Bondo used in original construction?

[PastTheBarb]

Im doing a almost full deck replacement in my 1996 2100 CCDV. I was hoping it would be only the deck but now Im finding rotten and wet stringers.
Ive cut parts of three stringers out and all of one. I was surprised to see what looks like bondo under some of the stringers used and fill where the stringer didnt
meet the hull. Its pink and somewhat soft. I can dent it with my finger nail. Is this normal?

Im planning to use 3/4" Hydrotek marine plywood to replace the stringers and the deck. I like coosa but its hard to get on the west coast.
Im considering going with 1" for the stringer repairs. ???

The more rot I cut out the more I keep finding. Im changing the name of my boat to "Can of Worms".

 

[warthog5]

I was surprised to see what looks like bondo under some of the stringers used and fill where the stringer didnt
meet the hull.

It's not Bondo........Well who knows? You said it was soft. Usually it is resign putty.....a mixture of polyester resign and Cabisol for gluing. But it's VERY hard. It' looks the same.

 

[1801Steve]

In 1996? Who knows? Might be some sort of adhesive.

 

[PastTheBarb]

Im also thinking a lot about how to layout the new plywood deck. The most efficient use of 4x8 foot sheets is to run
the 8 foot lengths port to starboard. However that leaves joints without support. The old deck had some cracking at the joints. Im considering designing it so most all joints are over stringers and routing a one inch stepped joint screwed to the stringer (see attached picture). Is there folly in this plan?

 

[Legal Bill]

Maybe it is just me, but assuming there is enough space, I would thru-bolt and then glass in some cleats on either side of the stringer so you have a pretty wide mounting face to support the deck. You can screw the deck sections into the cleats and not worry about screwing fasteners into the endgrain of the plywood stringers you are building.

 

[PastTheBarb]

Thats a pretty good idea. What would you make the cleats out of? Then just butt the plywood together and screw to the cleats?

 

[warthog5]

Your lap joints will work well...I've done them like that before 2in wide using a Router......By the way you loose length in the 4ft with that type of joint. Don't leave the fasteners in permanently. epoxy glue ...aka epoxy resign and Cabisol mix.....will be stronger than the wood.

I have also done it by scarfing the plywood.....I still have the Mikita planer and the scarfing jig.

After the panels are cut and joints made.....before install..... Glass the bottom side of the wood....avoid glass into the joint area. A layer of 6oz to 12oz cloth will be fine and easy to manage.

When installing.....and gluing.....Use drywall screws....Have the holes predrilled.... When the glue is kicking off [In a Green state] Remove the screws.

 

[PastTheBarb]

Thanks Warthog! I was going to use a 1" lap but if two is better Ill go that route with the cabisol mix to glue them together. Im going to use the 6oz clothe that came with the West System kits to glass the underside. Should I use a thick bead of the mix on top of the stringers? The original construction used 5200 in some places while others seemed to be epoxied. If I remove the screws while in the green state will the holes "self heal" or should I dab additional resin into them? Of course it will all be covered in glass in the end.

I cut that main stringer back a couple of feet. Im onto solid wood but its just a little damp. Im going to cut at least another foot.

 

[Legal Bill]

Thats a pretty good idea. What would you make the cleats out of? Then just butt the plywood together and screw to the cleats?

I thought you might be using wood for this project, hence my recommendation to glass it like your stringers. You could build them like that before you install them. That said, I made cleats for a recent project and used 1/2 inch Starboard. The bulkhead and two pieces of starboard gave me a 1 and 3/4 inch wide surface to mount a 2 inch wide flange that in turn supports a large deck hatch.
I attached the flange to the cleats using two rows of countersunk screws. The cleats were attached to the bulkhead with through bolts and adhesive. The holes drilled in the bulkhead for the through bolts got two coats of two part resin. In your situation, I’d probably use two 1x2 inch lengths of ash running the length of the stringers. I’d glue them to the plywood and then glass the whole thing.

 

[warthog5]

Holes will not "Self" heal. You can wipe some resign putty in them before you add the top glass.

Speaking of that.....Whats your plans for the top lamination?

6oz will be fine to cover the bottom.

I assume your going to use A-B Fir Marine Ply?

 

[sailmaster]

Thats a pretty good idea. What would you make the cleats out of? Then just butt the plywood together and screw to the cleats?

When you do the layout plan to install kleats on the underside. Problem with all of this is how to keep it dry when in service. minimum size for the kleats is 7:1 3/4 plywood would be 21/4 or 5 1/4 inch That said bigger is better but over 10 1/2 becomes a waste

 

[sailmaster]

HEY GUYS POSSIBLE MISINFORMATION
When you are talking about resin you should ID the resin you are using
POLYESTER
VINYLESTER
EPOXY

and there are a whole stack of sub groups in between that will have major effect on job and lifespan of repair

Poly is finishing or laminating ( either waxed or unwaxed )
Vinyl is not common for the DIY crowd
Epoxy has Huge number or variables and is the most pricey of the crowd and will fail if used with the wrong reinforcements

Poly is NOT RECOMMENDED for a single ply of woven material the bond will be poor and often resin starved
Chopped Strand Mat should be used to get a better bond and strong thought should be given to mechanical fasteners ( staples) and multiple plys

Epoxy can be used to bond thin woven cloth. Lots of different cloths out there made from different materials. for a water resisting layer the cheaper stuff is better as the expensive stuff is made of stronger fibers that are harder to work with. I prefer "Boat Cloth " which has standard glass fibers that are not twisted. It lays real flat. Uses less resin, but does not go around or into corners as well. The other extreme would be Satin or Crow Foot weave which is twisted fibers in a very flexible weave that goes most places you ask it to.

 

[sailmaster]

It's not Bondo........Well who knows? You said it was soft. Usually it is resign putty.....a mixture of polyester resign and Cabisol for gluing. But it's VERY hard. It' looks the same.

A lot of putties contain TALC that when suspended in Polyester resin will absorb water and get soft. Pink may be from the red dye used in the catalyst to help with proper mixing. The bonding process for stringers, floors and the sole can be challenging and some guys would cheat intentionally under catalyzing the putty to give a long work time sometimes causing a permanent under cure. Parker seems to be well made, but I have seen this in other so called PREMIUM boats. ergo possible answer for SOFT putty

 

[PastTheBarb]

Im using 3/4" Hydrotek marine plywood. 6oz cloth on the underside of the deck but havent settled on the top glass. Im still reading and researching. Ill check out "boat cloth". For the replaced stringer portions Ill make peanut butter with cabosil to glue them down and tab them in with 1708 cloth strips then glass over with woven cloth of some thickness T.B.D. Everything will be done using West System 105 Epoxy and 206 slow hardner.

 

[PastTheBarb]

Hey Warthog...thanks for all the advise. What cloth would you recommend for the topside of the new deck? What would you recommend for tabbing the deck? Ill use cabosil peanut butter to fill the gap between the deck and sides of hull. This my first project of this scale. (Maybe my last

 

[warthog5]

Crap...Had a whole story typed with links...and it dissapeared.

US composites 2 to 1 epoxy.....Not West System. Epoxy : Epoxy Resins and Hardeners

 

[sailmaster]

Crap...Had a whole story typed with links...and it dissapeared.

US composites 2 to 1 epoxy.....Not West System. Epoxy : Epoxy Resins and Hardeners

The US Comp stuff is cheaper and more than good enough

 

[sailmaster]

Im using 3/4" Hydrotek marine plywood. 6oz cloth on the underside of the deck but havent settled on the top glass. Im still reading and researching. Ill check out "boat cloth". For the replaced stringer portions Ill make peanut butter with cabosil to glue them down and tab them in with 1708 cloth strips then glass over with woven cloth of some thickness T.B.D. Everything will be done using West System 105 Epoxy and 206 slow hardner.

If using epoxy make your peanut butter paste with cotton fiber NOT Cabosil
A silica putty gets very hard and brittle and can point load
Obviously your 1708 is EPOXY OK ?? not all of it is
I like the BIAX vs the 90 because it is more flexible assume you are talking stich and not roving
when you butter in your stringers make sure you put in a radius
if you are doing cloth use at least 1 layer of 10 oz 2 is better
do you have a pattern determined or are you going smooth ?

How are you finishing it ?

remember interlaminate prep is VERY important with Epoxies
unlike laminating Polyester

 

[PastTheBarb]

A friend gave me almost a full bolt of 10 Oz cloth. So Im planning to glass the stringers in with two layers of cloth and one strip of the 1708.
Not sure what order to lay them in. The 1708 is a four inches wide roll. Im thinking Ill lay a 12 inch swath of the 10 Oz (6" on the hull and 6" up the stringer) and then an 8" swath and finally the 4 inch 1708. Then Ill lap one layer of the 10 Oz over the top of the stringer down to the other glass completely incapsulating the stringer. This is for a partial stringer replacement. I did a sample test of the 1708 and the 10 Oz cloth and they both wet out nicely with the west system epoxy.

How thick should the peanut butter bedding be under the stringers? Parker left about 1/2 inch of that pink stuff. I acquired some foxed cotton to make peanut butter but I also have cabosil. Im still torn on which way to go.

For the deck I think Ill use the 6 Oz cloth on the underside and two layers of 10 Oz on top. Ill tab the edges with the 1708 after peanut butter adhesive with a radius to the hull. Im hoping to lay the second layer while the first one is still green but that is going to be tricky, its a lot of area.

Ill send pictures. Wish me luck!!

 

[PastTheBarb]

The rebuild has finally begun!!! The Demolition phase is finally over and I glassed in the first pieces of new wood. This is the framing of the scupper basin, at least that's what I call it. Parker constructed it from 1/2 ply. It was soaking wet and coming apart. I'm using 3/4 inch because its what I have as scrap from the stringers. Next Im installing the new stringer portions that I scarf cut out. I'm going to bed the stringers in about 1/2 inch of peanut butter adhesive as that is what Parker did.
I guess Ill butt the new stringer to the existing with a thin layer of peanut butter. Then, of course, tab to deck and totally encapsulate all the new wood.
Any comments or advise is appreciated.

LET THE FUN BEGIN!!!!

Maybe I should start a new thread titled deck and stringer replacement.