Major hull repair - paging the Glass Guru's!!

[hammerhead_77]

I've spent the last several weeks reading everything I could find on this site (a lot!) and others about doing repairs on a fiberglass boat... I'm hoping the gurus of 'glass will chime in here on my best path forward. Here's the background;

I was given a 1987 25' Bayliner Cierra. Its not the boat I want, but it is the boat I can afford right now... All in all, it wasn't a bad situation: ~422 hours on the rebuilt Penta 225D, 280 drive was overhauled 8 years (about 100 boat hours) ago.

This boat had an accident at some point that resulted in an impact to the starboard side...actually many impacts...I'm thinking perhaps swinging or drifting into some rocks over in Lake Havasu. Anyway, the original owner had some kind of repair done, but it looked like it was painted with appliance enamel instead of gel coat. The main repair spot felt "soft" and would flex, so I knew from my studies here that the glass was de-laminating. There were also two new gouges where my uncle (who gave me the boat) hit the corner of a post of some kind - I think while the boat was on the trailer...

Here's what i started with:


This is the spot with the bad repair...


I'm going to take a wild guess and say that there is probably automotive bondo under here instead of glass and resin.


Last and actually least, here is the gouge in bow... this is fairly straight forward since it is just a gouge, everything around it remains solid. no flex.



So.... I knew I had to do something about this. the boat isn't something i plan to have for too long, but I know if I get water starting to penetrate the hull I can end up with that delamination spreading...and since I fish offshore in mexican waters, i really don't like the idea of a flexy, soft feeling hull. After reading lots of stuff here, i knew that the only way to do it is to get the sander out and find out what's under there... and that's the part I would like the glass gods to take a look at. [to be continued]

 

[hammerhead_77]

Glass gods... tell me: how screwed am I? Am I doomed, or is this the way its supposed to go?

I started grinding it out and I found ... BINGO! automotive bondo and automotive primer. It became fairly easy to figure out where the delamination was by wat parts of the foam(?) came out like grains of sand versus the solid stuff.

This is what I found. the delaminated parts are obvious.... so I chased them until I found solid material... the inner layer is rock solid.


Here's what it looked like after i chased it all the way..everything in there is solid now.


a side view. i was a little surprised that the glass isn't thicker, but the inside layer is rock solid.

so, glass guru's: how does this look? do I just start laminating in layers of cloth and resin? Are these margins big enough?


any advice from those who know is welcome. My play is to glass this back up, build in some gel coat, and then shoot the top coat of gell over the whole side from the red part to the chine.

 

[Newbie@boats]

I don't know anything about fiberglass but it almost looks like a fork lift poked the side of the boat good luck! Im sure someone will chime in and you'll be on the water in no time!

 

[Corjen1]

Hammerhead, you might have better luck posing this in the restoration forum . You are on the right track though, there is a ratio of depth to scarfing that is needed for a structural repairs.

If you ask the Moderators, they can move this to the correct forum and the guys who do this regularly, and are way smarter than me, will chime in! Im pretty sure Woodonglass has the ration posted somewhere, I just cant remember at the moment.

Good luck!!

 

[jbcurt00]

Moved

 

[sphelps]

Your on the right track ... Can you get to the inside of the bad area's ? I am guessing multiple layers of 1708 starting small and each layer a couple inches bigger .. All wet on wet ... I have also seen and tried repairs, just not this large, starting with a large / full piece .. Then each layer a little smaller than the previous layers ... I prefer that way but I'm unsure of which way is stronger ...

 

[Woodonglass]

Ya dun rite gud HH77!!! Wipe em down with Acetone a go to town. Here's my recommendation for your layup schedule. For all your lay ups I'd recommend a CSM, 1708 CSM Layup. This will give you the strength and the best cosmetic look. You may need on additional layer of CSM depending on the depth of your "Dish Out" in your sanding. You'll then finish up with Fairing material and final sanding down to 320 grit. Here's how your layups on all the repair spots should go.

Blue- is a layer of 1.5oz CSM

Green is a layer of 1708 approx. 2" larger than the CSM Layer


Red is a layer of CSM approx. 2" larger than the 1708

As Stated if Needed another layer of CSM could be applied for thickness if needed.

 

[hammerhead_77]

Thanks much! I'm headed to the fiberglass supply tomorrow to pick up materials. Do you think I should expand those margins farther? We are looking at about 1/16th inch of gelcoat, 1/8th inch of glass, and 1/8th (maybe 3/16th) of foam (or matt?) Maybe 5/16th-3/8th total depth... not nearly as much as I thought it would be.

how should I plan on building up the Gel coat? i know the first coat or two without wax go over the repair and act as a bit of a final filler. I sanded the whole side with 240grit and plan to put the final coat on the whole starboard side from the cap to the chine... Anything else for me to think about here?

 

[Georgesalmon]

Just an FYI. I've been looking at your pictures and am pretty sure what you called "foam" that came out as grains of sand is actually a product called "coremat" (look it up). It was used both as a way to cheaply make the structure thicker and thus stiffer and as a pattern blocker for the 24oz woven roving or balsa core. Made of polyester threads and filled with microspheres. Anyway, the repairs suggested by Woody will solve your problem. You might need another layer of 1708 just where the coremat is missing (you can see where the white color is gone). Coremat was sold in either 2mil or 4mil and you want to make up that missing thickness with fiberglass. If you plan on spraying the gelcoat remember that you need at least 18 mils to hide the colors of glass underneath it. I suggest you use a surfacing agent (wax) in every layer and sand before the next layer. If you don't do that and want to sand and fair you will load up many pieces of sandpaper.

 

[gm280]

Once you get the layup that WOG suggested, you will be amazed how solid it is going to be. If there is still some depth issues, do another CSM layup. Once all that is sanded correctly, it will be very solid and secure. When doing the final sanding, use a long board with guide coat to feather everything in properly. JMHO!

 

[ondarvr]

George S is right on the coremat, you may just need to add a small amount of glass to replace its thickness. Although on adding wax to each layer of gel coat I'd say no, this complicates the process and slows things down. You won't be sanding on the first few coats, only the last one, adding wax requires you to thoroughly sand every layer because 100% of the wax needs to sanded off before another layer can be applied.

 

[hammerhead_77]

Georgesalmon - that's the stuff - coremat! it was really easy to find out how much to take out...its actually very solid in the places where it is still bonded. Not too worried at all about building up the thickness, I'll just keep adding layers as you and WOG suggested.


ondarvr - Thanks! That's my plan... I'll just sand the last coat. I'll be putting maybe two coats on the whole thing and extras where the new glass is going...

 

[Woodonglass]

Based on your specs, I would change the layup schedule to the following, 1.5oz CSM, 1708, CSM,1708, and Then 2 layers of CSM And yes I would knock it back just a bit further to allow a bit larger lay up. Just about 3 inches. You're gelcoat needs to go on about the thickness of 2 pennys and then sand it down to the thickness of one penny so if your patch is a little low the fairing material and gelcoat will blend it all back in nicely. Start out on the smaller patches and that will help you get the Knack for doing the repairs.:nod:

 

[hammerhead_77]

Thanks much, Wood! You are a rockstar...but you knew that! I hit the supply shop today, and I'll be posting pictures of my first layups tonight.

 

[hammerhead_77]

FYI...people who do automotive bodywork repairs on boats should be tied to chairs and beaten with hammers.

I spent the afternoon and several packages of sanding disks trying to get all the bondo, primer and appliance paint off the hull. gelcoat comes off in a hurry with a huge cloud of dust...this appliance paint just melts, smears, and gums up the sandpaper. Thought I would get the first set of glass on it today, but it took all my time to try to get through all the gooey paint.

 

[Woodonglass]

Try using a heat gun and a scraper!!

 

[hammerhead_77]

Today was good with lots of progress... I'll get some pictures up tomorrow. A scotch pad with acetone took that paint right off...would have saved me $20 of sanding disks if i'd have tried that first!

I got 4 layers up today: CSM-1708-CSM-1708. holy smokes, that stuff is STIFF! I'm amazed at how hard it got and how my ability to flex the hull by pushing on it went away within a couple hours. this is gonna be strong!

It went well with just a few rookie mistakes...

• one batch of resin kicked in the cup while i was trying to saturate the 1708...the sun was directly on it for a few minutes. Moved the mixing table to the shade and no further issues. Cost: a couple square feet of ruined 1708 and 8oz of resin...no biggie.
• found out how hard it can be to hold a piece of 1708 up while trying to brush the resin on...started saturating them on a sheet of plywood and them putting them in place. Cost: just some time and a little frustration.

Tomorrow I have to hit it with some 240 grit to smooth it out, and grind out one little air pocket that showed up in the last layer of 1708. After that its the last two layers, and its on to fairing and sanding, sanding, sanding...

A couple easy questions for WOG or anyone with experience:

1. when working on vertical surfaces like this, what is the best way to apply the resin without having the material fall down, the resin drip all over everywhere, etc? I'm just using a chip brush and then going over it all with a metal roller. Is there a better technique?
2. when I sand down the original hull, there is the white gel coat, then a nice thick layer of resin, then the glass mat. I know this was layed into a mold from the other side, but my material does not have that deep layer of resin...its just enough to completely saturate the cloth with a little squeezing out under the roller... Is that what the fairing material is going to do, or am i going to layer on enough gelcoat?

my many thanks to those who have given advice so far! I gotta say, as nervous as i was about starting this, it actually isn't brain surgery! If you can lay tile or set masonry, or do drywall, with a little advice and a lot of reading ahead you can handle fiberglass repair. Now, like those other things, it may not look like it would if WOG or some other pro did it...but I really believe that this is going to be strong, safe, and if i put in enough time with a sander and filler it might even look OK.

 

[gm280]

Today was good with lots of progress... I'll get some pictures up tomorrow. A scotch pad with acetone took that paint right off...would have saved me $20 of sanding disks if i'd have tried that first!

I got 4 layers up today: CSM-1708-CSM-1708. holy smokes, that stuff is STIFF! I'm amazed at how hard it got and how my ability to flex the hull by pushing on it went away within a couple hours. this is gonna be strong!

It went well with just a few rookie mistakes...

• one batch of resin kicked in the cup while i was trying to saturate the 1708...the sun was directly on it for a few minutes. Moved the mixing table to the shade and no further issues. Cost: a couple square feet of ruined 1708 and 8oz of resin...no biggie.
• found out how hard it can be to hold a piece of 1708 up while trying to brush the resin on...started saturating them on a sheet of plywood and them putting them in place. Cost: just some time and a little frustration.

Tomorrow I have to hit it with some 240 grit to smooth it out, and grind out one little air pocket that showed up in the last layer of 1708. After that its the last two layers, and its on to fairing and sanding, sanding, sanding...

A couple easy questions for WOG or anyone with experience:

1. when working on vertical surfaces like this, what is the best way to apply the resin without having the material fall down, the resin drip all over everywhere, etc? I'm just using a chip brush and then going over it all with a metal roller. Is there a better technique?
2. when I sand down the original hull, there is the white gel coat, then a nice thick layer of resin, then the glass mat. I know this was layed into a mold from the other side, but my material does not have that deep layer of resin...its just enough to completely saturate the cloth with a little squeezing out under the roller... Is that what the fairing material is going to do, or am i going to layer on enough gelcoat?

my many thanks to those who have given advice so far! I gotta say, as nervous as i was about starting this, it actually isn't brain surgery! If you can lay tile or set masonry, or do drywall, with a little advice and a lot of reading ahead you can handle fiberglass repair. Now, like those other things, it may not look like it would if WOG or some other pro did it...but I really believe that this is going to be strong, safe, and if i put in enough time with a sander and filler it might even look OK.

Hammerhead, Of course it will look great. If you know how to do auto body type work, this will come out prefect. And as you can now see, it is going to be extremely strong and solid. Amazing how fiberglass and poly resin works like that. I say you're doing it right. Post some puctures. We love pictures. JMHO!

 

[Woodonglass]

Roll your resin on with a 4-6" roller. I like these ...

Harbor Freight sells em CHEAP!!!

I always roll resin on the surface first and then stick the mat or fabric to the wetted surface this holds in place. I use the roller and start rolling from the middle out towards the edges to always get the wrinkles out. I use the least amount of resin possible trying to drive the resin from below up thru the cloth. I add more resin when and where needed. As soon as the mat/fabric goes clear, you're done!!! move on. People always have a tendency to use to much resin on the first coat. It's NOT totally necessary to fill the pattern of the fabric with resin. If you want a smooth surface lay a final layer of CSM over the top of the 1708 and it along with the fairing material will yield a smooth finish.

 

[hammerhead_77]

Ok, so we are getting close...
I've got six layers on the large repair: csm-1708-csm-1708-1708-csm ... all sanded down and ready to start fairing in. it doesn't show real well, but after sanding the heck our of the top two applications, its actually fairly smooth.



I am using glass beads and resin as the fairing material. nothing really exotic here, i basically treat it like bondo....layer it on and then sand it off until there are no high spots. again, I don't think i can make this look like any of the guru's on here would, but I'll tell you that it is now very solid where it used to be kinda spongy where the glass was delaminated from the core mat.

As the last thing tonight I finished fairing the small spots and layered two coats of fairing material on the big patch. the first one got knocked down with 120 grit before the second went on. I'll do 120-240-320 on the second coat tomorrow and then get things tee'd up for the gel coat. I'm planning on 3 coats of gel,..one spot painting where the repairs are, one on the whole starboard side, and then the final one with wax.