67 - 22'2 Flatback Diver Rebuild

[OldSkool67]

well after a week with the flu and finally getting my hoist back I got the motor off the boat. Not a lot of progress this weekend but at least something got done.


Ive been searching for a post I saw a while back and cant find it anymore, someone had a break down of the different types of cloths, mats, weights and uses for each. Im not very sure of what I should be doing in some places and it would be a big help if anyone knows where that is.

[RickK]

We have a bunch of Master Rebuilders that can fill you in on what they used. These guys already made the mistakes we haven't yet so their help is a blessing. Of course each has a different experience.
For me (not a Master yet but I did stay in a hotel a few days ago   ) my research shows 1808 is a 18oz cloth that has it's weave at 90 degrees to itself, so good longitudinal strength (front to back).  1708 is a 17 oz cloth that has the weave at 45 degrees.  I read somewhere that the 1708 is as good or better than the 1808 but I'm sure that someone has a preference in certain situations.  People I talked to said they only use 1708. Today I layed 2 full length layers on my stringers - 1x1808 and 1x1708 - best of both worlds. These cloth come with 3/4 oz mat stitched in.  They soak up about 2oz of resin per sq ft.  4 layers of 1708 equals approx 1/4".
You can also get the cloth without mat if you don't need the build up.

Then the question is Epoxy or Poly - good luck on this one.  Per the advise of a Master Rebuilder I researched "epoxy's bonding strength vs polyester resin" and epoxy came in at 2000 while poly came in at 100 - so it's a no brainer when it comes to bonding stuff together, like below the deck.  If you're going to paint, you can use epoxy everywhere.  I'm going to gelcoat so I need to stay with poly wherever gelcoat is going.

As for Mat - there is all kinds of densities, each with their own purpose.  I have 3/4oz and 1.5oz on hand - good stuff to add to the layers of your wood transom if you go that way.  The 3/4oz is a good way to take the irregularities out of a substrate. 1.5oz is a little denser.

Here are some links to vendors I have used:
I just ordered 7.5 gal of Epoxy from this one today: http://uscomposites.com/index.html
This company was referred by a Master Rebuilder - they treat him right: http://www.raka.com/
I get a decent deal on 1708 by the roll here - I think I may have bought too much now  :( (it's local to me but too high on some stuff): http://www.fiberlay.com/
You can also use Composites One and I think there is another in St Pete.

[gman 82 aquasport]

I'll give you the readers digest version of my rebuild,
I used only epoxy..I knew I was not going to re-gelcoat!
On my floor on the bottom side I used 17 oz 90degree, I also used 17 oz on the hull inside between the stringers and between the stringers and outside hull, I topped the stringers after refoaming with 1 layer of 6oz 12 in wide then cut pieces of 17 oz.
I bought rolls of tabbing glass, 4in, 8in, 12in came in 50 yard rolls and I had some left
Top of the floor is covered with 17oz ran bow to stern, then covered with a layer of 6 oz ran side to side with a 2inch overlap, sanded then flaired..not fun
Floor was tabbed to the hull with 8 inch then 4 inch over it, took both pieces up the side about 2 inches, this was after I had filled any voids with peanut butter( epoxy mixed with wood flour) and rounded it along the transition from floor to hull sides..
My floor was made with 3/4 inch AC fir plywood and all edges were covered with epoxy too...
Getting ready to make a hard top for my T-Top and will used 2-3 layers of 6oz and will used tabbing glass for the lip that will hang over the tubes about 2 inches..
Materials came from, uscomposites for the epoxy, If I remember correctly I got my glass products from boatbuildercentral Both treated me well and had good shipping turn around

[Capt. Bob]

Try this.
viewtopic.php?p=18970#p18970

From the Resource forum.

[gran398]

Try this.
viewtopic.php?p=18970#p18970

From the Resource forum.

Another fine find CB.

Seamark uses chop, then 1708 on their new hull layups/builds. AC fir all the way. Stringers wrapped and heavily tabbed.

That's it.

http://www.seamarkboats.com/Models_2200___2000.html

[OldSkool67]

thanks guys.

how many gallons of resin/epoxy do you think a stringer up rebuild goes through?

[gman 82 aquasport]

I first ordered 4 1/2 gallon kit(3 gal resin, 1 1/2 gal medium hardener ) mixes 2 to 1. That got me to the top level of the floor and I reordered the same..Had about 1 gal epoxy and 1/2 gal hardener left..All really depends on how many layers you intend to put down and thickness of your cloth will play a factor too..I would order enough to get at least to putting the floor down, probably a 4.5 or 5 gal kit..Then you can judge how much youv'e been using and reorder what is needed..It's better to have some left over than to be 1/2 gallon short and have to wait

[dirtwheelsfl]

thanks guys.

how many gallons of resin/epoxy do you think a stringer up rebuild goes through?

Ive got somewhere in the 25-30 gallon range in mine.

[RickK]

Certainly depends on what type of stringers you're going to make and how many.
I have used about 16gal of poly so far in my transom and stringers.  I will need a couple more gals to tab everything in when it comes to that time.
If you're going to lay a layer of glass over the bare hull to start with something new to attach to, figure 2oz sq/ft to calc that up to and then buy it all at once.
It's looking like I will have 27-30gal to get to the top of the stringers.

[OldSkool67]

so I have a few things that I cant seem to make a decision on

1. Why is it better to use 2 sheets of 3/4 coosa or kay-cell over one sheet of 1 1/2 for the transom?  The cost is about 100.00 more to go the 2 sheets route and it seems more labor intensive. thoughts?

2. Ive read and read and read some more on divinycell and nida core. Divinycell is about 50 a sheet more than nida core. aprox 400 to 500 more in overall cost. For someone like myself who does not have much experience with these materials or boat restoration in general what does it all really amount to? Is one that much easier to work with than the other? I will also say Im not against marine ply but I have not found a supplier that will deliver to my area and with paying freight its more than the composites.

Five hundred dollars doesnt make or break the rebuild, but it does determine how many widgets and toys I get when its all said and done.

[gran398]

. 1. Most everyone uses 2 sheets

  2. Nidacore does great

Keep us posted

[RickK]

I have no experience with that stuff in a transom.

[fishinonthebrain]

I went with 2 sheets of 3/4" coosa because that's all the supplier had they did not have 1 1/2". Nidacore is pretty stout its almost like cement board.

The other sheet material you mentioned would be good for decks or other fabrications not for transoms.

[RickK]

Might be a good question on one of Eugene's threads.

[OldSkool67]

I should clarify that the nida core is for the deck and is the 5 lbd density.

the coosa and kay-cell is for the the transom.