the sump. I actually ran the boat like this some for a couple years. You could see that hull flex as I went across the lake(sketchy.) Orignally I was going to scap in a peice of plywood and be done. I have had the boat since around ’06. It belonged to my father in-law and had been sitting in his barn in FL. roughly 6 yrs. since he moved to Al. He was the original owner 1989 Rivercraft. The motor wouldn't hardly run when I got it. I didn't invest any time in and it sat under a tarp for 2 yrs until we bought a house with a garage. This didn't help the neglected boat. My interest was not into fishing or boats at that time, motocross and bicycles, still is. Have plenty of friends with boats if I wanted too. Anyway I got hurt in '08 and tore my ACL. While I was home recovering I rebuilt the 1974 20hp Mercury. Now I had a good running motor and rotten boat. Nah, back to racing bikes. My brother was the reason we cut the floor out one afternoon the summer of '12. We grew up fishing and on the water. "Come on man you don't use this junk. I'll take it home to Ga. and use it." We took it out to the lake and that flexing hull and no lanyard kill switch scared him. He'd fallen out of a jon boat with 9.9 in the river that year and wasn't wearing the kill switch. Anyway I got the fishing bug again couple years ago and have decided to rebuild the "Goldmine." I started earlier this year while recovering from ACL reconstruction on my other knee. Now that y'all know the history. I'm asking for input on rebuild advice. Have a thread going in Bragging section too. I'm thinking epoxy and Coosa board. I've got 5 sheets in the garage and cardboard templates of the original stringers and sole. Shooting for something like L Walkers rebuild. Thanks!


----------



## Guest (Sep 6, 2018)

Epoxy is great stuff as is coosa! The coosa will be a heavier option over say nida core but it will be darn near bullet proof and you won’t have to worry about where you can and can not attach something without backing reinforcement of some sort. I’d use the coosa if I had it. Lay it up on a table with a couple layers 12oz cloth on both sides then cut to fit and tie in with 2layers of 12 oz biax +45/-45 and it will be light and strong! Place stringers around 12-14” on center to help support the floor. If you put a 3/4” camber on the decks you can probably get away with no supports under them, might need a 3rd layer of 10oz cloth on bottom side of decks to make the camber work. I just did one that is 6.6x7.4 using 3/4” honeycomb with no supports and a 1” camber that I can bounce on with virtually no deflection. I’m 250#’s! It has 2 layers 18oz cloth and 2 1.5oz csm with poly resin.


----------



## EvanHammer (Aug 14, 2015)

Boatbrains said:


> Epoxy is great stuff as is coosa! The coosa will be a heavier option over say nida core but it will be darn near bullet proof and you won’t have to worry about where you can and can not attach something without backing reinforcement of some sort. I’d use the coosa if I had it. Lay it up on a table with a couple layers 12oz cloth on both sides then cut to fit and tie in with 2layers of 12 oz biax +45/-45 and it will be light and strong! Place stringers around 12-14” on center to help support the floor. If you put a 3/4” camber on the decks you can probably get away with no supports under them, might need a 3rd layer of 10oz cloth on bottom side of decks to make the camber work. I just did one that is 6.6x7.4 using 3/4” honeycomb with no supports and a 1” camber that I can bounce on with virtually no deflection. I’m 250#’s! It has 2 layers 18oz cloth and 2 1.5oz csm with poly resin.


When you lay up the panels on a table how do you get the camber? Use some type of mold? Or do you have a top for the table designed for that? Curious how to get camber in a deck/floor you are laying up.


----------



## Guest (Sep 6, 2018)

You can do it a couple ways.
(1) prop up the ends of the board, should sag in center. Then lay it up, if no sag... if not, weigh the center of board down using waxed plastic, melamine, or anything slick that won’t stick to the wet glass between weights and glass. Once cured, you can flip, support the center and glass the other side.
(2) method two is really just opposite of method 1 in the weighing and propping stages.
Draw a center line on the board before glassing so you can see where to place the weight.


----------

