67 - 22'2 Flatback Diver Rebuild

[gran398]

Input based on that.

The nidacore is great, you'll be happy with it.

[Aswaff400]

thanks guys.

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

im at around 13.5 to 14 gallons so far in my rebuild i think the transom alone used 6 or 7 gallons...
outer skin
1.5oz csm
x3 1708
x2 1.5oz csm
3/4" penske board
1.5oz csm
3/4" penske board
x3 1708

i will be using nida core for the deck...

[dirtwheelsfl]

I would do the 2 pieces for the transom. Just for the fact that youll have 3/4 material scraps leftover and not 1.5" that would be hard to use elsewhere. Im not sure on numbers for stiffness of double 3/4 with glass in between versus single 1.5", but id bet the double will be stiffer.  

For a deck, both will need to have some kind of high density core glassed into it for any and all fasteners, which need to be thrubolted. Unless theres no access for a thrubolt, then you have to get creative. I wouldnt go with less than 3/4 for either core. And 2 layers of biax on each side, maybe just one on the bottom depending on how "bouncy" you like your deck to feel.  

Now are you talking about the nidacore honeycomb? Or the nidafoam? Divinycell is a much nicer foam than the nidafoam, and will be a tad less work than the honeycomb cuz you dont have all the open cells to fill...

[OldSkool67]

I would do the 2 pieces for the transom. Just for the fact that youll have 3/4 material scraps leftover and not 1.5" that would be hard to use elsewhere. Im not sure on numbers for stiffness of double 3/4 with glass in between versus single 1.5", but id bet the double will be stiffer.  

For a deck, both will need to have some kind of high density core glassed into it for any and all fasteners, which need to be thrubolted. Unless theres no access for a thrubolt, then you have to get creative. I wouldnt go with less than 3/4 for either core. And 2 layers of biax on each side, maybe just one on the bottom depending on how "bouncy" you like your deck to feel.  

Now are you talking about the nidacore honeycomb? Or the nidafoam? Divinycell is a much nicer foam than the nidafoam, and will be a tad less work than the honeycomb cuz you dont have all the open cells to fill...

The nida honeycomb.

I plan on through bolting all the hatch hardware and what not. Im not sure how the console will layout yet with the stringer design... never got that far in my head to be honest with you.

Is it a pain to back fill the open cells when you have an open section like where a hatch or inspection plate is going to be?

[dirtwheelsfl]

Not hard to do, just another step. Easiest way i know is to glue a strip of material to the edge and then radius and glass over that. I guess its not needed unless its gotta be a "finished" edge like a custom hatch, but for a pie plate ive seen em just left unfilled. Which wont hurt anything.

Heres some divinycell glued to an open edge.

[OldSkool67]

Got the transom out and some more grinding done. Anyone have any tips on getting that last layer of ply off? Doesnt sand or grind very well. I thought about letting it dry out to see if that helps.

Im trying to find someone in my area that can sandblast the interior at a reasonable price. Figure that will save me some major man hours in getting all the old paint off.

[RickK]

Air chisel is what I used to get the wood out.  If you can find a long chisel that is best.

[Aswaff400]

Got the transom out and some more grinding done. Anyone have any tips on getting that last layer of ply off? Doesnt sand or grind very well. I thought about letting it dry out to see if that helps.

Im trying to find someone in my area that can sandblast the interior at a reasonable price. Figure that will save me some major man hours in getting all the old paint off.

sand blasting saves a whole heckuvalotta time!

[OldSkool67]

Letting it dry out was a big help. Im ready to start the transom install... If I hadnt been lollygagging I would have already ordered the coosa.  :(  Oh well, I guess I will just go back to grinding other parts of the boat till it gets here.



I dont know if you can see in the picture but it looks like there is only about 4 inches of tabbing from the orginal transom. Does that seem right to you guys?

[Aswaff400]

that seems to be about how much was on my transom...

[OldSkool67]

well no joy on the sandblasting, two guys were a no show for a quote and the other wants 300 to show up and hourly from there.

I ordered my transom and stringer material, they should be here monday from Fiberglass coatings. I saved a bunch of money opening an account for my business and using my tax id#.

I went with the high density composite for the transom, 2 sheets 3/4.
I plan on using the following lam schedule, similar to the hefner rubuild but with 1808

3/4 oz mat
3 x 1808
3/4"  composite, 3/4 oz mat, 3/4" composite
3 x 1808
3/4 oz mat

I decided to go with a stringer build somewhat like LilRichard. 2" poly foam. Im laying to layers of 3/4 in the hull to give me a better surface to work from.

Undecided on the lam schedule for the stringers, maybe something like:

1x1808
1x3/4 mat
1x1808

any thoughts on any of this guys?

[RickK]

What are you going to use for resin?

The biax will have a cloth side and a mat side - When you are laying up against 17 or 1808 you should add a 3/4oz mat layer to mesh to the cloth side of the biax.  Look at your transom schedule - add 3/4oz on the outsides of the composites - just a thought.

[OldSkool67]

Im using polyester

Thanks for the info. I will make the change

[OldSkool67]

What is the reason for that btw?

[RickK]

Chopped mat gives the resin something to grab onto - seems cloth is too uniform.  Guess that's why they sew a layer of mat onto the cloth. Not sure you need the last layer of 3/4oz but as thin as 3/4oz is, won't hurt. You may need a veil cloth as the last layer - that's what I'm going with but I will have an open transom so it must be smooth.