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Thread: Best technology for wooding the hull

  1. #1
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    Default Best technology for wooding the hull

    Does anyone have experience with the Farrow System technology for wooding a carvel planked hull? If you're not familiar with it and curious, check this website: http://www.farrowsystem.com/default.asp (No commercial connection with me) It is allegedly quite different from high pressure "blasting" such a soda or sand and can be operated at low pressures such as around 25 PSI. Their proprietary method uses what sounds like a pumice slurry. I have seen impressive pictures of antique furniture cleaned using this without damage or rasied grain. I'm thinking about using it to remove many layers of bottom paint on a carvel planked, atlantic white cedar hull which is in excellent condition, including caulking, and should need little or no repair. I'm nervous about damaging the cauking, with no basis for that anxiety other than ignorance of what to expect, and would be grateful for any comments. Thank you.
    Jock B

  2. #2
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    Default Re: Best technology for wooding the hull

    Welcome to the Forum!

    Ordinarily everyone jumps in with dire warnings about damage from blasting, seemingly independent of the blasting material. Don't know what to say about the Farrow system, but suspect that blasting might damage the caulking or plank edges -- hard to know.
    "The enemies of reason have a certain blind look."
    Doctor Jacquin to Lieutenant D'Hubert, in Ridley Scott's first major film _The Duellists_.

  3. #3
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    Default Re: Best technology for wooding the hull

    That looks pretty impressive. My use for it this last summer would have been far different than your application since I knew I wanted to re-cork my boat. I would have have liked to have given this a try. Still making sure to avoid the seams though.

    I've got full access media passes for the Seattle Boat show. I'll see if I can find the guy and shoot some video of his product next week when I'm there. And make sure to ask him about spraying wood. In particular, cedar.

    DAN

    ADDED:
    hmm.... He isnt listed in the exhibitors list. Bad business decision to not be in the largest boat show in the country.

  4. #4
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    Default Re: Best technology for wooding the hull

    Dan:
    Farrow is an Australian company and operates is US by franchising. So, the listing for Seattle Boat Show may not reveal their presence. Typically the Farrow system is available through boatyards. I don't think they've been in US very long.

    For wooden boat people it's probably it's worth finding out since getting paint off with the various chemical systems is a messy, stinky and environmentally awkward process, sanding is really too hazardous for operator and neighbors and expertise with a torch and scraper hard to find these days.

    Wish I could be at Seattle BS...used to live there and sailed out of Shilshole Bay for 16 years.

    Jock B

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    Default Re: Best technology for wooding the hull

    Dan,
    Small manufacturers and businesses have been hard hit by the current trends. The first things to go are advertising and trade show appearances. Maybe they reckon the cost isn't worth the return.

  6. #6
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    Default Re: Best technology for wooding the hull

    Lew,
    So true.

    DAN

    Dont be such a troll, Lew.

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    Default Re: Best technology for wooding the hull


  8. #8
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    Default Re: Best technology for wooding the hull

    Bottom paint is best removed from a wooden hull with a propane torch and scraper. It's fast, the least messy, and the least hazardous to your health (obviously, you avoid breathing the fumes.) I don't really know what they mean by the "skill" not be too available these days. There's nothing to it but heating up the paint until it starts to blister and scraping it clean off. It's a no-brainer.

  9. #9
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    Default Re: Best technology for wooding the hull

    I'd second Mr. Cleek's advice but replace "good heat gun" for "propane torch".

    I looked at the video for this product, and it sure seems to remove paint from fiberglass. But personally I wouldn't use it unless I had seen it on a softwood like cedar, and until I knew a little bit more about how they dispose of the toxic pumice and bottom paint slurry that would remain.

  10. #10
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    Default Re: Best technology for wooding the hull

    I've done a lot of sand blasting, and as bosun supervised crew on ships doing sandblasting, often going through as much as three tons of black beauty (slag blast medium) in a single trip from Corpus Christi to New York.
    Blasting works great if you have two conditions: 1) the substrate (hull material) is harder than the coating, and 2) the substrate is of uniform hardness.
    I've tried sandblasting wood with both silica sand and black beauty, and I've used slurry blasters on steel.
    In the case where the paint is harder than the hull, as it is with most wood, once you're through the paint you quickly go into the wood. This may be acceptable below the waterline, but is not at all good above the waterline, unless you're planning to do a full job of fairing and smoothing the hull.
    My guess is that the lava rock that they're using is quite a bit harder than wood, and so you might have a real problem keeping from digging in along the work edge.
    The second problem is the variation of hardness of the wood planking. This might be worst with Douglas Fir, where there's a lot of difference between the early and late wood.
    I used to own a 64' wooden passenger boat, built 1932 with yellow pine planking. When we'd haul out I'd use the yard's pressure washer to blast off barnacles, scum, etc. I discovered that if I was very careful I could remove loose paint as well, and if I could get it started, I could peal off big sheets of topside paint. The trick was to have the blast angle at a very low angle, not blasting right at the wood. Pressure was modulated by how close the nozzle was to the plank. Yellow pine has early/late wood hardness difference, and if I got too aggressive the water blast wood take out the soft wood, leaving a ribbed appearance that either had to be sanded or filled.
    I also found that the water blast would remove any loose seam compound. At first it was a big pain, but after a couple years I'd piecemeal re-puttied the whole bottom, and it looked good, and seams didn't blast out anymore.
    I wouldn't recommend this on soft white cedar, or at least until I'd tried it below the waterline.

  11. #11
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    Default Re: Best technology for wooding the hull

    Shawn and I used a torch and sharp scrapers,keeping a tarp under our work made cleanup a snap. The work went quick and easy and fumes were minimal, we wore masks most of the time. As you heat up the area the seam compound softens and does not pull out as you go over the area.
    Finding the right torch took some experimenting,we were advised by a few people to use modified weed torches.Too aggressive for our taste,we finally settled on BernzOMatic,model jth-7,wand and belt clip,easy on the arm muscles. Nice flame spread and intensity,very efficient,propane seemed a better choice than MapGas.I would keep a small belt sander handy to touch up scraper blades.
    Steve and Mary Bauer have ,built a quartz heating devise that is said to work slick, no burning, we hope to have a demo in March.

  12. #12
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    Default Re: Best technology for wooding the hull

    Thank you, seo, for your post. It is never acceptable (in my opinion) to eat into the wood when media blasting. That's to say, not acceptable on the kinds of boats people on this forum are likely to be working on. Even with the bottom, there's a lot of loss if you blast, and the wood, depending on specie, will come away either "fuzzy" or highly grained, or some combination of both. When they develop a system that removes the paint only and not the wood, that's when this technique might be worth looking into.

    I can assure anybody reading that fairing a hull or bottom that has been sandblasted back to smooth is no laughing matter.

  13. #13
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    Default Re: Best technology for wooding the hull

    Quote Originally Posted by Lew Barrett View Post
    When they develop a system that removes the paint only and not the wood, that's when this technique might be worth looking into.
    I think I'm paraphrasing something you wrote some time ago, Lew: the wooden boat repair and maintenance market is a small niche. Maybe someone will invent a perfect paint removal tool for fiberglass and - miracle of miracles - it will transfer flawlessly to wood hulls. But none of us should hold our breaths waiting for someone to invent a bottom paint removal system for wood any better than heat and scraping.

    BTW, for those of you who have used both a propane torch and a heat gun, what do you see as the advantages of flame? A big heat gun produces all the temperature needed to soften paint and doesn't scorch as quickly or deeply, nor does it risk setting off flammables. So what do you see as advantages other than portability away from electric power source?

  14. #14
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    Default Re: Best technology for wooding the hull

    We were painting the house last summer and after stripping 115 years of old paint from some window trim with a heat gun Mary was looking for a better way. She did some research and wanted to buy one of those "Silent Paint Strippers" that were reviewed in WB a few years ago. I've heard good things about them but I'm just too cheap to spend $400 on a paint stripper. There is a similar American made infrared stripper but that one is $500! Then I found a web site that showed how to buy some parts and make your own infrared stripper - total cost about 85 bucks. So that's what I did. Works a treat. Mary could strip a windows worth of trim in about 1/4 the time it took with the heat gun. With none of the risk of using a torch. I haven't used it on the boat yet but we have big plans for this spring. I'll take some pics tonight, maybe a video.


    Steven

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    Default Re: Best technology for wooding the hull

    I suspect the appeal of open flame is how fast it is, and that the total working area can be significantly larger than with a heat gun. I don't strip hulls with heat guns every day, but in my experience, heat guns can really slow down in windy weather. A sharp scrapper is the most important tool for me in doing the bulk bottom clearing.

    The job sucks. It's really no fun to lay on your back and clear bottom paint off a big boat. Probably the most important tools of all are good respirators, sharp implements and young people.

  16. #16
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    Default Re: Best technology for wooding the hull

    It's possible that the most important accesory for removing bottom paint is a properly chilled cocktail shaker, ready for the end of the day.

  17. #17
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    Default Re: Best technology for wooding the hull

    Watch the strong young men wield the implements of destruction while sipping the cocktail! Perfect tool utilization

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