Ivo’s F1 Build, Campton Hills, IL

Starting at the End (30Nov2019)

Ivo's F1

First paddle. Very quick.  Huge amounts of reserve stability.  Note that I over bent the coaming and ended up with a recurve.  Brian suggested a way to fix that, and I will.  It seals better than a commercial coaming and skirt that I have used, but after being upside around 6 – 8 times, I get more leakage than I’ld like.  I needed to add side pads to keep me centered during rolling and I need to add thigh braces. Now back to the beginning…

Two days in the wood stacks and found barely acceptable wood. Then Day 1 Prep.

I spent two days in every lumber yard in the area and was able to find barely acceptable wood.  My shop is too small to process the wood as I would have liked, with my bandsaw and planer, so I set up some horses and used a portable circular saw and my Stanley jointer plane on the long pieces.  Once i got a straight square edge on the gunwales and stringers i used the thickness planer.  The shorter pieces will be processed on the band saw.  Progress after prep day 1 (6Oct2019); gunwales, jigs and forms. Part of the day was spent finding wood:

Making do

Parts, jigs and forms done after day 1 and material that is not to be part of the kayak.

I also marked the tenons on the gunwales.  ‘love the smell of cedar.

Prep Day 2

Wow that was fast. I now have all the wood cut to dimension.  The foredeck beams are drying.  I still need to bring a few pieces down from 3/4 to 11/16 inch.  And somewhere in the build, I think I will need to shape the stems.  I also need to make the special sticks.,  I have only gotten through the prep video, so I have no clue where those sticks fit, but I’ll get there.  It got too dark to keep working outside.  Also too dark for photos.  Have to wait until Saturday for the photos.  If I have time after work on Thursday, I’ll mortise the gunwales.  I am thinking of making a third jig for the first foredeck beam.  It does not look like it will quite be square to the gunwales, but won’t be at the flat beam angle either.  That could hold up the beam mortising if I make that extra jig.  (Did I mention that I am a bit of a perfectionist).

The prep video with the plans covered everything I needed to get the parts made.  This is a lot faster and more straight forward than I ever expected.

Building up the nerve to bend the coaming.  I am contemplating using ammonia for the bend.  It is supposed to make the wood more flexible than steam without any loss of strength once the ammonia evaporates away.  I have two coamings cut so I may experiment.  Also need to find ring nails, but don’t want to order the accessory kit until I find out if I can bend the coaming or if I will need a finished coaming.

In the meantime, it is time to start watching the build videos.

Photos from Day 2 and Ammonia Bending Experiment.

This weekend I had light to photo graph the second prep days work.  This completed all of the wood cutting and dimensioning.

All wood cut and dimensioned by prep day 2

I picked up the pieces and it struck me how little wood actually goes into a kayak.  Guess that’s why they are light.

Coaming Tapering Jig

I cut a 3/8 : 13 taper in some scrap wood and used it to taper the ends of the coaming.

The coaming and coaming taper jig

The jig worked very well.  I also made a 1/2″:13″ taper for the lip.  It also worked well.

I filled an 8 foot section of 1.5 inch OD PVC pipe and soaked the coaming in it for 90 minutes.  I then attempted to bend it.  When I looked at the broken ends of the coaming, I could see that the ammonia solution had only penetrated 1/16 inch.  The failure initiated in the dry wood rather than in the outer fibers.  The taper jig worked equally well on the second coaming, which is soaking overnight.  I’ll keep you posted on how that goes.  I am making a 5 degree jig for the first deck beam.  I need to get some longer 4mm x 1mm screws to attach the jig to my router.  I should order the accessory kit, but I want to see whether I need to buy the completed coaming.

I do not believe that bronze is compatible with ammonia and 304 stainless steel, which is compatible with ammonia, is not really compatible with salt water, so I wouldn’t use ammonia on an ocean going kayak.

More Ammonia Testing

I soaked a new coaming for 24 hours in 10% ammonia.  It broke.  Up to point where the thickness got to 1/4 ìnch it bent around the 7 inch diameter.  Looking at the break, the 10% ammonia solution soaked in about 1/8 inch from either face, leaving 1/8 inch in the center.  I solved the differential equations for diffusion into a flat media and found that the time it takes to soak in is proportional to the thickness squared.  This test and the previous test both conclude that 54 hours will be required to completely soak into a 3/8 inch thick piece of kiln dried white oak (diffusing across the grain).  That means it will take 96 hours for a 1/2 inch (probably less since it will also be difusing with the grain).  Also the 1-1/4″ coaming swelled against the inside of an 1-1/2″ PVC pipe.  I’ll need to use 2″ PVC pipe.

I bent the broken piece “backwards” with the thin end around the 7″ diameter.  Worked great and almost no spring back.  The coaming is as strong and stiff as the untreated oak.  A 2″ diameter pipe and cutting a new coaming and I will give ammonia another shot.  (I have the experience with steaming, but I want to experiment with ammonia.

BUILD DAY 1/2 27Oct2019

Could only work on the boat for a half a day.  I started the actual build today.  Kerfed the ends, bound them and pegged them.  That was easy.  These tenons have no square surface; how is this going to work?  Brian’s marking and cutting method is absolutely brilliant.  What looks like a daunting task took about an hour.  I had made an extra 5 degree routing jig for the first deck beam and it was spot on.  Did not have to wallow out any mortices.  Had a nice long look at the deck before I had to put it away.  The taut entry curve, the sweeping rise in the gunwales, rounded but trim aft curve; this would pass for a work of art.  Still have the straps on, since I had not purchased 1/8 inch dowel.  The 1/4″ dowel prep was done almost before it started.  I would never have thought to do it that way.  I need to get busy and order the backstrap and foot pegs.  The coaming rim is soaking in 10% ammonia and is going to soak for 54 hours before I try the bend again.  Off to a birthday celebration (Shh, it’s a surprise.)  No photos, the garage is a mess, but I’ll add some next weekend, when I can get it outside.


A 54 hour soak in 10% ammonia worked for 3/8″ thick coaming.  The other thing about bending with ammonia is that you have to bend achingly slowly and let the wood flow into shape.  I clamped the center and held the leather strap while I bent and compressed coaming to get an even curve.  It took about a minute to bend the small radius and get the coaming and strap behind the short pegs.  After that it was just go slowly and steadily around the rest of the form.  I used three spring clamps per side and just let the wood “flow” to the next peg and then attach a spring clamp.  The inner end stopped at a peg, which was convenient.  I used a small scrap to clamp the outer tail flat against coaming.  It is drying now.  I ordered the backstrap, foot rests, straps and ring nails from Brian.  Can’t find a good set of float bags that are in stock.  I am considering making the float bags myself.  There is some intriguing U-Maxi Clamp closure material from Illinois Tool Works that would be perfect, if I can find a place to buy it.  The TPU coated nylon is readily available.

The ribs need to be steam bent so that they will stiffen up fairly quickly after they are bent.  I don’t think ammonia will be appropriate, but I will try with one of them just to see what happens.  I also have a bending iron that I use for guitar side that I might try as well.

Had some daylight to photograph the assembled deck.

F1 assembled Deck

1Nov2019 I CAN’T COUNT TO 20!

I measured the ribs tonight and ended on the back at rib 19 not twenty.  I missed the “30” on the plans and put the first (2nd really) mortice @ 36 inches.  Everything was right, but I hadn’t made the first set of mortices.  Wasted about twenty minutes getting the router out, seting up, cutting two mortices and putting it back away.  I did remember to re-measure the ribs.  Ready for cutting ribs.

Broke the coaming lip when I tried to bend it, but was able to bend the broken half by taking the coaming off of the jig, clamping the front center and applying spring clamps side by side until the tight bend was made.  This kept the backing strap firmly anchored to the lip and had the lip supported every inch around the tight bend.  Had a second coaming ready for tapering.  14% strain in wood is going to require splitting the outer fibers or crushing the inner fibers.  I have been unable to hand hold the backing strap tight enough to keep the outer fibers from splitting without using spring clamps right next to each other.


I had spare shelving material 1 foot by 3 foot.  High density compressed wood flour, covered with a plastic veneer; no sense in buying something else.  I used this when I made the steambox; what could go wrong?  The veneer (really just film) let the steam through and the box fell apart within 12 ribs.  I’ll be making a new steam box.  The kiln dried bending stock had more severe run out and twisted grain than I originally thought.  Every rib that I thought was iffy, failed.  I got 8 ribs bent out of 12.  I had soaked ribs 1 through 3 in hopes of getting the heat through moist wood better than dry.  Ribs 1 and two cracked at a runout area. Rib 3 worked, but was swollen so that it would not fit the mortice.  I clamped it flat aginst the inside of the gunwales until it dried.  I was then able to put it in the mortices.  I found that I could remediate some of the poor bending with a heat gun using a cam strap and wood piece under the gunwales to hold the shape while I remediated the curve.

Another way to thin the ends to 1/4 inch:

Thinning rib ends

I used a band saw with minimal blade exposure to thin the ends.  Put a stop on the back to maintain the depth.  Worked like a charm.

Now to build back up the optimism to finish bending the ribs.


With the help of my son, I bent the coaming rim.  It has been soaking 4 days.  I clamped the backing leather tight.  I took the coaming off of the form and clamped the middle of the rim to the front of the coaming.  I slowly bent the rim (really let it creep under the weights of the clamps holding the backing strap) slowly.  When enough of it touched the coaming, Kevin added a spring clamp directly next to the last clamp.  Once we worked our way to the straighter section we clamped it and removed the clamps around the tight section.  I put the coaming with rim back on the form.  I clamped the center front and about 45 degrees to either side.  I then used four spring clamps per side and worked around the pegs.  First the inside tail then the outside tail.  Work very slowly when bending with ammonia.  It is on the form drying now.

I rebuilt the steam box with exterior plywood.  I used contact cement to glue aluminum foil to the inside of the plywood.  This should last.  Maybe I will find time this weekend to finish the ribs.

Saturday 9NOV2019

Found a small piece of oak that was air dried and long enough for ribs 1 and 2.  It was rift cut, but really straight grain.  I split it, planed it and used that surface to cut parallel to the grain.  They bent just as easily and pretty as Brian’s videos.  I split and planed the piece of kiln dried oak that I had been using.  The pieces ended up flat cut, but with very little runout.  It bent suitably, but not like the air dried.  All ribs are bent and in.  The keel height is set.  It is looking a lot like a kayak.  Monkeying around tweaking the rib shape to get the fit up to the keel as good as possible.  I did clamp blocks of wood along the gunwales spanning the mortices so that the mortices wouldn’t split.  Probably unnecessary, but i really didn’t want to hear that wood cracking sound.  I think rift cut air dried wood is the way to go for future ribs and coamings.

Sunday 10NOV2019 It’s a Hull!

Lashed the keel and stringers on today.  Lashed on bow and stern stems.  It looks like a kayak.  With luck I can peg the auxiliary stringers after work this week and it will be on to Day 3 in the videos.  I need to get busy, and order the skin and coating from skin boats.  I also need to find out about skinning in cooler weather.  Again it was too dark (and cold) for photos.  I’ll see about posting a photo if there is a day this week where I am home before dark.

I did deviate from the order of things.  I clamped the stringers on (in postion) without the rolling taper and placed a 5/8″ thick block against the stems to mark the end of the stringer to get the correct angle.  I also placed it above (but the kayak was upside down) to mark the end of the initial taper.  I made the initial taper 3/8″ shorter to account for the increase in angle as it get bent in the extra 5/8″.  I cut that bevel with a saw and then planed to the line.  From there I rolled the taper out to 32″.  Got a good fit of the stringers to the stem.

This is really a rewarding way to build a kayak.

I think I have a source for green white oak.  It will be cut to 8/4ths  I will definitely split it and plane a parallel surface so that there is no runout.  Then I will sticker it until i am reasy to bend it.

16NOV2019 And Just Like That, My Framing Days Were Over.

Day 3 work went really fast.  If I had ordered the fabric sooner, I would be skinning tomorrow.  My son was helping me today and that made for quick work.  Fabric comes in on Tuesday, so it will be next weekend before it is skinned.  This build went faster than I ever imagined it would.  I’ve really just been working one or two days on the weekends and we are skinning in five weeks from raw wood.


Repaired the lawn motor and put it away for the winter.  Put the blade on the snow plow. (We’ve had four snows, so I thought it was about time.)  Had to do some repairs and maintenance on the plow, so not much time for building.  Finished the coaming, and made the toggles.  Now just waiting for the skinning kit.  I ordered some dry/float bags from TRAK.


The float bags and skinning kit arrived this week.  The 20 l bags fit great.  I skinned the kayak today.  I don’t have tarred twine, but did have unwaxed bow string serving in the right diameter, Canada balsam and xylene.  So I used the refined rosin rather than raw pine tar, to tar the twine.  It worked well.  Was away from the house for 6 hours and did not get the skin shrunk.  It looked great except around the coaming.  I think i’ll be sewing some darts.


Wet the skin and used a steam iron on it.  I had no hope that it would shrink enough to remove those wrinkles, but it did.  Thank you Corey (Skin on Frame Boats).  The 840 primo is primo.  Letting it dry and off to the store to get roller pans and blue tape.  (I have to do something so I don’t start coating before it is dry.)

24Nov2019 (2)

Somehow, over the past month or so, a beautiful gossamer kayak materialized in my garage.  Drying and fitting is all that is left.

Finished coating

I couldn’t back up any further, but there it is.  Underneath you see enough 6/4 green white oak to make about 10 kayaks.  It is stickered until I can use it.  Robert Johnson at Johnson Creek Hardwood in Chadwick, Illinois listened to what I needed and cut straight grained sustainable white oak for me to pickup right off the mill.  (Also kiln dried feathered grain walnut crotch for a rifle stock and an incredible sycamore board for the back and sides of an acoustic guitar.)

Hope to finish up Thanksgiving weekend

28NOV2019 It’s Alive!

It is done.  Just waiting for the sealant to cure.

Ivo's First F1

I did not want to play with fire, so I used my soldering iron, which takes 1/4″ tips.  1/4″ is too large.  I turned about  the last 2 inches of a 1/4″ Al rod down to 0.21″ and then tapered the tip.  Inserted the 1/4″ end into the iron and tightened the set screw.  Plugged it in and waited until it pierced a scrap of the nylon. Then pierced the holes for the deck lines.  Piercing took about 2 minutes flat.

The Latigo strip were an exceptionally tight fit.  I made a deck line pulling tool.  I am showing it with some nylon line because the deck lines are all installed.  As soon as you can get one wrap over the end of the deck line it will hold.  It can be used as a lever for really tough holes way up in the bow or as a tee handle once you get things started.


First paddle.  38 F (3 C) air temperature.  Took some trusted advice from Brian’s video and got a Kokatat front entry dry suit.  Went for a little swim to test it and make sure I hadn’t acquired a gasp reflex since my windsurfing days.  All checked out, I took the kayak out in the shallows.  The lake I chose was waist deep for a long way out.  The kayak seemed a little tipping right at dead straight up. (Likely because the kiln dried ribs were creeping into a rounded shape for a few days after bending.  Once it leaned a bit, the reserve stability kicked in.  The kayak has lots of reserve stability.  I was practicing reflexive bracing and really had to work to get it to the tipping point.

It started icing and I came in.  Thankful for the drysuit.  A fellow with a white water C1 on his truck drove up and took a picture of it because he thought it looked like a work of art.  There are winter pool sessions coming up thoughout the winter that i will be attending.  I will be signing off for a bit, but will give a final report after I have paddled for a while.  Also, I am starting on a second F1.


Found a clear, straight grained cedar 4X4 and split it for 2 paddles.  Finished one paddle today.  It was really straight forward.  Won’t get to use it until about 20Jan2020.



View posts by Ivo
I am a nuclear engineer, but I am the son of a cabinet maker and have worked wood since I was 2 (yeah, but they didn't let me do anything but sand.) Any more my wood working is mainly guitars, speaker cabinets, and target rifle stocks.


  1. Chris
    January 4, 2020

    Nice work, Ivo, and I congratulate you on persevering with ammonia bending – sounds a terrible method to me, given the fumes and long soak time!! You’ve made a lovely boat and I wish you well on the water come the Spring. What’s she like to roll?
    I hope to start the skinning process in the next week or two. I don’t have tarred twine either but plan to use waxed whipping twine, which is both rot resistant and very strong.
    Happy New Year!

    1. Ivo
      January 5, 2020

      I haven’t rolled in it yet. It has been 40 years since I last rolled a kayak. I was up for practicing bracing in icy water, but my more rational self though better than rolling in icy water alone after 40 years. The pool sessions will start up in the middle of January and I will relearn rolling in the safety of the warm pool.

      What are you going to use to cover your kayak? I used the urethane from skinboats. It was odorless, just the right viscosity. My son was working with me and we had plenty of time for each coat. It cures to become a clear synthetic rubber.


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