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[glyn44]

just about to start my first ever scratch build. Fairey Huntress. The plan calls for 3mm lite ply, which I have bought. I have cut keel parts off of the plan and laid them out onto the ply sheet. There is an arrow drawn on each item, presumably showing the grain direction. Here is my problem. How do I know which way the grain is going. I guess that normally it would run down the length rather than across the width. Is this a correct assumption? Does it really mater with ply wood?G44

[inertia]

There is no need to assume anything. If you look at sheet 2 of the plan there is a title box in the top RH corner Just underneath that there is a double-headed arrow which is the same as the one replicated on all of the ply shapes. The legend under that arrow says "Direction of SURFACE grain".
I had hoped that would be clear enough when I drew the plan - sadly it seems I was wrong.
Dave M

[grendel]

ply tends to bend better in one direction than the other, if the part curves you want the grain to be best for that curve

[glyn44]

Hi Dave, I know that the arrow indicates grain direction for each component, I was just unsure how to work out that direction when looking at the wood.
So as Grendel informs me I will the bend to give max strength/flexibility as required.
As a bye the bye one of my sheets measures 2.63mm!!! So think I will get another.
Cheers as always.

[chas]

What Dave is attempting to get across is that the word surface, refers to the direction of the grain you can see on the wood. If it isn't apparent on the wood, rub a little spit on the top, and the grain should be more obvious.
    Wood sizes tend to be nominal, so I doubt you will have any problems with 2.63mm. 

[Neil]

you will see the grain as darker flecks of wood in the grain these darker flecks run in the direction of the grain, and were the fibres making up the timber.........Wood grain is the longitudinal arrangement of wood fibers or the pattern resulting from this.


simples.

[Tug Fanatic]

Let me show you with a picture. All these bits are mounted on two ply boards which have been varnished to make them look good & which brings out the grain. As Chas suggests wetting the surface helps make the grain more obvious.

The board on the left has the grain running across the picture and the board on the right has the grain running up & down the picture. The arrow on the plan tells you which way you want the grain to run for that piece of ply.

You can buy ply with the grain running in either direction but long narrow pieces normally, but not always, have the grain running in the long direction.


I don't think that I can explain it better as I have never considered it a problem.

[Tug Fanatic]

The ply that is the upright piece behind the lower row of boats has the grain vertically as marked. You can see by looking at it that the lines are generally up/down - that is the direction of the grain. I have modified the second copy of the picture to make the grain more obvious.


Ply supplied as sheets will always, in my experience, have the grain either up/down or across and never at any other peculiar angle.

[glyn44]

Yep ok and many thanks. Explained to perfection. I’ve got it now. Pieces will be oriented correctly.

[Tug Fanatic]

As a follow up to this all wood has grain & if you buy lengths of timber the grain will normally run along the length of the wood - the long direction. The thing is sometimes the wood runs nice straight grain along the whole length, which is strong, and sometimes it meanders its way along the piece of wood and the grain wanders off the side, forms a knot (where a branch went off) etc etc etc. This is weak. Look for wood with nice straight grain - at least for the bit of wood length that you are going to use. 

[nemesis]

A little tip is to Sand Seal the ply before you cut your pieces. It is easier to do it rather than when the boat is built. nemesis

[JimG]

I find wing skinning epoxy with added microballoons gives a smooth finish on sanding. The surface is harder and more resistant to handling damage.
Jim

[Brian60]

who's the stockist for these parts please Tug Fanatic.

[Tug Fanatic]

Not 100% sure but at say 90%


http://www.mastman.co.uk/