Hull repair, gel coat damage down to fiberglass

gatorfan6908

Petty Officer 2nd Class
Joined
May 17, 2010
Messages
149
For the nitty gritty:
1980 SEA OX 170
Outboard Boats
Length: 17'
Hull Material: Fiberglass
Beam: 6'
Engine: 1982 Mercury v6 90hp
Net Weight: 1100 (more with gear included)


Alright, there will be pics posted later, but since I am at work, I cant upload anything to this computer...
_After further exploration of the twisted world of repairs this boat is in, I found extensive damage to the gelcoat all the way down to the fiberglass, mostly on the front of the hull down the centerline. It runs from about the top waterline all the way to the bottom of the boat. Further to the rear, I found other areas where there are extensive scratches, gouges, and a few damaged areas down to the fiberglass. It looks like it was run aground ALOT. I cannot find an area where the fiberglass itself is damaged or has a hole, and I do not take on water when it is in the lake. It does not look like there is any core material in this boat.
My main question is what is the best way to repair the structural integrity of the gelcoat. I have read about hull repairs whereas there was a hole cut out, and reglassed in and applied with new gel coat. I do not believe that this is that extensive because I feel that it can just have resin and gel coat reapplied.
Also, is there any chance that water may have seeped inbetween the interior fiberglass and the gelcoat since the fiberglass was exposed? I know that the stringers are rotten and have to be replaced, but I feel I should repair the hull prior to the stringers and the deck.
If I were to sand each and every one of the cracks, it would take months. Is it possible to sand larger areas on the bottom of the boat, repair them, and move on to another section?
I also dont know much about mixing any resin or what typical mixtures consist of, so any insight to that would be great. Please reply back with any input you may have. Thank you.

Also, the pics will be posted this evening for anyone who will want to see them.
 

gatorfan6908

Petty Officer 2nd Class
Joined
May 17, 2010
Messages
149
Re: Hull repair, gel coat damage down to fiberglass

Here are the pics I wanted to load earlier. I mainly just want to get the original finish with a scratch free surface. Especially in the areas where the fiberglass is visible.
 

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gatorfan6908

Petty Officer 2nd Class
Joined
May 17, 2010
Messages
149
Re: Hull repair, gel coat damage down to fiberglass

I have more photos, but for some reason I cannot post them. They are pics of the bottom of the boat. Anyone who knows how to post more pics would be greatly appreciated.
 

solar7647

Lieutenant Junior Grade
Joined
Apr 23, 2009
Messages
1,218
Re: Hull repair, gel coat damage down to fiberglass

Videos on gel coat repair
part 1
http://www.youtube.com/watch?v=iWEE6SFUdpg

Part 2
http://www.youtube.com/watch?v=en-8SbhdF_k&feature=related

Unless there is a visible hole or crack in the fiberglas I would say water seeping through is unlikly. I had the same kind of damage on my boat.

What I did was sand the area well and clean with acitone I then applied a healthy amount of 3M marine filler. Once it was dry I sanded it to regain the shape of the keel and then painted the bottom of the boat thus covering the repair. You could also cover the keel with a keel gard after repair. I would suggest that if you beach your boat alot. The 3M marine filler is rated for both above and below the water line and has a very strong bond.

You can use the same method of addressing the hairline crack but the cracks need dug out to open them up and then filled. You have to do that regardless of how you fix the cracks weather with filler or gel-coat. If you use the filler though you will be addressed with the fact the filler drys a light green add you will want to cover it. You can eather use paint or a thin layer of gel coat to get a close match to the rest of the boat.
 

Shife

Chief Petty Officer
Joined
Oct 22, 2009
Messages
404
Re: Hull repair, gel coat damage down to fiberglass

While it looks ugly, it is most likely just cosmetic unless the boat sat in the water and water started attacking the inter-laminate structure.

This is what I would do if it were my boat:

1. Liberally flush out damaged areas with acetone to help evaporate out any moisture. Wet out damaged/exposed areas with neat epoxy.

2. While still tacky, mix up some epoxy thickened with West 407 Low Density filler to peanut butter consistency and fill voids.

3. Sand and fair cured 407. You will most likely need to apply a second coat of 407 to fully fair the surface. Do not use anything lighter than 407 as a fairing compound for this as the risk of moisture absorption becomes too high.

4. After final fairing roll on a coat of neat epoxy. Apply a second coat while still tacky. This will seal the laminate and filler from absorbing water.

5. At this point you need to cover/paint/gelcoat to prevent UV breakdown of the epoxy. If you were careful and taped off the surrounding areas you could most likely cover the repair with a Keel Guard. That would be my first choice as it would not only cover the repair it would prevent you from ever having to worry about it again. My second choice (assuming boat kept on trailer and not stored in water) would be a two-part paint such as Interlux Perfection. My third option would be to re-gelcoat the area.


That is just how I would do it. There is more than one way to repair this damage. Some methods will be good and some will be a waste of your time and money. You're likely to get all sorts of advice on this site, so I suggest you research the subject (research as in learning about proper repairs of this nature from industry experts, not by asking Joe Sixpack here) and make your own best decision. I highly recommend picking up a copy of Don Casey's This Old Boat. The book is easy to follow and does a great job of covering the vast majority of the usual recreational boat repairs.
 

gatorfan6908

Petty Officer 2nd Class
Joined
May 17, 2010
Messages
149
Re: Hull repair, gel coat damage down to fiberglass

Well, here is the deal. I bought some marine tex epoxy putty, im not too sure about the mixture, I believe it is 5 to one, not too sure if that is right or not.
ANyhow, my plan is to put enough onto the hull, more than what I need, and then I will sand it down to the form I need it. Is it better to do little at a time? because I dont have that much marine tex, and dont want to do too much @ one time and waste it. Any tips and tricks to using marine tex epoxy putty would be welcome. I have all the supplies I need to take care of it all. Thanks for any help!
 
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