Spraying Varnish on Wood Boat Repairs?
way
maintain. I fix every little ding as soon as I discover it. I
varnished a part of my splashboard a few months ago. I used masking
tape so that I would get a straight line between the part that needed
to be varnished and the part that didn't need it. It's not
bad--better than wavy strokes but obviously not as good as the
originally which I think is sprayed on. I am wondering if it is
possible to use something like an airbrush to apply the marine varnish
(for small touch ups) as I don't think there is such a thing as marine
varnish that comes in a spraycan.
I've noticed a Canadian boat builder who makes a composite and wood
boat--great for someone who likes the traditional wood but want to cut
some of the small maintenance work on scuffs down. I'd buy a one of
those in a heartbeat but I neither have the $ nor the storage space
for it right now. So for now I'll have to keep up with the work on
mine.
Henning Lippke
> I love my wooden boat even though it is a heck of alot of work to
> maintain. I fix every little ding as soon as I discover it.
I dare to say that it's easier to maintain a wooden boat than a
composite one. Simply because some basic knowledge in working with wood
is available almost with everyone. So small scratches can be worked on
with little effort and the structure itself is not harmed. After a few
years, you can go to a boatyard and let them clean out all the small
repairs... so far this seems to work.
But I'm also curious on qualified opinions, or better facts, comparing
composite and wooden shells in this matter.
(no time to look up words)
-HL
Tony Curran
maintain. The "man" himself gave me some of the original paint which I keep
for touching up nicks. So far so good. No serious damage.
Tony
Ottawa
"Henning Lippke" <nor...@usenet.org> wrote in message
news:buv2en$mbisn$1...@ID-122207.news.uni-berlin.de...
John Davis
I used to varnish boats all the time back in the glory days. I did
see spray spar varnish, but now that the polyurethanes have come out
and so few wooden hulls have a varnished finish, I doubt it is still
available. They keyes to a good varnish job are extreme cleanliness,
a very good brush, even application and moderate temps (65-80 F). I
still love that smell.
I opened the boathouse doors on a beautiful morning after applying
varnish to an eight, and every fly within a mile lit on the beautiful,
shiny and wet varnish . What a mess.
5...@yahoo.ca (way) wrote in message news:<3956d36b.04012...@posting.google.com>...
way
difficulty in repairing them. Aren't the scuffs easily be covered
with a dab of paint that can be applied from a spray (can)? Strictly
speaking of scuffs and small dings only, I guess I thought composites
were less work because the damaged areas are easier to dry out than
wood. When I find a scratch that has removed the varnish, and water
has penetrated the wood, I worry about how far the water has soaked
in/spread. I know that even after a little blowdrying on the spot it
may feel dry to the touch but there could be moisture still around it
under the surrounding areas protected by varnish that can't be dried
quickly. Also, in the winter it isn't so easy to get anything to dry
in an unheated shellbay with only 3 days between rows. I have seen
wood rot develop on the surface of a rib from water coming in from
screw holes on the opposite side an inch away. I think the water
crept through and started to show on the other side which is well
varnished. I am assuming that unless you have one of those honeycomb
boats, there are not moisture related (wood rot)problems to worry
about with composite boats.
Anyways I guess this is all a different topic from the original
posting.
Any opinions or advice on spraying marine varnish on touchups?
"Henning Lippke" <nor...@usenet.org> wrote in message news:<buv2en$mbisn$1...@ID-122207.news.uni-berlin.de>...
Mike Sullivan
way wrote:
> I know very little about composite boats so I never thought about the
> difficulty in repairing them. Aren't the scuffs easily be covered
> with a dab of paint that can be applied from a spray (can)? Strictly
> speaking of scuffs and small dings only, I guess I thought composites
> were less work because the damaged areas are easier to dry out than
> wood. When I find a scratch that has removed the varnish, and water
> has penetrated the wood, I worry about how far the water has soaked
> in/spread. I know that even after a little blowdrying on the spot it
> may feel dry to the touch but there could be moisture still around it
> under the surrounding areas protected by varnish that can't be dried
> quickly. Also, in the winter it isn't so easy to get anything to dry
> in an unheated shellbay with only 3 days between rows. I have seen
> wood rot develop on the surface of a rib from water coming in from
> screw holes on the opposite side an inch away. I think the water
> crept through and started to show on the other side which is well
> varnished. I am assuming that unless you have one of those honeycomb
> boats, there are not moisture related (wood rot)problems to worry
> about with composite boats.
>
> Anyways I guess this is all a different topic from the original
> posting.
>
> Any opinions or advice on spraying marine varnish on touchups?
I know it's been done but I' ve never done it, you'd have to cut
the varnish to spray properly which means putting on a few coats
where using a brush for small repair is so easy. Why worry about
the cosmetics of your small repair when you are likely refinishing your
boat every 1 or 2 years anyway and you can put a brand spanking new
clean coat on it?
I can always spot a repair varshishing, no matter how well done. It's not
like a car where you can make the new paint and old paint blend through
buffing and polishing. Normal wear will blend it in in a couple months also.
As JD points out, you can get a perfect coat with a brush, and I'd much
rather clean my brush off once than my sprayer 3 times.
Quality brush is important.
Mike
Matthew Turner
between the hard deck and the hull, before taping it over with a pin
stripe the same colour. Surprised at how well it works. It'll be even
easier to use varnish.
I've also spray varnished any number of wooden boats when I was young
and foolish and still doing repairs. It works particularly well on the
"guts" of a boat if you strip off all the metalwork first. Lots of
times the boats I was working on were down to bare wood.
It's got to be a good varnish, of course. I hate polyurethanes, but
that's just me. You also have to watch how you thin. Better to use
varsol/turpentine/paint thinner rather than lacquer thinners (toluene)
or other strong solvents (acetone, commercial autobody thinners). It
takes longer to dry, but there's a whole lot less chance of lifting
the coat unbderneath. Ask me how I know...
It should only take about 15% thinner to get spray consistency,
although that does vary between manufacturers depending on the "solids
content" of the varnish.
I wholeheartedly agree that varnishing is easier than using automotive
paints. There's that whole issue of colour-matching to deal with, and
you wouldn't believe how many different "whites" there are, or even
"blacks".
Then there's the issue of two-component automotive varnish. Staempfli
used to brush on a couple of coats and then do a final spray. It's
tougher than regular varnish, but uses those stronger solvents.
Spraying over a brushed single-component varnish again can lift the
finish and leave a small nightmare.
Expect to pay dearly for really good varnish and really good badger
hair brushes. Lee Valley sells a good set. They're worth the money,
but don't leave them lying around the boathouse or you'll come in some
morning to find them stuck in dried paint in a Tim Hortons mug that
someone's used to paint their blades.
Oh yeah. Keep up the good advertising! Really folks, unsolicited
endorsement!
Regards,
Matt Turner
Turner Racing Shells Ltd.
William R. Platt
"John Davis" <johnn...@yahoo.com> wrote in message
news:f4ba1e33.04012...@posting.google.com...
> thinkbox:
>
SNIP
> I used to varnish boats all the time back in the glory days. I did
> see spray spar varnish, but now that the polyurethanes have come out
> and so few wooden hulls have a varnished finish, I doubt it is still
> available
END SNIP
Very High Quality Spar Varnish, for both spraying and brushing, is most
definitely still available. By far the largest consumers of good varnish
are yachts--and there is still and always will be a healthy demand from that
market.
See Epifanes (my all-out favorite)
Z-spar Flagship
Interlux
Classic Yacht (Philadelphia Resins)
In most cases, spraying is merely a matter of adding a spraying thinner.
But spraying is more technically demanding, and usually inferior in quality
and longevity to a brushed finish. It is more difficult to ensure a good
bond with spray--especially for the amateur.
Regards,
Bill
William R. Platt
To add:
"Polyurethane" is a bad boy only because where we usually see it emphasized
is for indoor floor coatings, where a hard-wearing surface is desirable. On
a shell, you need flexibility and toughness more than hard wearing, along
with resistance to UV light. "Long Oil" based varnishes are generally
superior to Poly in the flex/toughness. I will note however that some of
the best (in fact the very best in my opinion) one component "long oil"
varnishes are infact blends of long oils and Urethane resins.
What makes a department store or hardware store finish, even "spar varnish"
(like McCloskey's or Minwax) unacceptable is 1st the lack of good UV
absorbers, and second, the flexibility and toughness of the finish. I have
tested Epifanes and Z-spar against the regular stuff and found the time
exposure difference extraordinary.
On the one vs two component business, I will add that it is usually ok to
put a one-component varnish over a two component varnish, but not the other
way around (for the resons matthew lays out). Some systems (e.g. Epifanes)
have special tie coatings to make it possible to put two components over 1
components.
Regards
Bill
"Matthew Turner" <ma...@turnershells.com> wrote in message
news:4310826c.04012...@posting.google.com...
Mike Sullivan
"William R. Platt" wrote:
> Excellent advice from Matthew Turner, I agree with all of the points.
>
> To add:
>
> "Polyurethane" is a bad boy only because where we usually see it emphasized
> is for indoor floor coatings, where a hard-wearing surface is desirable. On
> a shell, you need flexibility and toughness more than hard wearing, along
> with resistance to UV light. "Long Oil" based varnishes are generally
> superior to Poly in the flex/toughness. I will note however that some of
> the best (in fact the very best in my opinion) one component "long oil"
Also, you get much better penetration with varnish than Polyurethane.
Much better for protecting the wood from the moisture.
Mike
Carl Douglas
I've read the various comments with interest, but not with total
agreement (nothing out of the ordinary there ;^) ). I note, but do
not accept, the sense that a) wooden boat clear finishes must somehow be
fragile & b) that there is a great mystique in finishing such boats.
The answer is "It all depends".
High-quality modern wooden & wood-composite shells are finished to give
at least as tough and hard-wearing a surface as any other form of
construction. In our case the first stage is a surface impregnation and
sealing with clear epoxy resin. That primed surface is then sanded
level & then sprayed with several coats of clear 2-component lacquer.
Lastly, this lacquer finish is fine papered & machine polished.
Our clear lacquer is a high-quality automotive clear finish - as used
for the final coats of modern vehicles & by some other racing shell
builders. I don't hear too many complaints about the durability of such
finishes, either on cars, or on our shells. Indeed, the clear finish is
much tougher than a normal automotive paint finish alone. We'd only
expect one of our boats to need re-finishing after severe abrasion or
other rough physical contact. For minor nicks & scratches we have
various simple remedies, depending on whether the client is close by or
half-way around the globe.
Now to the business of what happens if such a finish is chipped.
Contrary to popular belief, wood is very water-tolerant. Sure it shows
that it has become damp. But it has to be left a very long time before
it starts to deteriorate - incomparably longer than it takes your car to
rust after a ding. Well-laminated wood constructions are highly moisture
resistant, the water migrates inward only slightly & if you allow the
damaged zone to dry out (a few days in a warm dry atmosphere) it is
usually invisible.
How you then make good the surface damage depends on how the original
finish was applied. We do not recommend applying varnish directly, & we
would anyway avoid all traditional & single-pack finishes except
so-called moisture-cure polyurethane. The first job is to re-seal the
surface damage (subject to whatever repair & preparation first needs
doing) with a compatible clear epoxy, usually assisted by the
application of gentle warmth. Then level that cured surface to just
below the original finish with fine papers & a hard block, finishing off
with Scotchbrite. Mask off the rest of the boat & spray several fine
coats of an appropriate 2-pack polyurethane (or acrylic) clear coat
finish (suitably thinned) with an "air brush" (a small spray gun). The
surface will dry very quickly, so re-apply at intervals maybe as short
as every 30 minutes, depending on conditions & material.
Done in that way the finish adhesion will be perfect. No other
finishing materials are anything like as hard or as durable.
Now some cautionary advice:
1. You can't repair a finish unless the substrate is completely dry.
The same applies to glass, carbon & Kevlar constructions, all of which
have the tendency to absorb water if damaged but, unlike wood, don't
show you it has happened.
2. Modern 2-component finishes are far tougher than anything else in
common use, yet they are really quite resilient. They are far better
than traditional finishes. But they must not be applied on top of
traditional finishes such as yacht varnish. The residual oiliness in
those traditional air-drying materials (which rely on the reaction of
atmospheric oxygen with various natural "drying oils") is an effective
release agent, causing other materials to flake off after a time. So
you must know what you have there already before you can do a proper DIY
repair.
3. Polyurethane & acrylic 2-part automotive finishes all contain
isocyanates. Isocyanates are poisonous and allergenic. If you spray
them, you _must_ wear an air-fed mask so that you have no chance of
breathing in the sprayed vapour. Otherwise you must apply by brush,
suitably thinned out with a slow thinner to preserve a wet edge - brush
slowly with a well-filled brush or you will not adequately wet the
surface.
4. Good finishing depends on good preparation. The surface to be
lacquered should be 100% abraded (no residual shininess) to make it
receptive & entirely free from any kind of contamination (grease from a
finger print, or worse, can wreck a finish).
If your boat has a traditional varnish finish it can still be refinished
by spraying (use a suitable solvent dilution to allow proper
atomisation). First you must fully seal the substrate, which must be
done by applying diluted varnish in several consecutive coats, either by
a brush or with a lint-free cloth. Then you must sand the old & new
materials to a constant level. But, again, it is absolutely essential
that the surface to be sprayed has been fully abraded and is truly clean
before spraying. The devil is in the detail, and most revarnishing that
fails does so because the surface was plain dirty or unabraded in
patches (you have to really look hard to see what you may have missed -
especially in the corners).
HTH -
Carl
--
Carl Douglas Racing Shells -
Fine Small-Boats/AeRoWing low-drag Riggers/Advanced Accessories
Write: The Boathouse, Timsway, Chertsey Lane, Staines TW18 3JY, UK
Email: ca...@carldouglas.co.uk Tel: +44(0)1784-456344 Fax: -466550
URLs: www.carldouglas.co.uk (boats) & www.aerowing.co.uk (riggers)
Matthew Turner
My dislike of single-component polyurethanes is that they're
formulated for the DIY crowd who want to, say, varnish a chair in one
application. The stuff goes on thick and glossy, so people like their
chairs etc. but it also chips off thick and glossy leaving bare wood
underneath, and in my experience it doesn't re-coat well at all.
My favourite varnish used to be a relatively inexpensive Valspar that
I believe was bakelite-resin based with UV filters. Not made any
longer. Some varnishes won't cure over top of epoxy, either.
On "this side of the pond" lacquers are nitrocellulose based, and
there's not much of a chemical reaction. It dissolves in toluene, and
you need a whole lot of coats to build up layers.Automotive lacquer
used to be like that, and I don't even think it can be bought anymore.
What you use also depends on the application. Varnishing wooden oars
or re-finishing an old boat is fair game for single component
varnishes, especially if they belong to a club and the other option is
they never get done. Two-component sprays are probably well beyond the
capability of most rowing club repair bays. Even then, they're easier
than two-component paints that need to be colour-matched, or
(shudder!) have metallic finishes in them. I think this area is
getting to be a concern with the number of different finishes being
used by companies. It's in everyone's interest if the boats aren't too
difficult to touch up.
Spraying equipment is costly if it's good, and the better the
equipment, the better the chance you'll do a good job. If you do go to
buying a small airbrush, get one that's gravity rather than siphon
fed. I don't use any siphon-fed equipment in my shop. Also, the whole
question of HVLP (high volume low pressure). Usually lots more
expensive, but reduces overspray and makes life a bit easier. That's
only for larger touch-up guns and full size spray guns, though.
The other reason a good spray outfit is incompatible with rowing clubs
is cleaning. You can easily drop $500 on a good Devilbiss JGA HVLP and
another $500 on a pressure cup, and if one person leaves it full of
2-component paint, it all becomes a doorstop.
Hope that makes the issue even more convoluted and confusing....
Neil Wallace
"Carl Douglas" <Ca...@carldouglas.co.uk> wrote in message
news:oJTcAen8...@rowing-cdrs.demon.co.uk...
snip
>(grease from a finger print, or worse, can wreck a finish).
"or worse"?
Not too sure what you mean Carl. It just doesn't scan right. What's worse
than a finger print? My mind boggles.
Should that read...................
(grease from a finger print, kebab, weeping pustule or anal fistula, can
wreck a finish).
Neil
(not a fan, but perhaps an exponent of, wrecked finishes)
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...... it's the mercury your honour.
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