Bottom Paint Question

[Cheechako]

As is likely becoming apparant, this is a big, dirty job with material costs etc. For a first timer, you will undoubtedly have some crescent gouges.... maybe a lot of them. You will then be wanting to fill these in, and then need to sand the filled areas again. (One note to the great info above: When you put on a brand new disc, they are real sharp and this is often when you will get a deep gouge.... the technique changes as the disc gets duller!)
Like I said originally.... sometimes the best thing is to sand the real loose stuff by hand and just put paint on. Seen some pretty lumpy bottoms after DIY'ers tried this task. Or, let an expert do the dirty work and work a few hours overtime at your job while he's under there!

[albergsailor]

didnt mean to leave this hangin but when you say soft pad i hope your not talking about the kind with the hard backing on them. I know i tried those before and the pad did not curve anywhere near enough to contour to the hull of the boat. Then you end up gouching into the gelcoat. I typed in soft pad at the fisheries supply and came up with those foam hard backed pads. I envision a pad that has ALOT of flex to it. a sand paper disc thats larger then its small backing plate that fits on electric diegrinder in my mind would be better than one of those hard backed disc that are only good for maybe walls in houses. Im not gonna be starting painting mine for a couple weeks but my buddy is in the delimma right now so were trying to figure this out. thanks for all the responses but im still confused as exactly what pad to use because the one that im posting up here i know does not contain the right flex to do the job most efficiently without alot of goughing, well on second thought maybe this one doesnt have a hard backing and is very flexible its kind of hard to tell it just looks so much like the ones they sell at harberfreight/home depot that are very stiff with hard backs.

[minaret]

That's the one I use. You need exactly the right compromise between stiffness and flexibility so you can sand as fair as possible in as large an area as possible and still do it on a substantial curve. If you have concerns you can get soft pads in different densities/backings for different degrees of contour. Howeveer, this is total sanding geek stuff and probably unnecessary for your needs. The one from fisheries will do you just fine.


Flexpad Sanding Pads | SouthShore Mfg

[albergsailor]

i gotta run its time to leave the hotel but that red one looks even better or is that the same one?? i just talked to a lady at the fisheries place b4 i read ur post and she said thats what u use ur absolutly right thanks

[Lancerbye]

Having had this done 2 years ago I don't envy you. I have always done everything on the boats I have owned by myself, however when faced with this task two years ago I decided to have a yard do it. Had I been younger I would have tackled it by myself. There was 20 years + of accumalated bottom paint of various types on a 44ft boat that has a 13'9'' beam. The boat was bottom tented and two young employees went at getting it down to the gel coat. The outside temperature was in the high 70s and under the tent probably 120. It took them three weeks to get it off working 8 hours a day, using grinders, chemicals, scrapers and anything else that would work. The original Quote was $9000 the final bill was $18000. Sandblasting was not allowed in the yard. If I were to do this again I would hire the guys myself at a yard that allowed corn blasting. The job took 4 weeks which uncluded the removal of the old paint, 5 coats of Interprotect barrier and 4 coats of CSC bottom paint, lift out and return, plus the 4 weeks of yard storage time .

[BambooSailor]

Minaret,
I noticed that you call from Seattle. I am planning on refinishing my bottom soon (early April), but my concern is that minimal temperature for applying most epoxies and paints is 50F, which does not happen in Seattle area until mid May (or later). How do you deal with this minimum temperature requirement during colder months?

[minaret]

Originally Posted by BambooSailor

Minaret,
I noticed that you call from Seattle. I am planning on refinishing my bottom soon (early April), but my concern is that minimal temperature for applying most epoxies and paints is 50F, which does not happen in Seattle area until mid May (or later). How do you deal with this minimum temperature requirement during colder months?

We tent all bottoms and use large forced air diesel heaters to heat the inside of the tents. Due to the risk of contamination from the diesel exhaust we use expensive high-temp ducting from the heaters so they are never inside the tent or even very close. This is not equipment the average user would find easy or affordable to acquire, we spend a lot of money maintaining them. They are finicky and require constant care. Retrofitting with marine water separators/filters helps a lot.


Here's a link- Heatstar 90,000 BTU indirect fired heater

[Cheechako]

It's 51 today! Better hurry.....

[BambooSailor]

I'd like to thank Minaret for his recommendations and help with my bottom paint project. He shopped with me, showed me what to get (and what not to) and even allowed me to use his account to make the expense more bearable. I tried to follow his advice, although encountered several setbacks during my recent haul-out. First, I built a tent to contain all sanding dust (shipyard requirement), but was not able to build it strong enough to withstand three days of near gale/gale winds (up to 45kts sustained), mainly because I was not allowed to drive stakes through tarp to the ground (again shipyard requirement) and had to rely on weight of wooden blocks I was able to find around yard, which, with few exceptions, were no match for strong winds. I sanded bottom using 36 grate 8" disks on Makita polisher/sender. Plenty of power, but to sand the area that is usually above waterline took about 10x longer than permanently submerged portion which, later with practice, I was able to sand at rate of 1sq foot in less than a minute. I used chemical paint remover to remove what remained close to paint line. Sender produced huge amount of dust, both very small and large particles, which was very difficult to control and eventually dust made its way everywhere on the boat. Cleaning took 2 days. Everybody else in the yard was using smaller 6" Fein vacuum assisted senders, no dust, no tents, no overalls with full-face masks and many filters (which btw allowed some small particle dust in the mask), etc. Next time I think I try that. It probably is a slower process, but with cleaning included it could end up faster. For pros line Minaret who knows how to manage dust, big sender is way to go. I followed the process as described by Minaret earlier in this thread and results are very good (I think and hope). Bottom looks like new. Smooth, clean, faster, and boat even seems to be sitting higher in the water.
Thank you, Minaret again .

[minaret]

Glad you are happy with your results. There certainly is a big learning curve, I'm guessing if you had to do it again it would go much smoother. Proper tent building is an art form, and that particular yard is pretty exposed and can be very windy. A multihull is particularly difficult to tent well too. We roll 2x4's up in the bottom edge of the tent plastic and then set big cement blocks on them. Almost everyone blows their first tent because they don't realize the forces that can be involved, and often because they don't want to spring for preservation seal. This is bad because of possible staining on deck if the dust gets wet before cleaning. Also takes forever to clean. I know its a miserable job, and those guys with vac sanders look like they are taking it easy compared to what you were doing, but as I said before I much prefer a day of herculean labor to a week or two of drudgery. If you end up doing it again some day I predict you get out the big sander by day three, now that you know how. Happy to help out, will do again anytime, no beer necessary.

[Celestialsailor]

My friend used a 6" Bosch sander with vacuum port, shop-vac with a special throw away bag and 40grut discs. I was amazed how dustless the operation was. It took him most of 2 days to do a Peterson 44.

[Blue Stocking]

You CAN'T BUY that type of karma Minaret.

[shamrock]

I removed several coats of paint off my 35 foot bottom last spring in a little over one day with a scraper by myself. it was a dirty job and was not easy, but the paint did come off pretty easily, right down to the gelcoat.

I'm curious why it was relatively easy. I can't imagine paying 18,000 to remove bottom paint?

[minaret]

Originally Posted by shamrock

I removed several coats of paint off my 35 foot bottom last spring in a little over one day with a scraper by myself. it was a dirty job and was not easy, but the paint did come off pretty easily, right down to the gelcoat.

I'm curious why it was relatively easy. I can't imagine paying 18,000 to remove bottom paint?

I think lancerbye's 18k tale of woe and your story of ease illustrate a point. There are often huge differences in the amount of labor involved in a bottom paint removal from boat to boat. Some have only been painted with hard paint, which becomes chalky and then scrapes or sands easily. Some have only soft, which is impossible to scrape well, slower to sand, and a little gummy. Some have alternating layers of both, or extreme buildup, or god forbid coal tar epoxy. There are a thousand variables. The reason you can't understand 18k for paint removal is that you've never had to do a difficult one. Our bills used to occasionally be that high for similar jobs, although I've never spent anything like that amount of time grinding, it was usually all the lay days for drying that cost the most.

[Celestialsailor]

I thought I would breathe new life into this thread. It has very good information by minaret and others. I'm getting ready to move aboard in a few weeks and had planned to haul out then for a bottom paint strip, so I could use interlux 2000 as a barrier coat. So last month I went to a yard in Alameda to get a ballpark estimate of the haul. I was asked the length and I told them 35. I was then told that it may be 9 hours work at $95@hr. So I figured $1000 with materials...not too bad. So today I went to schedule and got a different story. Now they do not grind and only chemical peel and depending upon how many applications, could run into the thousands. Of course I got the "There is no way we told you that" from the counter-girl.
I'll go in a few days and talk to the yard manager directly to get this confirmed.
I'm glad I read what I did here about the time it should take to sand a hull down. I do understand it depends on the amount of paint layers. It's probably 4 from when I did some light chipping when I bought the boat out of a dry dock situation.