Which Epoxy Fairing compound and buying a longboard?

[Hoist]

I am currently restoring 2 GRP yachts which have some bad scuffing in the gelcoat.

Luckily none of this has broken through the gel however I am going to have quite a lot of fairing and filling this winter.

The size of affected parts ranges from 6" to 18" so I am looking for a good epoxy fairing compound that will work well in the cold shed.

I've also heard about longboard sanding devices and although they look torturous, I think a good one might be essential to get the finish perfect again.

Does anybody have any hints or advice.

The paint I will be using for the finished article is International Perfection Pro.

The epoxy compounds I've found available so far are the awlgrip and the Hempel Profair.

I am leaning towards the hempel as it has more info and specifically states its for GRP and flexible.

 

[Boathook]

I read somewhere, possibly this forum that someone used a car repair fairing compound for some small scratches as it was quick drying, use straight out of the tin, reasonably tough in that car panels do flex and was or seemed OK with 'all paint'.

 

[anoccasionalyachtsman]

I used West 407 for the first time this year, and found it surprisingly easy to fair with a 1/4" ply longboard. I saw no need for power tools other than taking the big drips and 'trowel lines' out.

Re: car body filler - many people on this forum repeat that it isn't waterproof. I've used it on keel repairs a few times and it's still there so I'm a bit sceptical. Not nearly so nice to fair though.

 

[Blueboatman]

Long board , you make yer own ! Eg 10mm plywood 100mm wide with a bought roll ( or two!) of quality sandpaper and a couple of 100mm bits of wood across the back face of each end , screwed through to clamp the sandpaper.
When I removed our teak deck and faired the bare grp substrate , I used a board 450mm long, for example .

My previous boat , I did hull work : I modified the stern shape and lengthened it a bit, so I used a correspondingly much longer fairing board because fair topsides are the ‘ make or break’ of this type of work .

You may want to try a 6mm plywood too where curves are a little more tortuous.. make, play, experiment, there is no one answer !

As to fairing compounds . In my quite limited really experience compared to say someone who does this for a living not for ‘ pleasure’ haha, just use any half decent reputable epoxy and use quality fillers . I really rate West systems additives and they are readily available in er larger containers..

And then finish off with non additive added epoxy barrier /sealer coat(s)

Many ways to skin that cat?

But, epoxy is your new friend !

 

[Bobc]

Probably the easiest to fair is an epoxy such as West or SP with microballons as a filler. You mix up the epoxy, then add the microballoons until it looks like Nutella. Apply with a scraper.

If you have large areas that you want to fair in, then SP hi-build filler/primer thickened up with microballoons is good for this. Do make sure though that you let each coat dry and set properly before adding the next coat, or you will get solvent entrapment, which will lead to bubbles appearing in the paint.

 

[fredrussell]

I once spent a whole day long-boarding an 8 metre race boat. Aye carumba! Graft. The boards we used were pro ones, made of fibreglass with comfy handles. Still had blisters a plenty.

 

[rogerthebodger]

Long boarding.

9mm ply 2.4 m long 100 mm wide.

40 grit emery paper.

Epoxy fairing compound.

 

[michael_w]

This might turn out to be one of those jobs it's better to pay someone else to do. Similar jobs include knocking up concrete by hand or digging large holes in the ground.

 

[Keith 66]

West with low density microballoon filler is what i usually use. As for longboards why? Fairing is hard enough work without making it purgatory, If you have bad arthritis working a longboard wont do you any favours!
I have two 18" ones rigid & flexy that take standard size body file strips, they are used just to give an indicator of where to sand. Use a black aerosol can to dust the surface & show where the lows are.
Then its Air file time or if there isnt enough air supply the Rupes long bed orbital sander, always work diagonally one way then the other, Random orbital sander with feather edge foam pad is used as well. Last boat i did this way was a 28ft foam sandwhich rowing Gig, singlehanded it was faired to a very high standard ready for paint in three days.

 

[Hoist]

thanks for the advice everybody.

here is some pics for reference.

I possibly made a mistake by sanding scratches into hollows but I am not shy from hard tedious graft

Ultimately I am not expecting show quality, but anything is more presentable than what was allready there.

At least the Gelcoat is close to triple thickness of modern boats

The below took us approx 6 hours with 2 people for above and below waterline

 

[Hoist]

Progress report. I am definately getting better at not making depressions.

Filling has started on the small area's with the normal plastic padding stuff.

Still undecided on which product for the large area's which I have marked with the hashed points. These are larger depressions that I think are too big for normal filler.

 

[James W]

410 microlight. VERY easy to sand.