I came up with pretty much the same system except I use a heavy 3-1/2 thick jig. The angle I use is 10 to 1 and with good quality white pine its stronger than the joint and behaves as one piece. I suspect you're right perhaps about better bending fairness at 16 to 1 but I am cutting 3/4" thick carvel planking for a 28 ft hull and it bends plenty fair. My heavy jig also has a big wood handle sold as a wood float handle which I screwed to it and it makes a huge difference in ease of use. I also cut a full 3 inch depth on 10 inch blade. So all my planks are 3 inches wide. I don't like the clamps so a single screw through the plank into the jig holds it secure. Out of the way of the saw naturally.. Using glass microspheres in the epoxy makes a mix still stronger than the pine (I tested it in various ways), yet it sands twice as easily to a feather edge. I agree the 90 degree part is extremely crucial yet I still get subtle inaccuracies. But its okay because the glass microsphere/ epoxy blend fixes a multitude of sins. It even functions as a gap filling glue for edge-glued carvel planking that sands flush easily.
It's really nice to add an off switch to the table saw that can be operated by your thigh, knee or foot. Sometimes something goes wrong--maybe the piece of wood you are sawing has some tension bound into it that is released during the cut. This can cause the wood to abruptly warp and bind up on the blade. Often you feel it happening, and stop feeding the stock--but you are getting noise and vibration and just know that you can't let go of the wood with even one hand to reach for the switch. These switches are available.
Absolutely agree. I’ve never actually doing these kind of cuts in real life because I have access to longer wood. doing this with any frequency, I would probably add a knee or foot switch.
That idea works great - one suggestion is to use a "few" 1/8" dowels as pins (say 5 in a 2x1x2 pattern) . Makes it a LOT stronger and no movement when drying or under stress. Even toothpicks will work.
Looking for some advice on repairing a broken sailboat mast. I need to patch on about a 4' piece on the bottom. The mast is constructed with spruce using the bird's mouth method. I think some kind of scarf joint would be the strongest, but I'm not sure how to do it for this application. Thoughts? Cheers and thanks in advance!!
I was thinking the same, my knee is in easy reach, that is how I normally turn off the saw in general. That second hand isn't stronger than the motor on any table saw. Not even close, I don't care if you are a competitive strongman, saw is going to win.
In the last few videos, I've been wondering why the qajaq hanging on the wall behind you has the middle of the 6th rib cut out. Is that to keep your heels from catching when entering or exiting?
Although I can’t prove it I feel like tight bond has some sort of adhesion issue with red cedar. Urethane is more waterproof and dries faster. Epoxy is ideal but a pain to work with.
Just on machine safety, I don't understand why all large power tool don't just come with a foot switch so it is only on while your foot is on the switch, that way as soon as your foot is off, the motor is off. You know it makes sense right. Both hands are free to control the job while your turning on or off and if you get a fright, the motor is immediately off before you even realise that you jumped, let alone thought about fumbling for that red button.
@@capefalconkayak Thanks for that. I ended up buying a West System 875 Scarffer after getting tired of stacking and hand planing or using a router sled. Being able to use a circular saw eliminates the need to "guess" all of the pieces at once and instead make individual scarfs. One of these days, I hope to make some SOF amas for a trimaran to cut down on the weight.
I would never use Gorilla polyurethane glue. It is not as strong as Titebond. If you look up their own numbers online--you will find out that this is the case. I discovered, when making laminations that are bent a long way and the glue line is loaded in sheer-- that it just does not hold. Of course, with a 12:1 scarf and a gentle bend, you are fine with that glue. But it is not a superior glue. That is pure hype. I have done thousands of scarfs with West System epoxy and have also glued up very highly stressed laminations with it. Sorry--I don't mean to sound critical! I totally admire your work and the building systems you have developed! I'm particularly impressed with all the prototyping you do!
Hey Ian, I agree. I’m mostly using gorilla glue here because it’s quick and easy and strong enough in this application. I don’t work with epoxy because it’s expensive and it’s a mess to deal with and it’s also impossible to get in small quantities inexpensively which means that I would have to recommend students buy a pretty sizable quantity for just this task when they already have the gorilla glue for other things we do on the boat. I also like it because it’s waterproof. I’m still not sure what I think about titebond 3 for this application. Can that handle continuous moisture and continuous stress on the joint without creep?
@@capefalconkayak Your scarf ratio is such that most glues would be just fine. Some old time boat builders swear by Elmer's Plastic Resin glue--a powder mixed with water. I haven't used it except for bungs. You are right, epoxy in such small quantities is an expense and inconvenience. WEST G-flex, however, is available in small 1:1 kits for about $30. It consists of two 4oz bottles. It would save someone who was struggling to cut a decent scarf. We use it for White Oak and any other difficult to glue woods.
Unless Gorilla Glue changed their formulation in years past most boatbuilder and repair guys would not use it at all...If they have changed to a polyurethane adhesive maybe its better now... I'd only use epoxy or titebond III if it was not on a boat. r
You have taught me so much about boat building.
I came up with pretty much the same system except I use a heavy 3-1/2 thick jig. The angle I use is 10 to 1 and with good quality white pine its stronger than the joint and behaves as one piece. I suspect you're right perhaps about better bending fairness at 16 to 1 but I am cutting 3/4" thick carvel planking for a 28 ft hull and it bends plenty fair. My heavy jig also has a big wood handle sold as a wood float handle which I screwed to it and it makes a huge difference in ease of use. I also cut a full 3 inch depth on 10 inch blade. So all my planks are 3 inches wide. I don't like the clamps so a single screw through the plank into the jig holds it secure. Out of the way of the saw naturally.. Using glass microspheres in the epoxy makes a mix still stronger than the pine (I tested it in various ways), yet it sands twice as easily to a feather edge. I agree the 90 degree part is extremely crucial yet I still get subtle inaccuracies. But its okay because the glass microsphere/ epoxy blend fixes a multitude of sins. It even functions as a gap filling glue for edge-glued carvel planking that sands flush easily.
The push pins are a dang good idea
It's really nice to add an off switch to the table saw that can be operated by your thigh, knee or foot. Sometimes something goes wrong--maybe the piece of wood you are sawing has some tension bound into it that is released during the cut. This can cause the wood to abruptly warp and bind up on the blade. Often you feel it happening, and stop feeding the stock--but you are getting noise and vibration and just know that you can't let go of the wood with even one hand to reach for the switch. These switches are available.
Absolutely agree. I’ve never actually doing these kind of cuts in real life because I have access to longer wood. doing this with any frequency, I would probably add a knee or foot switch.
That idea works great - one suggestion is to use a "few" 1/8" dowels as pins (say 5 in a 2x1x2 pattern) .
Makes it a LOT stronger and no movement when drying or under stress.
Even toothpicks will work.
Thanks you so much for this information; it will work great for my 1x3 ribs for my boat build. How would I scarf 2x6's to create a long keelson?
Thank you for this excellent video! Cheers.
Looking for some advice on repairing a broken sailboat mast. I need to patch on about a 4' piece on the bottom. The mast is constructed with spruce using the bird's mouth method. I think some kind of scarf joint would be the strongest, but I'm not sure how to do it for this application. Thoughts? Cheers and thanks in advance!!
Hard to describe but they also have recommendations of grain orientation when there is grain runout.on the scarf joint.
Hi Brian, do you have a favorite 2 part polyurethane for applying to the dacron?
Nicely, thanks
Great fantastic video!!!
I fab aircraft spars,using 12:1. Adhesives are different,but the longer the scarf the better ! Any idea what shear values Gorilla Glue has??
No clue on the gorilla glue. It’s not as strong as many other options but it’s more than strong enough for what we do and it’s quick and easy to use.
Get yourself a paddle table saw switch that arranged so that you can hit with your knee. I feel so much safer having one on my saw.
I was thinking the same, my knee is in easy reach, that is how I normally turn off the saw in general.
That second hand isn't stronger than the motor on any table saw. Not even close, I don't care if you are a competitive strongman, saw is going to win.
Спасибо, хорошая техника.
Could use a foot pedal switch!!
In the last few videos, I've been wondering why the qajaq hanging on the wall behind you has the middle of the 6th rib cut out. Is that to keep your heels from catching when entering or exiting?
Correct. You see this a lot in historic kayaks.
why not use Tite Bond III ?
Although I can’t prove it I feel like tight bond has some sort of adhesion issue with red cedar. Urethane is more waterproof and dries faster. Epoxy is ideal but a pain to work with.
@@capefalconkayak That explains some experiences I've had with TB and cedar in the past
Just on machine safety, I don't understand why all large power tool don't just come with a foot switch so it is only on while your foot is on the switch, that way as soon as your foot is off, the motor is off. You know it makes sense right. Both hands are free to control the job while your turning on or off and if you get a fright, the motor is immediately off before you even realise that you jumped, let alone thought about fumbling for that red button.
A foot switch is an option
maybe table saw needs a foot switch hmm
Much better proposition than trying to scarf 4 mm marine plywood!
Are you on Instagram? @shipwrightskills Just posted a really great jig for scarfing plywood
@@capefalconkayak Thanks for that.
I ended up buying a West System 875 Scarffer after getting tired of stacking and hand planing or using a router sled.
Being able to use a circular saw eliminates the need to "guess" all of the pieces at once and instead make individual scarfs.
One of these days, I hope to make some SOF amas for a trimaran to cut down on the weight.
I would never use Gorilla polyurethane glue. It is not as strong as Titebond. If you look up their own numbers online--you will find out that this is the case. I discovered, when making laminations that are bent a long way and the glue line is loaded in sheer-- that it just does not hold.
Of course, with a 12:1 scarf and a gentle bend, you are fine with that glue. But it is not a superior glue. That is pure hype. I have done thousands of scarfs with West System epoxy and have also glued up very highly stressed laminations with it.
Sorry--I don't mean to sound critical! I totally admire your work and the building systems you have developed! I'm particularly impressed with all the prototyping you do!
Hey Ian, I agree. I’m mostly using gorilla glue here because it’s quick and easy and strong enough in this application. I don’t work with epoxy because it’s expensive and it’s a mess to deal with and it’s also impossible to get in small quantities inexpensively which means that I would have to recommend students buy a pretty sizable quantity for just this task when they already have the gorilla glue for other things we do on the boat. I also like it because it’s waterproof. I’m still not sure what I think about titebond 3 for this application. Can that handle continuous moisture and continuous stress on the joint without creep?
@@capefalconkayak Your scarf ratio is such that most glues would be just fine. Some old time boat builders swear by Elmer's Plastic Resin glue--a powder mixed with water. I haven't used it except for bungs. You are right, epoxy in such small quantities is an expense and inconvenience. WEST G-flex, however, is available in small 1:1 kits for about $30. It consists of two 4oz bottles. It would save someone who was struggling to cut a decent scarf. We use it for White Oak and any other difficult to glue woods.
@@ianbruce6515 yeah, the G flex would definitely be my next choice and is pretty much the only thing you can use for poorly mated surfaces.
Unless Gorilla Glue changed their formulation in years past most boatbuilder and repair guys would not use it at all...If they have changed to
a polyurethane adhesive maybe its better now... I'd only use epoxy or titebond III if it was not on a boat.
r
I thought gorilla glue was always a standard polyurethane glue
Why would you even consider using gorilla glue? Please use tight bond three. Vastly superior
Thanks for the feedback, can tite bond 3 handle continuous immersion?
@@capefalconkayak its not recommended