Triton #78 topsides paint

[Figment]

Fairing battens.

Find a spruce board and cut a 3/8x3/8 batten such that there is only minimal grain runout. Actually, cut several, as you'll want different lengths, and you're bound to break a couple. After they're cut, let them sit for at least a week or so, turn them over every couple of days. They're all going to twist or curve a bit as they get used to life as a skinny stick, discard or shorten any that have an obvious hook or hard spot. Now put a bend in each and discard any that exhibit a hard spot.

In the case of my transom, all I had to do was lay the batten across the surface and see the daylight at the hollows to know how out-of-fair it was. For less obvious surfaces, chalk the batten and "saw" it across the surface at different angles. The chalk will rub off onto the high spots of the surface and you'll see what to fill and what to grind.

[Zach]

A method I'm real fond of, is spraying a real dry coat of a highly contrasting color primer.

While you long board, the low spots will show themselves by being a different color. High spots disappear into the original color. Not shooting for total coverage, but stripes and random misting.

I like the batten trick, will have to try that as its new to me!

[bcooke]

Spray method works but on my Triton the gel-coat is quite porous and the spray paint soaked up inside where all the sanding in the world wasn't going to get it out (short of removing the gel-coat)

I know they make nice fiberglass battens but I just searched for them and couldn't find them. They are out there though. Might take longer to find them than the week drying/adjusting period of a wooden batten.

-Britton

[rshowarth]

What is the difference between a fairing batten and a sail batten?

Can you use a sail batten as a fairing batten?

[Figment]

The spray method essentially leaves the role of the fairing batten up to the longboard. This is fine if you're looking to find small hollows or dings, but for finding unfair areas, you'd need a really long, consistent, longboard.

Of course most boats don't have issues with hard spots at bulkheads or way-out-of-fair transoms.

Would sail battens work? I don't see why not, so long as they're not the tapered kind. You might have to roughen the surface so it will hold chalk, though.
A fairing batten can be anything that, when pinned to three points, naturally springs itself to a fair curve.

[Ancient Race]

What is the difference between a fairing batten and a sail batten?

Can you use a sail batten as a fairing batten?

You can. But you need to distinguish between using battens as gauges, and using them as screeds. Battens are a fairly good tool for assessing the contours of a surface. Sail battens can also be useful as screeds on flat surfaces.

The object of fairing is to identify and fill the holes, rather than slather compound over the entire surface and then sand back to level. (I'm not sure it's necessary to actually chalk or otherwise mark the low spots. Watching the light play across the surface should give you a pretty good idea of where the low spots lay.)

Because of that, sail battens are not so useful in fairing curved surfaces, because they bow, but don't flex to conform to your desired line in the same manner as Figment's small spruce screeds.

Another problem with sail battens is that over time anything used to screed a surface is subject to being torn up by the surface.
So in the fairing process, there's a great deal of contact with hard surfaces as the screed moves over the high points. That's destructive to the tool. As the edge becomes distorted, it becomes less precise. The problem I've had in using sail battens as screeds is that they cost enough that I'm reluctant to pitch them when they've been degraded. Or clogged with resin, or whatever other medium, and likewise tend to draw imprecise plans or pick up material.

[Figment]

The object of fairing is to identify and fill the holes,

Well, now that sounds like "filling holes", not "fairing". The object of fairing is to leave a fair surface, a surface of uniform curvature in all directions.

(I'm not sure it's necessary to actually chalk or otherwise mark the low spots. Watching the light play across the surface should give you a pretty good idea of where the low spots lay.)

This works if the surface is glossy, or if it's a uniform color. Click back to the first page of this thread. ;)

[rshowarth]

screed
One entry found.

screed



Main Entry: screed
Pronunciation: \ˈskrēd\
Function: noun
Etymology: Middle English screde fragment, alteration of Old English scrēade ? more at shred
Date: circa 1789
1 a: a lengthy discourse b: an informal piece of writing (as a personal letter) c: a ranting piece of writing
2: a strip (as of a plaster of the thickness planned for the coat) laid on as a guide
3: a leveling device drawn over freshly poured concrete

OK. So a batten used to observe whether or not the surface is fair is a gauge. When you use it to level the fairing compound by drawing it over the compound material it is a screed. ???

[Figment]

Personally, I prefer "a lengthy discourse". :)

[Ancient Race]

Well, now that sounds like "filling holes", not "fairing". The object of fairing is to leave a fair surface, a surface of uniform curvature in all directions.

A fair distinction, Figment. ;-} I probably should have said that the process of fairing is filling the holes until the surface is uniform.

Too often, in attempting to obtain a surface of uniform curvature, people will tend to spread fairing compound over the entire surface, then grind back to a level that's true. You see it in many of the project photos here.

One of the differences between real plaster and drywall is that plasterers achieve a flat surface by working outward in successively finer, thinner layers, each of which fills the low spots in the preceding coat. Drywall, on the other hand, establishes the final surface with the board itself, and achieves an appearance of trueness by adding material above the desired plane in successively more broadly feathered coats, then sanding back to appear flat.

The point I was attempting to make - poorly, for which I apologize - was that unless you like to sand fiberglass, a sail batten isn't a very efficient tool used as an applicator, as, on edge, it doesn't flex to conform to the surface, and consequently leaves excess material that must be ground off.