Any tips?
cut.
(mostly on the outside…or the “perimeter”, if you will)
Brilliant!
Now… how do we set up a machine’s cutting path to do this? obviously you want to slow down the feed rate when you hit timber huh… How do we match the cutting path with the curve of the 2 curved pieces of wood or what have yous.
That what you mean deanbo? or your talking electrical planer?
Quote:
Brilliant!
Do you mean cutting a blank to make a perimeter stringer blank or do you mean planing a blank that already has a perimeter stringers?
good point.
Quote:
Do you mean cutting a blank to make a perimeter stringer blank or do you mean planing a blank that already has a perimeter stringers?
be vewy vewwy caweful…
Nah, just pop a line down the middle of the bottom of the board (assuming you don’t have a stringer or glue line). Draw your desired final outline on the board. Now, figure out where your perimeter stringer is going to be. If you’re going to use a balsa rail, I suggest 3/4" of balsa for your rails and redraw your outline just a little less than 3/4 inch from your finish outline. Cut out the board, clean up the outline, and you’re ready to glueup your stringers. If you can get full length balsa cut in 3/4" thickness, you’re better off, but you can also go get balsa strips in 3’ lengths and glue them up in staggered sections with good results as well, just more of a pain than full runs.
Hope that was helpful.
edit: Forgot to mention that Drewtang has a slick way of removing the perimeter section with a hotwire. I almost went that route, but got scared and didn’t.
another edit: Meant to say that the full length balsa strips cut to 1/4" thick, not 3/4" then three strips glued up on the rail for a finished rail of 3/4" thickness.
Hey deanbo,
contact Ken at Segway Composites he makes perimeter stringer blanks. He maybe willing to give you some info. By the way I heard that Silly (Paul Cannon) should be getting a shipment of ProBox Fin boxes pretty soon.
Mike
Funny you should ask. Give me a day or two to post the pictures. I am finishing my latest perimeter stringer blank and I took some instructive pictures… Using bending ply and 2 pound EPS. Hand cut. I will have some vital tips for the crew.
Drew has a slick hotwire set up, though. Very nice work.
I’m looking forward to seeing those pics. Thanks.
EPS?
Cut it with you router, use a full template jig. lightly clean it up with some 60 grit. You end up with 3 pcs.
Cutting is the easy part. Gluing it up straight is another story. And that trick is a secret, but with a little practice you’ll get it.
Oh, go on…
Getting ready to glass a board that I put perimeter stingers into the blank. This was my 2nd try at putting in perimeter stringers. I wish I could give you some good tips, but I need some myself. I’ll pass on what worked for me.
I’ll try and take some pictures tomorrow before I laminate the board.
deanbo you can cut out your board lay a full run of paper onto the cut main piece and trace a template for your stringer. Just make it a bit wider so you have some room for adjustment during the glue up.
Cut out three stingers from your material. One is a template and the other two are your stringers.
If you cut the center stringer out of an existing blank of the same size as the one that you will re-glue with perimeter stringers then it makes a perfect template and it will be the perfect length.
I used my glass wet out table that I stretch plastic over to brush on the polyurethane glue on the stringers. Do one at a time. Don’t wet the pieces with water like it says to do on the instructions. It can make the glue foam too quickly causing problems.
Wear gloves and prepare to get very up close and personal with foaming polyurethane glue, it gets everywhere and sticks to everything.
I used just enough tape to hold one side together as I glued the second stringer in.
I didn’t have long clamps so I used old bike inner tubes to wrap the blank once both stringers where in. I needed 6 tubes to get a good clamp on a 6’5" blank. The poly glue doesn’t stick to the rubber.
The tubes allow the cut-offs to move a bit so that you can line everything up while the glue is going off.
If I was to do this more often then I’d make some kind of a simple jig to hold the stringer onto the board as I worked on the other side. Either that or just do one side at a time.
Not going to get too involved, Eric Zhang is listening:) But here are a few tips. We’re doing 99% Perimeter Stringers in production now. We can only make up 4-6 blanks a day (depending on when my helper shows up). I think it’s rad that it’s a totally custom deal, and really hope it stays that way. I brought some blanks to the January expo, everybody said the same thing: “they’re sweet, but how do we put 'em on the machine??”. I said that’s the point, they don’t go on the machine. Here are some basic tips. Obvious one: I don’t even attempt to do 'em by myself. Get a helper, even just for an extra set of hands (wifey, kids, neighbor, bum). Second, make a set of clamping jigs, basically stringers to go on the outside of your cut offs so you’re clamping (or innertubing, I like that idea) to something solid instead of spongey EPS. I just used some scrap material from my stringer guy’s wood shop, they’ll last forever if you clean the glue off once in a while. Lastly it really helps in the long run if you can build a glue rack that is shorter than the blank but still holds everything very stable and flat. You really have to work at a method to get all 3 foam peices level, that’s the big trick. To cut off pieces I use the hotwire set up I built, but has anybody tried using a jigsaw with the slide rule guide? I always thought that would work too.
Deanbo,
If you want more PM me or give me a call.
Cutting a perimiter stringer blank on the APS 3000 isn’t that big a deal. Takes a little setup time to get it right, plus you have to slow down the general machine speed to deal with stringers out towards the rail, but it’s not that difficult. 20 dollar up charge.
Been meaning to use the machine to try and make perfect, custom perimiter stringer blanks, but I haven’t gotten around to it yet. The concept, briefly was to take the design file for the board you want to make, narrow it, change the slices so the board has a flat deck and square rails. Get an EPS stringer-less blank, cut the deck side to 90 degrees and pull it off the machine. From here the plot gets hazy. Maybe glue up high density poly foam out on the rails with PVC stringers? Or bamboo?
In theory, you would have a blank with perimiter stringers that perfectly parallel your design file.
All I need is time and money. I can’t seem to get either…
Mahalo! I think I saw pictures from the expo. You had a few with the blue high density foam on the rails. From the pictures it looks like you have it down, thank you for the tips.
Yeah 3" blue painters tape is a poor subsitute for a second person. I laugh at how messy it gets.
I got the idea for the innertubes here on Sways. I like the road bike tubes better, but if you cut mountain bike ones in half they also work great. I got lucky and accidentally cut the stringers about 1" too wide. It helps if they stick out from the deck and bottom so the rubber tubes have some contact with the stringer. Made it easier to align the pieces.
For sure about the jig, thats amazing that your doing it without one. Looks like I’m going to have to introduce the kids to Mr. Gorilla glue.
I have an adjustable rocker table that I could cover with plastic to use as a jig. I was thinking that you could lay the pieces in one by one and hold them in place with sand bags. Once it was all together you could strap or clamp and take it out.
Sounds like your having similar thoughts to me. I’ve been checking out Markos Lost outlines for a rough guide in terms of dimension. Then maybe just straight balsa or basswood (no curves whatsoever) and likewise for the outside foam. Then clamp. Take down the excess wood with an electric planer. If your foam on the outside is the same width all the way through, pressure from the clamp should be even in all clamped places right?
only if your stringer cut is accurate
My stringer cuts are always accurate! You buy! Only $50!!