alternative to sand blasting

Discussion in 'Metal Boat Building' started by tony c, Oct 4, 2017.

  1. messabout
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    messabout Senior Member

    Are you aware of soda blasting. The media is bicarbonate of soda, not as evil as silica sand. The advantage is that it washes off easily, leaves no residual granules hiding in the pitted areas. Downside is that it is much more expensive than sand. This is a method used to good advantage by engine rebuilders.
     
  2. M&M Ovenden
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    M&M Ovenden Senior Member

    Marks wife this time, not Mark. But going to say the exact same thing as Mark. Move the boat!

    If you got this boat for free, and if you have looked at it thinking you might get a few bucks for scrap... then you have more then a little blasting to do.
    Sandblasting is double purpose, which, if you have a steel hull to renovate you need to accomplish: 1. Clean the steel 2. Provide an anchor pattern for the paint.
    If there was any better way to do this then sandblasting, I'm pretty sure big industry (ships, bridges, other infrastructure) would use it rather then dealing with environmental constraints.

    How many of people responding have actually worked on a full 50ft hull? Seriously, do you have any clue the work it represents to clean all that surface? The options presented are completely unrealistic on economical and time scale to clean a full 50ft hull... and I have a pretty good idea what I am talking about here.

    Also, bringing up silica sand when talking of sandblasting is mute argument, in our days and age, it should not be used to do the job.... not even a question. Options to silica sand are multiple and don't have to be soda blasting (which would not provide best anchor pattern for your paint anyway). There are all sorts of sanblasting media which one would call "sand" which are silicaless, affordable and will do the job well for a steel hull. My favorite has been copper slag, followed by coal slag. Copper slag is very heavy and carries a lot of energy into blasting the steel, its heavy mass also makes it a lot less dusty then other sands (there is still dust thought and the stuff is very black)
    The real environmental issue with sandblasting is not as much the blasting media as the paint you are taking off the boat.

    Need to add: no matter how you put it, sandblasting sucks but thats part of building or renovating a steel hull.

    Murielle
     
  3. Poida
    Joined: Apr 2006
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    Poida Senior Member

    Hi Tony
    You didn't say where in Australia you are, and I didn't see any information as to whether the boat is seaworthy.
    Moving it overland would be expensive, sailing it somewhere else would be cheaper.
    But if you were in Fremantle for example, you would probably be up ship creek without a paddle.
    Poida
     
  4. Nick.K
    Joined: May 2011
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    Nick.K Senior Member

    An option that they may allow would be a recirculating blaster. These machines suck the grit and crud back in to the machine and then separate the grit for re-use. The actual blast area is under a cowl which would take some getting used to and probably be slower than open blasting. There would however be a big saving on clean up time and although the blast may be slower, this would be balanced by improvement in visibility inside and also being able to see all of the blasted areas (not covered in grit). A disadvantage is that you will need a very large compressor since the vacuum is also generated by air flow.

    http://www.nederman.com/en/products/product?product=89076

    (There are other makes too. In Ireland this equipment is available for rent for blasting inside tanks, public open spaces etc)
    [​IMG]

    Post some pictures of the boat and close-ups of the corroded areas.
     
  5. Angélique
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    Angélique aka Angel (only by name)

    Before starting any work and making costs, best make a financial plan first I think, just to see if you can and want to carry the project financially up to completion.

    And best also make a time planning before starting the works I think, this to see if you can and want to invest the needed time till the boat is ready.

    P.S. - If negative on one or both of these two issues, then best sell this boat, before she drags you down . . :confused:
     
    Last edited: Oct 6, 2017
  6. Angélique
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    Angélique aka Angel (only by name)

    From post #1 - ‘‘ . . . full internal fit out . . . ’’

    Does that mean there is no interior ? - Or that the interior needs to be taken out ? - Or . . . . . . ?
     
  7. Angélique
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    Angélique aka Angel (only by name)

    Was the boat internal blasted when new ?

    If not, then this might be needed too, as long time condensation and/or leakage from windows and hatches can cause severe inside corrosion on bad protected but hidden areas.
     
  8. Nick.K
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    Nick.K Senior Member

    Good point, corrosion inside is usually more serious than out.
    This week I blasted the underwater area of a steel Vandestadt yacht, the steel was perfect on the outside but as I was blasting little dark moisture blots started appearing in places around the plated keel... In the last month I've done the forepeaks and shelter deck areas on two 70ft trawlers and made holes in both from inside when outside they were as good as new.
     
  9. Angélique
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    Angélique aka Angel (only by name)

    How long are you allowed to have the boat there on the hard anyway, while working on her . . ?

    And this is also where the financial planning and the time planning already meet each other.

    What would this place, where you can't even do the work properly, cost you for the duration of the whole project ?
     
    Last edited: Oct 7, 2017
  10. Nick.K
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    Nick.K Senior Member

    This is where I expect to be today if the rain holds off..
     

  11. Angélique
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    Angélique aka Angel (only by name)

    Hi Nick, following the above video, I've answered the caterpillar question here on the Random Picture thread . . :)
     
    Last edited: Oct 7, 2017
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