Repairing a steel hull

Discussion in 'All Things Boats & Boating' started by Jason Crum, Jul 16, 2006.

  1. Jason Crum
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    Jason Crum Junior Member

    I would like some info on spraying fiberglass over th exsisting steel on my 1974 Stardust house boat.It has some slight pin holes and I dont want to replate the boat. Anyone ever heard of this being done::?: Thanks in advance for your input,Jason
     
  2. Redsky
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    Redsky Senior Member

    perhaps you should have somone survey the hull in general with a thickness tester..if you have multipal pinholes.
    to me that is a fair indication of a lot of wear and a survey even in general should tell you whether or not to spend money on fixes however there are also comments in this thread about house boat/barges http://boatdesign.net/forums/showthread.php?t=12643.
     
  3. Jason Crum
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    Jason Crum Junior Member

    Thanks

    I did hire a surveyor and he is the one who suggested this process. He said he had surveyed two boats on the coast that had this done and had no problems. I just bought his boat in June of this year. We would really like to keep the boat. Some one put brass thru hulls in her and you know what happened next.The man we are talking with to spray the chopper gun said he would put 3/4 inch on her and then gel coat it. This will go al the way up the bow and transom. It will be like a steel boat in a bath tub.He is using VE resin with a 8 blade gun. Structually the boat is sound the problem is at som point someone plated it over the original and cutting all this out would be a problem. Thank you in advance for any input you might have,Jason.
     
  4. Redsky
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    Redsky Senior Member

    seriously if somone just edge welded large patches over corroded areas of the boat....buy a cheap angle grinder and grind the welds off one of the patches...that ought to tell you enough....
     
  5. Jason Crum
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    Jason Crum Junior Member

    I dont understand what your getting at with your suggestion.
     
  6. Redsky
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    Redsky Senior Member

    you said "Structually the boat is sound the problem is at som point someone plated it over the original " if somone has just edge welded patches to the originial hull like a bandaid over the top given your boats issues id be tempted to take a 4" angle grinder and grind off the welds on one of those patch panels and have it off the original hull ,, if someone had added this material w out treating the problem before hand a fiberglass bathtub will only further hide the problem...anng given the fact that you have pinholes leads me to believe that the patch artist did not treat the corrosion problem properly beforehand.
     
  7. globaldude
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    globaldude court jester

    Jason, you have a serious problem brother !!.
    Be sure to remove & or [ if possible ] fully treat the rusty areas so as it will not "blow up " under your fibreglass over coat .
    Just remember steel expands seven times it's original thickness as it rusts, more than enough to push off any fibreglass coating -- no matter how thick it is. Rusting steel can & does rip apart & bend good steel in it's effort to expand.
    I can't imagine a proper steel repair being as expensive as glassing over a problem area.
    Example ; I once owned a 37' sloop - steel - and while chipping at some " surface rust" in the bilge, noticed it appear to change colour !?.
    I touched the area to find it was wet !!!.
    Short story -- it had pin holes, so next low tide, I cut out the area of pin holes , [ I only had to go about 50mm back to good steel ] preped the area for full penetration weld, made a new plate to fit , welded it in, painted it with 2 pack epoxy and antifouled it. ALL on the one tide . Back to as new condition & good for another 20 odd years -- or better as the original owner had used tar based paint of the day .
    Steel is real !, cheap to use & work ---- if you can weld it yourself - it's not hard to learn . Just look at a few welder type people and ask yourself, am I as clever as him ?. sit down [ get comfortable , it's a "key" ] and weld together lots of old scrap steel, 1st down hand, then vertical . Get through one packet of rods & I'll bet your'd bet getting quite confident . Just remember [ when starting to weld - ie stick to steel ] STROKE DON'T POKE . stroke to establish the arc or you'll get stuck & steel bits & curses will fly everywhere .
    Sorry, but I really think you'll need to cut out the rust areas or you'll pay & then it'll come back & bite your ***.
    Pete.
     
  8. MikeJohns
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    MikeJohns Senior Member


    I wouldn't do it.
    This doesn't sound like a recipe for a long term reliable fix. Expansion coefficients are different for a start so don't expect the GRP to remain adhered to the steel then youll end up ( a few years down the track) with acidic fluid pockets finishing the corrosion job in short order.

    You will end up with a rusting mould inaccessible for repair. Far better to actually patch the hull. In most instances the corroded through parts will not be as extensive as you think, steel is also the most easily repaired hull material so use the advantage you have.

    Incidentally old steel hulls beyond repair have been ferro-cementeed over with great success and this is a much better solutiuon since the expansion coefficients match and the alkaline environment is protective to the steel.

    Cheers
     
  9. Jason Crum
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    Jason Crum Junior Member

    Thanks to all !!

    I am replacing the steel on the bottom. Thank you all for your time and thought on this matter. Jason:D
     
  10. Redsky
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    Redsky Senior Member

    i think most of us agree that you'll be happier with it properly taken care of...and while swimming is fun haveing to forceably do so in cold! unfriendly! water! suddenly! is no fun at all in the very least.
     
  11. gpaladin
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    gpaladin Junior Member

    Good choice IMHO

    It is a matter of isolating the steel from air, water and salt.

    Since it is better done by repair-sandblast-paint than spraying fiberglass all over it (with or without repair and sandblasting first) I think you made a good choice.

    It is fun to work in steel anyway. To make repairs all you need is a welding machine, some steel plates and a good will :)
     

  12. yachtwork
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    yachtwork Junior Member

    Greetings-I cover this subject in Metal Boat Maintenance and Repair by Scott Fratcher.

    The short answer is no, this is not a good idea. Patching is far faster, cheaper and lasts longer. For a house boat a lot of people have been successful in cementing over the outer hull, but I have never attempted this, just heard the reports. Thing is steel and cement get along well, but steel and fiberglass don't.

    You can see Metal Boat Repair and Maintenance at-
    http://www.lulu.com/content/paperback-book/metal-boat-maintenance-a-do-it-yourself-guide/2255485

    Good luck and send in some photos of how it went.

    Scott
     
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