bare fiberglass hull - how to proceed?

[willyd]

I'm looking for advice on a boat project. I have acquired a trailered 25' sailboat which the previous owner ground off the gelcoat and outer layer of mat on the entire hull below the waterline. I have found all sorts of advice on how to rebuild the hull with epoxy, but I'm looking for a cheaper solution.

Would it be OK to recoat the hull to replace the ground-away material with polyester resin (e.g., Evercoat Premium Marine Resin), then sand smooth and fair, or should I use a filler, such as Evercoat Rage or Evercoat Marine filler?

Also, bottom paint manufacturers like Interlux and Pettit have directions for applying bottom paint to bare fiberglass - this implies I don't need to worry about gelcoat, correct?

So, in my search for the cheapest way to get this boat back in the water - a layer or three of marine resin, followed by a few coats of, say, Pettit Unepoxy bottom paint - or would this be pure folly?

Thanks for any advice!

[the1much]

i'll probably be shot at,,,but,,heh,,if ALL they ground off was the first mat layer,,i would ( thinking of cheap AND safe) put 2 layers of matt (after grinding for you "mechanical bond") then this may sound like your spending more,,but you wont in 6 months,,anywayz,,then gel-coat the area,,,then apply your bottom paint.
the "mat" they ground off isnt there for "strength" its for the heavier layers to "hang" on to,,and so the fabric doesnt "print through" onto your gel.
i NEVER would recommend that anyone "just put on bottom paint" the crap starts wearing off the VERY minute you stick it in the water,,very LITTLE "water proofing",,,and when they say its a "barrier" paint,,,they just mean a "barrier" from green gunk and barnacles,,hehe ;)
o.k.,,,thats my 1.6 cents worth.
welcome to the forum,,and sorry i was the first ya met hehe ;)

[Landlubber]

willyd,

May I suggest that you start with a layer of 300 gsm csm, wet out and followed by a layer of 600gsm woven rovings, this will replace what was ground off ( one would assume it was because it was osmosiced).
After doing this, in the same day if possible, you then let it set (at least overnight) and then get a nice 8" random sander and lightly sand flat(use say 120 grit alumunium oxide frecut paper), smoothing out the lumps only really.

Then with a solventless epoxy resin, roll a nice wet layer over the whole bottom, repeat this process and then leave for a week. resand then.

Apply another coat of solventless epoxy resin.

Then , using an epoxy primer/fairing compound. roll another two coats onto the abraded surface, allow to set for at least a day, and then sand the whole bottom fair.

Reapply another primer coat of epoxy primer, then follow up the same day with your favourite antifouling. Another coat the next day and she is ready to launch.

Have fun, a 25ft boat is a nice size to work on, you never get tired of sanding as there is not much bottom on her.

[PAR]

Landlubber has it right, you have to seal up the mat or other exposed fabrics, which will not resist moisture working it's way into the matrix.

Fair it up with whatever fabric you like, then barrier coat the bottom with straight, unthickened epoxy or gel coat (not paint). Apply enough coats (minimum of three if epoxy) to insure it'll be water tight. Now you're ready for paint prep.

[willyd]

What's wrong with replacing the lost mat - a cosmetic layer - with filler? Is it a flexibility issue since I'd have to fill such a large area? The stigma of having a boat that's basically all bondo?

[the1much]

it'll crack in a year of flexing,,and if your cost is to be watched,, filler will be more $ and WAY more work.everyone else will give ya the"specs" i imagine
hehe ;)

[PAR]

Bingo, the Much . . .

[willyd]

i'll probably be shot at,,,but,,heh,,if ALL they ground off was the first mat layer,,i would ( thinking of cheap AND safe) put 2 layers of matt (after grinding for you "mechanical bond") then this may sound like your spending more,,but you wont in 6 months,,anywayz,,then gel-coat the area,,,then apply your bottom paint.
the "mat" they ground off isnt there for "strength" its for the heavier layers to "hang" on to,,and so the fabric doesnt "print through" onto your gel.
i NEVER would recommend that anyone "just put on bottom paint" the crap starts wearing off the VERY minute you stick it in the water,,very LITTLE "water proofing",,,and when they say its a "barrier" paint,,,they just mean a "barrier" from green gunk and barnacles,,hehe ;)
o.k.,,,thats my 1.6 cents worth.
welcome to the forum,,and sorry i was the first ya met hehe ;)
Why two layers of mat? Wouldn't the original lay up have had just one?

[the1much]

you need to put more on then you think was there,,,that way everything can be faired,,is NO way someone ground JUS 1 layer of mat,,so ya need more,,then fair to right thickness ;)

[willyd]

the1much - you're in Texas, so is my boat: so can I use your driveway to do this repair? That way I can just pound on the screen door whenever I've got a question instead of sending innumerable postings.

[the1much]

head over,,but driveway rental is $2.99 an hour hehe ;)
and info is free after a week rental ;)

[ratrace2]

the1much - you're in Texas, so is my boat: so can I use your driveway to do this repair? That way I can just pound on the screen door whenever I've got a question instead of sending innumerable postings.
Yea, don't fight the "much", just do what he says...........heheh

[mongo75]

Two layers of matt w/epoxy, not poly or vinyl resin, will do it right. You could do it cheap and quick, but you're pretty much destroying th hull in the long run. You pick your choice...

[willyd]

Thanks to everyone for their input. I've been looking at various sources on the net to determine what quantities I'll need of materials. My boat is 25' X 8', which X .85 gives 170 square feet of hull surface, according to the formulas used for bottom paint. If I use 170 square feet of 1.5 oz. mat, with 4 ounces of resin per square foot (according to fiberglasssite), that yields 680 ounces, divided by 150 oz./gal, gives me 4.5 gallons. For the first layer.

My question: how much more resin should I factor in for the second layer?

I'm assuming that the second layer will be laid up on top of the first, while the resin is still wet.

[the1much]

i dont know how ta do all that math stuff,,,,but,,,if your math says get 4 1/2 gallons,,,,then get 7 ,,,trust me,,,,you'll never use all ya resin in every bucket you make,,,then theres the "sh!t,,i jus stepped in the resin bucket",,,i'll let these other math knowledgeable dudes tell ya the rest hehe ;)

[ratrace2]

I'm assuming that the second layer will be laid up on top of the first, while the resin is still wet.[/QUOTE]

All at once, maybe I missed something......I thought you would do a layer: mat/rov then let it kick.
then do another layer of mat/rov.......etc....

[the1much]

man,,i typed,,then,,had to read every damned post again,,hehehe,,man its a big "meds" night,,,,but,,anyways,,,you should be doing all layers at once,,wet out,do a layer,,wet out,,do next layer,,and at same time be doing your next section over, so that everything lays flatter and are better "weaved",,,,i think,,,maybe i missed something or jus "confused",,but im sre the real epoxy dudes,,L.L. and Par,,and all will give ya better experienced advice.

[willyd]

I finally got possession of the boat and sort of did, sort of didn't follow your advice. Vinylester was nearly as low in price as polyester resin, so I went that route. I've put on one layer of 1.5 oz. mat and things went well, except for getting glass fibers all over everything I touched and ruining a pair of jeans that were on their way out, anyway. You all advised me to put back on two layers of mat, but with one layer on it looks pretty close to the old, pre-ground, level.

I read from Zahnisers' site that they put several layers of vinylester as a barrier coat on top of the mat. Is this just straight resin, or is something mixed in?

Also, how to do the last coat - can I just make a surface coat (w/wax or cure it by covering it in plastic), sand this when it's done, then paint? Or should this final coat have fillers mixed in? If so, which ones?