What's your experience with power fairing boards?

Discussion in 'Boatbuilding' started by CatBuilder, Apr 28, 2012.

  1. CatBuilder

    CatBuilder Previous Member

    Good tips, pdw, thanks. I already use a supplied air system all the time. It is better (no fumes) and actually cheaper. The activated carbon filters are quite expensive over the course of a boat project.
  2. mydauphin
    Joined: Apr 2007
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    mydauphin Senior Member

    You can find a real good used compressor for not too much money, then probably sell after your done. I bought a 185 cfm for $800 and sold it 3 years later for $1000. Yeah it was a big compressor, had a perkins diesel running it. Point is those cheap compressors are disposable but you are going to burn then out, and may have to buy another before you finish boat. Borrow, rent or buy a used bigger compressor if you can, not 185 of course.
  3. CatBuilder

    CatBuilder Previous Member

    I already bought my compressor, but thanks. It has a 10,000 hour warranty and they come out the next day. Ingersoll Rand.
  4. waikikin
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    waikikin Senior Member

    Good choice, I've had one for 26 years.Jeff.
  5. CatBuilder

    CatBuilder Previous Member

    Oh.... My.... GOD!

    I have created the best fairing tool in the history of the world! :)

    Nothing like a 36" x 4.5" power board!! WOW!!!
  6. pdwiley
    Joined: Jun 2008
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    Location: Hobart

    pdwiley Senior Member

    I agree, good choice, one of the best brands and if you put more than 10K hours on it working on this boat, I'd say it's time to consider a career change...

  7. CatBuilder

    CatBuilder Previous Member

    Exactly! :D

    When I heard a 10,000 hour warranty, I was pretty sure it would last the 1000 to 2000 hours I have left on the build.

    The thing is incredible. It runs very smoothly and I doubt it will ever break down before I sell it. It is rated for continuous operation, meaning you can run it to run tools continuously without cycling.

    It uses a special (expensive) synthetic oil, which allows for the continuous rating.

    Quite happy with the set up.
  8. Steve W
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    Steve W Senior Member

    Cat, lots of good advice above so i wont repeat it but remember, you will still be doing a fair amount of fairing by hand so i suggest you find a local supplier of Fartrock, otherwise known as Foam glass insulation. If you are not familiar with this stuff it is a truly amazing product, it comes in a box of, i think 5 slabs about 18"x24"x4" so you cut it into 24x4x4 and use it where you would use your small automotive longboard, but it cuts like 36grit leaving scratches like 80grit and remains sharp until it is worn down to nothing, its also cheap compared to sandpaper. I have bought it from a local wholesale building supply house,only about $45 last time i bought it but that was probably about 8 yrs ago. Once you try it you will know why its refered to as fartrock. A couple of power tools i like are my National Detroit mud hog 8" air DA and a 12" plywood pad on a sander/polisher, a friend of mine swears by the Helicopter and one could easily build your own.


  9. mydauphin
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    mydauphin Senior Member

    Cool, lets see pictures.
  10. mydauphin
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    mydauphin Senior Member

    Is this what you are talking about.
  11. Steve W
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    Steve W Senior Member

    Yes, that looks like the stuff, its messy to use as it abrades away as you use it but in doing so it continually exposes fresh cutting edges so cuts the same from start to finish and wears to the curve you are sanding. It does a great job of knocking off the highs, i wouldnt tackle a fairing job without it. My first exposure to fartrock was during my time at Kiwi Boats on the Kialoa project in 1980.

  12. mastcolin
    Joined: Jun 2005
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    mastcolin Senior Member

    So what compressor did you end up with? You mentioned an HVLP gun. Dunno what make you bought but some of these eat air - you are looking at 15cfm and above easily.

    Your compressor will have to be 3phase. You won't get enough air through a household 230v supply kit. Sorry. Your cat is big. You will need long air hose, this drops pressure. You will need a air filter. This drops pressure. You will add on connectors. These drop pressure. Buy the widest hose you can get. You will need 1/2inch,3 8th min. Depends on your compressor. The bigger it is, the less issue you have. When you spray keep the hose as short as possible otherwise you will see the pressure drop if the hose is too narrow.

    For your info, Devilbiss used to have a great beginners guide to this all:

    This tells you all about compressors, pressure drops etc. I hope it ain't too late...

    Don't get obsessed by sanding. You fill the hull fair. With the batten. You should only be lightly sanding surface between layers enough for further applications to slide on ie the highs should be sanded. The lows should be unsanded. I fair superyachts in Holland. No one uses a powerboard. We use 200mm da sanders with p40 between coats. Some painters (us for example) will board sand using a 1m board (2men) on LAST filler layer before fininshing filler. Depending on project we will then maybe also board the primer. Feadship and Huismans NEVER board, and they are going to be better looking than you will achieve. No disrespect:)

    We reckon on 10m2 per man per hour for a deep sand with machine. You will sand 2m2 per man per hour with board. For a filler sand between coats you should be whizzing over 30m2 in a hour no problem. This seems little but you try doing this quicker on 600m2:)
  13. CatBuilder

    CatBuilder Previous Member

    I appreciate the input, but the board worked amazingly well. It took an initial (below the glass) fairing job that would normally take 2 weeks and allowed us to complete it in 3 days. Foam sanding, then one coat of bog, then a second coat of bog. The hull is now ready for glass (resin infusion), then a final 2mm fairing (which will then be covered with primer).

    This is a one off, so the initial core has to be faired. This isn't an existing boat or a normal female mold - it's a plywood/batten form the core is laid up on first, then infused over after fairing. (then a small fairing/smoothing for the general perfecting for paint) Because it is a one off and not from a true mold, there is a lot more work to be done to get a yacht finish.

    What is the "200 mm da sander" you are talking about? I am not understanding this term, "da sander."

    Ah, you are not understanding my electricity. I'm in the states. 230/240V is not normal household. It is the industrial, high power. I am running 230/240VAC on a 50 AMP circuit. That's not like your standard 240V house power that you are picturing in the Netherlands. Our standard house power here is 120VAC on 20 amps. There are two different hot wires (each at 115/120VAC), no neutral and a ground. This takes 2 legs of the local 3 phase power and puts them directly into the engine. This is full, industrial power and a very good brand compressor. It is an Ingersoll Rand.

    Let me try to elaborate in metric for you:

    11,500KW electric circuit (230/240VAC @ 50 amps)
    230 liter air tank
    .5 cubic meters of air per minute (509,000 CC's per minute or 18.1 CFM)
    135PSI (sorry, didn't get a chance to convert this one)
    5HP / 3.7KW electric motor on compressor

    Already have air filter, dryers, etc... etc...

    I am using P36 and P24 between coats as this is rough fairing at first, then onto the fancy stuff later. The P36 is plenty for the power board. On the hand boards, we are using P24 to save time. Both work well.

    That PDF link appears to be one of the best links I have ever seen posted on this website. Thank you very *very* much for that. I will keep it on my computer to study before the spray job begins. Do you know of any similar PDF's that take you from bare fiberglass, up through the moment you start spraying? Like the fairing and finishing steps?

    I planned on boarding the primer (high build epoxy primer). Is that a good idea?

    I am trying to find the fastest way for 2 men to get a boat faired and painted and looking good. That is the idea here... that's why the power boards... so we could do the rough sanding more quickly and of course, the compressor can now be used to HVLP spray the hulls as well, instead of contracting the work out.
  14. CatBuilder

    CatBuilder Previous Member

    Also, if you are spreading bog with a batten, what do you use for a batten in that case - and do you throw it away after each use, or do you clean it?

    And... how do you suggest a fairing job go in general? Do you have a number of steps you could list, as well as appropriate tools to use, materials used and what grit of sandpaper to use between the different layers, all the way up through a high build primer and final clear coat?

  15. michael pierzga
    Joined: Dec 2008
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    michael pierzga Senior Member

    The smell of 545 and .... just listen to those DA's wail....a boatbuilding symphony.

    a 200mm DA is a beast and needs plenty of air.

    The FIEN 200mm electric is a good tool but will probably burn out halfway thru the job. Air is the way to go.

    most painters are DA intensive..not to much board sanding and are very professional with a bog batten. Laying bog is the art when fairing..
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