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MICHAEL S
12-24-2003, 01:25 AM
What a great forum! Your responses to my postings have been wonderful – both in quantity and quality. I seem to have generated a little friendly (I hope) controversy as well (add floatation – don’t add floatation. Make sails – buy sails). Although after reading some of the other postings (POW for instance) I think I’m on pretty safe ground.

There seems to be some Kharma happening to me lately that is driving me toward water. Or maybe it’s just cabin fever. It started this last summer when I by chance glanced through a copy of WoodenBoat. I have been thinking about making a small sailboat ever since I saw the little Clancy boat Norm Abrams built on the New Yankee Workshop, but after looking through WB I kind of fell for the little shellback dinghy instead.

A few weeks ago I purchased the model and the book on building the full size boat. I had not built any ‘scratch’ type models before and was surprised how much I enjoyed it. I enjoyed it so much I blew off my work and finished it in about three days! (I paid for that with several late nights of work trying to catch up.)

Now I was hooked. If I had the cash I would have ordered the shellback dinghy kit from WB right away. Instead, I started trying to find and price materials to build it from scratch. I guess I haven’t mentioned (in this posting anyway) that I live in Colorado about two thousand miles away from and almost two miles above the nearest ocean. At first I despaired. I could not find marine plywood. I could not find marine paint. I could not find marine anything. So I resigned myself to wait until the money was there and buy the kit after all.

Then I found this forum and started posting questions to you folks (If I couldn’t build it at least I could talk about it?). Now I’m really hooked. So today I took the 90 minute drive to the only lumber yard in the state that carries marine plywood. It is AB fir plywood, not the mahogany that most of you recommend but it will have to do. I know I know, there is such a thing as mail order – but I don’t want to wait and with Christmas and all money is particularly tight right now. Also I have a few days off and I want to use them.

So tomorrow I start scarfing!

I know you all wish me luck.

Happy Holidays to all and thank you for the inspiration,

Michael S.

P.S. On the way home from purchasing the plywood I happened to stop in a local thrift store and found a wetsuit, scuba tank, two buoyancy vests, flippers and weight belt, all in my size, all in new condition, and all for only $125! Kharma! I think I see a road trip coming on…….

On Vacation
12-24-2003, 06:27 AM
LOL, I told you there was roads leading you out of bondage!!!!

cs
12-24-2003, 06:31 AM
Congrts Michael! You are embarking upon a journy where you will expierance the highs and the lows, Please check your sanity at the door.

Chad

On Vacation
12-24-2003, 06:59 AM
Originally posted by cs:
Congrts Michael! You are embarking upon a journy where you will expierance the highs and the lows, Please check your sanity at the door.

ChadBe carefull Chad, Speelchecker will be long in a bit, to point out your sanity checked at the door. ;)

NormMessinger
12-24-2003, 08:04 AM
Good for you, Grasshopper. But don't dispair about your distance from the saltwater. You are almost in as good a situation as I am, equidistant from two of the Earth's great oceans and half that to to Gulf. Now imagine how far Oyster would have to pull his rig if he wanted to wet his skiff in the Pacific.

The fir plywood will make a perfect boat for you. I made our first MacGregor, Oughtred designed sailing canoe, from AB fir marine. It is a bit heavier than the second one which I made from BS1088 okoume from Boulter and there was some checking in the face veneers that epoxy saturation would have minimized I think. You'll be proud. And we will too, vicariously.

Willin'
12-24-2003, 09:30 AM
Welcome to the sanitarium Michael smile.gif

Now look out, 'cause here comes some free advice!

Don't worry about marine paint. Your shellback probably won't live in the water anyway, and if you're like me you'll keep your baby well sheltered when not in use. I've gotten excellent mileage out of run o' the mill oil base paint found at your local hardware or big box store. A lttle penetrol works wonders, they can usually match colors with the traditional marine paints and the cost is more wallet friendly, especially after having repainted twice in the first year (those first scratches are really painful).

The other benefit to scratch building is you can choose how fancy or plain you want to go. I put a little brightwork on mine to make it stand out from the hundreds of painted out tenders I've seen around. You may not have that option if you buy the kit.

Lastly, despite the well intentioned and knowledgable advice from our members here, it is not essential that you use Sitka spruce, old growth genuine mahogany or white oak grown on the north side of the hill. While those materials have all proven their merit over the years, garden variety lumber yard doug fir, pine and spruce will get you on the water just as well and a lot cheaper. And no matter what it's made of, you'll be proud and we'll be complimentary when you post the pic.

Hope you enjoy the process, Shellbacks are sweet boats.

Cheers,

Mark

JimD
12-24-2003, 10:04 AM
Originally posted by Oyster:
LOL, I told you there was roads leading you out of bondage!!!!I though makin' your own boat was just a new road to bondage :D

Jon Etheredge
12-24-2003, 10:07 AM
It is AB fir plywood, ...

So tomorrow I start scarfing!
Michael,

You may already have a good plan for cutting your scarf joints but I'll throw in an option that you may not have considered...

I usually cut scarf joints with a hand plane. With a sharp plane iron this is a pleasant task that is quick enough for my needs. Fir ply is a different story though. It always seems a chore. Lately, I have been using a 50 grit belt on my trusty Porter-Cable belt sander and this has made the task much easier (but noisier) and I find the results to me of much better quality. The belt sander eliminates the tear out and other problems that seem to be unavoidable when trying to cut scarfs in fir ply. I'll still use a hand plane for other, easier to work, materials but the belt sander is my tool of choice for the fir play.

This technique probably won't be to everyones taste but it does work well for me,

Have fun on your project!

Bob Smalser
12-24-2003, 10:13 AM
using a 50 grit belt Try 26 grit to take it down even quicker and 50 to 80 grit to finish.

Bob Smalser
12-24-2003, 10:30 AM
using a 50 grit belt Try 26 grit to take it down even quicker and 50 to 80 grit to finish.

MICHAEL S
12-24-2003, 11:01 AM
So ‘belt sander’ is not the dirty word I assumed it was. Since no one mentioned it till now I assumed they were a no-no. I’m sure some out there do think it’s a no-no and to an extent I agree – nothing can ruin fine woodworking faster than a belt sander. But careful use of one sure can save a lot of time and elbow grease.

I was kinda planning on using one anyway and not telling anyone.

Thanx for the tip and don’t worry - I’ll be careful.

Michael smile.gif

P.S. I do own a hand power plane but have found it even easier to ruin a project with it than a belt sander. Maybe I just need more practice.

NormMessinger
12-24-2003, 11:11 AM
Didn't you tell us in another thread that you were a carpenter? That probably precludes the need for adivce on how to do a specific task. I prefer to have the kids use the belt sander to make scarfs in plywood. Less chance of damage to board or limb. Power plane to knock down the high spots and a good sharp hand plane to hone the edges is my personal weapons of choice however.

Shoot, with the joint filling capacity of epoxy a feller could probably use a shingling hatchet.

MICHAEL S
12-24-2003, 11:29 AM
Thanx Norm,

No kids around but maybe I'll let the golden retriever puppy do the difficult bits for me.

:D

Jon Etheredge
12-24-2003, 11:35 AM
Shoot, with the joint filling capacity of epoxy a feller could probably use a shingling hatchet.
When I was in boatbuilding school in Norway, I did use a hand axe for cutting scarf joints in solid timber planking smile.gif

At least in the Trondelag region (around Trondheim), an axe is used for almost all joinery in tradtional boat construction. The axe is kept razor sharp (as in shave your arm hair sharp) and the results are as smooth as if cut with a plane. No epoxy in the joints though, the faying surfaces are just given a coat of unthinned pine tar and then the joint is rivetted together.

Back to the fir ply though...

If I am cutting a scarf in thicker fir ply, like 1/2" or more, I rough it out with a power plane and then finish up with the abrasive plane, a.k.a. belt sander. For the thin stuff I just use the belt sander.

There's always more than one way to skin a cat though! By far, the best method is the one that you are most comfortable with.

JimD
12-24-2003, 12:01 PM
Originally posted by MICHAEL S:
So ‘belt sander’ is not the dirty word I assumed it was.
Thanx for the tip and don’t worry - I’ll be careful.

Michael smile.gif

:D Oh yeah! Belt sander is still a dirty word, depending who you ask. Trouble is they do such a damn good job and I'd be lost without one. And I suspect there's a lot of closet users out there who try to keep their belt sanding habits one of those dirty little secrets :cool:

Captain Pre-Capsize
12-24-2003, 07:29 PM
Michael:

This place saved my skin more than once last winter building my first skiff. You are in the right place!

Merry Christmas!

On Vacation
12-24-2003, 07:33 PM
I use a power planner, and finish mine off with a MIlwalkee 6000rpm. soft pad, 40 grit. Duck!

Banjo
12-25-2003, 05:06 AM
:D Oh yeah! Belt sander is still a dirty word, depending who you ask. Trouble is they do such a damn good job and I'd be lost without one. And I suspect there's a lot of closet users out there who try to keep their belt sanding habits one of those dirty little secrets :cool: LOL I agree with JimD here smile.gif

I use mine a great deal. Use your dust bag all the time and collect the powder to use with epoxy for joint gluing and fillets that wont be seen. Saves a few bucks too.

With practice they are very good at fairing up your stringers, plywood chine overlaps etc etc. Just be carefull which way you sand so you don't rip outer laminations off. Sand a little and check often!! It's very easy to take too much out if using a course paper. ;)

Good luck with the project.
Oh and Happy Holidays or as we say over here still "Merry Christmas" ;)

Banjo...

[ 12-25-2003, 06:07 AM: Message edited by: Banjo ]

daddles
12-25-2003, 05:51 AM
Arrrrr, go away you lot. Here I was, finally admitting defeat and saving for a thicknesser, and now you're talking about flamin' belt sanders. Let me buy one toy before getting me interested in another please.

Sheesh.

Why the final decision to buy a thicknesser? Probably had something to do with that the 32mm plank I turned into a 20mm plank the other day, courtesy of Dad's power plane and Dad's Stanley 4 1/2. That and the fact I can get a really cheap Ryobi for a really cheap price at the moment - yeah, I know there are better brutes out there, but I can't afford the Ryobi, let alone an expensive one.

By the way - we've had Christmas here already. Total score: 600mm ruler, wooden mallet, square, four big clamps, two smaller ones, wheels for my Triton and Dennis Lillee's autobiography. I'm happy.

Merry Christmas to the lot of you: may the grain be straight and your plane be sharp.

Cheers
Richard
Dennis Lillee is a cricketer, one of the greatest fast bowlers ever. I don't know if he's ever built a wooden boat, but ...

John Blazy
12-25-2003, 02:36 PM
Just wait til Michael gets done and is asking all the finishing questions. That'll stir the soup again. :D

I share your enthusiasm Michael. I started on this forum after I was already half way done with my boat.
I warn you, there is an intoxicating effect when water is mixed with wood. Nothing like the gleam of sunlight off mahogony with aqua water in the background.
http://www.imagestation.com/picture/sraid81/p68681008a6efaa8e67bcaf4358d5bc6e/fb045760.jpg

Meerkat
12-25-2003, 02:50 PM
Michael; If you can possibly stretch to buy the needed marine grade ply, it would be a good thing. It would make building easier (better material) and your boat would last longer. If that's not possible (someone will doubtless call me on this), but some of the top grade Luan at Home Despot might even be a better choice than Doug Fir. I got 1/2" 4x8 for $15.50 awhile back there and it seemed to have a good number of plys (5?) that where all the same thickness ("balanced").

There's good dinghy sailing not far from you: Cherry Creek Reservior (mind all the PWC and water skiers!) and ?Chessman? (sorry forgot the exact name) Dam Lake off to the south. Then, there's that big lake up by Granby, but careful of sailing mountain lakes - wind gusts can be extremely unpredictable and I don't have to tell you how fast Colorado weather changes ;) Plus, if you fall in, the water is cold enough to have your gronicles hiding behind your kidneys for warmth ;)

I used to work in Golden and lived in metro Denver (Aurora, Lakewood, Louisville) for some years. Golden is only about 1,000 feet (or less) above "the mile high city", so "2 miles" is pushing it just a bit! ;)

[ 12-25-2003, 03:53 PM: Message edited by: Meerkat ]

MICHAEL S
12-26-2003, 06:32 PM
I just finished the glue up on my last scarf. The cutting was fairly easy - I used the power plane and finished with the belt sander. I tried doing the final smoothing with a hand plane but was getting to much breakout (as I believe someone warned me I might).

The final product seems mighty fine to me. :cool:

Meercat, I know the address says Golden but I actually live in Wondervu, a small town west of Golden (too small for the Post Office to deal with). The actual altitude is 8,888 feet. I know, I still exaggerated, but don't all Americans exaggerate? (You should see the size of my blankety-blank) ;) :D Too late for the plywood tip but having done a fair amount of finishing softwoods I think I may have a few tricks to control the grain checking. :rolleyes:

So far the difficult bit has been wrestling around and finding space for the ten and twelve foot sheets of plywood I've created.

Still Having Fun, Michael smile.gif

Jon Etheredge
12-26-2003, 09:03 PM
Too late for the plywood tip but having done a fair amount of finishing softwoods I think I may have a few tricks to control the grain checking.

Still Having Fun, Michael
Glad to hear you are having fun.

Would you be willing to share your ideas on finishing?

I am planning to experiment with applying warmed linseed as a "bulking agent" on bare fir ply prior to finishing with oil based paint. I believe that I read of this approach in articles by John Gardner and/or Richard Jagels (the wood technology guy from WoodenBoat magazine). Many people claim success with epoxy and glass but I don't wish to do that on my current project. Maybe you have some new ideas? I'm interested in hearing your thoughts.

Meerkat
12-26-2003, 10:05 PM
A popular/notorious ;) sealant around these parts is "CPES" - Clear Penetrating Epoxy Sealant. In this and other sectons of the forum there's a large amount of discussion on it. Google it for more info from the web. Dunno if it helps prevent checking.

Michael: I sort of dimly recall Wondervu - I think I managed not to blink once or twice going past! ;)

MICHAEL S
12-27-2003, 12:06 AM
Hey Jon,

Probably nothing new but this seems to help quite a bit. I'm sure you are familiar with pre-stain sanding sealers. The idea is to make the contrast between hard and soft grain less extreme and to make the stain absorb more evenly. When applied they raise the grain which must then be sanded back down. With multiple applications the grain raises less each time and you get a smoother surface.

PLAN A.....
I carry the idea a little farther and lightly mist the bare surface with water to raise the grain and then sand smooth. Repeat a couple of times then proceed to sanding sealer. Then on to primer and then to paint sanding between each coat.

In essence, just more coats and more sanding.

It also depends on the type of wood and grain orientation and how well it takes to sanding. If the hardness/softness between grains is extreme it is easy to scallop and accentuate the grain. Hand sanding blocks work best. Also, any oversanding during the process will just expose unsealed grain below and it's back to square one.

Again, probably nothing new and a lot of effort on larger projects but on a smaller scale I have had good success in achieving a very smooth surface. Don't know how it will perform in a marine application over time. But the smoother it is to start with the longer it will stay smooth?

PLAN B....
I have little experience with epoxy but I did just glue some 1/4" and 1/2" plywood together. I used a fairly thick coat to join the pieces but I was impressed by how thinly a coat can be appied using drywall knives. So plan B is a thin coat of epoxy just before the primer and paint. Not intended for strength (no fiberglass) just for smoothness.

Michael

JimD
12-27-2003, 12:28 AM
Mikey, forget all the checking/proud grain crap about fir plywood and get to work on building the damn dinghy, ok? smile.gif

Meerkat
12-27-2003, 02:33 AM
Michael; Forget about plans A and B. You're still thinking land based. The marine environment is different. You need to seal this wood tightly to prevent water getting in at all as far as that's possible. You also have to keep after your seal to keep it working. Water is your enemy: it never gives up, it's very sneaky and it will rot your boat faster than you might believe possible.

The CPES I mentioned goes on with a brush and really penetrates the wood and sets up an epoxy barrier. Epoxy is not waterproof entirely (unless you get some specialty products - and some say those are only better, not perfect), but it's a strong start. After the CPES, you prime and paint. (I think I got this right, but there's been a gazillion threads on finishing/painting/sealing/preserving and you should look them up. I think Bob Cleek is the resident expert - search on his name along with the terms I just mentioned.)

On Vacation
12-27-2003, 07:10 AM
PLAN B....
I have little experience with epoxy but I did just glue some 1/4" and 1/2" plywood together. I used a fairly thick coat to join the pieces but I was impressed by how thinly a coat can be appied using drywall knives. So plan B is a thin coat of epoxy just before the primer and paint. Not intended for strength (no fiberglass) just for smoothness.
=================================================

I hope you thickened the epoxy mix with a thickening agent like cabosil in your joints.??

Jon Etheredge
12-27-2003, 09:38 AM
Michael,

Your idea of raising the grain sounds like a good one for improving the initial smoothness of the finish. But the "checking" issue is actually something much different.

As time passes, the surface of the wood will develop small cracks. The cracks are usually refered to as checks. This seems to occur primarily in the soft (light colored) portions of the grain. I don't understand the cause of this myself. The checking is most pronounced on ply that is exposed to the sun and weather. A painted surface that is exposed to the sun and weather for long periods of time is almost guaranteed to check. I can tell you this from personal experience.

I have heard that epoxy alone will not stop the checking on a surface that is exposed to the sun and weather for long periods of time (I'm talking about a boat that sits on a mooring all summer for example). Many people that say that glass and epoxy will stop the problem but there are others that claim that the checks will still telegraph through the epoxy and glass. If the anecdotal information that I have read on this is correct then sealing the ply is not in itself a cure for checking.

My own opinion is that if you choose to use fir ply, you should accept that there is a high probability that it will eventually check if the boat is exposed no matter what you do. A boat that is stored inside may eliminate the problem or at least avoid it for much longer. Epoxy and glass is the accepted "best" method and I'm sure it will delay the checking (possibly indefinitely if the boat is stored inside).

As I said in a previous post, I have also read that "bulking" of the surface of the plywood with linseed oil prior to painting may decrease the amount of checking that occurs. I don't have a good explanation for why this might work but I do have a theory smile.gif I don't believe that the linseed oil is sealing the wood in any sense. After all, linseed oil is hygroscopic (attracts moisture). Instead, I am wondering if by attracting moisture, the linseed oil is keeping the wood surface at a slightly elevated moisture level and therefore keeping it swelled up so it doesn't check. It is just a theory but maybe somebody else can chime in with more info. I'll be trying the idea out myself on a project where I can tolerate the checking if (or when) it still occurs.

Keep having fun!

Meerkat
12-27-2003, 02:20 PM
Just speculating, but maybe the checking in doug fir is caused by UV exposure? UV can penetrate through some materials fairly easily, so maybe epoxy/glass isn't sufficient protection without some sort of additional coating. There's an aluminium impregnated epoxy sealer I'm interested in trying as a possible solution. It also reflects IR (heat) pretty well and I wonder what effect that could have on the epoxy.

botebum
12-28-2003, 09:23 AM
Michael, re: storing your long sheets of plywood- I just slung them up from the living room ceiling and bought my wife her "very own" long-billed fishing cap so she wouldn't notice them hanging overhead. Worked like a charm! The thickness planer in the bedroom is still a bone of contention though.

JimD
12-28-2003, 10:10 AM
I'll throw my two cents in one more time then leave you all to your madness :D Michael, good sir. Here's my final recommendation. Before you cut up that big sheet of scarfed plywood put a layer of four ounce FG on it. Then proceed with building as usual. I guarantee you won't have any grain showing through in the end and you will have done about all there is to do to curtail the checking. I think you're trying to fix something that ain't broke. There have been many tales on this forum and others from folks who have tried to solve the so called problems of fir plywood and all they have managed to do is make matters worse. If you're that concerned about the properties of fir there's only one other solution: switch to some other wood. Bon chance.

On Vacation
12-28-2003, 11:38 AM
botebum, please send me an e-mail, please with an address with it. I need to chat with you.

Gary E
12-28-2003, 12:44 PM
Back in the 50's we used a product called Firsite, or Firzite, a case of CRS prevents me from rembering the spelling or the manufacturer's name. Well, anyway it prevented checking and raised grain, it was clear and you never knew it was there even if then stained and your finish was varnish.

G