Sanding Longboard Dimensions

Discussion in 'Boat Yard Basics' started by WhiteDog70810, Jul 24, 2010.

  1. WhiteDog70810

    WhiteDog70810 Mostly Harmless

    While this task is still a bit off, what are the dimensions of the longboards you all have used to fair your hulls? I've found 4.5"x30" and 2.75"x16" boards. I think at a minimum I'd like the 30" for a flexible board and the 16" for a rigid board, although I can see the argument for making one of each. Of course I plan on making my own since they run about $60 on line!

    If I glue velcro to the bottom to hold the paper, would I still need to add a pad?

    I'd probably use 1/2 ply to make them (might use 3/8" ply for a 16" flexible board). Anything thinner seems too floppy, but I am curious what you all think.

    I am sure all this stuff is online, but I get too many surfer sites when I search "longboard" and the results from "torture board" (yes, this is a correct, if aged, term) are not what I am looking for!

  2. WhiteDog70810

    WhiteDog70810 Mostly Harmless

    Also, I was thinking 60 grit followed by 80 grit would be adequate for a work boat finish.  I want it fair and smooth but not shiny.  It will ultimately be camo anyway.


  3. Brett

    Brett > PRO STAFF <

    I'm too lazy for hand work,
    I prefer the pneumatic sander used in auto repair/body shops.

    Glen-L has a how to, middle of page:
  4. paint it black

    paint it black Paddling away...

    If thats what you want, I'd just go with what's known as a "hand file" or "line sander" in the body shop world.
    Harbor Freight has a great one for cheap.
    When I owned my own body shop, I had got a $300 from the SnapOn truck.
    The moment I used it, it broke.
    The SnapOn truck was still outside.
    I went back and exchanged it.
    Tried that one and it broke again.
    I got my money back and spent those $300 over at Harbor Freight on a ton of pneumatic tools.
    Some didn't last, some are still working to this day.
    Even if they didn't last, they were $20-$30.

    I'm still using one from harbor freight for about 5 years now.
  5. firecat1981

    firecat1981 BBA Counselor

    hell if it's gonna be camo anyway why even bother fairing it? Smooth it out a little and roll a gloss coat of epoxy on then do a few coats of primer sanding lightly in between. Paint it and go fishing!
  6. Conch_and_Cracker

    Conch_and_Cracker I Love!

    When I fair, I typically use a fairing board made from what the size of the file board paper. 2-3/4x 16 1/2. I use sticky back paper, norton seems to hold up better than 3m. Make sure it is as flat against the surface as you can get it or you will sand a flat spots in the hull. I have worked in several boat shops that power sanders where not allowed and now I prefer to do it all by hand if there is a lot of flam and flair to the hull. I just feel you get a better finish. depending on how much your taking off start with 36 grit and go to 80 grit, after that it's a small sanding block with paper of 150 to 220 and then wet sand with a block with 320.
  7. WhiteDog70810

    WhiteDog70810 Mostly Harmless

    Thanks guys.

    Despite the future camo color scheme, I am fairing the hull just to know I did it. It would be wasted sweat to others, but I like it when you can look closely at something utilitarian and see that the builder cared.

    I don't have a compressor and I will be sweet talking my wife to dump money in this project this fall as is, so I am stuck with hand tools. I am okay with that because it is a small hull and the curves are simple. I may have to upgrade my palm sander to a RO sander if I burn it up.

    I was surprised to see that Glee-L rec'd using 1/4" ply for long boards. That seems really, really floppy, but the guy has done it more than me. I am not going to bother with the velcro. I am sure it is convenient, but that paper is a lot more expensive.

    What would be a good material to make the pad out of that the PSA paper will adhere to? I was thinking a sheet of rubber from an inner tube could epoxied to the board.

  8. Brett

    Brett > PRO STAFF <

    Self sticking felt, sold at craft stores.


    And if you're worried it'll fall apart if it gets wet
    I tested for that already problem.

  9. Swamp

    Swamp I Love!

    I'm not sure you want a pad on a fairing board, it might defeat the purpose. Buy regular paper, cut to size, and use cheap spray adhesive.  Let it tack up and stick to the fairing board (plain wood), you will be able to remove it if you let the glue tack up first.  You can spray the board instead but I've found that you end up with crud sticking to it before long.  If the paper gets stubborn to remove use some heat (heat gun, hair dyer, etc.).  I've done that to make custom shaped sanding blocks.  Cheaper than buying PSA paper but akes longer.  Oh, if you spray more than one peice of paper make sure to keep it where dust can't get to it.
  10. WhiteDog70810

    WhiteDog70810 Mostly Harmless

    I've heard of going without the pad. A thin pad spreads pressure more evenly across the paper. Mostly it prevents the edges from digging in.

    Thanks for the felt idea.

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