Sanding the bottom of a H31

timtim · Mar 21, 2013

McZube, I just finished sanding all the way back to gel coat on a 26' S2 and it took me a good two days. Used a electric 5' sander with vac attachment. Also had cyclo bucket to catch most of the paint and dust before it gets to vac. I hope not to have to do it again for a long time. I was told boat yard could have media blasted it for about $900.00, wish I went that route. sander $60.00, vac $75.00, Filters 3 @ $15.00 each, sand paper $50.00, drop cloth $10.00, mask and eye protection $40.00, my time priceless!
I think the painting will be the easier step of the bottom job.
I'm learning a lot with my first sailboat, always something to work on.

Mike Culik · Mar 21, 2013

Hi McZube,
Buy a Makita 5” orbital Model BO5030K (single speed) the variable speeds burn out!
Buy 36 and 80 grit hook-n-loop disc’s (you can get them online in bulk cheaper but then you have a box or two sitting around).
Use a standard shop vacuum but get a Gore style hepa filter for it or you’ll burn the vac motor out with the copper dust.

I sanded, barrier coated and painted my H25.5 two times in the last 8 years and my H31 August of 2011 when I bought the boat…including the iron keels.

My first experience was with a Sears HD variable speed 5 inch orbital sander. It lasted 10 minutes!!!!! Replacing that (warranty) with the same exact model resulted in exactly the same results. Fortunately my marina rents Makita sanders and vac systems for us “do-it-your selfers”. That got the job done…two afternoons, one per side for the H25.5 because that was all the contorting I could take at a time.

So for the next time on the H25.5 I had bought a Makita Model BO5030K and hooked it up to my Sears HD shop vac with 10ft of 11/2” hose and 10ft of 2” hose. I also replaced the standard filter cartridge with a Gore hepa filter..and wow the whole combo worked great!

Fast forward to the H31. Because of the extensive blister repairs (West epoxy materials), keel refurbishing, fairing and re-sanding it took 4 weekends of prep and 2 weekends to barrier coat and paint the keel and bottom with the help of my very competent sailing partner.

Two other notes: 1. Get a good respirator 2. Take your time and do it right…there’s way too much cost in coating materials vs. your time to have it peel or flake off prematurely.

Regards, Mike

richk · Mar 22, 2013

If the paint on the hull is soft (ablative) why not try wet sanding with a drywall sanding pad? This avoids the dust problem and I've been using it for the past five seasons...much easier on me and the marina.
Rich

Tally Ho · Mar 23, 2013

How careful do you have to be about digging into the gel coat? I was looking at a bigger boat today (if I can sell mine), that has a failing bottom paint job on it. Marina guys says it would be $5,000 to take it all off and redo it. I assume they just mean strip it down to the gel coat, seal and paint it...I would be up for doing it myself, but, worried about sanding into the gel coat....

tomgrigsby · Mar 25, 2013

Tanqueray said:
How careful do you have to be about digging into the gel coat? I was looking at a bigger boat today (if I can sell mine), that has a failing bottom paint job on it. Marina guys says it would be $5,000 to take it all off and redo it. I assume they just mean strip it down to the gel coat, seal and paint it...I would be up for doing it myself, but, worried about sanding into the gel coat....

5K? You should talk to another marina guy. Hauling, fairing the existing paint rough edges, 2 coats of good paint and relaunch for saltwater here is in the neighborhood of $1,200.00 If the stripping alone was $4,000.00, that's 40 hours at $100 per hour. Wouldn't take anywhere near than long to strip regardless of whether sanding, solvent stripping, or media blasting. $5K is criminal. Or, things are more expensive there. :neutral:

Tally Ho · Mar 25, 2013

tomgrigsby said:
5K? You should talk to another marina guy. Hauling, fairing the existing paint rough edges, 2 coats of good paint and relaunch for saltwater here is in the neighborhood of $1,200.00 If the stripping alone was $4,000.00, that's 40 hours at $100 per hour. Wouldn't take anywhere near than long to strip regardless of whether sanding, solvent stripping, or media blasting. $5K is criminal. Or, things are more expensive there. :neutral:

Good advice. Thanks.

Amos Cape · Mar 25, 2013

That is way to much. I'm having my Hunter 30' done on Tuesday at $150 per hour and should only take 3 hours. Then the cost of supplies. Good luck!

Jared1048 · Mar 25, 2013

1985 hunter 31 here. I just did this a few months ago and it was a lot of work.

80 grit paper and rental of a Fein sander at $70 /day. Took us about 3 days of sanding. We took our time and did it right. Professionals next to us complimented us on how good of a job we were doing and this was our first time.

we had some spots that we had to sand down to gel coat as the layer's above were still "soft". Same for the keel. We pretty much stripped the keel all the way down to metal. Used a metal primer for the keel then added new layers of barrier coat then anti-foul.

If you mess up or rush a layer then all the work above it is going to waste. Take your time and have a pizza party to recruit friends and family over to help. Its a lot of work but if you have 4-7 people working its not so bad. Be sure to read the instructions and follow the drying times between coats.

best of luck!

Jared

Ray Bowles · Mar 25, 2013

You need to be careful when sanding that you do not get into the gel coat or go through it. If you seriously get into it you ruin the seal coat or barrier cost that protects the bottom from water intrusion. A barrier coat should be at least spot applied to these areas.
Ray