Best way to add a stringer

Alright, this weekend I took the giant leap into shaper-dom! Well, sort of… Here is my dilemma.

My blank is a recovered pop-out that I successfully striped down to the foam. Being as such, the blank has no stringer. I went to my handy lumber supplier, got enough wood for a stringer and ran home drooling at the thought of creating my first board. Then, my over analytical brain began its usual process. Hopefully someone can help me with these questions:

  • Should I cut the outline/shape the blank before I split it in half to add the stringer or should I add the stringer and then finish the shape?
  • Is there a good way to duplicate the rocker from an existing board?
  • Which is the best choice for bonding the basswood to the PU? (Gorilla, Elmers or something else)
Thanks in advance for the help.

Hi, i’m not a pro…neither an am. but i’ll try to help you:

  • Cut it before

  • Yes, measure it using a

straight reference and a rueler (hope it’s the correct vocab…in any case i’ve learned it reading the archive…as always)

  • I think the best choice is epoxy.

Cheers… flavio—> just a learner.

Cut it in first. Gorilla is strong, fast, relatively cheap, and shapes away easy. Its also yellow & foamy, so don’t leave any gaps between the foam & stringer - clean up your joints.

Excellent guys.

Thanks and keep em coming!

stringered blanks are easier to shape cuz it keeps the blank from bending while shaping…there are many ways to duplicate rocker…none are easy

if i wanted to duplicate rocker, i’d just make a rocker template of the original board, use the template to cut my stringer (allowing a little room for error and touch-ups), and then glue up the blank to the properly-rockered stringer. it may not be perfect, but it sure would be close. and it isn’t fast, but i don’t think it’d be all too difficult.

Thanks for the advice everyone. I think I am going to take a crack at making my own rocker gauge similar to the commercially available ones. I want to copy the rocker from another board for my first one and this appears to be the easiest way to duplicate the rocker.

Only problem is that the popout is pretty flat and the model board has more rocker. I am not sure I can fit it inside the existing foam but I will do my best.

At the very least this will be a great teaching experience. Just mowing foam is pretty fun so far!

Thanks again!

One thing I’d consider before cutting out the outline is gouges that might occur from the clamps… I’d split it and glue the stringer first. You might also consider running some masking tape along the cut each side/top & bottom so glue doesn’t get all over the blank. If the blank is close to your desired thickness, you don’t want to shave a lot of foam getting the glue off. Automotive inner tubes sliced into rings might be good for clamps.

Onemunk,

Agree with the others on cutting the rocker shape into the stringer first. Any glue is fine…Gorilla glue (Elmers now makes their same version for about half the price), or yellow glues such as “Titebond”. Regular white Elmers glue would also work fine. Either choice will be stronger than the foam / wood itself, then the glass job packages the whole thing anyway. When applying glue on large / long surfaces I like to use an old plastic credit card to get a clean even spread of glue (hard to get a thin even spread down a long surface with a brush).

It doesn’t take a lot of glue and you don’t want excessive glue bubbling out everywhere only to ball up and mess up your shaping job later. Squeeze or pour a couple of long continuous lines of glue down the length, then with light even pressure spread it down with the edge of the credit card held at about 45 degree angle to the surface. Glue all mating surfaces. I like Mellor’s suggestion of bicycle tubes wrapped as clamps (first heard of that idea from Jim Phillips). The home depot type stores sell rubber pond liner material (same as inner tubes) which is perfect for cutting into long lengths as a clamp wrap.

Optional tip: When glueing up a lot of stringers and sections of wood at one time I sometimes run dowels through the sections to keep them all referenced together so that they don’t slide around when wet with glue and pressured with clamps. Consider drilling a 1/4" hole through the center of your stringer in three places (toward the nose, at center, and toward tail) through which you can run a small dowel into each half of the foam. The length should be the thickness of your stringer plus about 1/2" or more into each side foam section. This is not for strength, but for referencing the stringer in the exact place, and so that it won’t to squirm away out of place when its clamped between the foam sections.

I set two sawhorses apart about 2/3 the length of the board apart from eachother. Straddle the stringer(s) between two sawhorses by setting it lengthwise between the two (nose running off one and tail off the other). Round off or shape the ends of the dowels into a point and place through the holes of the stringer. Carefully set the two foam halves on either side of the stringer and gently slide the sandwich together with enough pressure to make an indent from the dowels into the sections of foam. Now drill the small holes at those reference spots and your ready to glue. By placing the belly of the board and stringer(s) on the sawhorses it will help keep all pieces flat and on the same plane when clamped, as you want to take lots of care not to clamp a twist in the board.

Hope that gives you some ideas that might help. Enjoy the ride!

Richard

Richard and John,

Thanks a million everyone. Excellent tips on clamping and the dowels, I wouldn’t have thought of that until after the glue was applied and they start squirming (much to my dismay).

I hope to get back on the project this weekend. I’ll post pics if I can get some.

munk

Hiya,

pickin up on this thread to ask if anyone has advice as to what types of wood are suitable for stringers, apart from Balsa 'cuz where I am there ain’t much Balsa and what there is is too short.

If you go to a bicycle shop, they will probably give you the busted innertubes (from when they fix flat tires) out of their trash for free!

basswood, cedar, oak, spruce, poplar

If it’s a pu blank, then you can glue it up with lam resin and a little white pigment…thats the way Clark used to do it.

Also split your blank first, transfer the rocker to the wood stringer, cut the stringer to a very close shape. Doing this will really help you align the 2 halves together (if you keep it rough shaped then you run the chance of sliding off center and not seeing it). Also, Take your planer and clean up the blanks flat edges. If your worried about using a planer you can subsitute a 2x4 by 24 in long with some 60 grit glued to it. The longer the pcs of wood the better. Also sand and flatten your stringer material, make sure you take out all the mill marks (mill marks look like waves running cross grain in the wood). You’ll probably end up taking too much product off of one side or the other, this is why you want to split it glue it first. Then shape it, that way you can compensate from the stringer out…just make sure you get it straight.

If you get everything flat and smooth, you won’t need much resin or glue, and you won’t need much pressure to hold it together. Dry fit it a few times before putting the goop to it. Too much pressure will only buckle and distort the blank, ie too many rubberbands on the tail might pull a vee or concave in it. Equal pressure over the entire area…maybe like 4-6 bands.

-Jay

extra clamps and as many friends as possible extra hands are pricles when glueing up blanks

  1. Cutting the blank: best done with a circular saw with a long straight ruler as a guide.

  2. Marking blank profile (rocker) on stringer material. That’s when you may modify existing rocker by bending the blank more or less at nose and/or tail.

  3. Glueing, using all kind of straps. Check on both sides (deck and bottom) that there are no gaps between foam and stringer. Hope that helps…



as always, a picture’s worth many words. thanks balsa.

Hello fellow Dutchie,

Quote:

Fibex

Check these guys,

I use Canadian maple for its flex

Greetsz from Soul

yo! thanks! das n goeie tip!