Question for the fiberglass experts.
 

Question for the fiberglass experts with concern to stringer repair:

I am restoring a 1982 Carrera 24. I have allready removed everything and am down to the stringers. The stringer coring is rotted, but the glass/cloth is not damaged or fractured.

I realize that the stringer coring on this boat is (was) wood. What is the problem, as only the coring is rotten, to cut the caps off the stringers, remove all the coring material, then prep and fill with epoxy. Then recap the stringer. Can it not be done because of the additional weight of the epoxy, that it would be too ridged, or what?

Thanks for the advice.

E.S.

Re: Question for the fiberglass experts.
 

Eric,
I would think if you cleaned out all the rotten wood and cleaned inside and scuffed inside properly (for the epoxy to bite into the old glass). Why not slide a new piece of plywood or sheets of pluywood glued together into the cavity? Make the wood large enough to fill most of the cavity and count on the epoxy to fill the rest.
I would justfill the cavity with enough thickened epoxy so that it oozes out when you cram the new wood in. That way you would have no air gaps. smooth off the top and glass over.
The West system book shows that for partial stringer repair.
Dan

Re: Question for the fiberglass experts.
 

I would not do it that way. I would be to concerned with secondary bonding problems and getting ALL the air out.

Jon

Re: Question for the fiberglass experts.
 

Thanks guys, guess full removal and replacement is the way to go.

E.S.

Re: Question for the fiberglass experts.
 

I've got a 17' correct craft that looks like it needs stringer replacement too. I'm thinking of going with a product called seacast. What do you guys think?

http://www.transomrepair.com

Re: Question for the fiberglass experts.
 

Check out this website, rotdoc.com.......penetrating epoxy CPES.

Re: Question for the fiberglass experts.
 

I would cut the caps off and clean and sand the insides. then use a foam coring (in front of the engine stringers) wood for engine mounts.Then fill the gap with a slightly smaller core and fill with a slow cure epoxy. Most of the structural capability comes from the spreading of the stress across the glass.

Re: Question for the fiberglass experts.
 

What type of foam coring would you use? It would not be possible to use a type of pourable expansion foam and fill the voids, or would it? The stinger glass\mat thickness is about an 1/4". Is that normal for this age boat with wooden cored stringers?

Thanks for the insight.

E.S.

Re: Question for the fiberglass experts.
 

Seacast seems like a good product. Grind off the tops of the stingers, clean them out, and pour this stuff in.www.transomrepair.com

Re: Question for the fiberglass experts.
 

What type of glass cloth was it built with tri-layer 1708, 1808 or a woven like and older chris or scarab? Also what was the wood core, ply or solid. This matters in your replication of strength and flexibility. You can fill some types like woven because the strength is in the glass and the wood is a filler only. If it is a smoother type like the 1708 (nicer finish) and is wrapped over solid wood in 2 coats equaling about 1/8" you need to replace whole stringer. In my opinion if you can't make the call, find out lay up from manufacture..

Re: Question for the fiberglass experts.
 

The core is ply and the glass cloth is the rougher woven that looks to be 22oz and the cap and sides of the stringers are about 1/4" if not a bit thicker. You can see the woven pattern in the stringers. From the original spec sheet from the boat they say "Heavy duty competition lay up, stringers, bulkheads, all hand laid," don't know if this means anything but the stringers are alot stiffer than most I have ever seen, and even with the coring gone, I can not even flex them in any direction. Sorry to sound inexpirenced in this, but I am.

Thanks for the help,

E.S.

Re: Question for the fiberglass experts.
 

I would be concerned to use the pour in stuff in stringers. That stuff is used for transoms and the transom see's different stresses then the stringers. I guess you can try and check with them about if stringers would be a good use for it. I know the grinding out option is not apealing but I still think that it is the only good way to do it. I find it very hard to believe that you will be able to get out all the air on the sides, there is very little strength in resin with out glass so if as you push the stringer down and as it forces the resin up from the bottom you may push the laminates outward and leave a unacceptable gap in there.

As for the foam you would probably want at leaste a 8 pound or more foam.

The issue that I look at is that the boat was engineered to be put together the way it was. Unless you have a Marine engineering degree redesigning things may not be such a great idea.

Jon

Re: Question for the fiberglass experts.
 

I would stay away from products like seacast, they are too ridgid. The core material I would use is called nidacore. you could use airex or some other marine type of foam. Dont use expanding foam, you could split the stringers. 1/4 inch should be thick enough for caping stringers. After you have cored and filled with epoxy. you should close the repair with at least one layer of 1810 bidirectional glass.Dont use polyester resin. You will not get the bonding as with epoxy. You can email me if you need advise.

Re: Question for the fiberglass experts.
 

Jon,

I tend to agree with your thinking, I am just making sure before I cut into these things. I had been reading somewhere that some builders used plywood cored stringers, just to core the form, and used a heavy lay-up of cloth as the strength. This is similar to what "Gary Thrasher" seemed to imply in his previous response as well. It makes sense as my stringers are at least 1/4" on the caps and sides, much thicker, allmost double than most that I have seen, and of a much heavier cloth. The stringers cores have been rotted or empty for quite awhile now, many years, and the previous owner wave jumped this boat on a reqular basis, and there was no structural\hull damage, which I would have expected lets say on a boat with reqular built stringers if they were missing their core material.

Not sure at this point,

E.S.

Re: Question for the fiberglass experts.
 

My Formula used plywood for the stringers. You may have seen it on my stringer replacement thread. We glssed them out of the boat then tabbed them in. This served two purposes. First we were able to vacume bag them (not really required but it was cool to be able to do), and it was much easier that way. I was not using huge sheets of glass and trying to work it all in and get the resin to soak into it. By doing it out of the boat we were able to possition the glass perfectly for less waiste, then shoot it with resin out of the chopper gun (with the cop turned off) and then shoot a little chop btwn layers for added strength. From there I just used 8" wide tabs to bond them into the boat. When you do your tabbing make sure that you stagger the edges. You do not want them to all end in the same location. a good 2-3" stagger is enough.

Again let me suggest that you do not cut out more then one stringger at a time and make sure that the boat has plenty of sapport under it so that you do not loose the shape of the hull.

Re: Question for the fiberglass experts.
 

It sounds like the glass strength type constrution like a Chris vs a Baja of the 80's. Wood was only used as form for sringer cofiguration. This is a good combo for easier repair. All the filler suggestions above are good. Be sure to use the 12/1 ratio of grind vs patch. In other words what ever depth you grind in you have to spread that out as you taper it on an angle up to original height covering 12 times the depth.1/8" = 1.5" taper bevel to top. 1/4" = 2.5" minimum. More is better but not past 18/1 then you are just making a hard spot. Good luck, it is not hard and you will be proud of yourself when your done. drop a line to email it you want faster reponse I dont get on OSO much.

Re: Question for the fiberglass experts.
 

Gary, tried your email, but I think it is incorrectly listed in your profile. Check it out.

Thanks,

E.S.

Re: Question for the fiberglass experts.
 

sent you contact info

Re: Question for the fiberglass experts.
 

My 28 scarab needed two bulk heads and the stringers replaced from the fire wall into the cabin. I had to remove everything in my boat , from the motor and every thing in the bilged and the cockpit , floor and gas tank, all the way onto the cabin.

There was NO WAY I was putting wood back into the boat only to rot again.

I cut the tops off all the stringers and gutted the rotted wood out . I got about 25 gallons of Seacast and re filled all of them.

Think about it for a minute.

If the wood rotted why would you reinstall wood.

check out the seacast web site . Its lighter stronger and will never rot.

this is in a 28 Scarab with a 600 Hp motor that I beat the hell out off. Once the seacast was installed the boat is solid as a rock and faster than ever.

Check out there website. the video dose no Justice . the product has been improved and is easier to work with . If it wasn't for seacast I would of rather junked the hull.

Good luck

Paul

Re: Question for the fiberglass experts.
 

HotBoat,

I have looked into SeaCast, and even posted some questions on their site. Have had no responses yet. One of my concerns with the product was that they indicated that it was not recommended to use epoxies with their product, for example to re-cap the stringers that were cut open on the top. I want to use epoxy on my rebuild because of the added strength.

Any insight?

Thanks,
E.S.

Re: Question for the fiberglass experts.
 

Use Vinnylester. It gives you the benifiet of both. I find it MUCH easier to work with then epoxy.

Jon

Re: Question for the fiberglass experts.
 

Why would anyone want to use epoxy? Vinylester is far superior. Seacast is a pretty cool product. My friend has done a few transoms with it so far with very good results.

Re: Question for the fiberglass experts.
 

How so, maybe I am a newbe with this stuff, but what are the pro and cons of each?

Thanks,
E.S.

Re: Question for the fiberglass experts.
 

Vinylester is better than polyester but not even close to epoxy. If you don't care what your boat weights. use seacast, but if you do you will use a foam core and SLOW CURE epoxy. the slow cure will allow the air bubbles to escape... Epoxy will stick far better than vinylester and is alot less toxic.

Re: Question for the fiberglass experts.
 

Let me start off by saying that I do not have the desire to argue with anyone and I am NOT an "Expert" in fiberglass fabrication. OK...

I used epoxy, West Systems in fact. Google the name and call their tech line. They will give your all the info you ever needed and then some.
Epoxy is FAR stronger than vinylester. Plywood is/has been used in boat constuction for years and is reliable and cheap. The Seacast product was interesting to me and I considered it. The didn't because it was too difficult to plug all of the holes in my transom and the cost was significantly more expensive than the plywood/epoxy route.
My opinion (Everybody has one of those, too) is to cut the top of the stringers, hog out ALL of the old wood, cut new wood, use West epoxy with their powder glue to thicken and then install. Use your engine mount holes to locate a clamping system in order to maintain a straight edge and uniform bonding.
If you are mechanically inclined to attempt this yourself, you can accomplish the job. It's really not that difficult. i redid the transom in my 33 Fountain. It was my first and I would put my work up against anyones (I'm just an average backyard wrench). My total cost for the project was just under six hundred bucks.

Tell you what. Get the area stripped of all mechanicals, buy the materials, send me a plane ticket and I will help you build it.

Re: Question for the fiberglass experts.
 

How does this look? Allmost empty to the bow. You can see all the pics on my "Carrera 24 Project" thread. Where should I send your ticket? :D

E.S.

Re: Question for the fiberglass experts.
 

Eric,

Nice meeting you, and BS'ing today. Gotta get together for :drink: when we have more time(my girl is just as impatient :D ). Whatever you do, if you need a hand, let me know. By the way, great idea on the cabin/bow pads, I think I am going to go that route.

Rick

Rick

Re: Question for the fiberglass experts.
 

Same here. Keep my number if you need a help on anything once you start putting that bad azz Pantera24 together. You got a deal on that one. Looks awesome.

My girl is from Brazil and being that she has never riden in a powerboat, she does not know what all the big deal is about. Only time I have really seen her take notice, was one time we were at Pantera and she saw Jo's raceboat being worked on. She keeps going on about that big black speedboat with the green eyes on the side. Well at least she has good taste, in boats as well. :evilb:

E.S.

Re: Question for the fiberglass experts.
 

Epoxy is definatly stronger and has less fumes.

The problem with Epoxy is that it has a very slow cure time so it takes a lot longer to finish a job, It is much thicker so you really have to work to get it to saturate into the glass. This often causes people to use more resin then they otherwise would with poly or Vinnylester. There is also a huge cost difference btwn the two. If the utmost strength is needed then Epoxy is the way to go no doubt about it. If you are doing a job like this then Vinnylester is stronger then new and more then ample. It has very good secondary bonding characteristics. Another consideration is that if you plan to paint over the Epoxy then you have to use something that will not react with it. Any Vinnylester or Polyester based paint will not work for you. There are ways to do it but it adds to the work that you have to do.

As for the Foam, wood, or what ever to replace what was in there I just would need to know why it got rotten in the first place. In my boat is was very obvious as to why it rotted. They never capped the tops of the bulkheads. Now that is done It will not rot again in my life time. You can also use a Marine Mahogony Plywood that is designed for stringers. This wood does not absorb water like a lot of the others. Foam is of course the best but again it ads quite a bit to the costs.

Jon

Re: Question for the fiberglass experts.
 

Minx,

You can PM me. I'd take a trip to FLA anytime, esp. this time of year. I'd rather take a trip for the booze, but there is always time for that...