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Thread: Progress on the Tom Blake Hollow Hawaiian Surfboard

  1. #1
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    Default Progress on the Tom Blake Hollow Hawaiian Surfboard

    Both decks are installed. There are 918 fasteners in the board now, with only 6 more to go! The drains are installed as well.

    I've got a sealer coat of Le Tonkinois Huiles Bio Impression on and sanded. A second coat was applied, giving the results shown in the video.

    I intend to use all of the sealer, coat after coat, until its used up. No need to waste what is in the tin. Would there be any issues with this?

    After that, I have an unopened tin of Le Tonkinois Classic. The board will get several coats of that as well, reserving one or two in the tin.

    You folks here on the WBF forum are very helpful. Its not just the direct responses to me, but the body of information searchable via the internet. Wow, has the WBF been helpful!

    Brad

    PS. First video post. Hope this works!

    https://www.instagram.com/p/CGKxVRxn...=1v3nrqrscfvhh

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Good to see your progress on the board, Brad. From what I can see in the vid link, it looks a though you have opted for plywood sheetng on top and bottom?...if so, should do the trick for strength and water tightness.

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Quote Originally Posted by Lugalong View Post
    Good to see your progress on the board, Brad. From what I can see in the vid link, it looks a though you have opted for plywood sheetng on top and bottom?...if so, should do the trick for strength and water tightness.
    Hi Lugalong

    For this prototype I have opted for 3mm bottom and 9 mm top decks. Okoume BS1088. The purpose of the prototype is to trial techniques so that when I get to the teak, I will have confidence and have already made my mistakes, of which there are a few. (Why do I hear Sinatra?)

    The plywood is tortured. It has curvature port to starboard AND bow to stern. That is why the decks, per specification, are made in two halves. The center seam is deceptively tricky. On the flat, the joint is a very slight curve. On the board, its dead straight. The bottom seam isn't as tight as the top seam, simply because that one came first.

    I also applied quite a bit of analysis to the thickness of the top deck. I wanted them to be as light as possible, but still support the load. I first determined the beam elongation(stretch) at elastic limit. From this, I determined the maximum deflection before rupture. Then, treating each layer of the plywood as a beam, I distributed the load (me). Using beam analysis, I then determined the deflection this would cause and compared to the deflection at rupture. Eliminating the plywood thicknesses that would rupture, it was then a straight-forward selection of the lightest one that wouldn't feel like a sponge under my feet.

    Brad

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Quote Originally Posted by Tom Blake Surfboard View Post
    Hi Lugalong

    For this prototype I have opted for 3mm bottom and 9 mm top decks. Okoume BS1088. The purpose of the prototype is to trial techniques so that when I get to the teak, I will have confidence and have already made my mistakes, of which there are a few. (Why do I hear Sinatra?)

    The plywood is tortured. It has curvature port to starboard AND bow to stern. That is why the decks, per specification, are made in two halves. The center seam is deceptively tricky. On the flat, the joint is a very slight curve. On the board, its dead straight. The bottom seam isn't as tight as the top seam, simply because that one came first.

    I also applied quite a bit of analysis to the thickness of the top deck. I wanted them to be as light as possible, but still support the load. I first determined the beam elongation(stretch) at elastic limit. From this, I determined the maximum deflection before rupture. Then, treating each layer of the plywood as a beam, I distributed the load (me). Using beam analysis, I then determined the deflection this would cause and compared to the deflection at rupture. Eliminating the plywood thicknesses that would rupture, it was then a straight-forward selection of the lightest one that wouldn't feel like a sponge under my feet.

    od choice, of 3 mm plywood for the bottom, and the 5/8"decks are way more than strong enough... don't know how you would calculate for foot pressure on the deck areas beGotween frame and stringer, because this is going to be where the ply experiences max load. Structure as a whole is monocoque and therefore becomes a beam in i's function as a unit... as I see it, anyway. Being a boat and board builder, structural integrity is largely taken care of in terms of feel for the material, along with experience. Engineering calcs (as in your case) serve good purpose, and I guess you should be able to determine that you have built in a large safety factor. Using 6 or 7mm Oukume for the decks would have been OK, I think.

    Brad
    Good choice, of 3 mm plywood for the bottom, and the 5/8"decks are way more than strong enough... don't know how you would calculate for foot pressure on the deck areas beGotween frame and stringer, because this is going to be where the ply experiences max load. Structure as a whole is monocoque and therefore becomes a beam in i's function as a unit... as I see it, anyway. Being a boat and board builder, structural integrity is largely taken care of in terms of feel for the material, along with experience. Engineering calcs (as in your case) serve good purpose, and I guess you should be able to determine that you have built in a large safety factor. Using 6 or 7mm Oukume for the decks would have been OK, I think, but as a practice run for forming thicker teak planks, you have the right approach.

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Quote Originally Posted by Lugalong View Post
    don't know how you would calculate for foot pressure on the deck areas between frame and stringer, because this is going to be where the ply experiences max load.
    For the benefit of all those who might follow, here is how I did it. By parts.

    First, examine Vera Campbell's board
    Vera.jpg
    We need to zoom in, and so the inset does.
    BeamDiagram.jpg
    The beam we want to analyze is the blue rectangle. There is one fastener at each end. We must respect thin membrane limitations, or the deck will bulge between fasteners, green wavy line.

    But plywood is not a monolithic piece of wood. It is comprised of layers. So a beam within the blue rectangle is a plywood layer! When computing beam deflections and the like, it is important to consider the beam height, as the stiffness goes by the beam height cubed. Forest Products Laboratory guidance shows this approach, as each plywood layer is analyzed separately, and the plywood thickness then in aggregate.

    The force to apply to each layer is then my mass, subdivided by:
    a) I have two human feet, divide my mass by two
    b) Each of my human feet is 12 inches long. Distribute the mass found in (a) equally over contiguous beams, by the beam width.
    c) Each layer of the plywood takes equal distribution of the mass in (b). Divide by number of layers.

    Excellent. I now know the force to apply to each beam, and I know the beam dimensions.
    Charts.jpg
    The Elastic Limit chart shows how much each layer can stretch before rupture. The elastic limit of Okoume is applied to to the beam cross sectional area. Note that it will take ~800 lbf to rupture a layer of 6mm plywood, but 1200 lbf to rupture a layer of 9mm plywood. Why? Because both have 5 layers, and therefore the thickness of each layer is greater in the 9mm plywood.

    Note in the chart Force per Layer, the same force is applied per layer, for the 6 and 9mm plywood because they each the same number of layers.

    Okay, so use Fixed-Fixed beam deflection formulas to compute the deflection of a single layer of plywood, given the force located at the length-wise center of the beam. The third charts shows the result, the 6mm layer shows over 1" of deflection, while the 9mm layer shows less than 0.5" of deflection. The 6mm layer ruptures, yet the 9 mm layer does not! Why? Because the maximum deflection at rupture is ~0.725" for the longest (weakest) beam analyzed.

    I could go thicker, of course, but then the weight penalty of a thicker deck comes into play. My volumetric computation places the board, in total, to be 61 pounds (Tom said ~70 to 75 pounds). The actual weight of the board, without the varnish, was 56.6 pounds. Adding varnish will make it very close indeed, which was 4.8 pounds in the two tins.

    So my sense was that I would rupture or crack a 6mm deck (just under 1/4") but NOT rupture a 9mm deck (just under 3/8").

    Your mileage may vary. There are other ways to analyze the decks, but this method lent itself well to the mathematical lofting I've created for the board.

    Hopefully,that 10,000 foot overview gives a sense how I did it. I can provide the equations if interest exists.

    Brad

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Quote Originally Posted by Tom Blake Surfboard View Post
    For the benefit of all those who might follow, here is how I did it. By parts.

    First, examine Vera Campbell's board
    Vera.jpg
    We need to zoom in, and so the inset does.
    BeamDiagram.jpg
    The beam we want to analyze is the blue rectangle. There is one fastener at each end. We must respect thin membrane limitations, or the deck will bulge between fasteners, green wavy line.

    But plywood is not a monolithic piece of wood. It is comprised of layers. So a beam within the blue rectangle is a plywood layer! When computing beam deflections and the like, it is important to consider the beam height, as the stiffness goes by the beam height cubed. Forest Products Laboratory guidance shows this approach, as each plywood layer is analyzed separately, and the plywood thickness then in aggregate.

    The force to apply to each layer is then my mass, subdivided by:
    a) I have two human feet, divide my mass by two
    b) Each of my human feet is 12 inches long. Distribute the mass found in (a) equally over contiguous beams, by the beam width.
    c) Each layer of the plywood takes equal distribution of the mass in (b). Divide by number of layers.

    Excellent. I now know the force to apply to each beam, and I know the beam dimensions.
    Charts.jpg
    The Elastic Limit chart shows how much each layer can stretch before rupture. The elastic limit of Okoume is applied to to the beam cross sectional area. Note that it will take ~800 lbf to rupture a layer of 6mm plywood, but 1200 lbf to rupture a layer of 9mm plywood. Why? Because both have 5 layers, and therefore the thickness of each layer is greater in the 9mm plywood.

    Note in the chart Force per Layer, the same force is applied per layer, for the 6 and 9mm plywood because they each the same number of layers.

    Okay, so use Fixed-Fixed beam deflection formulas to compute the deflection of a single layer of plywood, given the force located at the length-wise center of the beam. The third charts shows the result, the 6mm layer shows over 1" of deflection, while the 9mm layer shows less than 0.5" of deflection. The 6mm layer ruptures, yet the 9 mm layer does not! Why? Because the maximum deflection at rupture is ~0.725" for the longest (weakest) beam analyzed.

    I could go thicker, of course, but then the weight penalty of a thicker deck comes into play. My volumetric computation places the board, in total, to be 61 pounds (Tom said ~70 to 75 pounds). The actual weight of the board, without the varnish, was 56.6 pounds. Adding varnish will make it very close indeed, which was 4.8 pounds in the two tins.

    So my sense was that I would rupture or crack a 6mm deck (just under 1/4") but NOT rupture a 9mm deck (just under 3/8").

    Your mileage may vary. There are other ways to analyze the decks, but this method lent itself well to the mathematical lofting I've created for the board.

    Hopefully,that 10,000 foot overview gives a sense how I did it. I can provide the equations if interest exists.

    Brad
    Thanks for the offer to supply equations, and sure, your calcs have taken care of loads applied under foot, even though there will be times when total body weight is supported on one foot, so the 9mm ply does prevent"rupture", where the 6mm ply may not, correct.But there is structural support by frames and stringer as well as the ply, and considering each ply "layer" (laminate) individually, does not fully cover the combined strength of the laminate structure as a whole .Deflection resulting in rupture is eased as there is no real point loading, due to flesh and bones or water being te points of force to be considered.
    Pics of the board being used should be something to see.

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Quote Originally Posted by Lugalong View Post
    considering each ply "layer" (laminate) individually, does not fully cover the combined strength of the laminate structure as a whole....

    Pics of the board being used should be something to see.
    Hi Lugalong!

    Covering the first point, direct reference to Forest Products Laboratory FPL-059 should be made.
    textgram_1602528978.jpg
    When utilizing this equation, I find that for uniform layers in size and material, analyzing the entire stack produces an identical result to analyzing one individual layer, to 6 decimal places (millionth of an inch). Probably close enough. If your layers are not uniform, or contain differing species, you should utilize the entire stack equation and not evaluate a single layer.

    To put this in perspective, if it was a treewood deck, one monolithic layer, then the equation states Ec=E, or the modulus of elasticity for one layer is equal to the modulus of elasticity of the (one layer) stack.

    You raised a bunch of completely valid objections, like standing on one foot, and the distribution of mass along my foot instead of a point, etc. I agree, 100%. It will be impossible to analyze all circumstances, all loadings etc. When Roebling estimated loads for the Brooklyn Bridge, built in the 1800's, he didn't engineer it to the line. Roebling provided a safety margin for all the oddball cases, like how many folks he could cram into a trolley car. As do I. Given rupture at 0.72" for the longest beam, under my load cases, the 9mm deflects 0.35". That's a 2 to 1 safety margin. Whereas the 6mm deflects 1.17", obviously rupturing.

    Engineering equations are a way to make educated judgements. I cannot be sure there will never be rupture under all circumstances. I think I will be okay, based on the analysis. Experience also provides a great way to make educated judgments. Yet I am not about to build 20 or 30 boards in order to optimize deck thickness! This is the first one, so analysis will just have to do.

    Pics of the board being used? Yessir! Video too! The enthusiasm of surfers for one of these boards is off the charts. If they have any interest at all, it goes from 1 to 100, instantly. Everybody wants to ride one. Its the 12 to 18 month build time that puts folks off. Not to mention the bazillion fasteners if done properly, or the conundrums of deciphering Tom's cryptic direction and specification. The board simply cannot be built exactly as he specifies.

    Example. Tom states the board should weigh between 70 and 75 pounds when complete. He further states both decks should be " thick. If the decks are that thick, the volumetric calculation indicates a 100+ pound board.

    There will be a series of trials, all documented. There will be waves ridden, all documented. Of course I will share. That's the spirit of aloha after all!

    Brad

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Fascinating stuff Brad.
    The board looks amazing, love the screw heads. 35kgs+ that's a heavy surf board, be sure to warn me to get out of the way before you drop in.

    Also, I like the way you glide gracefully between metric and imperial..
    It's all fun and games until Darth Vader comes.

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    You know you are an engineer when that is the part of the photo you zoom in on...

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Quote Originally Posted by gypsie View Post
    Fascinating stuff Brad.
    The board looks amazing, love the screw heads. 35kgs+ that's a heavy surf board, be sure to warn me to get out of the way before you drop in.

    Also, I like the way you glide gracefully between metric and imperial..
    Hi Gypsie

    The board is only heavy in comparison to a modern day board. In Tom's day, the competition was a solid redwood plank, which was over 100 pounds! Tom's boards were the light weight alternative. Heh. Lightweight. Not.

    The board is also over 170 liters in volume. The only dropping in will be by others, since I will catch waves much further outside than most! If/when that happens, they will be crushed by this monster. My apologies to all in advance. Don't sail in front of an oil tanker, don't surf in front of a genuine Tom Blake Hollow Hawaiian Surfboard. Add my 16 stone to the weight of the board, and "Look-out, here he comes!"

    Tom specifies that the board be mechanically fastened, with the seams made water tight by "Jeffery's Marine Glue" (asphalt). So fasteners and asphalt it is!

    Units: Almost all units are human created. International clients cause unit conversions, everywhere. Write your units down next to your numerical values to eliminate confusion. Easy-peasy.

    Brad




    For the benefit of non-surfers,

    'dropping in' means to catch a wave that someone else has already caught. A right of way violation. Similar to port/starboard right of way.

    'Outside' means further away from shore.

    If I am further from shore (outside) I will catch the wave before others do. Since I will be on the wave before they catch it, if they try to catch the same wave, they "drop in". This is a social error.

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Hi RGThom

    I assume you are referencing the Vera Campbell image.

    That's a teak board. Made for Tom by one of his commercially licensed manufacturers. Tom often took his royalties in boards, not cash and we are aware of only one teak board being commercially made.

    Since the board is identified later as Vera's board, we can only assume Tom traded it to her for ... erm ... uh ... other things!

    You should know that the build is being followed by nearly 200 surfers right now. I need to be able to communicate with them using images known to surfers. Vera Campbell, with her teak board, is definitely one of those images. It was convenient to use here as well.

    Engineers have an eye for numbers and figures. Nothing was missed! ��

    Brad

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Further progress on the Tom Blake Hollow Hawaiian Surfboard

    After 4 coats of Le Tonkinois Huiles Bio Impression (sealer), I waited several weeks to be sure of a full cure of the varnish and to avoid varnish fatigue. I scuffed with 400 grit and applied the first coat of Le Tonkinois Vernis (varnish).

    https://www.instagram.com/p/CHYd0Pon...=1are2ii740zyf

    While I'm pretty happy, I can observe the frames (ribs as Tom calls them) telegraphing through to the surface. Its okay for the prototype but I'd like to do better on the next revision.

    The decks deflect slightly under load, and when the sander comes upon a frame (rib), the stiffness dramatically increases and thus the sanding is different.

    What can I do to improve the situation?

    Brad

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Quote Originally Posted by Tom Blake Surfboard View Post
    Further progress on the Tom Blake Hollow Hawaiian Surfboard

    After 4 coats of Le Tonkinois Huiles Bio Impression (sealer), I waited several weeks to be sure of a full cure of the varnish and to avoid varnish fatigue. I scuffed with 400 grit and applied the first coat of Le Tonkinois Vernis (varnish).

    https://www.instagram.com/p/CHYd0Pon...=1are2ii740zyf

    While I'm pretty happy, I can observe the frames (ribs as Tom calls them) telegraphing through to the surface. Its okay for the prototype but I'd like to do better on the next revision.

    The decks deflect slightly under load, and when the sander comes upon a frame (rib), the stiffness dramatically increases and thus the sanding is different.

    What can I do to improve the situation?

    Brad
    Brad, you don't want to be sanding through the ply veneer, so it could be a good thing to stick with hand sanding and feeling your way with the paper under your palm..... finish of the board (being old -time organic), does not need to be 'flatted' in such a way that high spots are all knocked off. Just ride over the slightly contoured surface as you sand and use an orbital action.

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Hi Lugalong!

    Yes, I have been hand sanding, being terribly focused on sanding through. No machine sanding for me thank you! One thing surfing does is give you tremendous upper body strength and a resilience against fatigue! After paddling for a mile or three, the burn may start but who can resist those endless seconds of joy!

    The telegraphing wasn't obvious when I was done sanding. I stepped the grits up from 60 to 400. After 400, the board felt beautifully smooth as I ran my hands over it. I thought to myself that it felt awesome.

    To my eyes now, the board looks like the Hindenburg Zeppelin. Every internal strut and frame is telegraphed. I am 100% fully aware of the builder's focus on the defects that no one else sees. I can point out each nail that somehow managed to go wrong out of 900+. Each and every one that offends.

    Would a long board sander help? The frames are 12" on center. If I wanted a longboard sander to always be on at least two frames, it by necessity would have to be > 24" long. Anything that long concerns me. How to keep the pressure in the middle of a 24" span the same as at the ends?

    Brad

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Quote Originally Posted by Tom Blake Surfboard View Post
    Hi Lugalong!

    Yes, I have been hand sanding, being terribly focused on sanding through. No machine sanding for me thank you! One thing surfing does is give you tremendous upper body strength and a resilience against fatigue! After paddling for a mile or three, the burn may start but who can resist those endless seconds of joy!

    The telegraphing wasn't obvious when I was done sanding. I stepped the grits up from 60 to 400. After 400, the board felt beautifully smooth as I ran my hands over it. I thought to myself that it felt awesome.

    To my eyes now, the board looks like the Hindenburg Zeppelin. Every internal strut and frame is telegraphed. I am 100% fully aware of the builder's focus on the defects that no one else sees. I can point out each nail that somehow managed to go wrong out of 900+. Each and every one that offends.

    Would a long board sander help? The frames are 12" on center. If I wanted a longboard sander to always be on at least two frames, it by necessity would have to be > 24" long. Anything that long concerns me. How to keep the pressure in the middle of a 24" span the same as at the ends?

    Brad
    Having spent thousands of hours sanding and fairing shapes to a fineness that is mirror smooth, I am trying to help you avoid being led in that direction. Sanding/fairing to perfection, simply means 'knocking-off/ sanding off high spots, so that there are no contours on the surface, and which either means removal of surface material or addition of filler. Your board (being veneered sheetstock) does not want either of those, so try and find a way to live with it rather than change it.A long block spanning one or more rib spacing is intended to knock-off or take-off material higher than the low spots between the ribs, and which means going through some of the veneers that are within the high spots "telegraphed" by the ribs. Contour of the outer laminate/veneer is what you need to follow, rather than remove with a long block.

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Hi Lugalong

    Its the next board that I'm (likely over-) thinking about. The next board will have solid wood decks, not plywood. So no worries about bursting through veneers.

    Plywood was just a means to an end. It helped me to understand the processes without dropping big cash on long boards, wide and thin at the same time. So i got to try out how to put the decks on, investigating thickness, stress in bending and fineness of shape. Custom millwork to get those long, wide yet thin boards will likely run me a fortune! (Can't wait to convince SWMBO that I must spend this money and nothing else will do.)

    I'm a bit concerned about water flow over the surfaces of the board. Those telegraphs will create turbulence and affect the ride. They are small, of course, and only apparent with low sight lines and lots of illumination. In general, they are insignificant. Maybe I am, as usual, over thinking this.

    On a similar note, I'm not too happy with the silicon bronze annular ring nails. Setting those fasteners flush was more challenging than I thought. The screws were cleaner, more manageable and easier to set flush. I'm likely to dispense with the nails and go 100% screws.

    Brad

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Quote Originally Posted by Tom Blake Surfboard View Post
    Hi Lugalong

    Its the next board that I'm (likely over-) thinking about. The next board will have solid wood decks, not plywood. So no worries about bursting through veneers.

    Plywood was just a means to an end. It helped me to understand the processes without dropping big cash on long boards, wide and thin at the same time. So i got to try out how to put the decks on, investigating thickness, stress in bending and fineness of shape. Custom millwork to get those long, wide yet thin boards will likely run me a fortune! (Can't wait to convince SWMBO that I must spend this money and nothing else will do.)

    I'm a bit concerned about water flow over the surfaces of the board. Those telegraphs will create turbulence and affect the ride. They are small, of course, and only apparent with low sight lines and lots of illumination. In general, they are insignificant. Maybe I am, as usual, over thinking this.

    On a similar note, I'm not too happy with the silicon bronze annular ring nails. Setting those fasteners flush was more challenging than I thought. The screws were cleaner, more manageable and easier to set flush. I'm likely to dispense with the nails and go 100% screws.

    Brad
    Hey Brad, sure the solid wood will allow longboard fairing to remove a wavy surafce and it is worth starting with the longboard fairing on the ribs, before you even screw down the planking... for this you could get by with a 2" strip of grit bonded to a flexible board spanning more than 4 ribs ( use a board with similar spring to that of your covering planks, but obviously cut to the width of the grit strip.Contact glue does the job.

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    I wanted to store my 1929 Jeffery's Marine Glue brochure in a safe place. What better place, thought I, than the magazine in which he specified the marine glue.

    So I opened the magazine to the page and read the words "Jeffery's quality C Marine Glue"

    Referencing the 1929 brochure http://forum.woodenboat.com/showthre...to-Use-It-quot post #12, brochure page 18, I observe the following words "Jeffery's Liquid Marine Glue C Quality"

    Now that is a fairly close match!

    I do not think the "C" refers to a grade, rather, I think it is referring to "Sea Quality".

    The directions in the brochure indicate that the product is used without heating it. That is huge for me!

    It would be physically impossible to apply Marine Glue in the manner Tom describes, should it require heat. Tom states that we spread the glue on the ~48 linear feet of the frame of the board, then apply ~48 feet of cloth and then another layer of marine glue on that same 48 feet. Then and only then are the decks applied. There is no way to hold the glue at high temperatures given this description. I was stymied. The C Quality Marine glue does not require heat!

    Tom's description of application matches the description of application given on page 18 of the brochure as well.

    So now I have the exact target for these seams. This is has significant relevance to my build.

    I want to ride the exact board Tom specifies, not some random look alike!

    Brad
    Last edited by Tom Blake Surfboard; 11-15-2020 at 06:57 PM.
    Building the July 1937 Popular Mechanics
    Hollow Hawaiian Surfboard
    Patented by Tom Blake in 1932

    www.instagram.com/tomblakesurfboard

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    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Quote Originally Posted by Tom Blake Surfboard View Post
    I wanted to store my 1929 Jeffery's Marine Glue brochure in a safe place. What better place, thought I, than the magazine in which he specified the marine glue.

    So I opened the magazine to the page and read the words "Jeffery's quality C Marine Glue"

    Referencing the 1929 brochure http://forum.woodenboat.com/showthre...to-Use-It-quot post #12, brochure page 18, I observe the following words "Jeffery's Liquid Marine Glue C Quality"

    Now that is a fairly close match!

    I do not think the "C" refers to a grade, rather, I think it is referring to "Sea Quality".

    The directions in the brochure indicate that the product is used without heating it. That is huge for me!

    It would be physically impossible to apply Marine Glue in the manner Tom describes, should it require heat. Tom states that we spread the glue on the ~48 linear feet of the frame of the board, then apply ~48 feet of cloth and then another layer of marine glue on that same 48 feet. Then and only then are the decks applied. There is no way to hold the glue at high temperatures given this description. I was stymied. The C Quality Marine glue does not require heat!

    Tom's description of application matches the description of application given on page 18 of the brochure as well.

    So now I have the exact target for these seams. This is has significant relevance to my build.

    I want to ride the exact board Tom specifies, not some random look alike!

    Brad
    If Jeffries Liquid glue cannot be found anymore, Scandinavian and Shetland boat boulders used Stockholm tar and cloth in exactly the same way.
    It really is quite difficult to build an ugly wooden boat.

    The power of the web: Anyone can post anything on the web
    The weakness of the web: Anyone can post anything on the web.

  20. #20
    Join Date
    Jan 2020
    Location
    Suffolk County, New York, USA
    Posts
    115

    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Quote Originally Posted by Peerie Maa View Post
    If Jeffries Liquid glue cannot be found anymore, Scandinavian and Shetland boat boulders used Stockholm tar and cloth in exactly the same way.
    Hi Nick

    Thanks for that.

    In building the prototype, I used Henry's 208 tar. It has a very high asphalt content, consistent with Jeffery's No.2, but it is kept spreadable at room temperatures with a lot of naphtha. I was pretty happy with the resultant seam.

    The prototype has permitted the investigation of materials, tools, techniques and results. Once the prototype is done, it will be ridden into destruction as I build the board again. I am hopeful to get closer to Tom's specification in every criteria, hence the intense focus on the precise Marine Glue. I am 100% sure that the C Quality Marine Glue is long discontinued. Just figuring out which Jeffery's Glue is a big step forward. Knowledge is power. Now I know! Onwards!

    Brad
    Building the July 1937 Popular Mechanics
    Hollow Hawaiian Surfboard
    Patented by Tom Blake in 1932

    www.instagram.com/tomblakesurfboard

  21. #21
    Join Date
    Sep 2015
    Location
    Whangarei New Zealand
    Posts
    906

    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Just guessing that it was the 'yellow' Jeffry's marine glue rather than any of the tar/pitch/bitumen containing grades (being coloured to suit a board rather than boat deck seams). Rosin and shellac might be the ingredients of the grade used on the board. Earliest memories I have of a glue anything like marine, are from a tin with a bulls eye label, which might have been one ingredient that along with heat and rosin also come to mind.... this was in association with a solution being painted on copper wire windings of a homemade arc welder back in the 1950's.

  22. #22
    Join Date
    Jan 2020
    Location
    Suffolk County, New York, USA
    Posts
    115

    Default Re: Progress on the Tom Blake Hollow Hawaiian Surfboard

    Ready for Splash!

    https://www.instagram.com/p/CILgfWgH...d=a40q6vthgwrs

    Thank you everyone, for all your helpful comments! This would not have been possible without the Forum!!

    Brad
    Last edited by Tom Blake Surfboard; 11-29-2020 at 03:29 PM. Reason: Spelling & Grammar
    Building the July 1937 Popular Mechanics
    Hollow Hawaiian Surfboard
    Patented by Tom Blake in 1932

    www.instagram.com/tomblakesurfboard

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