What's your experience with power fairing boards?

Cat you are way to worried about the sanding. Put it on right the first time and you won't have to sand that much. This is were getting a true fairing person will save you money. Otherwise you are just putting on material and sanding it off.

Save your sanding dust, you can add that to epoxy to make nice putty for corners.

 

I'm not doing any sanding on then off. My employee is a whiz at this stuff and it's not like a monkey couldn't do it if you showed him the technique. I just don't have months to waste.

You are reading into this incorrectly.

It's all the time consuming passes for all the various layers that is the issue. I need to speed it up.

As they say, "time is money.". This is a business, not a hobby, so i am under a different set of circumstances.

 

I know, it takes months for a crew to do a 100 footer.

 

That's the thing with cats, when it comes to square meters they're "much bigger" vessels. My favourite(if it there is such a ting) fairing tools are long(6M) aluminium channels(1" x 1/2" x 1/8") to define overall longtitudinal fairness being used with wax & release agent as a "bog batten" - & then using the fair bogged strips as a guide for screeding. My Baily No. 7 plane is another favourite - cuts highs off & I use other shorter planes on where I may have had to top up smaller holidays in the surface, the planes are satisfying to use & on topping up you wont end up with a sanding halo around them, of course guide coat & various long boards come into play also. Jeff.

 

There is another device (used and photographed in my build thread http://www.boatdesign.net/forums/boat-building/my-little-piece-peace-25962-63.html#post317663 ), known as the "Helicopter" it is a brutish thing that has 4 blades about a foot long and takes various grits of sandpaper and works in a rotary motion really getting large flat areas smooth very quickly... The device was hired from ATL... My supplier of composite stuff, on the Queensland Gold Coast...

then finish off with long "torture-boards" up to 3 ft long and worked longitudinally on the hulls... Lastly fine grit in shorter boards of a foot long or less to get at the fiddley parts... Subcontract it out to experienced labourers/slaves and watch over the work carefully with your straight edge and plastic fair rule to check there are no bumps or holes (a 3 to 4 ft lrngth os perspex about 2 inches wide and an eighth of an inch thick but carefully kept and 'true')...

 

The cheap inline sanders are single piston types and will not preform well, plus shake your hands to death in short order. The duel piston setup on an inline sander is the only way on a large job.

 

Thanks for that tip, Par. Hutchins it is, then.

 

Those inline sanders can only be used on flat surfaces no? No good for curved surfaces or can you fit a flexible board to them?

 

Inline sanders can be used on curved surfaces. Cat, the Hutchins is a nice machine, but you can get double action sanders for a lot less, just look at the specs.

 

It is how you run sander, Sometimes your horizontal. Others at 45degrees, You use different cuts at different times, with different colors. Then last layer much thinner grit. First layers I use big grits like 36, to cut fast and make next layer grab good. Next layer different color, then increase grit to 60, then 120 then material gets thinner, go 220, last layer about 400.

 

Found a double action sander for $69 at Northern Tool. I won't even begin to say what the compressor (18CFM) cost to run a pair of those!

But, it will come in handy saving me labor and rent costs, as well as saving me from farming out the paint job. Got the compressor today and plan to epoxy one of my existing torture boards to the double action sander plate tomorrow afternoon for a test run when the bog is kicked on Tuesday.

Still have to get the 230VAC wiring done too, but that should be easy to do tomorrow afternoon.

Thanks for the input.

 

Bit late now but my solution to the compressor issue was to have 2. I've got a 10 cfm (nominal) one for painting, plasma cutting, staple gun etc etc. I've also a 120 cfm unit for serious air delivery, mainly sand blasting.

IIRC Glenn Ashmore converted a belt sander to a long board sander by building a much longer shoe for it, said it worked for him on RUTU. I didn't pay a lot of attention because I don't expect to do this myself.

PDW

 

Sanding tools typically need lots of air, so yep, you'll need a big compressor.

 

I looked at the 2 compressor situation and it didn't work out price wise for me here in the States. It was more cost effective to get one big one. Well, not big like 120CFM, but more like 18CFM. Still huge to me.

I also didn't expect to do much of this myself, but as I see how hard it is to find people, with the right tools and the one guy I have (and possible another one), I should be able to get a lot done in the time it would take to find some fairing crew.

Of course, there is also painting I can do myself now, which saves about a mast of money.

 

Air compressors generally are sold by companies that lie about their capacities. Especially in the small sizes. I'd either buy at least 200% of the expected capacity (which will reduce cycling times anyway) or test in the shop before buying.

My big unit is a Hydrovane industrial 3 phase good for over 100,000 hours run time if serviced every 2000 hours or so. I don't expect to ever wear it out. For most jobs it's too big and the small one is a bit small so 20 to 30 cfm is the sweet spot I think. I've my eye out for a Hydrovane in this size range.

You are correct about the painting, I've applied some 70 litres of paint on the inside of my hull using spray gear. Painting around transverse frames and longitudinal stringers is a major PITA but a lot easier with spray gear than a roller/brush. There are 7 coats of paint on the interior, 8 in the hard to get at spaces in the stem and transom areas.

Buy lots of filter canisters or a complete closed air breathing system. I didn't use epoxies inside so I used a double canister mask. Had I used epoxies I would have gone to supplied air breathing gear.

Rig a big extractor fan/tube to suck the vapour out. I used my welding fume extractor.

PDW