Help with my restoration. Nida stringers/deck

I am replacing bulkheads/stringers and deck. I decided to go with Nida-core Honeycomb, because I was afraid to put wood back into the boat. Having become more educated reading this forum I realize that I would have been fine epoxy coating exterior or marine plywood. Now that I am into the project, I'll just finish with the Nida.

Here is what I have done so far. I have gutted the boat and have cut out the stringers/bulkhead from the Nida panels. I laminated two 4x8 Nida panels with Polyester Resin and one layer of Chopped Strand Mat on each side. I realize now that this was not adequate and I should have continued laminating multiple layers of matt/cloth/mat...etc. (live and learn I guess)

I have now purchased epoxy resin and Biax. My plan now is to tab the stringers and bulkheads into place with epoxy and biax. I will go all the way up the top of the stringers and bulk head with at least two layers of the 12 oz biax tabed in with epoxy resin.


Respectfully
KP

 

I hope for you (yes seriously), that is Ilan or PAR, and not one who is "senior" only by age or duration of membership!

See further comments inserted in your post.

Regards
Richard

 

Apex,

Ilan sent me a PM, so I think he will guide me along as well. I was planing on using a fillet. I am going to mix cabosil into the epoxy I bought from Raka to get a peanut butter consistency. Then I will make a nice round fillet from the hull to the face of the stringer and bulkheads. I'm I on track here?

 

You are!

Ilan is the right one to guide you further (he has forgotten more about that stuff than the "warlord" ever will know).
And Raka is a good resin.
Cabosil should be not the first choice when you have to sand the area. It makes sanding pretty tough. But ok for fillets though.

But let Ilan go ahead with this task.

Regards
Richard

 

Are you going back with the inboard power?

 

Yes, I have a vortec V6 and mercruiser alpha 1 going back in. I still have to make the motor mounts and build up the transom. I thought about using the form technique and pouring the transom with nida, arjay or seacast pourable transom. I might even make a small form for the motor mounts and use the leftover pourable transom for that also.

 

I know some people who have went that route and never had a problem

 

OK...thanks War Whoop. The pourable transom just sounds easy and It would be nice to make quick progress on this.

Ilan suggested I use epoxy, cabosil and a filler like glass microspheres to make my fillet compound. I haven't heard from him today. The fillet compound is only going to be used at the base of the bulkheads and stringers to make a nice inside curve so the biax will not have to do a 90 degree bend...correct? I only have about 50 ft worth of bulkhead/stringers. I would think a 1/2 gallon of epoxy resin with the cabosil and microspheres added would be enough? What do you guys think? I am just going to use regular un-thickened resin for the tape...correct? What is the recipe for making the fillet compound, what are the ratios of resin, to cabosil to microspheres?

thanks.

 

Make it thick like peanut butter. The right mix has to be tested with the resin you are using, there is no general rule.

Right, the fillet makes the glass follow the curve without loosing contact, but it acts as a strong glue also!

The cabo/ballons mix makes it easier to sand, in case you need sanding there. But it makes it more expensive and a bit weaker too. If you dont need to sand in these areas, just leave the microballoons/spheres out.
The tape must be doen with unthickened resin, yes.
If ever possible, try to work your tape over the green fillet (not completely cured), that makes it much stronger than a secondary bond. And it never can separate.

Herman provided a simple and good way to work clean on such fillets.
He uses a Aluminium tube of appropriate size (just a short piece) and runs it along the area between hull and bulkhead. That makes two black lines on the hull and BH. Now one can apply a tape along these lines. Then you work your filler into the corner, using the same Al. tube. After kicking of the resin you can remove the tape and have a perfect, clean fillet.

Regards
Richard

 

We used equal parts resin and glass bubbles and added cabosil until it stopped sagging. But my fillet work was always done with 45 degree foam strips.

 

Hey guy forget the Aluminum like someone else suggested go down to the local hobby shop and by hobby sticks for your fillet , nice radius and disposable and if you dont want to use the bubbles because most people are working on a budget go with just Cabosil which will work just fine considering everything will be glassed over .

 

Great advice from both of you. Thanks

 

The hobby sticks are the way used since ages, but you have to get rid of the excess filler afterwards. The tube/tape trick saves the cleanup part.
Foam fillets are the common way in boatyards, they just dont add any adhesive force. If that is not required, the foam fillet is the cheaper and easier way of making a good transition.

 

LOL if the fillet is of the same material as the bulkhead and set in adhesive then it is better than a cheap paste.

 

I assumed already you build your craft with cheap paste!

When the foam is of the same quality as the panel, and glued in with epoxy, it is still weaker than a solid epoxy fillet, of course.
But how would you know that?