OOAK Table Tennis Forum

Another idea for your scientific minds is varying the orientation of wood grains. Instead of 90 degree one on top of another, what would happen if you have a gradual change in the angle from one layer to another?

Idea is that a gradual structure (helicoidal) would have more compressive resistance (harder feel) in all directions. As in TT, we are only concerned about unidirection compression, would this make any difference in blade design?

https://royalsocietypublishing.org/doi/ ... .2017.0538

Would this kind of design produce a denser reinforced impact feel using the same materials without increasing weight?

See here: viewtopic.php?f=58&t=33591&p=363681#p363681
While you found this nice research paper I had allready glued a prototype/test!

There's a Dr. Neubauer (IIRC) blade with plies that are at 45 degrees to the length. That layer is partially exposed near the handle. In fact, the layer is split in two, with the grain meeting in a "V" in the middle of the blade (don't know if this is contrary to the "continuous" rule). Can't remember what it was called - perhaps the Kung Fu or something of the sort.

Iskandar

No, it won't work considering the compressive resistance of helicoidal structures in the elastic range, including fibre–matrix modulus ratios, pitch angles of helix reinforcements, interlayer rotary angles between adjacent horizontal fibres and numbers of helix reinforcements.

It sounds like you understood.

Here it is, a new blade. Stiff, slow, soft at low impact and still stiff, still slow but harder at big impact. And it vibrates.

I have studied the Nexy's diaries these months and I came up to the burned wood epoch of their blades and it made me, as a homebuilder, very curious to experiment. So I have made a burn test to see if I can replicate the process in my kitchen using my electric oven.

I have burned 3 pre-cut cores like this:
- ayous 3mm
- kiri 3mm
- balsa 4mm

The first conclusion is that the wood lost (a lot of) weight, like this:
Ayous: 28.3 g --> 20.6 g
Kiri: 27.5 g --> 22.1 g
Balsa: 20.3 g --> 16.8 g

Heat removes moisture, the question is does it stay out? Leave the veneers in a humid environment overnight and check again.

Curious on any impact on hardness and density?

And, depending on temperature, it carbonizes the wood structure a bit. Otherwise it wouldn't get dark.
And, it shrinks the wood structure -> the pores become a bit bigger ---> in theory this would/should help it vibrate more.

I have no idea if this will get to a harder wood.
Maybe only if that moisture taken out by heat would be replaced by some resin.

From the reviews that I have read on the net, the blades that use burned cores have more feeling.
To me, it means that the wood "works" more (flexes, vibrates, etc.) on impact.

Letting it somewhere humid, hmmm ... it started to snow here.

For the balsa core, at least, it was too much. If I press it with my nail I can mark it easily.
Kiri and Ayous are still the same.

Regarding density ... the same volume with less weight -> less density. On paper, at least.
But what can be felt at impact ... we will see.

Iskandar

After 20 hours exposed to elements here it is:

burned Ayous 20.6 grams --> 21 grams
burned Kiri 22.1 grams --> 22.7 grams
burned Balsa 16.8 grams --> 17.3 grams

So ... hmm. That can be a way to get some lighter OFF blades.

Yeah. Quite a few manufacturers (including Butterfly) sell or have, in the past, sold blades that have been autoclaved, or baked, or even vacuum-baked. Some of the Donic offerings actually look charred slightly, from what I understand.

Which means... why not DIY? There's a whole thread about it here:

viewtopic.php?f=43&t=25232

Iskandar

I'm curious. One of the blades in your "package", the Valiosaurus MkII has a very dark spruce layer. Has that one been baked?

No, that is some sort of canadian pine. It is it's natural color.
When I built the MarkII i did not made any experiments with burning.
"Burning" is something I have made experiments with in the last 2 weeks and I burned only wood cores, no veneers and no entire blades yet.



Sounds nice what this guy was doing ...