wood board orientation

General Discussion
1

sorry that this is compsand stuff but…

we got some 4"x1"x10’ cedar boards we’re resawing this weekend into 1/8" thick strips

I couldn’t find any good 8’ boards without alot of knots and tears so I decided to go 10’ and cut off 2’ for the bottom strips.

my brother and I were arguing over lunch today about how to orient the bottom 2’ panels

there’s two schools of thought on this from what I can tell

the first is to orient all the boards in a herringbone pattern to increase the flex of the bottom

I’ve never experienced this but some here that have, have said is does change the flex pattern for the better.

the second if to run a single front to back board down the middle and angle the timber on both sides of the center board.

CMP used to do this alot but he used Obeche which is a stiffer and springier wood for the center board and balsa for the sides. We don’t have obeche but could use redwood in its place.

so there’s five questions that I don’t know if any one here can answer them or will want to answer them here because of foreign spys as I don’t know if this is confidential secret sauce build data

but here they are:

Question 1:

Will angling the boards in herringbone pattern increase the flex versus running them parallel or is it just cosmetic? And should they point forwards or backwards? Never seen any backwards yet

(PS my brother says it’s just for looks and you can make more money doing it that way cause these are donation boards)

Question 2:

what is the angle of cut? I believe I heard 60 degrees mentioned quite a few times but what difference does it make in the exact angle you choose?

Question 3:

does a straight herringbone work differently and create a different stress/fracture pattern on the bottom from the deck versus a herringbone bottom with a center plank?

Question 4:

Is there any benefit flex wise in using a whole bunch of 2" wide strips of wood versus the typical 3"-4" wide strips? The wider the board the slower to resaw it… And you can get a big bundle of 8’x2"x1/4" redwood lattice strips dirt cheap that you can plane down in no time.

Question 5:

we’re thinking of using a router table to lip or bead and cove the edges of the planks for a strong glue up joint using yellow wood glue as we build out the skins plank by plank with clamps. Bad idea?

As you can see we’re starting to think more like woodshop or hollow wood board guys than foam surfboard builders…

And no we’re not overlapping the bottom skin to the rail to avoid those problems and running the deck planks fore and aft with just a slight lap of the solid rails. Our wood choices are cedar, poplar, redwood and maple. Although I’d like to try bass, cypress along with paulownia.

The reason for all this is we thought we’d try to bag up bunch more blanks with bottoms after resawing and planing the wood down into skins this weekend and wanted to do some in real wood like the rest of you instead of the instant tiki wall covering.

The two super stiff tiki wall covered models we showed earlier with be eventually veneered using contact cement and either various 1/42" wood panels or preprinted japanese washi before being glassed with double 4oz a sealer… That was the reason we encased the foam in a complete bamboo shell ala surftech. They will also have 3/4" rails built up from 1/8" strips of cedar. Should end up as some good rideable wall hangers for some good local causes…

With a new bandsaw, thickness planer and jointer, we now can have all redwood, cedar and paulownia strips we want and will soon have some 1/8" boards of mango, koa, and wiliwili to play around with too instead of just ordering balsa strips from lonestar or national.

I was surprised at the weight of the paulownia I ordered but I love the grain patterns and multi colors of the cedar. It’s amazing the grains and colors you get as you cut and plane down through aboard like that way different than the flatness if pre-machined balsa. The economics of cutting your own planks is amazing especially if you need the equipment for other home improvement tasks. An 8’x4"x1" cedar board is $4.00 at Lowes. If I can get better at resawing and get at least 5 strips from that one board I can almost cover an 8’ piece of foam in cedar from anywhere between $4-$8 a side that’s half of what a single sheet of the tiki wall covering currently costs us… Each piece of woodworking hardware was about the cost of a single board it’s just space issue at this point but the door is wide open at this point for all kinds of things in the making… Maybe you can see why we’re starting to think this way…

I have to thank and admit that watching Jim Phillip’s DVD over and over again as he crafted his balsa planks was the inspiration for getting some proper woodworking tools.

And sorry if it not’s foam or fiberglass related stuff…

2

phew, a breath of fresh air…

My thoughts, if you’ll have them -

The only one of my compsands that has broken (creased) had 45 degree orientated wood fish-boning the length of the bottom.

When it buckled, it blew out along the 45 deg panel join.

So that tells me it does affect it…

One other board got a stress crack in exactly the same place.

I think it matters more for thicker skins, increasing less as your sandwich core gets thinner.

Kit

3

Don’t be sorry about asking about compsand stuff. It might be too on-topic for some folks here, but it is still the very reason I come!

I’ve never done the herringbone or angled stuff, so I can’t speak to that from experience. I think the first thing to remember about all of this stuff is all the flex patterns are going to be seriously dependent on total board thickness. If your boards are going to be any kind of normal thickness, you’ll probably find as I have that they’ll be very stiff and you should plan the shape accordingly.

I don’t think you’ll see any difference between angled with herringbone and anged with center strip. Hopefully there won’t be any movement between your boards, in the seams… With all the support given by the perimeter stringers and connecting shell of skins, I’d really doubt that there’d be any appreciable difference, especially, again, in boards that aren’t superthin like bert’s.

So, my answers for questions 1-3 would be, “pure cosmetics”.

Some will surely beg to differ, especially given my admitted lack of experience with angled boards. I think the magic is in the rails, and I have a board with skins made from leftover scraps, none longer than 12", whose magic backs up my belief.

Questions 4 and 5:

By the end of the process of bagging and glassing all of your seams between strips should have a nice layer of resin between them. They should be acting as a single panel, actually the whole board should be flexing as one, and I don’t see the need for a bead/cove seam like you’d see in some kind of wood boat with many more areas that flex independently from each other. For the same reason, I don’t think any one width of board is better than any other when making the skins. Danny Hess uses a single sheet of ply for his skins, and I’ve used everything from five 4" wide strips to thirteen strips ranging from 1/8 to 4" wide. If everything is put together properly, the skins should act like single sheets no matter how wide the strips that compose them.

If it were me, I would definitely avoid building out the skins and gluing them up first. The reason for this would be that by bonding the seams while the strips are all laid out flat, you’re creating a single sheet of wood that is going to be very difficult to get compound curves with. The reason that I (and long before me, CMP) can pull compound curves on balsa skins composed of strips is that the strips can shift in relationship to each other when put under vac pressure. Try to do that with a flat sheet, and you might find seams and strips cracking.

Again, all cosmetic.

And if they are to be donation boards, by all means, make 'em pretty first.

Glad to see you’re still plugging away at it, and still here! Hope I helped somehow to reinforce your continued desire to participate.

Now, speaking of being on topic, here goes an off topic thread. :slight_smile:

4

i wouldnt orient the end grain balsa toward the rail

its the most likely place for water intrusion

and it will run up the endgrain if you get holes ,dings or pins in the rail

if you do it

seal the endgrain really well

lapping the bottom skin is better

it ties everything together,has little effect on flex

and makes the board more durable and less likley to pinhole

not only that

its easier as well

shape, skin thickness and core thickness/density has a lot more effect on flex

though it will be a bit more flexi if you do do it diagonally

but not 100 percent neccesary to make a board flex

or as relevant as density and thickness and shape

5
Quote:

i wouldnt orient the end grain balsa toward the rail

its the most likely place for water intrusion

and it will run up the endgrain if you get holes ,dings or pins in the rail

if you do it

seal the endgrain really well

End grain is way more ding resistant though silly so you are much less likely to get water intrusion in the first place Ever try crushing end grain? :slight_smile:

6

Stoked that you are getting back into it again Oneula, we just got a bandsaw too, they rule !

Looking forward to seeing what you come up with.

One comment: diagonal grain with the planks running right across the board works really well (instead of herringbone which has weak points at the joins ) Just run the bottom planks in the opposite direction,

Like this:

:slight_smile:

7

oneula,

I’ll concentrate on #5, since I built my first HWB using cove and bead strips. They work amazing when building strip-by-strip over a wooden form. Similar to tongue and groove, it allows the strips to stay flush when they’re unsupported on the inside, which is often inaccessible during this type of construction. And they can be compressed together at angles. I actually built my rails using the same strip technique - it’s pretty amazing what type of bend radius you can get.

However, that ability to bend can also be a liability when building skins on a table. I tried this recently and found it near impossible to keep the skin compressed from the sides without having buckles form in the skin – requires a lot of planing to fix this. I’m definitely using square edges on my strips for my next skin. Save the cove and bead for when you’re making HWBs strip by strip.

I don’t think the extra surface area will add much to the strength of the glue joint, esp after you add all that glass and epoxy.

There are other disadvantages:

Lots of extra time to make coves/beads

The router bits are expensive, and I couldn’t find them for less than 1/4" strips

The cove side is very fragile, and easy to break, leaving a scar on your skin.

Since the joints are not vertical, they “move” as you sand, making wavy lines on your board.

You’ll need more strips, since they aren’t as wide after the cove/beading process.

So, lots of disadvantages, no advantages for your application. I’d keep it simple.

keep up the compsand dialogue!

seagun

9
Quote:

With a new bandsaw, thickness planer and jointer, we now can have all redwood, cedar and paulownia strips we want and will soon have some 1/8" boards of mango, koa, and wiliwili to play around with too instead of just ordering balsa strips from lonestar or national.

Beautiful! The possibilities are now left to your imagination http://www.lagunatools.com/index.asp?PageAction=VIEWPROD&ProdID=15 http://www.suffolkmachinery.com/1_2_blades.asp http://www.lagunatools.com/videos.htm

11

ma

12

Aloha Epac,

You nailed it with your suggestions. I use a Laguna “resaw king” carbide blade on my 5 hp Laguna “Resaw Master” band saw. Once you go carbide on a bandsaw you don’t go back. I can resaw material well over 12" thick with a finish that’s equal to a sanded surface to 150 grit, which often leaves no reason to run it through the planer or jointer. The “timber wolf” blades from Suffolk are tops also.

Oneula, hope the bandsaw opens some new paths for you. Stay on it!

richard mccormick

13

I don’t know if I still have the detail pics, I’ll check tomorrow… But what I found with veneer was that it would do some compound curves pretty easily, but when trying to get the veneer to bend up the curve of the nose and at the same time wrap the rails, I was having to make relief cuts to get it to lay down on the rails. Softener helped a little, but I really think the epoxy softened it as much as the expensive stuff from joewoodworker. If you’re just going to take the veneer out to where the rail layers begin, then it could probably be pretty easily done. But if you’re thinking of wrapping the rails like surftech does, it is a real bitch.

14

ha

15
Quote:

I use a Laguna “resaw king” carbide blade on my 5 hp Laguna “Resaw Master” band saw.

Nice! Im jealous.

16

First, I know nothing about “compsand” boards…

My reason for running the wood at an angle: scarcity of long balsa in the PNW…

This deck and bottom strips are 3" x 1/4" strips, set at 45 degrees…

Square edge, glassed on the inside…

Flex: not much, but very “alive”…

More at: http://www.hollowsurfboards.com/Board_14.htm

17

Aloha Oneula - Yeah they are expensive, but you can make any bandsaw work to it’s limits. Good guilds help a lot. If you use steel blades, which are fine but not as accurate, you just have to leave more material for the thickness planner to clean up. This all sounds wonderful !! All of those links are just information, not necessarily the only way to go. http://www.carterproducts.com/product_list.asp?p_id=6&cat_id=12 http://www.carterproducts.com/category.asp?id=6 Keep us posted, I’m excited for you. ps - remember to use push sticks (5 fingers on each hand)

18

lo

19

those Laguna’s are made in Italy and don’t weigh as much as the old cast machines. I have the 16" saw and move it around w/o any problem.

The size is relative to the work you need to do. If I was going to give you advice, it would be to try to drop the length down if possible on a smaller machine. Otherwise cut wider rips and plane more, burning up more material into shavings.

Regardless, I’m stoke for you.

20

hi paul

im sure you know heaps about compsands

that board looks neat

and the rail material caps all the end grain

thats really important for balsa

one pin hole on the rail

and it can run up the whole plank turning it black and moldy