blade grain orientation

[Adam T]

The wood that I have on-hand and available to use for my blades, has the grain running across the width of the boards.  When looking end on and the board lying flat, the grain is oriented like =====, perpendicular to the wind.  From what I see and read, the reccomendation is to have the grain running perpendicular to the board width; ||||||, parallel to the wind.

I'm willing to take the time to cut, reorient, and glue back together.  My question is at what blade length would you draw the line between it making little difference vs. reasonable significance.

The material is cedar, and I'm looking to carve 6' blades - 12' diameter.

[Norm]

In other words a 2x4 with the grain running

crosswise you could break across your knee?

...IMHO I wouldn't even make ornamental

windmills with that!

Of course others may have opposing opinions...

Even corrigated plastic I make with the length

of the blade running parallel with the corrigations.

[wdyasq]

My 'drawing the line' would be in blade thickness rather than length. And, it would be less than 3/4"(19mm).

If one has wood grain in this orientation == it will move more in the 'up-down' dimension than the "left-right". Each time it expands (Usually due to moisture), it will crush the wood fiber. This eventually caused the bolts holding the blades on to become loose. The problem is less with the grain in the ||| direction.

Ron

[HaroldCR]

 Down here, in Costa Rica, there is not a variety of types. I have only found the typical white glue. Is this sufficient for gluing blades, as described above

[Flux]

I don't understand your comments about grain perpendicular to the wind and parallel to the wind.

You should end up with grain along the blade length. If you end up with grain across the blade length keep the things less than 6". I wouldn't even consider cross grain for a prop.

Flux

[Flux]

If that is PVA glue I wouldn't use it, even the water resistant variety really isn't .

It is strong enough if you can prevent water affecting it. If your climate is very dry it may be ok  but I wouldn't trust it here UK.

Flux

[Adam T]

OK, this may get wordy, but it will probably put any confusion to rest.  The two wood grain orientations I am talking about would be described as 1). If the blade is positioned along the trunk of a tree.  Root and tip are up and down, the leading edge and trailing edge of the blade are to the left and right, the face of the blade towards the bark or the heart of the tree.


2). If the blade is positioned along the trunk of a tree.  Root and tip are up and down, but this time the leading and trailing edge are towards the center and outside of the tree, and the face and back side of the blade are to the left and right this time.  


I hope this is a better description.

[bob g]

years ago i restored a late queen anne victorian house

it had a huge veranda with a  roof that curved around the turret/bow windows section

the gutter system was wood with lead plate lining soldered in, and of course it was all falling apart

i decided to rebuild the gutter system using 1x2 clear ceder boards that had routered edges so that when 9 pieces were assembled it would make up the rain trough

and also make up a visually appealing exteriour facade.

i went to the yard, and was allowed to preselect boards that were agreeable to bendig, the ones with the grain laying flat to its width would bend a bit, but the

boards that had the grain across the thickness of the board would bend far easier and make a tighter arc. (now i may have this backwards, its been about 20 years)

the point being go to a lumberyard and select a 1/2 of each in cedar and do a flex test,, then decide what is important to you.

if you want a board that can bend a bunch without breaking, you obviously want that grain orientation, if on the other hand you are concerned with flexing back and hitting your mast, they maybe you want the other orientation so the board will be stiffer.

one other problem with the flat grain is cupping if they get wet or damp, so maybe

you want to orient to take advantage of this cupping should it occur in the future

before you decide to carve the blade?

fwiw

bob g

[Adam T]

eh, not as wordy as I anticipated, though I did include two 1000 word quivalents.

[Flux]

Thanks for clearing that up.

I would be perfectly happy to use either form of grain direction as you show it. It's not cross grained as I thought you first meant.

For large props you may have to laminate but I have never done it with props up to 10ft.

Flux

[Tarquin]

Hi, I believe that the wood shown in the second illustration is known as quarter sawn, and is normally more expensive but looks nice with certain wood types (oak).

I don't know if it is any stronger.

T.

[wellusee]

I am over thirty years at woodworking and all the answers are correct. Long straight grain in any job is a gift. Its nice to see someone get nice clear help like that .Enjoy.

Paddy.

[wellusee]

Hi all.

Cascamite that's the stuff we use here in soaking wet Ireland. http://www.technologystudent.com/joints/casca1.htm

If you put some oil on a threaded bolt then place the bolt in a jar of Cascamite with the head out of course .Then next day unscrew the oily bolt leaving perfect threads behind.

Handy for making a "trammel"  for large circles.

Paddy.