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Thread: Fairing a surface

  1. #1
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    Default Fairing a surface

    I知 in the process of removing the old sick paint from my trunk cabin sides. The surface material is 75 year old vertical Western Red Cedar staves. So in the process of sanding, how do I know I知 not creating hills and valleys in this soft material? I of course keep the sander flat and moving and try to sand as evenly as possible. But then are there tricks to checking fairness? Do you close your eyes and run a hand over it and chalk circle high points? Or do you prime it and then visually check and correct it? How do you good finishers keep the surface fair?

    Ive sanded more since this pic, but this is the surface in question. I知 hoping to put a gloss white finish on it but that will show any divots or unfairness I may have created.

    82CD1682-84B9-4964-9F52-F1B73BE31F83.jpg

  2. #2
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    Default Re: Fairing a surface

    After you finish sanding, put a thin coat of easy sanding primer on and then long board the surface. Low spots will retain paint. You don't need to get carried away long boarding if you are willing to use filler. That is fill the low surfaces, long board again, reprime and repeat. You should have a pretty fair surface after two to three rounds.

  3. #3
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    Default Re: Fairing a surface

    Primer and longboard works, but you can sometimes jump in earlier, depending. If you rub a chalked batten on periodically as you sand, you'll be able to see how it's shaping up... or down
    David G
    Harbor Woodworks
    https://www.facebook.com/HarborWoodworks/

    "It was a Sunday morning and Goddard gave thanks that there were still places where one could worship in temples not made by human hands." -- L. F. Herreshoff (The Compleat Cruiser)

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    Default Re: Fairing a surface

    I have some z-spar High Hide primer. But not sure that is the best thing to start with on bare wood. Seems kind of thick to penetrate as a sealer. Maybe I should put a thinner sealer primer on first?

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    Default Re: Fairing a surface

    Ron, you really need to hook up with an experienced wooden boat painter in your neighborhood. Somebody who's done it for a living, not some internet idiot.'

    First, you don't ever remove paint on a surface like that with a sander if you want it to remain fair and if you intend to paint the surface with a gloss finish, every bit of unfairness will definitely be highlighted by your brutal sanding job.

    Paint is properly stripped with a sharp scraper and a heat gun with a gel paint stripper to get into the nooks and crannies, if need be.

    When down to bare wood as perfectly square and smooth as a baby's bottom, seal the wood with CPES (Smith's Clear Penetrating Epoxy Sealer.) (Do not use "thinned" epoxy adhesive resin!) You can also seal the surface with shellac. The purpose of this is to inhibit moisture absorption by the wood which results in blistering and peeling of the paint.

    Apply a sanding undercoat, preferably by spraying to avoid brush strokes which have to be sanded fair. You can build the basecoat faster that way. It should fill all the tiny nicks and imperfections. If those are too deep, used "surfacing putty" (sometimes called "glazing putty.") It must completely cover the darker wood so that the surface is absolutely white. Gloss enamel finish coats will not cover dark splotches. If you want a white finish, the undercoat must be pure white. Sand it fair to 220 grit smoothness. If any dark splotches show up start over with more undercoat sanded fair until all the dark is covered. Then apply three properly conditioned gloss top coats.

    You'll probably need a local pro to show you how (if you can find one to share the tricks of the trade.) Conditioning paint involves thinning and conditioning (Rx: Flood's Penetrol) until the proper consistency for application and leveling is achieved. That is dependent upon many factors, including ambient temperature and humidity which really can't be explained here.


  6. #6
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    Default Re: Fairing a surface

    All good advice Bob and I appreciate it. However it may be slightly overkill for this old workboat. My goal at this point is to get it considerably better than it was, and I think I知 getting there. But it isn稚 going to be a Bristol yacht finish. As far as 澱rutal sanders go, I知 reminded of the late Dudley Davidson (old PNW locals will remember him). A big guy with arms the size of tree trunks, he used to 層ood boats with a big old metal disc sander while singing opera under his respirator hood. And when he was done with that brutal disc sander, the surface was baby butt smooth and ready for paint. Now I知 no Dudley, but I do have some experience holding a sander flat and moving it gently in the right directions.

    I decided to to start with Interlux Pre-Kote and so far the surface looks pretty fair, of course the gloss coat may make a liar of me. Again I appreciate your advice and even tho I don稚 work to your high standards, it helps to know what the proper procedures are.

    87E5CBEC-EA32-4B00-8CF9-3B5C30ADCB2D.jpg

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    Default Re: Fairing a surface

    I dunno if it's neccesary to refer to the previous posters as internet idiots.

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    Default Re: Fairing a surface

    First off, that looks like a handsome vessel you're working on there. I did a lot of repair and rebuilding work in the Pacific Northwest and Alaska, including working on the Exxon Valdez oil spill repairing boats damaged in cleanup operations. I met Dudley Dix's successor who was operating a dry dock in Prince William Sound. He was the guy Dix referred to in the Wooden Boat article as the "perfect replacement: someone with a size 46 jacket and a size five hat". I've forgotten his name but I do remember he was some kind of funny...

    John

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    Default Re: Fairing a surface

    Quote Originally Posted by Phil Y View Post
    I dunno if it's neccesary to refer to the previous posters as internet idiots.
    +1

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    Default Re: Fairing a surface

    Will someone please explain/describe the use of the "longboard" in surface prep? I've seen references to it, but would like to see/hear/read a description of the procedure.
    Thanks
    pvg

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    Default Re: Fairing a surface

    A longboard is a flexible, but not floppy sanding board that you put sand paper on full length. The board should be flexible enough to conform to the hull, but stiff enough to span low spots. There are handles of some sort on the back. The idea is that the board can be bent to conform to hull curvature and spans a long enough distance to sand out imperfections. I have seen long boards from 18" to over 6'. Boards over 2.5'-3' normally require two people. How long you use depends on the hull form. When fairing in a new plank I normally longboard diagonally across the plank. It is tedious work.

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    Default Re: Fairing a surface

    Quote Originally Posted by Phil Y View Post
    I dunno if it's neccesary to refer to the previous posters as internet idiots.
    What do you call 100 attorneys at the bottom of the sea?
    Simon

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    Default Re: Fairing a surface

    Ron she’s looking really ��
    Simon

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    Default Re: Fairing a surface

    Thanks Todd D, good description; sounds like it's not used on plywood/lapstrake hulls like many Oughtred designs?
    pvg

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    Default Re: Fairing a surface

    I won't pretend that I'm a painter, but I've seen some good ones do good work and it seems like their general process is to start with smaller and less precise tools such as grinders and disk Sanders and slowly work up to longboards. In particular most painters I've observed have used different color fairing compounds and primers to help differentiate highs and lows. All that said there do exist folks who can fair a boat with nothing but an angle grinder.

    Nicholas

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    Default Re: Fairing a surface

    Quote Originally Posted by LISC View Post
    What do you call 100 attorneys at the bottom of the sea?
    Im an attorney, so you'll have to explain that one to me.

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    Default Re: Fairing a surface

    Quote Originally Posted by LISC View Post
    What do you call 100 attorneys at the bottom of the sea?
    I believe the correct answer is:

    A good start...

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    Default Re: Fairing a surface

    Quote Originally Posted by ron ll View Post
    That's an interesting way your deck was laid. I'm not familiar with that approach. Can you provide some details on the way the outer planks are nibbed into the inner ones?

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    Default Re: Fairing a surface

    Quote Originally Posted by Junkyard Dog View Post
    That's an interesting way your deck was laid. I'm not familiar with that approach. Can you provide some details on the way the outer planks are nibbed into the inner ones?
    Not sure I would call it "nibbed". But these are true 1-1/2" fir planks visible from under as well. I should also note that this deck has been a problem leaker in late summer.

    foredeck.jpg

  20. #20
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    Default Re: Fairing a surface

    If you are referring to this, it is a common way to avoid a "feather edge" so narrow that that you cannot get a fastener into it.

    IMG_4065.jpg

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    Default Re: Fairing a surface

    Quote Originally Posted by Canoeyawl View Post
    If you are referring to this, it is a common way to avoid a "feather edge" so narrow that that you cannot get a fastener into it.

    IMG_4065.jpg
    Yes, that is what drew my interest. I'm used to seeing sprung or curved planks nibbed into a straight, king plank in what we would call Yacht Lay, or straight planks nibbed into a curved margin plank in what we would call Ship Lay.

    This is a sort of reverse nibbing that I've not run across before. Very interesting, and thanks.

    Apologies for the thread drift.

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    Default Re: Fairing a surface

    I am coming in late with this but, I often use a form of long board that is used in body and fender work to fair surfaces. This is an air powered tool, that can be purchased from Harbor Freight. It is called an "air file" or "in line sander". I bought mine from Harbor Freight for around thirty dollars. Amazon has them as well. I wouldn't leave home without mine!
    Jay

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    Default Re: Fairing a surface

    Quote Originally Posted by Jay Greer View Post
    I am coming in late with this but, I often use a form of long board that is used in body and fender work to fair surfaces. This is an air powered tool, that can be purchased from Harbor Freight. It is called an "air file" or "in line sander". I bought mine from Harbor Freight for around thirty dollars. Amazon has them as well. I wouldn't leave home without mine!
    Jay
    Excellent idea! Will it work with a small 2 gallon compressor though?

    Oops. Just realized this has no dust collection which is a deal breaker when working in the water at the marina.
    Last edited by ron ll; 06-03-2018 at 02:44 PM.

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    Default Re: Fairing a surface

    Quote Originally Posted by ron ll View Post
    Excellent idea! Will it work with a small 2 gallon compressor though?

    Oops. Just realized this has no dust collection which is a deal breaker when working in the water at the marina.
    There are in-line sanders that have dust collection. http://www.hutchinsmfg.com/View-Prod...roup_id=424052
    The pain in my old shoulders makes the cost easier to justify.

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    Default Re: Fairing a surface

    Quote Originally Posted by Phil Y View Post
    I dunno if it's neccesary to refer to the previous posters as internet idiots.
    If you've got a better term, by all means go for it. The internet is full of bad information, and even intentional misinformation, as most recently proven by national election results. There was no intention to specifically identify or address any previous poster in this thread as an "idiot." (I myself assume the risk of others' disagreement whenever I post as well.) The simple fact, however, is that in internet DIY sites such as this one, the advice given in responses is usually about 20% dead wrong, 50% "not the best practice," about 20% correct only if you allow for reasonable minds differing, and 10% absolutely correct to professional standards. The reader has to have a rather critical mind to discern the truth of it.

    Some will argue that they aren't interested in a professional level result. That's their choice. It's a shame in most instances when its a well-built boat to begin with because the first purpose of paint and varnish isn't appearances, it's protection of the wood beneath it. Preparation is the most important job in finishing work. Fair bare wood is the best substrate for sealers and paint or varnish. The less fairing compound the better. (Fairing putty isn't really intended to cure the problem of a six-inch "dish" caused by a moment's inattention with a disk sander, either.) Poor painting and varnishing, particularly with respect to initial sealing, results in joints eventually soaking up moisture and promoting rot. In this instance, for example, I expect a professional yard's first step would have been to remove all the fittings, such as the portlights' outboard trim rings, and wooded beneath them, and then, after sealing well and completing the paint job, replaced the trim rings, bedding them anew on top of the new paint job with proper bedding compound. This creates a water tight seal around the portlights. Just taping and painting to the outer edge of the trim rings doesn't ensure a continuous coating. There's no need necessarily to pull the trim rings when later adding maintenance topcoats if there's no separation between the older paint coats and the trim rings and such, but when one is wooding the entire area, the extra work of wooding, sealing, and rebedding the fittings will likely save a lot of work down the road. It also makes the painting a lot easier, reducing the time for masking and lessening the chances of runs and curtains from the fittings. If there is an intersection between old paint buildup and the new paint, the paint coating will eventually crack at the "joint" between the old paint and the new where it meets the trim ring and will start to peel, if not rot, as moisture enters through the joint between the new paint and the old. The "professional job" is never "overkill," because the purposes of "professional level" work almost always have important practical purposes.
    Last edited by Bob Cleek; 06-03-2018 at 05:22 PM.

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    Default Re: Fairing a surface

    Quote Originally Posted by Jay Greer View Post
    I am coming in late with this but, I often use a form of long board that is used in body and fender work to fair surfaces. This is an air powered tool, that can be purchased from Harbor Freight. It is called an "air file" or "in line sander". I bought mine from Harbor Freight for around thirty dollars. Amazon has them as well. I wouldn't leave home without mine!
    Jay
    I'm betting you don't use it to strip paint, though, do you?
    Last edited by Bob Cleek; 06-03-2018 at 05:27 PM.

  27. #27
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    Default Re: Fairing a surface

    Ron, an amateur's perspective FWIW here, since I just did this exact job last year. I stripped the cabin on Petrel with a heat gun and scraper (maybe verboten at Shilshole, at least without a tarp?) and then went over it with a RO and 80 grit. Cedar just like yours. I'm sure the experts will tell me that 80 grit in a RO is guaranteed to result in the complete destruction of that soft wood and render it unpaintable but the cabin staves were pretty rough to begin with, I was careful, and I ended up perfectly happy with the result for gloss paint. I think you could longboard the cabin on Snoose and it would look stunning for about six months. After which the joints between the staves will start to show again. And then it will still look stunning, it just won't look like a perfectly-longboarded, yacht-quality paint job any longer.







    (It does need another coat...)

  28. #28
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    Default Re: Fairing a surface

    Quote Originally Posted by Bob Cleek View Post
    If you've got a better term, by all means go for it. The internet is full of bad information, and even intentional misinformation, as most recently proven by national election results. There was no intention to specifically identify or address any previous poster in this thread as an "idiot." (I myself assume the risk of others' disagreement whenever I post as well.) The simple fact, however, is that in internet DIY sites such as this one, the advice given in responses is usually about 20% dead wrong, 50% "not the best practice," about 20% correct only if you allow for reasonable minds differing, and 10% absolutely correct to professional standards. The reader has to have a rather critical mind to discern the truth of it.

    Some will argue that they aren't interested in a professional level result. That's their choice. It's a shame in most instances when its a well-built boat to begin with because the first purpose of paint and varnish isn't appearances, it's protection of the wood beneath it. Preparation is the most important job in finishing work. Fair bare wood is the best substrate for sealers and paint or varnish. The less fairing compound the better. (Fairing putty isn't really intended to cure the problem of a six-inch "dish" caused by a moment's inattention with a disk sander, either.) Poor painting and varnishing, particularly with respect to initial sealing, results in joints eventually soaking up moisture and promoting rot. In this instance, for example, I expect a professional yard's first step would have been to remove all the fittings, such as the portlights' outboard trim rings, and wooded beneath them, and then, after sealing well and completing the paint job, replaced the trim rings, bedding them anew on top of the new paint job with proper bedding compound. This creates a water tight seal around the portlights. Just taping and painting to the outer edge of the trim rings doesn't ensure a continuous coating. There's no need necessarily to pull the trim rings when later adding maintenance topcoats if there's no separation between the older paint coats and the trim rings and such, but when one is wooding the entire area, the extra work of wooding, sealing, and rebedding the fittings will likely save a lot of work down the road. It also makes the painting a lot easier, reducing the time for masking and lessening the chances of runs and curtains from the fittings. If there is an intersection between old paint buildup and the new paint, the paint coating will eventually crack at the "joint" between the old paint and the new where it meets the trim ring and will start to peel, if not rot, as moisture enters through the joint between the new paint and the old. The "professional job" is never "overkill," because the purposes of "professional level" work almost always have important practical purposes.
    I know I'm just pissing into the wind here Bob but actually there's just no need to be offensive when you give advice. It just makes you look like a dick.

  29. #29
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    Default Re: Fairing a surface

    "Professional" just means someone paid for the job. There are all sorts of professionals on this forum and I haven't heard any of them agree on a single definition of "best" finishing technique yet (can we get a side discussion on varnishing going here just for fun?). Someone wake me when that happens. In the meantime I'm going to go on record as saying that a) I'm pretty sure we all agree that creating a continuous, unbroken film with good adhesion to the substrate is critical for protection and b) insisting on a single "100% absolutely correct" standard for professional finishing is ludicrous. No one really believes that an old fishing boat should be painted to the standards of the Hinckley yard. Not even Hinckley. And I would love to hear any professional boat finisher make that argument to a working lobsterman or salmon troller. In fact, I'd pay to watch it.

  30. #30
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    Default Re: Fairing a surface

    Quote Originally Posted by Bob Cleek View Post
    I'm betting you don't use it to strip paint, though, do you?
    As Herreshoff once stated, "Only a damn fool would do that!"
    Jay

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    Default Re: Fairing a surface

    Quote Originally Posted by Phil Y View Post
    I know I'm just pissing into the wind here Bob but actually there's just no need to be offensive when you give advice. It just makes you look like a dick.
    You're probably right, but I have no way of knowing who's going to take offense in the etherspere and more interest in seeing somebody get good advice, whether they choose to take it or not, than to stand silent because I worry about what people think I look like. I've never ever been able to master the fine art of graciously telling somebody they have their head up their ass. It's certainly a curse, I suppose, but I've learned to live with it. I guess the best course is to leave the blind to lead the blind in the course of their lemming-like migration.

  32. #32
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    Default Re: Fairing a surface

    Hey, I don't get offended by offensive comments made to me here. I just consider the source and forgive them.
    Jay

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    Default Re: Fairing a surface

    Quote Originally Posted by cstevens View Post
    "Professional" just means someone paid for the job. There are all sorts of professionals on this forum and I haven't heard any of them agree on a single definition of "best" finishing technique yet (can we get a side discussion on varnishing going here just for fun?). Someone wake me when that happens. In the meantime I'm going to go on record as saying that a) I'm pretty sure we all agree that creating a continuous, unbroken film with good adhesion to the substrate is critical for protection and b) insisting on a single "100% absolutely correct" standard for professional finishing is ludicrous. No one really believes that an old fishing boat should be painted to the standards of the Hinckley yard. Not even Hinckley. And I would love to hear any professional boat finisher make that argument to a working lobsterman or salmon troller. In fact, I'd pay to watch it.
    Chris, my definition of a "professional job" is simple: A professional job is one I'd be satisfied paying for. That covers a wide spectrum, depending on the circumstances. Other people's mileage may vary. There is indeed such a thing as a "workboat finish." It is not synonymous with shoddy workmanship at all. Often, it's only the difference between paint and varnish. The working waterman must always strike a balance between maintaining his boat and his bottom line and it often shows.

  34. #34
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    Default Re: Fairing a surface

    Chris, your trunk cabin looks great and you are absolutely correct about the wood coming and going. I have no doubt that by the end of the summer those seams will be so open you could play a harmonica thru them. This project was to get rid of the PO’s latex paint and the various touch ups that had been done since. The goal is improvement, not perfection. These are 75 year old boats that I think look pretty nice considering. And in the 15 years that I’ve had Snoose, I like to think I improved her. I agree with Mr. Cleek on one thing, there are idiots giving advice on the internet. The trick is to know which ones they are.

  35. #35
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    Default Re: Fairing a surface

    Bob, You are right! I have worked with some pros' that I wouldn't trust to sweep the shop floor without supervision! So, there is a lot of meaning in the term, "You get what you pay for!"
    Jay

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