Plank blowout!

[dmede]

I no longer need a moaning chair, I just sit right down on the cold hard cement and sob!

I steamed up plank #4 last night hoping to be riveting by Sat and getting the final set of planks started next week. Well now I’ll be spending this weekend re making plank #4 just like I had to remake plank #3.

Plank looked good, back 2/3 has great grain, front portion that is scarphed on had ok grain (it’s rift on the bottom edge but q sawn on the top). Well the scarphed portion apparently had a couple of stress fractures or something that I couldn’t see in the wood until steamed and bent in place. It cracked near the top in a dark line of grain that I thought was sound but was apparently a stress crack. The worse one is not visible in the pic, and runs the entire length of the scarphed piece, into the glued up portion right to the feather edge. It looks like the steam itself expanded these cracks open, is that possible?

The dark line above the crack is a glue line from the layup.


I'll be cutting the scarphed end off and re scarphing with a better peice of wood (also need to layup tghe new end as well to make the width). This put the brake on what was feeling like a good pace of work.

[S.V. Airlie]

ouch demede.. that hurts.
On the bright side, it did not stay together just long enough for a launch and say a short trip on the water. That could have been a lot more serious.

[dmede]

This is true, though oddly enough sinking the boat was the first thing I thought of when I saw the crack last night

It has also taught me something about the wood I have. Several of the boards have these long dark lines through them that look and feel sound but I now must assume are fractures in the grain line. They fall in the same lines as visable fractures in other boards, I'm guessing the trree suffered a big fall when it came down 60 years ago and cracked right through in a few spots, the deepest parts of these cracks must be tight enough to not show until stressed open.

[rbgarr]

That happened to me once with a 10" wide, solid mahogany plank and I collapsed on the floor, too. I also saw a visitor to a shop just touch a lapstrake plank that had been riveted on and it did that. I'd never seen anyone actually turn white before that.

Good luck.

[dmede]

Here's a blow up of that top pic. If you look close around the edges of the big crack you can see the wood is slightly off colored. Looking further down the plank you can see two more faint lines of darker color, one just above the other. The lower line is the second crack, and actually worse than the visible one. You can see how hard it is to distinguish the bad grain lines from the natural grain color variation in the plank.



Edited to add: in case it's not clear, the light line near the top is the cut of the gain and not one of the cracks.

[S.V. Airlie]

Good picture.. I can see the flaws now.. But I have a feeling that I would not have done pre split..
Again, ouch...

[pcford]

With due respect, it seems you are being a mite dramatic. Move forward with what you have learned. Likely, you can use the old plank as pattern for the new. Only loss was time and materials.

Not the first time something like this has happened. Nor the last.

The worst example of lost time I can think of right now was the following.

Guy walks in about Nov. 15 with an offer for me to finish a runabout that I had done some structural work several months earlier. Now anyone in this business knows if you ain't got a job by the middle of November which will carry you over to the middle of January, you aren't gonna get one. Nobody signs up in the holidays. Boatwrights can be, uh, motivated, at that time of the year. And the owner knew it. The boat originally had to have several planks replaced. It was an old boat, pre-war Chris. The old planking was very dark. I told the owner that it would be quicker to replace the entire side of the boat than to replace a plank here and a plank there. He did not want to do things that way. The new planks were significantly lighter. I bleached the entire boat side to even the colors. Now, I don't do that anymore; I dye or stain the light planks.

The problem with bleaching is that it "furs up" the immediate layers of wood cells. This cause the wood to be harder to stain evenly. I prepared the hull stained and varnish it to three coats or so. The owner arrived and said that the stain was not even enough. So I did it again. And again. The problem is that you can sand through the light bleached wood very easily. In short, it was a nightmare.

I was happy to see the backside of that boat and its owner.

[dmede]

With due respect, it seems you are being a mite dramatic. Move forward with what you have learned. Likely, you can use the old plank as pattern for the new. Only loss was time and materials.

PC, why do you always ruffle my feathers no matter what you say? I'm commiserating, it's part of the bonding experince and helps alleviate stress that would otherwise get taken out on things like co-workers or plaster walls No it's not a big deal but yeah I'm pissed about it and want to vent a little. I've already got my list of things to do to get back on track, just letting it out while I sit here at work wishing I was in my garage fixing the problem. ok?

edited to add: I'm just having fun with PC here, I've recived lots of helpful comments from him in the past. He just needs to be reminded from time to time that we are not all gruff professional builders or restorers here, some of us have day jobs and anger managment issues

[capt jake]

PC, why do you always ruffle my feathers no matter what you say?

It's what he does best!

[S.V. Airlie]

I'm on the fence here.
Pcford helped me out with some suggestions and concerns regarding Airlie which I am looking into. Yes, I got a bit hot under the collar but Pcford has been around the block so to speak..
At the same time, dmede needed to vent.I can understand that and appreciate it... Venting is good.I'd need to vent if it happened to me.....
Both of you have your place...

[Bob Smalser]

I've had the same experience more than once, and it's really no big deal.

Unless that dark line is a old bark inclusion that won't take glue, the plank can easily be repaired and rehung. If it is a bark inclusion, it can be routed out and dutched. Cedar loves epoxy.

Get the plank on a horizontal surface and heat up the wood using an electric blanket. When the wood is warm, spatula in unthickened epoxy followed by a heat gun that thins it so it flows into all the broken surfaces. Lightly clamp. Beltsand off the excess after curing. On thicker planks with worse breaks, I've even drifted oak dowels into the edge for reinforcement after the basic glue repair has cured.

With easily-split VG WRC and wide planks, it's easy to cause splits like yours by applying uneven clamping pressure when pulling the plank home. I temporarily cleat the plank sides using 2X stock so clamping pressure is applied equally across the surface of the plank using door clamps or Spanish Windlasses both top and bottom.

Now, this can be a big deal if you are gluing the laps and planks can't be simply removed to recut gains or repair splits. That's why traditional boats made from solid wood don't have glued laps.

[Jay Greer]

All is not lost! Look at it are part of a learning curve as well as a new challenge. You might try the Oriental approach of cutting the cracked piece out and adding a glued scarf that is strenghtened by the use of loose edge fitted tenons.
Jay

[dmede]

Doing an epoxy repair was my first thought after seeing the short but more open crack ontop. That one runs-out at the layup about 8" back. It's the lower crack that changed my mind since it runs the full length of the scarphed end and is tight enough to be a problem getting epoxy into (unless I open it up a bit myself).

To be honest the grain in the scarphed end is not ideal, the layup is rift, the bottom of the main plank is slightly rift, but it's center is q-sawn and thats where the splits are. It is captured by the scarph about 3 feet back from the front end and the main plank is all good grain and no dark lines indicating any bad grain lines.

You still think I migth be able to get away with an epoxy fix?

[pcford]

PC, why do you always ruffle my feathers no matter what you say? I'm commiserating, it's part of the bonding experince

I kinda thought that was what I was doing. A lost day or two ain't much. Lost weeks....well that starts to get serious. Makes some of us want to go to a corner with a blanket and whimper.

[Bob Smalser]

You still think I might be able to get away with an epoxy fix?

Definitely.

But why is the split area dark? Is it soft? Does it smell strongly of pitch like a windshake? Windshakes aren't common in cedar because they grow in lowlands, but aren't unheard of. Examine the sapwood of your other stock and find a bark inclusion. Is what you've photographed the tail end of one found in the heartwood?

If the crack is a resiny windshake or soft bark inclusion, it either needs to be routed out and replaced with sound wood or a new plank end scarfed in.

And if I had enough plank thickness to drift in a quarter-inch WO dowel to reinforce the repair, I'd consider that also.

Nothing you will ever do in wood will go together perfectly because neither you or the wood are perfect. Fixing mistakes efficiently and neatly is over half the skill acquired after you've got down pat which side of the line to cut on. Nor are you punching a time clock....it'll get launched when it gets launched....slow down, relax and enjoy the experience.

[dmede]

The dark area is not resinous and I don’t see any sign of bark inclusions. The end shot of the crack shows some darkness that is actually due to the cedar still being wet from the steam I think, it didn’t look like that before. The side shot of the crack shows the color very clearly. If anything it seems a bit softer than the rest of the wood, but with WRC it’s hard for me to tell. I have found similar veins of color in other boards that had a few small bug holes in them and were soft and punky.

As I’ve picked through my stack of lumber I can almost see how they went together in the log and there were some serious cracks in a few boards that get tighter as you go further into the log (if that makes sense). The boards that were deeper in don’t have a crack but do have dark lines that shadow where the crack is in the boards cut from above them. So the dark is either weathering that made it down the crack into the log, or is damaged wood from the crack trauma itself and is weak enough to split when lightly stressed? Just guessing.

some of the visible cracking in outer boards:

[Jay Greer]

Actually, I don't know what kind of a boat you are building. If it will be used in such a manner as to allow you to swim ashore if the plank goes south at sea, you can most likely, get away with forcing in epoxy with a syringe, putting the plank in place and allowing the swelling to tighten it up. It may last just fine. Then it may not. Other wise, if you are losing sleep over it, hang a new plank. It aint all that hard to do.
Jay

[dmede]

On thicker planks with worse breaks, I've even drifted oak dowels into the edge for reinforcement after the basic glue repair has cured.

Bob, is the dowel glued down the length of crack or across it like a true drift?

I was considering chiseling out (or routering if I can get it flat enough), a 1/4" deep by 1/4" wide groove right over the thin long crack and gluing in a thin strip of WRC set in slightly thickned epoxy. That or I may just try to pry the board open a bit to allow unthickend epoxy to flow in. Will a hair dryer work ok in place of a heat gun? I have a heat lamp I can let sit over the fix while the epoxy seeps in.

[Bob Smalser]

As I’ve picked through my stack of lumber I can almost see how they went together in the log and there were some serious cracks in a few boards that get tighter as you go further into the log (if that makes sense). The boards that were deeper in don’t have a crack but do have dark lines that shadow where the crack is in the boards cut from above them. So the dark is either weathering that made it down the crack into the log, or is damaged wood from the crack trauma itself and is weak enough to split when lightly stressed? Just guessing.



Bob, is the dowel glued down the length of crack or across it like a true drift?

Will a hair dryer work OK in place of a heat gun? I have a heat lamp I can let sit over the fix while the epoxy seeps in.

That's not a windshake, that's cracking caused when the tree hit the ground. No doubt about it, I see it almost every day. When trees are falled purposely in hill country and the lay of the ground is wrong, a crosslog can be laid in the falling bed to both plan where the break occurs and shorten the cracking. Your tree was a windfall that didn't get such care.

Follow my instructions on warming both the wood and the epoxy and light clamping, and those boards will last as long as defect-free boards. Just warm the epoxy til it thins, not til it boils, and keep applying both in and around the crack until the wood won't soak up any more, making sure you get 100% penetration. Use thickened epoxy afterwards to fill any depressions. I find trying to inject cold wood using a syringe not anywhere near as effective providing you can position the board to use gravity. An electric blanket and hair dryer will work fine, although marital bliss generally requires the purchase of a proper heat gun. Get the blanket used from Good Will.

With a good epoxy repair and planks thinner than 3/4", I wouldn't risk drifts if you don't have a dowel or other jig and practice drilling edge grain. That's a belt and suspenders approach I tend to waste time on. But for future reference, WO or mahogany dowels can be purchased from on-line retailers, can be made at home, or you can even use bronze rod providing you countersink it so you don't hit it with your edge tools in fitting. Drifts are simply driven in using red lead as a lube with no gluing. Notch them lightly using an old chisel to make it hard for them to back themselves out with seasonal movement. Use a quarter-inch drill for quarter-inch rod....if the fit is too tight you'll split the cedar.

Done properly, these repairs are stronger than the surrounding wood. Get the epoxy right and you won't have to swim the boat home unless you hit a rock.

[dmede]

So I actually did this hot epoxy maneuver on some scrap boards a few months ago (per Mr. Smalser's advice on how to save the boards with major cracks). I was never confidant enought to use the boards as full planks and have been cutting into them for layups instead.

I decided to sacrafice the board and cut through the epoxy fix to see how far I got it penetrated and was surprised to find that it had migrated through a very thin crack all the way to the other side. My procedure for this was to use a sharp chisel and open up the top of the crack to create a small depression in which epoxy would pool over the crack. I alternated squeezing it in with a putty knife and blowing it in with a hair dryer. It worked like a charm as you can see in the pic.

[carioca1232001]

.......................................

Nothing you will ever do in wood will go together perfectly because neither you or the wood are perfect. Fixing mistakes efficiently and neatly is over half the skill acquired after you've got down pat which side of the line to cut on. Nor are you punching a time clock....it'll get launched when it gets launched....slow down, relax and enjoy the experience.

Singled this para out as it seems to provide the attitude which is necessary to successfully address the building and repair of wooden boats. The last sentence fits me like a glove !

Which is not meant to detract in anyway from the overall appraisal and size-up of the problem and its solution.Which by the way, is not covered in the US Navy´s 'Use of wood as a shipbuilding material' reference text.