Cleaning and waxing (?) hull of DSll

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Cleaning and waxing (?) hull of DSll

Postby SCKDAYSAILER » Sat Feb 23, 2019 11:29 am

Just purchased a 1975 DSll and it is in need of a good cleaning. The hull is in great condition but it does need to be cleaned. What do all y’all recommend?


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Re: Cleaning and waxing (?) hull of DSll

Postby tomodda » Sat Feb 23, 2019 6:16 pm

What exactly needs to be cleaned off? If just mildew and general crud, wash it like washing your car. My favorite for cleaning is TSP, TriSodium Phosphate - you can get it at your local hardware store (wherever that might be, that big orange box store has it, over with the paints). It's a powder, mix it with water and go to town. Deep grime may require a power washer, easy enough to rent or borrow. A last washdown with paint thinner or mineral spirits (NOT acetone!) is good for final detail work. Mineral spirits in particular are really good for lifting bits of crud or adhesive off the surface, kind of lubricates them as you rub it off. And you may want a paint scraper, depending on what you're cleaning - plastic or metal scraper?, think it through.

If things are really, really ugly, you may want to consider sanding off a bit of the gelcoat with an orbital sander - start with 120 grit, don't press down too hard, just let the sander do the work. Go up to 600 grit, over even 1000 grit. Use fresh disks, you're only hurting your hull trying to "extend" a dull sanding disk. Estimate 2 disks per pass over the hull. A certain large online retailer from Seattle sells a nice assortment pack of sander disks, 240 up to 1000 grit, 10 disks of each grit, for 15-ish bucks. Don't sand thru the gelcoat! It's about a 1/4 inch thick (guess how I know?). Be extra careful at the keel. Anyway, sanding off the crud is only if it wont respond to less radical options.

Waxing... now you get into a real quandry. Are you going to race? If not, don't bother, IMHO. If you are trying to improve your times, wax is not necessarily the answer... As the parts of the boat where you're worried about water friction are - by definition - completely submerged, you actually don't want something that causes the water to bead, i.e. wax. You want something that causes the water to run in a nice sheet. Plenty of ppl want to sell you their "magic gunk." My suggestion? Forget that, get yourself a food-grade silicone lube spray (CRC makes one, $7-8 a can) and spray it on prior to your race. It will flake off pretty quick, but it's cheap and easy to apply. Why "food-grade"? Just my guilt at flaking silicone + god-knows what into the water. Silicone is no big deal, but I have no idea what they use as a carrier in the spray bottles from Auto-Zone. Just sayin'.....

Ok, there's my crazy ideas for a rainy Saturday. Best thing of all for hull cleaning and prep is, of course, elbow grease! :mrgreen:
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Re: Cleaning and waxing (?) hull of DSll

Postby GreenLake » Sat Feb 23, 2019 6:40 pm

Local marine store sells something called "serious soap". Mixed that at the prescribed ratio and keep it in a spray bottle. For when needed. Otherwise mostly just rinsing and using a sponge if visible dirt.

But it all depends on what your hull surface is like. Mine's been painted. If you have gelcoat of a certain age, that surface can get pretty rough and may actually soak up chemicals. 3M makes something called Fiberglass Restorer that combines a light rubbing compound with wax. That might be appropriate after an initial cleaning to buff out some of the roughness and seal.

Unfortunately, you can't use wax on seats, floors and decks. If rough and chalky after cleaning you could buff those out first with a rubbing compound and then something like 3M's FinesseIt II, which is a very fine polish that restores shine (well enough that you can use it polish scratched CDs).

I've waxed my boat on occasion, and have used FleetWax (a pretty hard wax from a can).

There are various products that add an acrylic layer that's long lasting, shiny and perhaps not as slippery as wax: NuGlass I believe was one of the brand names. Chemically, these are related to floor products like Mon&Glo.

Mostly though, I apply some liberal amounts of neglect and focus on sailing . . :D
~ green ~ lake ~ ~
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Re: Cleaning and waxing (?) hull of DSll

Postby GreenLake » Sat Feb 23, 2019 6:43 pm

May I recommend a publication here that I enjoy reading: Practical Sailor. They have actual product tests for lots of things used on sailboats. Even though they focus on keel boats of a certain size, much of it is of interest to dinghy sailors. When you subscribe, you get access to their long list of prior tests. Ad free. Recommended.
~ green ~ lake ~ ~
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Re: Cleaning and waxing (?) hull of DSll

Postby tomodda » Sat Feb 23, 2019 7:41 pm

Thanks for the tip on Practical Sailor. And I fully agree with you. Working on the boat is fun for wintertime. But as soon as it warms up outside (over 50F, at least), I'll be sailing.

Besides, with dirty hulls, you can't actually SEE it while you're IN IT sailing. Same theory applies to dirty cars...
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Re: Cleaning and waxing (?) hull of DSll

Postby TJDSII6630 » Thu Mar 21, 2019 4:36 pm

I'm in the short rows of doing the same thing. Here is what is working for me.
Put the boat on the ground and careened her so the upper side was at a comfortable working height.
Then I washed that side of the hull to remove any sand or grit.
Even aggressive compound was not very effective, so I wet sanded with a half sheet sander with 320 grit wet/dry paper.
Spray paper with lite oil and it will last longer in the water.
Use enough water to wash away the "sanding dust".
It won’t take long to learn a good pattern so you evenly sand the surface.
Work with short sections, about 3 feet long until you get that side looking pretty even.
I did one side at a time.
Mine had bottom paint so I only had to work on the side.
The molds are not perfect and time may have put little highs and lows in the hull.
I also noticed I could see the pattern of the roving in places so do not try to get it perfect.
Each finer grit will remove the scratches from the last as well as sand a bit deeper so do not try to get all of the fade out on the first try.
My boat is turquoise and had faded to about as light a blue as you could get.
Wash hull and repeat with 500 grit paper and again with 1200 grit, rinsing the sander between each grit to remove any course particles.
I still had some places showing fade and roving pattern but most of that came out with the buffing.
I got a cheap 8 inch buffer and a bag of pads that tie on.
I also got an aggressive buffing compound and a fine compound from a parts house.
Now is the time to be clean. You do not want to contaminate the fine pads with course compound or grit from the sander.
Again, buff in small patches with an overlapping pattern. If you cannot get the remaining fade out you can go back to the 1200 grit but be careful about sanding through the gelcoat, especially on the corners.

I do not agree with it being ¼ inch thick and would go with this information,,
which indicates .018 to .020 as best.

But, if tomodda has ¼ inch thick gelcoat……..
I did not go through but chips on my boat indicate the .018 to .020, but I did not put the mic on them.
A big hunk did pop off the top of the transom a few months ago and was every bit of 3/16 and I “glued it back with gelcoat, but, still be careful.
After you get tired of buffing with the aggressive compound clean the buffer, your hands, the work area or table, and hull to remove all of the compound residue.
If you get any of the course compound on the new pad or hull you will not get as good a final polish from the fine compound.
Now go to town with the buffer until you like the results, wash the hull and apply a good wax.
Repeat on the other side and transom.
Finally, go show off the new look!
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Re: Cleaning and waxing (?) hull of DSll

Postby tomodda » Thu Mar 21, 2019 11:09 pm

Great write-up on how to repair gelcoat! My 1/4 inch gelcoat was a guesstimate and in retrospect, way too optimistic. Maybe 1/8", judging by some spots that simply chipped off. But my boat is from 1957, the very early boats had very generous amounts of resin.

Bottom line, be careful not to grind thru your gelcoat folks! And old hulls CAN be restored with plenty of elbow grease and patience.
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Re: Cleaning and waxing (?) hull of DSll

Postby GreenLake » Fri Mar 22, 2019 12:32 pm

Very nice write-up, Teddy!

About the gelcoat thickness. While it is well above what you would get with paint layers, it can't be applied too thickly or you get cracks. The only place I could imagine 1/4" is if someone filled a small hole with pure gelcoat.

I have a place like that on my boat: the side deck on my DS1 had been drilled for jib leads positioned outside the coamings, but the boat was delivered with jib tracks inside the coamings. The factory filled those holes with matching gelcoat, something I discovered when I inspected the underside of the deck.Still, even there, I think there's less than 1/4" . .
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