Springer build

The weather will not cooperate to allow me to finish my XPS insulation build! On to the next project:

When I built a few of the composte boards with wood rails or wood perimeter stringers they had a decided amount of projection out of bottom turns. Not HUGE, but enough to feel it.

Sunnova, and some others, insert on certain of their boards what is referred to as a springer. This photo shows the spring in the middle of the board running from just in fron of the back foot and ending around the front foot. Cool pic!

Now, this build gets a bit complex, because the springer is place in the middle of the board at what is referred to as the Neutral Axis...that point in the board where opposing forces of tension and compression meet. Also, the springer must be free floating to allow the most "twang" if you will that will create projection.

What I have done, is hotwired the rocker and then "split" the rocker at the neutral axis. Then I will route out an inset in the top and bottom pieces and place the springer in, before laminating the top and bottom back together.

The bottom rocker hotwired in - template still attached:

Next a straight hotwire at where I calculated the neutral axis will/should be - more ZEN than science This is before the cut, templates attached:

The cut made and template removed. The top of the board will need a ton of shaping to get to the final dimensions.

Jeff, I wish you lived near me...everytime I see one of your new build/fix threads I wish I could take one of the boards out for a spin.

But keep all the wakesurf stoke flowing! Hopefully one day I can finally start my wakesurf design/shaping infatuation - I've learned so much from all your posts, and being outside the core of surfing (Midwest), I fully appreciate all the insight as to what is going on and different ideas that are going into surf shapes and design! All-in-all, thanks much!!

Sinko, thanks so much for the props! I always enjoy when I can stir some interest. Do be sure to share with us when you start building!

Very very interesting Jeff.
What type of material are you going to use for the "spring"?

I'm torn Matt...the couple of composites that I built with internal structure, I used Balsa, but I bought an extra piece of Basswood (which I'll be using for stringer material). The Basswood's return rate is...I don't know 100 x faster than the Balsa. I'm sure as a kid you took one of those wooden rulers and twanged it over the side of your desk. It gets that harmonic vibration going - that's what the Basswood is like. 1/4" Balsa has some return, but it's almost sluggish in comparison.

Matt I'm sure you've seen the discussions, in the "see thru" picture of the Sunnova, the ends of the Springer are tapered - almost to a point. Reducing the volume allows some "flex" in that area. I would think that tapering on the other plane - the thickness could also provide some flexural changes.

Anyway...I do believe that I'll use some 1/4" Balsa for this experiment.

Springer shaped and the outline traced. Next I need to route all of that area out!!!!!!!

I routed the inside of the outline using a straightedge to let me run the router quickly and accurately.

After I did the entire outline, I just quickly ran back and forth to clean up the interior.




Test fitting the springer material into the cavity.

I forgot to get a picture, but I laminated the top and bottom "halves" with 2 oz eglas and TAP Super Hard 4 to 1 epoxy. Then I tucked the entire billet into the bag until the epoxy cures.

jeff - this is such an interesting build -- i hadn't seen the sunova on sways - so this is all new to me. are you using 2lb foam?

You have to check out my build thread this morning, I spoke with Breanne Ashley about epoxies last evening.



I thought for sure you would have been all over this, before me. I'm using 1 pound, and I have a sheet of Divinycell that I intend to skin with. The next step will be the perimiter stringers. I want to hit the fin boxes so I need to do a bit of tracing and 'eyeballing'

I didn't glue the springer in - it's fully floating. I used a razor blade to cut the wetted out glass around the edge of the springer and I laid down a piece of wax paper over the springer before I laid the wet glass on it. Hopefully that will work!

It looks just like a hotwired blank. There is a slight line you can see on the side. This board will have perimeter stringers so you'll never see that, plus it should give some extra strength in connecting the top and bottom halves.

The only thing that will need some work is at the entry of the hotwire. It melts a bit of the foam and leaves an indentation. I'll fill it with spackle or expoxy and cabosil before skinning it.

Ok, so my first recommendation, should you undertake this type of construction, is do NOT forget where you inserted the springer

I laid out the outline and THOUGHT I had it measured and noted appropriately but it didn't look right. So I pulled up this thread and tried counting "inch" marks on the ruler in the picture Luckily I did as I was off a few inches!!!!!! Sheesh.

I didn't try and trim the top of the "blank" because I need the extra width so I could attach my templates for the single horizontal cut. Now I'll be mowing foam for ages.

Fatboy skimmer

Actually, I have to mow a ton of foam off the top and I intend to attach perimeter stringers to this.

I am preparing to bag the perimeter stringers of basswood. I have had trouble in the past with the stringers moving as the bag got tight. With two stringers it's hard to align them both and keep the bag from getting between the EPS and the stringer, so...I used some 5 min epoxy to "spot weld" the stringers on each side. Hopefully that will make it easier to epoxy them to the EPS.

I got the perimeter stringers in the bag this evening. Some pictures from this evening.

A builders trick for epoxy. The resin is pretty thick, but in some instances you need it to flow a bit. If you "nuke" it in the microwave it increases the viscosity. On this project I needed to "paint" the surfaces of the stringer and the foam, so I needed it to flow.

I use a disposal foam brush to paint all the surfaces.

On this build I was having trouble with the the perimiter stringers sliding when I would pull a vacuum, so I tacked them down. That leaves a tight area that the paint brush can't reach, so I "ladeled" some epoxy using a tongue depressor stir stick.

I also epoxied some rail material. The core is 1 lb EPS, I used 3 lb EPS for the rail material.

Everything in the bag and a vac pulled.

Side view:




From the tail looking forward:

Out of the bag and the perimeter stringers glued up - I have a ton of shaping to do on this, so the final board won't look much like this outline, but the stringers look kind of interesting out by the rails.

The above blank looks misleading, the outline will look something like this after I am done hacking it.

Very cool Jeff. I bet that has a nice flex response.

Thanks Show, time will tell. I meant to post here about the flex and get your feedback. On the skimboard build Caskimmer questioned me about thinning the tail to increase projection.

On this "blank", when I tried to twist it, there was this "different" response than I am used to. It literally had a twang on the rails. As you can see the stringer material has some level of tension as they follow an eliptical outline. There is something about the tension that causes the board to seek the return shape QUICKLY. It makes me wonder if I could pre-tension the springer material for the same effect, only in a different direction/plane?

I know the attached picture is another shining example of my artistic skills hopefully it's enough to give a visual of what I was thinking. I wonder if a pre-tensioned springer like this would increase response out of turns or upon ollie'ing off the lip? Or does the curvature need to go in the other direction?

I think you have it right.

I did some mowing of foam. Close tolerance blank at this point.

Man working with EPS with the charity build, I'm snow all over the house. I sweep the garage every day, I swept the basement and downstairs yesterday and I swept the upstairs today. I'm even noticing snow on the carpet at work. How do you deal with mowing all that foam?

Well, Judy chases me with a broom down the street and most of it comes off.

Luckily we live in the country on a few acres so I strip down to my socks (pause and visualize that for just a minute) shake my clothes out and then toss them in the washing machine (Judy is wanting me to BURN them, instead) before paradaing through the house.

Sorry you asked?

My rule of thums is hotwire as MUCH as you can and mow as LITTLE as you can. When I plane, I use the shop vac attachment, but it still gets everywhere.

Surfdad, I am LMAO with your comments!!

Gotta love a good laugh.

It has a slight single concave. A few issues on this build. The stringers need to be more inboard. That would have minimized the the arc...I'll have to see how that pre-tension affects the ride. The rails are a bit boxy as I was concerned about shaving the stringers down to much at the wide point.

I was GLAD that I started the cut for the split between top and bottom WAY forward. I cut a single concave in the bottom and I sanded a bit of the foam around the split. The epoxy and fiberglass was NOT easy to shape. Had it been necessary to significantly shape that part of the bottom, it would not have been pretty.

Normally at this stage of a build the edge of the foam is pretty floppy - not with the stringers at the edge. The Springer aslo stiffens up the tail and provides a significant rebound effect - I'm anxious to see how it rides after it's been glassed.

Fin boxes curing. This picture shows what I believe to be the most critical part of the alignment. I wanted the perimeter stringers to intersect the fin boxes, but more importantly I wanted them to intersect at the trailing edge of the fin. From my observations, this trailing edge seems to carry the most torque from rail to rail pumps. The leading edge of the fin is shorter due to sweep and as such does have quite as much torque applied to that area. Further the trailing edge of the fin, at the base, of the fins that James is using, is also the maximum depth of the particular fin...more fin area directly over the stringer.

In some early prototypes when the perimeter stringers intersected the boxes there was a measurable, if slight, increase in responsiveness to rail pressure, either turns or pumping. Hopefully this remains consistent!

I'm really interested to hear how this one turns out. I think the perimeter string and fan placement is going to be the bomb.

Here is a Shot of a Firewire Board

Great pic J.L. - that's the second generation Firewires where they were wrapping the rails with carbon. Although I read that Taj was riding one with the balsa rails PAINTED black.

I'm looking forward to how it rides also, Ed. Definately pushing the boundary on this uild.

Most of the EPS shops that manufacture foam have CNC hotwire machines, so they can cut just about any shape. Although I'm sure most are used to straight cuts. If progress can be made on the internal structure and the perimeter rails, these EPS shops can cut "blanks" and do the glue up probably for a bit more than an off the shelf blank.

One layer down, two to go.

The stringer looks so weird from the side.

Jeff, I have just started building my own boards and would like to take some of the sanding/mowing time down by using a hot wire. Could you explain this process a little bit. I have looked on the internet for different hot wire products, but I am pretty sure I can build my own! If I could at least get the rocker and the over all shape of the board down that would save me a ton of time! Any help would be great.

Also nice design, you have made me realize I have a lot to learn. Can't wait to see the final product, nice work!!! Thanks JON T

You go, Jon! I do love to hear of folks giving this a shot. It's great fun.

You're absolutely right, you can build your own hotwire for a few bucks and a 12V car battery or a car battery charger on a 6V setting can be your power source.

Our very own Show made his own hotwire bow and power supply - I'm sure he would share his details:

bigshow1960@yahoo.com

A few sources of DIY hotwire bows and power supplies:

http://www.swaylocks.com/forum/gforum.cgi?post=244604;search_string=diy%20hotwire;#244604

Show's DIY hotwire bow - read into the thread

http://forums.wakeoutlaws.com/t1553.html

There is a simple hotwire bow build on this youtube video

http://www.youtube.com/watch?v=P9IMIoJw61M

Matt S does a real good job with his hotwire templates, like you correctly concluded...the more you can hotwire the less you have to mow. If you look at some of his early build threads you can see his masonite templates basically have the rocker and DECK side cut to allow him to hotwire top and bottom rather than mowing foam.

I've also seen them made from PVC tubing. The RC airplane folks do a lot of this sort of thing and if you search some of those sites you can find a wealth of information.

Keep us posted and be sure to share your build as you progress!

Considering that I already had a battery charger in the garage my hot wire set up cost something like 5 or 6 bucks. The guides that I made maybe cost another 10 to 12 bucks. A 10'x4x6" billet of foam $45. The look on my wife’s face as polystyrene foam bits appear though out the house - Priceless.

Hey thanks a lot for the sites and the pictures this will help a lot. I will have to check into them and figure out how to build my own. Looks like I have another new project!!!! I will post some of the pics of my first gurage built board as I swim through the foam!! Thanks again, JON T

bigshow
were r u getting the foam from?

I took Jeff’s advice and looked up insulation in the yellow pages. It took about 6 calls to find the right outfit, Wayne’s Building Supplies. This outfit is a little rural. They are in the pole barn insulating business and anything else that you might want to stick EPS on.

http://www.waynesbuildingsupply.com/

show,
did you get 1 or 2 pound esp, all i see is 1 pound

I got 1 pound. They did have 2 pound.

do you see any problems useing 1lb. instead of 2lb.

1 pound foam is pretty flimsy stuff. More air and pentane than foam. I use it as a core for compsands. In unskinned builds, you can expect pretty significant pressure dents.

Most surfboards are built with 2 pound foam - either EPS or PolyU. The standard for skimboards for AGES was 5 pound Divinycell.

thanks , i will stick with the 2 lb

I have no basis for comparison.

Bottom 6 oz curing. It occurs to me that a better material for the rails would have been a 6 lb or 8 lb PolyU. EPS doesn't shape that well pukas and mess everywhere. PolyU is easy to shape and does have that static cling that EPS has, plus it's such a fine cell that there are no pukas when shaping it. The rails are the area that recieves the most shaping effort so this would have been a better choice.

Revenge of the bugs! See these spots?



Ok, so I let the bottom cure last night and when I go out into the shop this evening there is a "daddy-long-legs" laminated to the surface. I felt so bad he was still alive! Sheesh. So I tried to - I don't know free him, I guess and only succeeded in pulling two of his legs off. So I went from feeling bad to OH MAN that is awful. So I just put the poor thing out of his misery.

I go to finish laminating the top layer and in between the top and bottom layers is the COUSIN of the first guy!!!!!!!! Bugs are almost as bad as e.balsa.

Lam's all done...including the bugs

Bugs! Hey Jeff - that is too funny. After I sprayed my buddies' Van Halen Frankenstrat board I had a nice moth land and mess up the red in one spot. A nice black stripe went right over that spot.

Jon - if you can make a hotwire on your own - go for it. you'll be saving yourself some money - don't worry --there are plenty of other things to spend on when building boards! harbor freight, home depot and lowes all know me by name now.

as for the hotwire i got mine from a company called hotwirefoamfactory. they aren't cheap, but i'm not an electrician and the thing is pretty much plug and play. really easy to work with. plus the wires seem to last forever. haven't to replace one yet on dozens of cuts. i create my shapes on akushaper or boardcad (both free downloads) and then print out the outlines (rocker and profile) full size. tape the rocker to a piece of masonite and cut the rocker outline with an x-acto knife then mark with a sharpie. from there cut with a jigsaw (fine blade). it is best if you cut both pieces of masonite at the same time.

jeff - i'm so impressed with this build. you should put this one up on sways for sure!

Hey Matt - the joys of backyard building! Finally the weather warms up enough to use the epoxy and the BUGS land all over it. Thanks for the compliment 'bro.

Bugs...Sheesh. And you guys give me a hard time about Kokopelli art. Jeff you need to add more theme to the bugs. Maybe start up a new board company. Bugz Boardz.

Ed we give you a hard time about the obsessive use of the Kokopelli art, not the art itself. I am sure you would hear RAVE reviews if you swapped out your Kokopelli gnomes with ANYTHING else. Anything else - maybe you could test this theory out?

Board company names, maybe Blasted Bugz Boardz or Disagreeable Demonic anthropoD Sticks

BBB or DDD S and the logo could be 666

Finished and ready to ride. I didn't have any spare traction for the front that wasn't ripped to shreds

With the kickpad and fins, it's 58 oz. I was hoping for 80 with all traction so I think I came out about 8 oz too light - close though.

Where did you get that fin, sail boat keel?

Really - it's a Futures Vector II 437. Actually it's a tad shorter than we are riding with the Scimitar's 4.51.

Nice Jeff -- I LOVE the 437s

from that angle it almost looks like it is a center thruster fin just pushed forward about 8 inches too far...

Oh you're right! a huge 12" skeg - 11 inches up from the tail!

I want to do another perimeter stringer build with polyurethane rails. I had difficulty finding billet in the correct size, so I decided to build a box to mold the rails with pour foam.

I started by creating a hot wire template and a bottom lip for attaching the curved inner surface of the mold box.

I started by tracing the outline of the board and then offsetting that where I wanted the stringer to land.

I taped the pattern onto my "stack 'o e.wood" and cut it. This gave me a matching template which I will hotwire the EPS core with. The curve will then exactly match the lip inside the box that I will attach a vertical dam to.

Masonite hotwire template and plywood lip, cut at the same time to insure a perfect match.

I will "clamp" a vertical piece of e.wood that will follow the lip cut above. The vertical piece needs to be the same thickness as the stringer I will use. In this way the radius of the molded rails "should" match up eactly with the blank AFTER the stringers are glued up. This creates one last issue. The radius that is left on the plywood is the stringer width too small. I traced a line on the paper template that offset INTO the ply.e.wood to open up the curve.

I cut a rough shape that gave me enough area to cover the full amount of the rail, but didn't waste too much space such that I would need a gallon of foam.

You can see the shape the rail foam mold will look like when done.

e.Wood has a very porous surface and doesn't make a good mold surface. After I cut all the pieces I applied a coat of enamel on the surfaces that will make up the inside of the mold.



After I have sealed the e.wood, I will apply 5-7 coats of mold release wax and paint some PVA on the wax. After the PVA has dried, I'll assemble the mold.

I will olny make one mold as the rail shapes will be the same for either side. I didn't shape any rocker into these.

I'm going to use 4 pound foam for these rails. My available options in pour foam are 3 pound, 4 pound, 6 pound and 8 pound. 8 pound foam is pretty difficult to shape, 2 is easy. 4 and 6 are OK, but a bit of a challenge. The 4 pound foam will be decidely heavier than the core of the board and as such will be less bouyant. This will provide a better rail set and will make for more responsive turns as the rail will sink easier than the rest of the board.

Jeff, You have a job, right?

It's after April! Who works after April?

The bottom of the mold partially assembled.

I want to try a preloaded springer build as depicted in the incredible drawing , above.

Those that have been following along and not sleeping will notice that I cut an arc that was opposite of the arc in the rocker. In working the springer I discovered that this wasn't preload. As you weight the board, it didn't engage the springer - it caused it to flatten out and as such reduced or disengaged the springer.

Preload would need to be in the same direction as the natural flex of the board, basically have the springer already loaded for the flex into a turn or ollie.

The incorrect version - as the board is weighted it doesn't cause more tension on the springer it allows the springer to flatten out.



This is the correct version, basically the springer is already "engaged" and will try to straighten out when the board is unweighted.

I made an attempt to "fix" my design mistake, but I no doubt will abandon this project and start anew.

I attempted to undercut so that the springer would have the curve pictured in the "correct" version.

I need more stringers

Nice, where from?

Gloven:

http://www.golven.com/surfboards.html

The stringers have to be routed in. Interesting concept, I wonder how deep they go? Even if it's 1" deep it would make gluing up a ton easier!

It would be nice to see both sides of the boards. Routering makes sense.

The board gallery only shows the bottom of one board and that one has the stringers exiting at the nose and tail - I'd bet that one is a more standard glue up. I guess you could route all the way through with a drill bit chucked in the router.

More work on the mold for the HD PU rails. We are in the middle of a heat spell with highs reach in excess of 100 degrees so you have to work in the early morning or after sundown.

Huh - this was clear when I was reading it with my bifocals.



Principally it says that the product contains styrenes which cause nervous system disorders and cancer.

Use proper safety gear, boys and girls. I doubled checked this respirator after taking the picture. This one has organic filters, but the rest that I have are multi-vapor filters and that is the better choice.