Boat Buzz

I used to do auto body and paint but I know nothing about gell coat. I have a lot of spider cracks on the top of my hull. Can I just sand down it down to the fiber glass then prime and paint it. Is the spiders just the gell coat alone? I am going to sell the boat so I need to keep my cost down. I am going to spray the top a metalic blue can I use automotive paint and primer? Like I said I really need to keep my cost down. Thanks Roger

Hi Roger,
I noticed that nobody replied to your post so I'll share with you what I know.
Your spider cracks are probably confined to the gel coat and are not a structural issue however these are tough to get rid of permanently. These spider cracks happen because there's flexing in the fiberglass below the gelcoat and even though you can use body filler to make them dissapear, they will most likely come back. Automotive paint works great on fiberglass, just think Corvette. I know you're trying to make it look good to sell but it would be a dirty trick to "fix" it in this way. A more permanent fix would involve backing up the glass in that area with a structural support of wood followed up with glass mat and/or roving around it, then v-grooving the spider cracks or if this affliction covers a large area, grinding the gel off of the whole area down to the mat and re-gelling or if the area is to be painted you can use a high quality filler to replace the gelcoat there.

Craig

If I understand you right you are talking about reinforce all the top section with wood and glass mat underneath> I have spider cracks even on the edges this sound very difficult. I just want to sand down to the fiberglass and repaint it, I wont be able to do this successfully? Like I said I just want to sell the boat. I guess I am confused with your answer. I just want simple to sell. Thanks Roger

Hi Roger,
Sorry about the confusion. What I meant was to put some king of reinforcement like plywood on the back or inside of the existing fiberglass if you can get to that area in hopes of strengthening that area before you fix the outside part that shows. Then you can use a body filler (preferably one with "hair") on the outer surface and follow up with paint. This type of repair should last as long as the rest of the boat without new cracks.

Craig

I have a hatch on top of the bow so what you saying it reinforce the flat part of the bow on both side of the hatch so it doesnt flex? I have spiders clean down both sides of the top clear to the back of the boat edges are really hard to get to. I think I see what you talking about if you had an inclosed bow and just want to reinforce the flat side of so the bow wouldnt flex. But this is different. My question if I sand down all the gell coat to the fiberglass is the fiberglass going to have the spiders too? Or is it just the gell coat? Thanks! Roger

Ideally if at all possible you should strengthen the under side of the area where the gelcoat is cracked but as you say this may not be possible due to limited access.
Unless there is real structural damage to the area, the cracks should be confined to the gelcoat layer and if you grind down through the gel to the mat the cracks will be gone.

Ok that is what I needed to know. What grit sandpaper should I use? Thanks for your help Roger

Initially you can go pretty aggressive with 36 grit, 40 grit or 60 grit but as you get down through the gel you want to finish up with about 80 grit.
Just go slow until you get a feel for how fast you're removing material, 36 grit is VERY aggressive and a good way to remove a lot of material very fast and you can get in trouble equally fast. The determining factor is how thick is that gel coat? you won't know until you start grinding.

Isnt is going to ruin the fiberglass underneath if I take grinder to it? Shoudnt I take a electric sander with 180 wouldnt that be better the fiber glass is not real thick on the boat. Sorry to be a pain in the butt . But it sounds like a grinder would do more harm than good or is the gell coat really hard? I just dont know thanks Roger

You'll find that the gelcoat is quite hard and you would probably never get through it with that fine a grit. If you weren't trying to remove the gel but just prepping it for paint that would work great but you'll need something more aggressive for the project that's ahead.

Ok that answers my question. I will try a finer grit disc first untill I get comfortable with it. Thanks for putting up with me this is all new to me. Roger