Deep narrow gouge.... MarineTex & gecoat?

[dkellogg3]

Hey all,

Made a bit of a boo-boo docking, and caught my neighbors swim steps (yes, I left a note offering to pay their repairs). I now have a narrow, deed gouge above the waterline. What caught me was the plate at the ladders hinge, so basically, I impaled my boat on a very dull knife.



Considering the poor state of the gelcoat, I'm not too worried about the appearance at this point, so for now can I clean it, and put some marinetex in there to restore some strength and make it watertight? Then when I have more time I'd sand that down along with a bit of the surrounding gelcoat and re-gelcoat the repair and buff out the haze from the rest of the gelcoat?

Thanks,
Don

 

[SWD]

Re: Deep narrow gouge.... MarineTex & gecoat?

Clean out any loose stuff, stuff with short hair filler, sand, refill, then repair gelcoat.

 

[DeepBlue2010]

Re: Deep narrow gouge.... MarineTex & gecoat?

MarineTex is not the right product for this. Grind the damaged glass and reglass using layers of CSM, 1708 and poly resin. Take a look at this video for details.

https://www.youtube.com/watch?v=6N7YMr6E564

 

[dkellogg3]

Re: Deep narrow gouge.... MarineTex & gecoat?

Holy kamoley that's a lot of work for one second's worth of a mistake..... man.

I'm not going to get the 1/12 repair area unless I pull the rub rail.... guessing I'll have to do that.

Short of doing the full repair now and putting off the start of boating season any further, is there something I can do to get me through the season?

Thanks,
Don

 

[DeepBlue2010]

Re: Deep narrow gouge.... MarineTex & gecoat?

I am always reluctant to give a band-aid type advice but since you are determined not to waste the season over it – which I totally understand – you might be able to get away with glassing over the gouge from inside the boat only with few layers of 1708 to stop the gouge from further breakdown under stress. You can use marine filer from the outside for now. Do a good job grinding and washing with acetone from inside and use progressive layers as in the video. This inside fix will be your backing plate when the time comes to fix it from the outside.

 

[Woodonglass]

Re: Deep narrow gouge.... MarineTex & gecoat?

Don't use Marine Tex if you want to Gelcoat later. MT is Epoxy based and Gelcoat does not like epoxy. Do you have access to it from the inside?

 

[dkellogg3]

Re: Deep narrow gouge.... MarineTex & gecoat?

Going to have to check backside access this weekend.

So if epoxy (marinetex) is no good should I do as SWD suggests using polyurethane?

 

[DeepBlue2010]

Re: Deep narrow gouge.... MarineTex & gecoat?

You can use poly filler to patch the outside (until you have time for permanent repair) after you support the area - glass it - from the inside.

 

[dkellogg3]

Re: Deep narrow gouge.... MarineTex & gecoat?

Should I grind down the inside enough to smooth it for a good bond, or should I taper it out to maybe 1/2 the thickness at 1/12 and do the progressively smaller sizes of mat? I'm thinking if the "final" repair will be from the outside, I need only to smooth it and then put maybe 2 or 3 layers on the inside - all the same size.

 

[DeepBlue2010]

Re: Deep narrow gouge.... MarineTex & gecoat?

Your choice, both will work. If you are going for roughing the inside and support it with layers of 1708, don’t make them all the same size. Cut square pieces with every one larger than the other, etc. Start with the smaller piece and add the larger as you go. You decide on the actual dimensions based on how much space you have in the back. If you don’t have enough clearance on any side (I think it would be the top side near the rub rail in your case), you can make the second piece of 1708 larger from the other 3 sides of the square.

 

[dkellogg3]

Re: Deep narrow gouge.... MarineTex & gecoat?

OK... now... is the West System epoxy or poly? Woodonglass indicated that gelcoat and epoxy don't mix, but from what I'm reading, the West System is epoxy... what gives? Should I be using the 105/206 combination for the resin/hardener?

 

[Woodonglass]

Re: Deep narrow gouge.... MarineTex & gecoat?

For this small of a repair and for just a temp fix considering it's location, I'd use some 3M POLY Resin, CSM and the 6 oz Cloth from Your big box store. Use a R/O sander and some 40 grit or a dremel tool to sand and bevel the gouge from the outside until it was about 6" in diameter. I'd cut CSM and the Cloth circles onto wax paper in progressively smaller pieces, wet em all out at the same time and paste em all on at the same time small one first. Kinda Like this... Sand and fair and paint with some rustoleum paint to get a fairly good match and go boating.

 

[DeepBlue2010]

Re: Deep narrow gouge.... MarineTex & gecoat?

WoodOnGlass is absolutely right about that. You don’t use poly on top of epoxy (the other way around is OK). When I posted this video link, I wanted you to see the techniques of how it is done. You don’t have to use the same material but the techniques are the same.

 

[dkellogg3]

Re: Deep narrow gouge.... MarineTex & gecoat?

Csm?

 

[Woodonglass]

Re: Deep narrow gouge.... MarineTex & gecoat?

Chopped Strand Mat

 

[dkellogg3]

Re: Deep narrow gouge.... MarineTex & gecoat?

Thanks.

Deepblue, if i saw it right, the video you posted earlier shows them installing the larges piece of cloth first, then working to the smallest, but the graphic Woodonglass posted shows just the opposite. From a materials point of view, it makes sense to me to go from small to big. If the big piece were first, tensile stresses in the skin of the hull would pull on the large piece and tend to pop the smaller ones out from the face. Maybe i saw something incorrectly in the video?

Thanks guys!

 

[DeepBlue2010]

Re: Deep narrow gouge.... MarineTex & gecoat?

If he started with the largest piece in the video, this wouldn’t be correct. Maybe the guy forgot to flip the stack. It makes sense to start with the smallest piece so the next layer is adding extra support to the total repair bond to the original laminate. If you start with the largest piece, the total quality of your repair is as good as the bonding of the first layer to the original laminate.

Here is another video from TAP that shows the correct laminating schedule


http://www.youtube.com/watch?v=SsoKAHU5xUw

 

[DeepBlue2010]

Re: Deep narrow gouge.... MarineTex & gecoat?

I went back and reviewed the first video link I posted from West Systems and it was not a mistake. The guy actually said “as in any structural repair, start with the largest piece first” This doesn’t make any sense to me at all. As I said, the bond of the repair will be as good (or bad) as the bond of the first layer!!

 

[DeepBlue2010]

Re: Deep narrow gouge.... MarineTex & gecoat?

I went back and reviewed the first video link I posted from West Systems and it was not a mistake. The guy actually said ?as in any structural repair, start with the largest piece first? This doesn?t make any sense to me at all. As I said, the bond of the repair will be as good (or bad) as the bond of the first layer!!
I went back and reviewed this book The Fiberglass Boat Repair Manual: Allan H. Viatses, Ed Davis: 9780071569149: Amazon.com: Books

Here is a snippet that clearly states that smaller pieces need to go first followed by the bigger pieces. The first video I posted a link to was wrong about that. I apologize for not paying attention to this mistake in the video before posting a link to it. If any of our resident fiberglass experts see a reason why we should start by the larger piece, please shim in.

 

[Woodonglass]

Re: Deep narrow gouge.... MarineTex & gecoat?

If you do it my way on wax paper or plastic then YES you start with the largest piece first. You are making the patch at the work table and then carrying it to the boat. You will apply all the layers in "One Fell Swoop" and use the wax paper or plastic and an bondo spreader to smooth the patch over the repair. So to effect the repair at the table you would...
1. Place wax paper or plastic
2. Largest piece of CSM
3. Second Largest piece of Csm
4. 1708 piece thats a bit smaller than piece #2 with the cloth side DOWN Mat side UP
5. Smallest piece of CSM
Wet out each piece as you lay it down
Pick it ALL up and carry to the boat and stick it on over the gouge, smallest piece first WaxPaper/Plastic facing out.
Use a Bondo spreader to smooth it out
Wipe excess resin and squeeze out off with Acetone soaked rag.
Peel Plastic/Wax Paper off when patch starts to tack up

I HOPE this all makes sense.:facepalm: