Fairing question

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fallguy1000
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Fairing question

Post by fallguy1000 » Wed Jul 31, 2019 12:25 am

If you have to fair something like a tape ridge, how far away from the ridge do you need to go to fool the eye?

In the picture below, consider a blue tape ridge 1/16th inch proud and the black lines represent the side of the ship running 10 feet in either direction. The top and bottom edges start fair.

How far do you need to go to deal with the tape ridge?

Going 10' seems like too much.
94ECCFC4-C011-4C84-8AA7-AE0B28692606.png


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Evan_Gatehouse
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Re: Fairing question

Post by Evan_Gatehouse » Wed Jul 31, 2019 12:32 am

It depends on the curvature of the hull / deck.

On a totally flat surface you'd need to blend the fairing out for a much longer distance.

For moderate curve maybe 6" either side of the tape.
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fallguy1000
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Re: Fairing question

Post by fallguy1000 » Wed Jul 31, 2019 12:35 am

Evan_Gatehouse wrote:
Wed Jul 31, 2019 12:32 am
It depends on the curvature of the hull / deck.

On a totally flat surface you'd need to blend the fairing out for a much longer distance.

For moderate curve maybe 6" either side of the tape.
My hulls are very flat. I only have a few of these to deal with..

I also have some spots where I sanded through triax a tad. Should I neat coat those before I start to fair?

Thanks!
C5B9F84C-1D64-48C7-8687-57B16A2E2094.jpeg
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piperdown
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Re: Fairing question

Post by piperdown » Wed Jul 31, 2019 8:17 am

That's similar to taping drywall if you think about it. When I've watched the pros taping and mudding the widest knife I've seen was a 14 inch. Of course those guys start with an 8 and go 2 layers and one pass with the 14 and bam, smooth as if there wasn't a seam at all.

I think Even is right, about 6 inches on either side with the edges feathered.

Didn't you say you had a drywall guy that was going to help with the fairing?
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Re: Fairing question

Post by fallguy1000 » Wed Jul 31, 2019 8:55 am

piperdown wrote:
Wed Jul 31, 2019 8:17 am
That's similar to taping drywall if you think about it. When I've watched the pros taping and mudding the widest knife I've seen was a 14 inch. Of course those guys start with an 8 and go 2 layers and one pass with the 14 and bam, smooth as if there wasn't a seam at all.

I think Even is right, about 6 inches on either side with the edges feathered.

Didn't you say you had a drywall guy that was going to help with the fairing?
Yeah. I have a drywall guy coming at some point. But drywall guys are not as good as auto body peeps.

6" would show sighting down the hull...

I have a 20"+ trowel and a 30"+ trowel, but there comes a point when a guy can just go too far. A single hump could be faired back the 10 feet.

Maybe I need to get a flourescent light that can go up and down on a stick.

What about precoating my sand through spots?

Thanks. Maybe I need to also build a new base(s) for my Festool for some of the areas longboarding won't fit.
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piperdown
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Re: Fairing question

Post by piperdown » Wed Jul 31, 2019 10:55 am

fallguy1000 wrote:
Wed Jul 31, 2019 8:55 am
piperdown wrote:
Wed Jul 31, 2019 8:17 am
That's similar to taping drywall if you think about it. When I've watched the pros taping and mudding the widest knife I've seen was a 14 inch. Of course those guys start with an 8 and go 2 layers and one pass with the 14 and bam, smooth as if there wasn't a seam at all.

I think Even is right, about 6 inches on either side with the edges feathered.

Didn't you say you had a drywall guy that was going to help with the fairing?
Yeah. I have a drywall guy coming at some point. But drywall guys are not as good as auto body peeps.

6" would show sighting down the hull...

I have a 20"+ trowel and a 30"+ trowel, but there comes a point when a guy can just go too far. A single hump could be faired back the 10 feet.

Maybe I need to get a flourescent light that can go up and down on a stick.

What about precoating my sand through spots?

Thanks. Maybe I need to also build a new base(s) for my Festool for some of the areas longboarding won't fit.
I would neat coat if it were me.

I've got friends that have restored cars and also know a couple body guys (Dads from scouting). They all layer it on thick and sand it back down then look at it from all angles with bright lights. Even better is a bright day outside (according to them). Easy for them since they just roll it outside. Bit trickier for you since you'd have to have them on dollys. I'd get a couple of big bright lights that can be angled and use them to eyeball the fairing.
Eric (aka, piperdown)

"Give an Irishman lager for a month and he's a dead man. An Irishman's stomach is lined with copper, and the beer corrodes it. But whiskey polishes the copper and is the saving of him." --> Mark Twain

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Re: Fairing question

Post by fallguy1000 » Wed Jul 31, 2019 11:05 am

Thank you Eric.
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Re: Fairing question

Post by terrulian » Wed Jul 31, 2019 11:43 am

Light is more essential to the final paint/varnish than to fairing. The key to this is a guide coat of a light dusting of spray paint or graphite powder. This will do a good job of revealing the holidays. Cracker Larry used water but he was working on a covered concrete slab outside; I couldn't justify flooding my shop. The guide coat, in my case, had to be used several times but in the end you can get a decent result, even if you start with this kind of mess:
Image
and paint with a dark color, as I did.
Image
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Re: Fairing question

Post by OrangeQuest » Wed Jul 31, 2019 12:49 pm

Very nice Tony!! I think I see an ant crawling across the floor carrying a few grains of sugar in the reflection!
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Re: Fairing question

Post by piperdown » Wed Jul 31, 2019 4:31 pm

I agree and should have included that they eyeball it close after sanding down to match the contours but they use the lights (or sunlight) after the primer is on. And again after painting.
Eric (aka, piperdown)

"Give an Irishman lager for a month and he's a dead man. An Irishman's stomach is lined with copper, and the beer corrodes it. But whiskey polishes the copper and is the saving of him." --> Mark Twain

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