Hull repair on 1990 boat

[500dollar744ti]

Last October I made a repair to my hull after an unfortunate encounter with a concrete drain underwater at an unfamiliar dock.
That was here, http://forums.iboats.com/forum/boat-...ut-fixing-this

Now I have a crack NEAR the repair I made last year. The crack appeared two weeks ago after a good long pounding in very choppy waters.

I made a repair to this new crack with 1708 bi-axle and CSM, using polyester resin that was probably 9 or 10 months old. I've heard the resin has a shelf life and I don't feel like the stuff cured with 100% strengh, mainly because it cracked again. Could the shelf life have affected my repair?

This happened at the beach and I needed to put some kind of patch over it so I tried marine tex, I was skeptical it would hold, and it did not.

I pulled the boat out of the water and towed it home.

I suppose my best course of action is sand away all of the marine tex since it's epoxy, then sand away the bad glass at the cracked area and try again? I am going to look inside the boat for tabbing that needs to be repaired because I don't have this problem on the other side of the hull.

When I push on the hull on the opposite side of the crack in the same general area (with lots of force), it has no flex. When I push on the side with the crack, it has some flex to it. I can only assume that some tabbing needs to be fixed or reinforced on the inside so the outside isn't flexing so much? I believe they call that hull 'panting' and I think the panting on the left side is what caused it to crack again.

Now I purchased fresh resin to repair this, I have CSM and 1708 bi-axle. Am I on the right track here?

 

[500dollar744ti]

Maybe I did a crappy job in the first place? Should I just tear out that whole section where I previously repaired it and do it over again?

 

[Woodonglass]

Ok a few questions. On the first repair, did you grind the inside of the hull and then wipe it down with acetone prior to putting down the CSM and 1708 Layers? How many CSM and 1708 Layers went on the inside and how big were they. Same questions for the outside repairs. Grinding and layers and washdown with acetone???

 

[500dollar744ti]

On the very first repair, last year in October, I layered the inside as follows, CSM, CSM, 1708, The outside was CSM, 1708, CSM, CSM,

Still on the first repair, this is what the hole looked like after sanding..

The crack that appeared 2 weeks ago was on the outside just about at the edge of where I made the first repair. I'll see if I can get some pictures of my current issue and where it is in relation to the old repair.

I did clean with acetone between all sanding and repairs.

 

[Woodonglass]

What kind of Resin did you use?

 

[jbcurt00]

Off hand it looks like your repair was confined to too small an area. Esp since in the 1st pix it looks like you can see fractured fiberglass almost out to the edge of where you ground.

In the 2nd pix are those air bubbles behind the new work (all the splotchy white)

 

[500dollar744ti]

^^^ That may be the case, either way I decided to start over here.

Today I sanded away at the bad glass and found the crack to be fairly large. I cleared out all of the glass from my previous repairs as well but I don't think it would be wise to make repair on top of repair on top of repair.

Now I have a gigantic gash in my strake that looks rather intimidating.

Here's what I got to fix

 

[500dollar744ti]

What kind of Resin did you use?

Polyester resin from fiberglass supply depot.

I am going to sand the inside and get a very large sheet of 1708 to glass on the inside tomorrow. Is it ok to start with 1708, then CSM, then more 1708?

 

[Rickmerrill]

Hum, the last pic is not showing up, do you have a pic of the new crack before any grinding was done? Is the crack only on the outside or did it go all the way thru? Did you add wax to only the final layer of gelcoat or to others? On starting with a large sheet of 1708, the first layer is just something to build upon. I guess 1708 is ok to start with, not really needed but you should be adding successively larger pieces for overlap so start small. If you want more strength add more layers to the inside where it doesn't show. On the outside you want enough CSM so you don't grind thru it, then some filler to get rid of any imperfections, then brush on several layers of gelcoat, different directions to cover up brush marks, wet sand with increasingly finer paper and buff.

 

[500dollar744ti]

I don't have a picture of the crack, it did go all the way through though. I found some delamination between the previous repairs I made, the newest crack happened between the first repair and the second repair. I tore out all the glass I laid on both of those to start over. I probably had air between layers or something.

When I made all the original repairs, I only used wax with the gelcoat.

Also, is there a good way to get the air bubbles out without using one of those rollers?

 

[500dollar744ti]

One other thing I didn't think about is that the Poly resin I was using had sat outside in my shed over the winter time and it would have been brought down below freezing temps multiple times. Can that cause an issue with the resin curing properly?

 

[Woodonglass]

Yup if it froze it was prolly no good. Since the crack is extensive I would use CSM as the first layer on the inside to ensure good bonding. I'd also use 3" strip first then 6" strip of 1708 then 9" final strip of 1708. Always roll the resin from the center out towards the edges and this should help get the bubbles out. Don't over roll it. Once it goes clear, it's done. Key is to get it sanded well and washed down with acetone to ensure a good bond with the previous glass AND make sure your resin is GOOD.

 

[Rickmerrill]

I was typing this while Wood was typing - sorry if it's redundant. On the air bubbles you can use a chip brush to chase them out. Start from the center and work them out by dabbing gently and keep enough resin so you're pushing a little wave under the glass. Remember to wet out the surface before applying glass. You could also soak the glass in a large disposable aluminum serving/turkey roasting pan first. On shelf life and freezing I haven't found a definitive answer so it's best to contact the mfg and ask them. Here is what USC says about their resin: "Shelf Life: When purchasing our resins we guarantee their performance for 3 months after your purchase if stored at room temperature with their lids sealed. These resins can last longer than our 3 month guarantee, but we recommended testing a small cup of the resin before using it on an important project. Also, if the resins sit for over a month, we recommended shaking the sealed can or stirring the contents to ensure all solids are properly distributed." And what they as about their MEKP: "Due to the short shelf life of this product we recommend purchasing only what can be used within 2 months." So you can see the age of the catalyst is more important.

 

[500dollar744ti]

I have started sanding the inside, this is what the hole looks like from the inside..

Also, on the sanding part of it, do I need to sand the original roving to a completely flat surface or will that take away from some of its integrity? In the above picture at the bottom left I have sanded the roving flat, to the right of that area (lower middle of pic) I have not sanded it flat. I stopped sanding because I didn't know which approach to take.

Would this amount of sanding be enough or do I need to go until completely flat? I haven't sanded it all obviously but I'm referring to the center area that has been sanded..

Also noticed the original tabbing is cracked/broken. (I already started removing the bad part then decided to get pictures.) I want to sand it and re-glass that as well, it probably happened because I was storing my tools in that compartment in my ignorant early boat ownership and the tool box bouncing around in there was too much for it. That is probably why the outer skin flexes when I push on it.

In this next picture you can see the tabbing where it is bad but is the stringer supposed to be that far away from the hull? It's like a half inch away from the outer skin, the only thing that would have been connecting it is the woven mat fiberglass.

I would like to do the 'filleting' I think it's called when I do the tabbing, what do I need to make that nice rounded filleting so I can glass at a nice angle over it?

 

[Rickmerrill]

Not able to see the pictures on my ipad or my pc. For fillets (Peanut Butter) Wood's recipe is 1qt resin, 1.5qt Cabosil and 1/4 cup 1/4" chopped strand and use a large plastic serving spoon dipped in mineral spirits or acetone. You can adjust the Cabosil to get the thickness you want and only catalyze to the amount of resin used. Try to get it as smooth as possible.

 

[500dollar744ti]

Can anybody else see the pictures or do they only show up on my machine?

 

[jbcurt00]

Can anybody else see the pictures or do they only show up on my machine?

They are cached on your machine, so you see them, but nope, no pix.

Use photobucket & copy the IMG code for the pix you want to post. It looks like this:
IMG]http://i1246.photobucket.com/albums/download_zps9151c21b.jpg[/IMG
And pix show up IN your post rather then as attachments:

 

[Rickmerrill]

The unintuitive part to me is that you just paste the IMG link right into your text. Even if you get an edit/DB error just refresh, pic will be there as jb said, IN your text. Thanks jb, during the upgrade got my signals crossed and started trying to upload pics. I could see them on the PC but people kept saying they didn't post. Then I looked on the ipad and they weren't there. I figured since I could only see them from the box I posted from something like caching was going on.

 

[500dollar744ti]

Okay! I uploaded the pics to a site and pasted the img links on the first page! Can everyone see the pics now?

 

[500dollar744ti]

I want to fillet the strake where I'm making the hull repair, since I have a hole there now, how would I do that? One base layer of CSM then fillet and continue laying up on the inside? Or should I layup all my inside layers, then make a fillet and glass over that? Or just not do it at all.,

This area needs to be as strong as possible between the two stringers, I don't want to have a problem again.