Author Archives: Ben Mitchell

Lessons from Layer Two

July 11, 2013 8:11 pm ⋅

Layer two is done.  It was a giant pain, but it’s done.  We’re 2/3 of the way through planking the hull sides, after which we trim the edges of what we’ve already applied and move on to planking the bottom.  I’m hoping the bottom goes on easier because the sides have been exhausting.  Here’s the latest from the trenches:

A few learnings from this week’s labors…

First:  If you ever decide to build a boat, just buy the system for shooting plastic staples at the outset.  I cannot imagine pulling all the staples we needed to shoot in order to get a good bond between layer one and layer two.  Some planks seem like they’re more staple than wood.

Second: When you think you’re pushing hard enough and shooting enough staples, double down on each.  After we let the planking cure I went back and tapped all over the hull looking for hollow-sounding spots where the first and second layer weren’t well bonded.  I found more than I’d like.  According to Timm, this is not unexpected.  He told me a tale of his time at Bertram when the QC guy came out after every hull was built and found all the places they needed to go back and fix.  It still makes me grumpy that we didn’t “get it right the first time.”

Anyway, the root of the problem appears to be that I didn’t push hard enough and pound enough staples into the middle of each plank.  I focused on the edges trying to make sure I had complete contact along them, but didn’t realize that the planks were bridging the curves between the edges.  Sigh…

According to the Gougeon book, there are two things to do when you find voids.  Note I said “when.”  They, too, seem to imply that this is par for the course.  Anyway, option one is to cut out the affected planking and either fill that area with fairing compound (epoxy putty) or glue back in a piece of planking depending on the size of the area.  The other is to drill a bunch of holes, pump epoxy in as best you can, staple the hell out of it and hope for the best.  Perhaps as a function of exhaustion, I opted for numero dos.  Here’s a quick shot of the worst area.

You can see all the holes I drilled and all the staples I shot around that area after applying epoxy.  You can also see the circles I drew after it had a chance to cure for a bit which represent an area I need to spend some more time on tomorrow.

Anyway, a useful technique to determine if you have a problem is this:  Drill two holes in the area you think may not be well bonded.  Shoot some compressed air into the first.  If it escapes out the second, you’ve got issues.  If you don’t have a problem, just fill the two holes.  If you do, keep drilling holes until you get to a place where air doesn’t come out anymore.  Then put epoxy in a bunch of the holes and shoot some more air in to try to smear it around as best you can in the area between the holes.  Wear safety goggles and a crappy shirt for this because it’ll blow epoxy out the holes back at you.  I’m still picking it out of my hair.  Once you’ve done your best at forcing the epoxy throughout the affected area, fill each hole with epoxy for good measure and give it a few minutes to leech into any gap it can find.  Then go push as hard as you can and shoot a couple hundred staples into the thing to try to hold it all together while it cures.

I wish I could tell you I now have confidence that (a) I found every one of the affected areas, and (b) that I feel like all of the repairs I did are “100%”.  On both cases I’m nervous.  But I’ll tell ya, different pieces of wood have different noises, and the framing makes things sound different at different places even on the same piece of wood.  So finding all the problem spots ain’t easy.  And once you’ve found them, short of turning your entire boat to swiss cheese it’s pretty tough to find the full extent of the affected area in attempting to drill enough holes to open it all up to inject epoxy.  And even when you’re comfortable you did that right, did the air gun really blow epoxy into all the places it needed to go?  Who knows.

I take solace in a couple of facts, though.  First, this is in the boundary between the first and second layers of planking.  That means that assuming I learn some lessons from this and do better on the next layer, I’ll have 1/3″ of wood and a thick layer of glass that are integral over the top of whatever soft spots may remain.  That’s a pretty stout “hull” in its own right for an 18′ boat.  Second, and to the point I just made, Timm tells me he designed this thing to withstand 4G of pounding.  I’m building a tank, here.  If it’s a bit thin in some places, I’ll probably still be okay.

The bigger concern is that voids collect condensation over time, but if this develops some rot in 20 years… well… I built it the first time, I can probably fix it. :-)

My dad’s off to Fallen Leaf for the weekend.  I’m going to spend tomorrow dealing with the remaining soft spots I found, and then trying to do a better job of fairing the hull prior to layer 3 than I did before layer 2.  I think that’ll help minimize the number of places I get air bubbles.

Onward and upward!

-Ben

Posted in: Planking

Back in the Saddle

July 9, 2013 9:35 pm ⋅

Enough with the distractions.  We’re back to work as of Monday morning.  I didn’t write yesterday because I’ve lost the cable to get the pictures off my camera and I figured nobody reads anything that doesn’t have some eye candy.  Today I went and got the spare cable from the big boat.

Yesterday and today were both frustrating, but for different reasons.  Yesterday we began by pulling the remaining metal staples from the port side of the hull.  Our hope was that the UPS guy would show relatively early in the day – usually it’s by around 10 or 11am.  Unfortunately, by 2PM there was still no sign of him, so we pulled the plug.  My dad went home and I puttered about waiting for Mr. UPS, doing some assembly work on the CNC router kit I recently purchased.

Blisters notwithstanding, here’s a big part of the reason we’re waiting for the plastic stapler.  Normal staple holes from a normal staple gun look like this:

But pulling the handle  that shoots those buggers a couple thousand times a day is a recipe for angry hands.  So we bought a narrow crown pneumatic stapler (which is what Home Despot had in stock).  Here’s what those holes look like when the staples are removed.:

No bueno.  And if you zoom out a bit, you can see the extent of the destruction.  Note that in a lot of places the grain of the plank actually splits a bit on either side of the staple.  This isn’t a fatal issue, but it does create a lot more work between this layer and the next:

Anyway, while my dad was away I did a light sanding on the hull to get the biggest of the ridges and bumps out as well, but … and this becomes relevant when we get to the source of today’s frustration – it didn’t occur to me to do a more meaningful fairing of the first layer to fill in the staple holes and minor gaps between boards.  I just figured we’d put a thick layer of adhesive between layer one and two, and that we’d start planking first thing this morning.

As mentioned, at 4:00 or so, the stapler arrived.

All hail the stapler that shoots plastic staples, and the staples it shoots:

All hail the unfortunate price tag!

So the first thing we did this morning was to take that handy new stapler and finish the portions of the port side that weren’t yet done.  We had to dial the pressure in to get the right penetration, but that only took a few staples to get right.  Once done we were off to the races.  Here you see, in glory that can really only be appreciated if  your hands are thoroughly blistered from pulling metal staples, planking laid with staples that never need be removed.

You also see a bit of fairing compound smoothed over them.  Which is the source of today’s frustration.  As I looked more closely at the hull today, I realized that it was going to be a giant pain to get a gap-free bond between the second layer and the first without doing some more aggressive fairing first.

This warrants a brief side note.

When building a laminated structure such as a cold molded hull, it’s really, really important that there be no air trapped in your laminate. Air is not strong.  Air creates opportunities for condensation, which can lead to rot.  Air is bad workmanship.  When laying a new layer atop an existing layer, you want the adhesive to completely fill the gap between them.  The layer of adhesive can be thick, but you really want no air in there.

Okay, so with all those little staple holes, minor gaps between planks, and ridges where one plank meets another, it just started looking really unlikely that we’d get a good layup without a ridiculously thick layer of epoxy, which would be heavier, costlier, and somewhat less strong than a thinner one.  And so, we decided to shoot today in the head and smear a layer of fairing putty on the hull.  Once that’s done, it needs to cure overnight.

So tomorrow is really what Monday should have been.  The day we move on to layer two.

First thing in the AM we sand the putty smeared hull down to a more workably fair surface, and then we can get to planking.  I’m hoping if we push really hard we can do both sides in a single day.  It will be a loooong day, but I’d really like to get all three layers of side planking done by the end of Thursday.  My dad’s away over the weekend, and while I can’t really move to planking the bottom withouth a helper, I can do a fair bit of prep work once the sides are done.

I did find a silver lining in today’s shortened day though as well.  More work on the CNC.  It’s getting close!

 

-Ben

Posted in: Planking, Tools

Aw spit

July 5, 2013 12:33 pm ⋅

Taking a break from boat building for a few days does have its advantages.  My wrist is getting better, and my neck and back are improving as well.  This is all good.

So is spit roasted pork!

My buddy Tom and I fabbed a spit a few years ago to roast a lamb for a 4th of July party.  We expected this would be a single-use affair, but it’s turned out that we roast a lamb or pig at least once or twice a summer.  Always a good time.

Unfortunately, Tom’s wife had something go pear shaped with her eye this morning.  She’s a doctor.  Self diagnosis is “scratched cornea” but this is not her expertise.  Anyway, it’s bad enough they had to bail back to the city so she could see a specialist this afternoon, so they’re both missing out on the pig.  Bummer.  We miss you guys and, Michelle, we hope your eye makes a speedy recovery.

Here’s the pig we’ve got turning right now.

For those interested in the spit, the deal is this:

We welded up an a-frame assembly with holes on top of the frames into which we could insert 5/8″ threaded rods.  Each rod has an adjuster nut to set the height, and then there’s a bracket welded to the top that mounts two ball bearings so the spit can rotate freely in the groove.

At the drive end, the spit has a sproket welded to the end of the shaft that connects by chain to a gearmotor mounted to the leg of the a-frame. Sorry for the crappy photo.  The light is a bit tough right now and I don’t have my real camera.  The iPhone can only do so much.

The frame stays outside year round.  The roller brackets just lift out, and the motor comes off with a couple of screws.  For something that was built without longevity in mind, this has been a really robust solution.

-Ben

Posted in: Totally Unrelated To Boats

Getting ahead of myself

July 4, 2013 10:07 am ⋅

Though I may be away from my project for the weekend, my head is still very much in it.  I’m using the time to continue fiddling about with a design for the leaning post / console that I began working on a while back.  Thought I’d share and see if anyone has suggestions for ways to improve it.  Here’s a quick screenshot of what I’ve got in mind.

Screen Shot 2013-07-04 at 9.51.39 AM

This was done in Sketchup, which is a free 3D drafting program.  It has some limitations, and frankly at this point I wish I knew Solidworks or something of that ilk, but I can make Sketchup sing, I have a well-practiced workflow for getting parts from Sketchup to a CNC router and … did I mention it’s free?

Anyway, the idea here is that the leaning post (the thing you rest your butt on while driving) is built around a Pacific Edge 22 gallon baitwell.  22 Gallons is not a ton for a baitwell, but I have to keep reminding myself this is an 18′ boat.  Both from a weight and a footprint perspective, that’s about all I can muster.  Anyway, the idea is that I’ll buy the baitwell as a starting point, and then glass it into a bigger assembly so it all looks like a single unit.

On the sides, I’ll add some tackle storage in the form of these cool little tilt-out tackle tray holders.  Not shown, but in the teak part behind the seat pad I’ll put some Release Marine “No Bolt” rod holders. I like these because there are no visible screws on the top, which means there’s no place for salt water to collect and start corroding.  I’d like to put four of them on there, but I’m afraid that I’d start restricting access to the baitwell if I put two in the middle, so it may just be two on the outsides and maybe some drink holders in the middle?  Still TBD.

The center console (with the wheel) is tilted aft a bit primarily for visual appeal.  The front is curved for the same reason.  It’ll add work to do all this, but I think it’s worth it.  My current struggle is figuring out how to put access doors in the sides of the console that work well and look good.  To look right they need to be parallelograms.  But then they’ll open in a weird way.  And I’d really like to use off the shelf storage systems in it from the same outfit that makes the tilt-out holders above, but obviously they won’t be parallelograms.  I may just bite the bullet and put rectangular ones in there, even if it doesn’t look spectacular.  I welcome your thoughts!

All this needs is still in the daydreaming stage.  Once we turn the hull I’ll mock it up in cardboard to check the dimensions and then tune as appropriate.  But I want to get started building these before I “need” them because they’re going to take a while to do, and it’ll be good fodder for keeping busy while epoxy is curing in other places.

-Ben

Posted in: Musings

Clamps: On cheap tools.

July 3, 2013 5:10 pm ⋅

Hi, Folks.

At the insistence of my friend Tom, I’m taking a few days off of the boat build to host a group for the 4th of July at my parents’ house near Lake Tahoe.  This actually represents an unexpectedly welcome opportunity for my body to recover a bit.  The staple pulling, combined with the contortionist maneuvers often necessitated by the close confines of the space in which we’re building the boat, have me feeling pretty beat up right now.  I think I hit my head three times on the very sharp, very square edge of the platen on my Burr King sander in the past three days.  At least it didn’t draw blood.

As I sit here overlooking the lake, I’m poking around at the various photos of the build I have on my laptop.  This one caught my attention.

What you see there is a small fraction of the number of clamps you need to build a boat.  And you really need them in all different sizes and shapes.  C-clamps.  Bar clamps.  Spring clamps.  Large.  Small.  It’s daunting.  My neighbor Chris used to work at a boatyard building big fishing boats and says they had shopping carts full of the things.

Anyway, clamps are freaking expensive.  A good 12″ bar clamp from the likes of Jorgensen runs about $15.  Bigger clamps cost more.  And C-clamps are comparable.  This isn’t that bad if you’re buying 4 or 8 of them for occasional wood working projects.  When you need 100 of them to build a boat it’s a different story.  Especially if you’re not in the boat-building business and don’t have an ongoing need for a shopping cart full of them.

I ended up buying 40 12″ clamps from Harbor Freight for $3.99 each.  This is nowhere near enough, but I was skeptical about them and figured I’d limit my risk by starting “small.”  Fortunately my friend Wolfgang filled in the gap during the clamp-intensive part of the project with a giant pile of loaners, many of which are in the photo above.

Anyway, I was right to be skeptical.  These HF units are pretty much single-use.  I’ll build the boat with them, but they don’t have much of a future beyond that because they’re falling apart.  And what’s frustrating is that the fundamental flaw with them is so easy to remedy.  The connection between the grip you turn to tighten the clamp and the screw turned by the grip is ridiculous.  They just barely knurled the end of the screw shaft and pressed it into a plastic grip.  Torque it tightly and the grip starts spinning on the screw shaft, and once that happens it never really gets tight again.  There are a dozen ways they could have created that junction in a more robust manner that would still have allowed them to sell a $3.99 clamp.  They just didn’t bother to think it through.

Sure, the plastic pads would still be cheap, the bar would be a bit flimsy and the castings would be rough, but it would do what it’s advertised to do:  Clamp.

What I have now is a pile of soon-to-be-trash that really didn’t need to be.  I generally buy quality tools, and this reminds me why.  But for the life of me I don’t understand why cheap stuff can’t at least be thoughtfully engineered within the confines of its cost envelope.  Sigh…

-Ben

PS – If you know a source for affordable clamps (either bar or c-clamps) that represent a good value, I’m all ears.

Posted in: Musings, Tools

Staples

July 2, 2013 5:19 pm ⋅

My right wrist is throbbing.  I’ve iced it twice today and it’s still throbbing.  And I have blisters on my hand.  I’m sure there are all kinds of bad jokes running through your heads, but it’s entirely related to boat building, I assure you.  Yesterday we started the planking process using a staple gun similar to the one you probably have in your tool drawer.  These take a fair bit of pressure to pull and after 1000 staples (not kidding, there were about 250 left in a box of 1250 we bought that morning) my hand was killing me.  So we went to Home Depot and bought a $100 pneumatic stapler.  The only option they had was a narrow crown construction stapler. These are wonderful tools, and my wrist began smiling as I drove staple after staple with the mere pull of a trigger.  Unfortunately, however, the smile turned upside down today when it came time to remove them.  As this is a construction stapler, it drives those buggers deep.  Even at its lightest setting they’re fully bedded in the wood.  And there’s not much of a head to pull on to remove them.  Yes, we’re driving them through strips to facilitate their removal, but it’s still a nightmare getting them out.

Screaming wrist and blistered hand notwithstanding, the staples are out of the starboard side of the boat, and it’s really starting to look like a boat!  Yay!

We’ve also done about 75% of the first layer of the port side planking.  We would have finished but my dad needed to drive back to Palo Alto and the BART strike makes afternoon traffic a nightmare.  He wanted to leave early to try to beat the chaos.

The staples you’re looking at above (driven through the green strips to facilitate removal) are the last we intend to pull.  This afternoon I ordered a couple of boxes of Raptor composite (i.e.: plastic) staples and a special gun to shoot them.  It’s an expensive solution to the problem, but they sand like wood and can’t rust or rot so you don’t have to remove them.  They just stay in place and you finish the boat right over them.  After today, that seems worth nearly any price.

-Ben

Posted in: Planking, Tools