Stringer Repair with Epoxy and Woven - how many layers?

[Davetv1423]

i have a 20' sleek craft im redoing from stringers to transom.
gutted floor and the single (yep just 1) 2x4 stringer, ground 4" on both sides of new stringer "area" and wiped down with acetone

Currently have:

Wetted out and laid down 4" of woven roving in center of boat - let sit for 20min with epoxy resin.
Laid in my new pine 2x4 at around 10', then 4' and another 2' to get/deal with hull bend.

Immediacy after this tabbed both sides of this 2x4 with 24oz woven r with a s ton of high grade epoxy resin, then did the further 4' and then 2'.
Project took all of my 1.3 gallons of Epoxy i purchased for $94 bucks also but looking at the work now i see much more was used than needed and this was also done on Thursday and i felt it today (sat) and some of it is til tacky and even some very wet....>??????

Boat mech/repair buddy of mine saw the original single stringer and was shocked so he suggested "Boxing" in the rear if planning on going high HP (like over 150 to 250). So taking this advice and running 2 2x2 pines up 4' each side of the main stringer in the ready chimes.

*First time doing stringers but have built some bolster seats prior.
*Front of stringers (bow) i know is a disaster - and need a solution (saw-zaw tip off then cover with>?).

Any comments welcome - but main questions are:

-how many layers of woven do i need with using epoxy???
*I've read prior woven is overkill for stringers, but also that others are using "multiple layers" of other product.

-if i need to add another layer am i having to sand anything to do this?
- i hear epoxy sticks to anything
- i also have some exposed 2x4 form being exhausted (over) the job doing this all at once / along with 2hrs of grinding.
-so can i wet out only this top 2x4 or do i need to cover it with another 4" or 6" or 8" strip of woven (i bough strips of 8")...

-another question would be seeing How (#@#+% expensive Epoxy is - can i used Poly Resin for the 2nd two stringers....?
*asked the fiber company and they said if i knew the original manufactures choice or product i could but if i didnt - to use epoxy (hence, said the company selling it to me

- suggestions there?

-last question (beers on me

- i hear about boat "hooking" and am concerned. Boat is already blocked with 5 pillars - see pics.
Prior to the main stringer ad i did level it 100% from star to port if that helped. Not looking or a "blueprinted" boat nor plan on running close to 100mph just don't want to spend 100+hrs and $3k on a boat that runs sideways....

Any and all help, comments (good or bad) welcome - thanks so much.
Plz also see pics -
Dave

 

[Davetv1423]

here are my pics

 

[ondarvr]

Stop and throw out just about everything you've heard about using epoxy or doing glass work.

​Don't use more epoxy than necessary to wet out the glass, epoxy alone does not add strength, you need the glass.

​If it's still sticky and wet then something is wrong, like not being mixed correctly, which means you need to remove all the suspect laminate.

​No you can't use polyester now, you went epoxy and need to finish with it for any areas with epoxy on it now.

​The fiberglass place you got the info from doesn't know much, you could have gone typical polyester for thing from the start.

​Don't use pine, get exterior grade plywood at least.

What weight roving did you buy?

​Roving isn't over kill, but there are better products to use with epoxy

 

[Davetv1423]

here are my pics =transom is next / started also...

 

[Davetv1423]

i hear ya.. and thanks for the feedback.
i used pine 2x4 because it was more pours than pressure treated to soak up that resign.
the woven was 24oz
did buy marine grade plywood for the floor and used poly resin and CSM on both sides.
when mixing i used a speed drill on high with a paint mixer for 1 -2 min... (did you mean ratio of resin to hard was off or just not mixed "enough")..?

 

[jbcurt00]

Resins (epoxy or polyester) needs to be well mixed, in the right ratio, and in the right ratio for the working temps.

So if the epoxy, 2 or 3days later, is still WET, not just slightly sticky, something went wrong. Old epoxy resin or its hardener, can also effect curing.

Hard to pinpoint what went wrong, remotely via the internet. Any of those factors could be the problem.

 

[archbuilder]

Dave I have to agree with JB and Ondarvr, something for sure is wrong with the mix or the epoxy. As bad as I hate to say it, It needs to be redone. I was happy to see another Sleekcraft on here! Nice looking boat!

 

[archbuilder]

By the way to answer your question, a lot of people use 1708 biax for stringers and structural work. A couple layers of that would work fine, and its much easier to use that woven.....that stuff is a pain! I don't use epoxy for glass work, but there are some good suppliers out there. West Systems and System 3 have really good products. I have used some of their products for different applications and have been very happy.

 

[ondarvr]

Your best bet is to start reading threads here on stringer repairs (there are hundreds) and look at how they did it and the materials used, this will give you a good idea of what to expect.

 

[lckstckn2smknbrls]

Pressure treated and exterior are 2 different things.
​You should be doing the transom replacement from the inside of the boat.

 

[CrazyFinn]

Pressure treated and exterior are 2 different things.
​You should be doing the transom replacement from the inside of the boat.

This comment made me re-read what you have posted... Dave - are you planning to do the transom AFTER you do the stringers? How?

The usual method is to do the transom first, from the inside of the boat, so you don't have to re do the outside gelcoat or finishing. Then you do the stringers so they are tight to the transom.

Never mind - just looked at your pics and it looks like you have already peeled the outer skin off. It can work that way, but requires a lot more precision glass work and finishing...

And pressure treated has no place on a boat. Normal spruce/fir exterior grade plywood works just fine, along with poly resin, 18 oz weave with a mat backing works fine for the glass. I think that 24oz roving would be a pain to work with...