Sanding, stripping hull to gelcoat - cost/time?

[Deltasailor]

Take care not to inhale the sanding dust. Poison!

[ramblinrod]

Originally Posted by hsi88

I own a Catalina 30 that I would like to strip down to the gelcoat so it can be faired and painted with a barrier coat. The quote I got from the marina was about $5K, with $3K of that for blasting the bottom. I got a separate quote for just blasting the bottom at $1500. Boat is located in a boat yard in Deltaville, VA. Have ready access to both electric and water.

Have given thought to doing the job myself. I have several sanders with vacuum attachments. I can also use a chemical stripper and scraper. Or perhaps sand and follow-up with my portable blaster, which is too small for doing the entire bottom of the boat.

The boat is 4 hours away. Don't want the job to take longer than perhaps a long weekend. Using 40 grit to get through the worst of it, I want to clean the boat quickly, basically doing most of the work myself. Any blister repairs and fairing would occur at a later date.

1) Can I sand the bottom to gelcoat in about 12-16 man hours?
2) Is chemical stripping worth the effort? Does it save time?
3) Should I just pay the guy to blast the boat for $1500.
4) Is there a faster or cheaper way to do this I'm not thinking of?

I saw some other threads that talked about doing this for bottom paint, but that is not quite the same as taking it down to gelcoat. I have no experience working with hulls painted with bottom coatings as all my prior experience has been with trailered boats. Any suggestions are welcome.

Thanks!!

This is one of the services I offer, and do several boats per year.

And it is one of those jobs that if you are gonna do it, you gotta do it right, or you'll have a whole lot of blood sweat and tears into it, for crappy results.

First things first, check the marina regs. Some will not allow you to strip a boat on their property. Others have stringent requirements for environmental contamination prevention.

If you are OK to go, place a ground tarp extending 5 feet all the way around the perimeter of the boat, and a skirt tarps from above the waterline to the edges of the ground tarps.

(This will prevent contaminating your boat, the yard, and other people's nearby boats.)

The best DIY removal method is carbide tipped scraper, followed by 60 grit RO sander.

Plan on 8 hours per day for 3 days at a very fast pace, working with your arms over your head all day.

Wear a full hazmat suit. (Tyvek hooded suit with boots, rubber gloves taped to the sleeves, full mask with organic respirator.) If you can smell it, the $#%$# is getting into your lungs, and that is bad.

If you hire a contractor to blast it, get a copy of their commercial liability certificate, and in writing that they will be responsible for any environmental clean up or damage claim. Talk to several others who have used them and are happy. (The vessel owner can be left on the hook to pay for professional cleaning of the yard and several boats.)

Take moisture readings of the hull, above the waterline (to establish a baseline reading) and below the waterline, about every foot, across and down the hull. (Best to draw a picture and record readings on that.)

Use a dremel or grinder to grind out any blisters. Do it now.

Allow about 6 months for the hull and blisters to dry out.

Recheck moisture readings and ensure below the waterline readings are near above the waterline readings.

If so, dust the hull off, and then wipe with acetone (2 rag method).

Apply one coat of barrier coat.

Fill all blisters.

Fair all blisters.

Apply 3 more coats of barrier coat, (alternating colours each coat to ensure 100% coverage).

Apply antifouling after performing thumb print test on final barrier coat.

In total, including doing under cradle pads, you will have 40 hours (min) and more likely 60 hours. Your costs, including safety gear will be about:

Tools: $400
Materials: $800

Do not use cheap anti-fouling paint! (Or you'll end up having to do this again 6 or so years down the road.) Top quality ablative paint will cost you far less in the long run.

There is absolutely no point in applying barrier coat over blisters you intend to repair later, you have to remove everything you just spent all that work preparing and applying.

If you don't have enough time before the boat goes in the water, just slap on a coat of high quality ablative, and leave the bottom as is until the next scheduled lay-up on the hard when you can do it right.

When it is done right, be very careful the first time you pull into a slip after launch, she'll coast forever after you shift to neutral.

[hsi88]

Originally Posted by ramblinrod

This is one of the services I offer, and do several boats per year. And it is one of those jobs that if you are gonna do it, you gotta do it right, ..... When it is done right, be very careful the first time you pull into a slip after launch, she'll coast forever after you shift to neutral.

Thanks for the reply. It was very thorough and really covered the steps I need to take if I go with a service or do it myself. I'm taking notes!
.

[hsi88]

Bought a few things to try out cleaning the hull. Also contacted the company to let them know I'm very interested in having them do the job. This stuff won't go to waste, I will pick up some experience and see for myself how hard this job is. I've sanded some old runabouts, but their bottoms were already pretty pristine thanks to being trailered. This will be a new experience!

[Martin S]

This one is tough to answer without knowing some basics. Have you owned the boat since new so know exactly what is on the bottom? How much do you value your time versus paying someone else?
Always assume it is worse than you expect.
I just had mine stripped back to the epoxy base layer as she is 18 years old and I had no idea what had gone before. I am glad someone else did it as several difficulties were encountered. Not all antifoul layers were as expected. Where labour costs are low, scrappers seem to be used even on the largert vessels followed by sanding. It is perfectly doable for this to be DIY, just expected it to be worse than planned and a miserable job. If it turns out ot be better...pat yourself on the back.

[hsi88]

Well, I had the bottom soda blasted. Mike Sharpe of Mike's Soda Blasting located near Annapolis MD drove down with his equipment and completed the job in about 5 hours. This included tenting, blasting and cleanup. I couldn't be happier. Easily saved me about a month of weekends (at the speed I work) and of course, saved me an aching upper body. Some small repairs here and there and its ready to paint. Took it down to the thin barrier coat that was already on the bottom and did no harm to some of the previous epoxy repairs. Price was reasonable, especially considering the long drive down to Deltaville VA from Annapolis and the high quality of the work. The boat might actually see the water this year!

[Three Sisters]

Great. Good to hear you are all-around pleased with the outcome.


What are your findings using the Citristrip pictured earlier ??

[hsi88]

Originally Posted by Three Sisters

What are your findings using the Citristrip pictured earlier ??

I did not try it. Had already committed to soda blasting and did not want to make a mess. I tried the scraper and have used sanders. Both take a lot of arm work for very long periods of time.

I have used strippers before on motorcycle tanks, but much, much stronger (Methylene chloride). Still took several coats and had some sanding to do. I'm just guessing here, but suspect it would have taken at least two coats to clean the bottom. Not sure if this stuff can be rolled. If not, you are talking about a lot of brush strokes, let alone the effort to scrape while the paint is soft. As others may have mentioned, the paint tends to re-harden as it dries. So LOTS of work compared to having someone blast the bottom in a few hours, with ZERO mess for me to cleanup and haul away.

I see soda blasting as the easiest and safest way to clean a boat bottom. Mike even brought some glass bead in case he hit some really tough spots. I use glass bead and water (vapor blasting) to clean motorcycle cases, so even this is safe for cleaning to gelcoat, just more expensive.

I appreciate the input of all concerned. I am trilled with the decision I made and it gave me an important lesson in boat restoration. Although I am still an avid DIY advocate, there are some jobs that are best left to those equipped to do the work. Had the boat been closer than 4 hours away, I probably would have done the work myself. But with the distance and the expense of travel, etc. these things added up and made the cost very comparable. I did some shopping, got lunch and came back to a finished boat. No aching muscles, no cursing and turmoil, priceless!

[Suijin]

I'm surprised Mike's quote was competitive with Deltaville's local blasting guy, even aside from drive time. I'll keep his name in mind for Naptown friends looking to get blasted.