I was thinking about doing a scarf similar to the Bob Simmons boards shown here…
http://www.surfingheritage.com/reg50.html#boardS10
I’m having a hard time figuring out how to accomplish this task. Has anyone ever done scarfs like this with wood of contrasting colors. How do you get the curve to be nice an continuous? It seems like this would be hard to achieve if I cut the rocker out on the boards beforehand with a bandsaw.
Thats not really a scarf joint in the true sense of the term, but this is how I would go at it.
Method #1
Cut the shape on the board and true it to the line. Then trace that shape onto the contrasting piece, and true that to the line. Glue together with a good gap filling glue (polyurethane).
Method #2
Attach contrasting piece to the board with double stick tape and cut the curve at the same time. The only draw back to this method is that you may be shy the thickness of the blade. Again use a good gap filling glue, but try to get the joint as tight as possible for superior strength.
Hi Swied,
I was happy to see one particular word: “Bandsaw”. Hopefully, it’s a big one.
Now, how to go about it ? Here’s how I would tackle it.
If you have cut out the rocker already, that’s okay, providing you hung onto those pieces you cut away from the bottom. Get maybe a little double stick tape and put them back where they were, temporarily.
Then, the piece to be put on - scarph isn’t really the right term, lets say ‘fitted’. I would use a continuous curve, a circular arc would be ideal, done from the centerline. There’s a good reason to use a semicircle, that I’ll get to in a minute.
Okay, stick it all together, both basic board and the nosepiece stuck on top of it and head for the bandsaw. Cut your curve in both. This should make for a pretty near perfect fit, though you may want to take up the blade tension some so that you won’t get the bandsaw blade twisting in the cut. I would use as wide a bandsaw blade as you can besides. You will probably want either a support table for the tail or something similar.
Then, check for fit. This is where that semicircle comes in - if it’s not perfect, more doublestick tape plus some sandpaper, maybe a sanding belt cut into one long strip. If it’s a semicircle, then you can just move the nose piece as shown with some sandpaper in between and it should true it up pretty good, good enough to be glued nicely.
Pardon the rather crude sketch
hope that’s of use
doc…
Need a little more info. What kind of wood are you using? Is it a rider or a wall-hanger? Varnish, poly resin, or epoxy? Balsa - Use white glue such as Elmers. PVA yellow glues such as Titebond will leave a dark line on the light balsa. I would use A Titebond type yellow glue for any other wood. Poly glues such as “gorilla” do not gap fill! Despite the promo, the poly glues are inferior. Messy, non-gap-filling, require very tight joints and clamping, and are not as strong as other glues. I have been stating the inferiority of poly glues for the last few years, and the most recent “Fine Woodworking” magazine highlights a cover story article describing a scientific test comparing various glues and shows the inferior results of poly glues.
Richard
Need a little more info. What kind of wood are you using?
Balsa with a Mahogany scarf.
Is it a rider or a wall-hanger? Varnish, poly resin, or epoxy?
It will be a rider. I’m happy with the Varnish that I used on my first board, so I’m going to stick with that.
Balsa - Use white glue such as Elmers. PVA yellow glues such as Titebond will leave a dark line on the light balsa. I would use A Titebond type yellow glue for any other wood. Poly glues such as “gorilla” do not gap fill! Despite the promo, the poly glues are inferior. Messy, non-gap-filling, require very tight joints and clamping, and are not as strong as other glues. I have been stating the inferiority of poly glues for the last few years, and the most recent “Fine Woodworking” magazine highlights a cover story article describing a scientific test comparing various glues and shows the inferior results of poly glues.
I have been using Titebond III waterproof glue. Since the scarf will be a dark Mahogany color I don’t think the glue line will show. I used Titebond on my first balsa board and didn’t get any dark lines. I think that it may be because I used a jointer and a thickness planer to make the boards straight before gluing. You don’t need much glue if the boards fit together well.
I agree with your assessment of gorilla glue and other similar brands. Poly resin and epoxy are also bad. They fill the gaps but it is difficult to plane and sand.
I hate to say it doc, but I’m having a hard time understanding your illustrations. What are the green elements? I think I need to just stare at it for a while, and it will come to me.
Is the scarf you are describing an attachment to the front of the board? I’m looking to increase the rocker by adding the scarf.
Ah - well, it wasn’t an especially good illustration;
Okay- the green stuff, think in terms of a bandsaw seen from overhead or the side. As it happens, my bandsaw is green.
As to increasing the rocker, uhmm-if it’s the nose rocker you want to add to this is where maybe a vee cut in the nose and a little judicious bending might work out, if it’s foam. If it’s all wood, then a thicker piece than is currently there is maybe your best bet
That help any?
doc…
Aloha swied,
Your answers clear up what you’re trying to accomplish. Sounds like your bottom line attempt is to get more rocker. ?? Is it a Simmons style board (which had very little rocker) or do you imply that you want to do a scarf joint like his to achieve a more modern rocker? There are a few things you can do to add rocker to flat timbers. It ultimately comes down to a compromise of effort / labor vs aesthetics. You state it’s a rider, so I assume function is primary over art, though I dedect you want a “looker” as well. ??
Plan #1. Joint / plane the top deck and the bottom of the beam of wood before bandsawing out the rocker profile from that board. When you cut out the deck rocker profile you’ll end up with the long piece (scrap) with the curved bottom left from the bandsaw cut. Take that “scrap” and turn it upside down and reglue it onto the bottom of the beam before you cut the bottom rocker profile on the bandsaw. This will of course give you a thicker beam from which to cut a more rockered bottom profile. You’ll have a clean deck with no gluelines, however you’ll have a glueline on the bottom at about 1/3 back of both nose and tail.
Plan #2. If your beams of wood are a fair amount longer than the desired length of your finished board plan you can use the offed ends to add the nose rocker. Again joint / plane the top of the beam, then cut off say 18" from the end of the beam. Flip over the offed end and glue it back onto the top of the same end you cut from with about say 9" hanging out past the end of the cut off beam. Hope that makes sense to you. Ex.: You want a 9’ finished board, and you have 10’ + long balsa beams. Do the trial and error mock-ups and math before hand of course, but the piece you cut off and glue back on top will hang out and beyond the end of the beam to give the desired overall board length you desire. The reason I mentioned flipping over the offed end above, is to enable you to keep the similar grain and color of the beam together where the glueline will be. Soooo, if you’re beam is 3" thick with a little natural bend (use it for rocker), the glued on extra 3" piece will add for your rocker. I use the above dimesions simply as an example, but you’ll have to figure what lengths will work out for you. Once the glued up beams are dry, joint / plane the sides of the new glued up beam, as these sides will be glued together with the other beams and stringers to give you the width you need for your planshape.
Plan #3. This one is more labor intensive. Equip your bansaw with a fine cutting blade and ample fence set to about 3/8" (or so) from the blade. Run your balsa beams through the bandsaw to produce lots of 3/8" thick strips x whatever width beams. Nine such strips will produce a 3 3/8" thick stack of wide strips (if my math is correct). Build a form (plywood) the length of your desired surfboard plan x the width of one of your individual balsa beams, on which to glue and clamp your strips. This form will be cut to the shape of your rocker outline nose to tail. With many clamps and using “slow-set” Titebond or other similar PVA yellow glue, clamp all your strips onto the form. After dry, remove the new glued up rockered laminate beam from the form, joint and plane the messy glued sides. If your beams are 6" wide you will need to do this process four times to produce a blank 24" wide (less the planer passes plus the stringers). Granted, this is a lot of work. You’ll end up with a gluelines shere you plane through the layers, however they will be minimal and decorativesly uniform, not to mention helping layout your rail lines visually. The board will be very strong and stiff (stringers do that anyway). Nose and tailblocks will conceal the layered gluelines on the ends. Solid wood old-school rails too??
Anyway that gives you three methods and I can’t type anymore. Hope that gives you some food for thought.
Enjoy the ride,
Richard McCormick
Cut a block out and glue it on. it’s just a peice of wood attached on to the top of another peice of wood. The art is in the nice round continious scarf joint from perfect planing, shaping, and sanding…nothing mystical or magical. It’s round because it has a belly.
Get ye hand plane, and sanding block
-jay
RichardMc
In response to the gap filling qualities of poly glue, in my experience it fills gaps quite well. I glued on a piece of a Redwood step that a friend of mine had broken off. It filled the gap and after a month of being stepped on, it’s still holding strong. Just my observation.
BINGO !
Cut a block out and glue it on. it’s just a peice of wood attached on to the top of another peice of wood. The art is in the nice round continious scarf joint from perfect planing, shaping, and sanding…nothing mystical or magical. It’s round because it has a belly.
Get ye hand plane, and sanding block
-jay
<img src="http://www.surfingheritage.com/images/S10.jpg" alt="" class="bb-image" />[/url]
Circa early 1950s, Bob Simmons, Balsa Twin Fin Spoon, 10’8”
Early twin fin with a concave bottom and a scarfed-on spruce nose (an additional piece was added to the length so that more kick could be shaped into the nose of the board). “These were so difficult to build that very few were made and those mostly for himself, which he would later sell or give only to people he liked
The picture of the Simmons board that this guy is referring to has a balsa board with a big radiuses cut out of it with a corresponding redwood nose piece like what Doc was describing, nothing like scaring for thickness build up for rocker.
Okay- the green stuff, think in terms of a bandsaw seen from overhead or the side. As it happens, my bandsaw is green.
As to increasing the rocker, uhmm-if it’s the nose rocker you want to add to this is where maybe a vee cut in the nose and a little judicious bending might work out, if it’s foam. If it’s all wood, then a thicker piece than is currently there is maybe your best bet
I see it now that you told me that the green was the bandsaw. You actually did a good job with the illustration. It’s like one of those posters where you have to cross your eyes to see the image. As soon as you see it once you can’t understand why you couldn’t see it before. 
Plan #1. Joint / plane the top deck and the bottom of the beam of wood before bandsawing out the rocker profile from that board. When you cut out the deck rocker profile you’ll end up with the long piece (scrap) with the curved bottom left from the bandsaw cut. Take that “scrap” and turn it upside down and reglue it onto the bottom of the beam before you cut the bottom rocker profile on the bandsaw. This will of course give you a thicker beam from which to cut a more rockered bottom profile. You’ll have a clean deck with no gluelines, however you’ll have a glueline on the bottom at about 1/3 back of both nose and tail.
That’s a good idea. It cuts down on the amount of wasted wood and gives you a clean deck.
Cut a block out and glue it on. it’s just a peice of wood attached on to the top of another peice of wood. The art is in the nice round continious scarf joint from perfect planing, shaping, and sanding…nothing mystical or magical. It’s round because it has a belly.
Get ye hand plane, and sanding block
It sounds simple, but I’m having difficulty grasping the concept in terms of the execution. Bill offered to show me the method Bob Simmons used. I’ll keep everyone updated on my progress. I haven’t bought the wood yet.
Swied, Resinhead is right: the darker wood is simply a darker piece glued on top of the front part of the deck. All flat lumber. When it gets shaped, then you see the oval shape at the glue-line. Not complicated. Not cut on a curve. Just shaped roundish on the bottom. The curved contrast between the woods will take care of itself. Think of a stringer that’s off center on a surfboard: it starts out square and after you put the rounded curve in the rail, the stringer at the rail edge looks oval. Same principle.
Doug
It’s like one of those posters where you have to cross your eyes to see the image…
( Chuckling ) … well, now you know how I drew it, with my good eye and the other one that’s not so good.
Now, a thought -
If you do it a lot like I said before, but without the ripping from the deck side rocker cut used as a shim, I think you’ll be able to do a nice job, with a thinner piece that’ll need less shaping to get the additional nose rocker you want.
If you don’t have a really big bandsaw then it can get kinda tricky - I think a 14" might be about the minimum ( with some slick moves ) and of course the bigger the better. If, for instance, you can get access to a real honker around 30-32", that will go real easy.
Hope that’s of use
doc…
hope that’s of use
Here’s a simple way of getting more rocker from a thin piece of wood or foam. Draw your rocker onto the blocks and then cut the wood or foam along the line you draw.
Take the piece that would be waste and glue it to the top of the piece you just cut. It will have a nice shape that follows the bottom rocker, and you just need to thin it out the way you want it.
I’m pretty sure this is what Simmons did to get more rocker into his boards. This is how I was planning to get a wood board made out of 3" x 4" planks.
