OOAK Table Tennis Forum

Hi everyone, I started a project today. I have a Yinhe Pro13s which was slightly damaged. I am replacing the koto layer with limba (outer carbon side). [The purpose of these posts is basically to provide enough details of the many minor steps so someone else could follow the process]

My progress so far: removed handle on one side; removed koto layer, stripped back to ALC.

1. Weighed the blade @ 93g. Then put it in a small oven at 100 degrees. I used a 10mm chisel to get under the edge of the handle initially, after this I could use a putty applicator. Periodically I put it back in the oven with the putty blade wedged inside. I think this worked well.

Overall, a pretty clean removal. Most of the gunk in the photos is glue. Just one bit near the top of the handle cut into the wood. And as we can see, Pro13s is partially hollow handle!

2. I weighed the blade again without handle, and then used a scalpel to cut a vertical line in the top wood layer. I used a chisel to scrap this off. This process is the same as I've seen others do when repairing blades. Cutting in 5mm strips worked best for me. It is pretty easy to separate the wood from the carbon, but still need to be careful as the blade can catch the carbon.

Next I used the chisel again, both horizontal and vertical strokes to clean up the remaining wood (took quite a while, but fun enough to do). Finally I sanded it to get the remnants, and hopefully some glue off.

That's where I am up to today. I am waiting for a few clamps to come.
I have a sheet of 5mm limba which I was going to use, but as the koto I removed is said to be 6mm, I may wait for some 6 mm sheet.


Why am I doing this? Because I like the directness of the koto, but I miss the dwell of limba on my backhand. I know that Yinhe Pro12s already has limba, but this is on the forehand side. And in any case, I couldn't find a Pro12S cheap. This blade cost me about $10 (or 58 Chinese RMB) second hand (I didn't post a photo of this, but one side of the blade was bashed up). It occurred to me that a layer of wood on carbon should be a lot easier to remove than a layer of wood on wood.


Blade weights: 93g at the start, 81 without handle, 72 without the koto layer.

I think it was important to sand the carbon layer in addition to removing the wood, to remove excess glue if possible (though I didn't notice any - and it could be that some of this glue is absorbed into the ALC) this is because the glue adds additional (unnecessary) stiffness. Next step, I will be mixing my own glue, and I think it is important that it is thin and evenly applied, for the same reason. Anyone have tips? Please let me know

I have other images but don't know how to efficiently add.

Some things I hope and expect as a result of doing this modification:

Expect - limba will give me a feeling of slightly more dwell, and the limba will result in a slightly higher throw.

Hope - the blade will have slightly slightly, infinitesimally more flex (as a result of switching koto for limba on just one side)

Great little project, fascinating! Thanks for posting!

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Progress today:
1) Traced and, using a scalpel, cut out the limba
2) Traced and cut a template which will be used to clamp the new limba layer to the blade.

The limba is so thin you can even cut it with regular household scissors, however, not wanting to be too cavalier, I used a scalpel, tracing it along the outline two or three times (not pressing too hard at first to avoid the easy mistake of cutting directly along with the grain). I cut direct along the traced line; as it is traced from the blade, the tracing is larger than the original.




Used a hand held jigsaw for cutting the template - first time to use one.



Noticed the blade was not perfectly flat, but a little concave on the side the limba was removed - perhaps as a result of removing the handle and using the oven... So put it back in the oven for a few minutes @ 100 degrees celcius, and then used the template to clamp it down. It is flat now. Have to keep an eye on this.

Still waiting on more clamps.
Anyone know how thick the koto ply on a Viscaria is?

Glued and clamped.
I cut from a sheet of .6mm limba and decided to use that.

The glue is epoxy. 30ml + 10ml bottle = 3 to 1 mixture.
I tested it on some sample wood and it was very slow drying, and doesn't have the usual araldyte toxic smell.

I applied to the blade using a sponge. Maybe not ideal as the sponge absorbed a lot.
The layer I put on was very thin.

Next I put one clamp on the handle end, then used a rolling pin along the new limba, the idea being to squeeze excess glue out. My idea is to have no more than necessary (but for all I know I applied too little!)

Then I clamped it.



Let's see tomorrow.

Glued successfully! Not sure about the curing time of this epoxy- no instructions came with it and the seller did not respond. It was slow drying but I left it to cure overnight.

Sweet spot resounds in the centre of the blade, top edge has a dull response, made me worried there was gaps, but the other side makes a similar sound. Actually, I wish I had had more clamps for clamping the epoxy.

Next, cut the excess from the blade edge with a scalpel - again cutting through the wood in several strokes. It is easy to go through in one stroke, but risks cutting along with the grain (which you don't want, as virtually no where is the blade grain-straight).

Sanded the edges with 600 grit;
Sanded the blade face with 2000 grit (personal preference);

Instead of epoxy I used wood glue (titebond) for the handle. Massive fan of titebond. I think that stuff is amazing. Thicker layer than the epoxy but still pretty thin. Looks like there's a slight gap at the very top of the handle. In the future, a proper wedge should be cut so the clamp sits level on the chamfered end.

Finished, basically.

Handle on.
Finally, I added a mixture of wood glue and wood dust to fill the mangled side of the blade (where it was originally damaged). Although wood glue shrinks I'd rather not use epoxy due to its stiffness

You can see the "good side" and the "mangled side" below.
Still waiting for the wood-glue filler to dry so I can sand it. But I am calling it done. Hopefully it plays well .

The blade went down 3 grams from its starting weight - to 90.3, probably as a result of lower density limba. After adding the wood filler it is a bit over 91.

Looks good! Let us know how it plays?

_________________
OOAK Table Tennis Shop | Re-Impact Blades | Butterfly Table Tennis bats
Setup1: Re-Impact Smart, Viper OX, Victas VS 401 Setup2: Re-Impact Barath, Dtecs OX, TSP Triple Spin Chop 1.0mm Setup3: Re-Impact Dark Knight, Hellfire OX, 999 Turbo
Recent Articles: Butterfly Tenergy Alternatives | Tenergy Rubbers Compared | Re-Impact User Guide

I can report that on the limba side (backhand) the blade is playing as I wished it would. I have Dignics64 1.9mm, and am able to lift the ball and get good placement (which I wasn't able to do as well when I used koto as it was too aggressive), but also hit fast.

I am not sure about the forehand side, where I use 729-08 ES (recently switched from H3). I would say it feels softer than it used to: e.g. slightly more dwell.
In other words, changing one wood ply on the other side does appear to have significant influence. However, I will need to continue testing and getting used to it.


Next task is to repair the dyed koto side, which was also damaged - just replace the damaged section rather than the whole ply.


Finally, importantly, some things I would do differently next time:
1. Use more clamps for the gluing - at least one more - to ensure even and sufficient application of force.
2. TRY applying slightly more epoxy, so as to get a bit of overflow when clamping (barely happened on this occasion) - just to give peace of mind that the glue was well done.

That's all! Project stamped big SUCCESS.
If I find some other damaged blades I will consider trying this again e.g. changing one ply of an outer-carbon viscaria clone to limba.

The project continues with repair of the dyed koto side of the blade. Splinters were easily lifting due to the original damage. Photos in reverse order

This is my first repair. Since the blade was damaged all along the edge, I decided to be lazy and replace it all in one go - one straight cut of about 12mm width, one patch.
In the future I won't do this*.

1. Clamped a metal ruler to the blade, then cut with a scalpel.
It is too hard to hold the ruler there, so clamp it at both ends to ensure a straight cut.
This is a tip I picked up during my limba replacement process.

2. Used a chisel to remove the koto layer. As the 1st photo shows, where it had been damaged, the koto lifted very easily. However, it was, much trickier to remove the rest, being hard not to dig into the ayous.

3. I sanded it with 600 grit, just to even out. ... Even if all the koto was removed you can't be sure it is level due to dents or manufacturing imperfection.

4. Waited several days for some dyed koto to arrive. Contrary to information on the internet the Pro 13s dyed koto is not 0.8mm but 0.6mm. I had a 0.8mm sheet, but it was... too thick. The 0.6mm sheet was from a different supplier - you can see the dye is much too dark! (But nevermind). Cut a strip of koto.

5. Used wood glue and clamped using the metal ruler. You can't see where the patch meets the blade's existing koto when the ruler is clamped in place. But you can see if there are gaps at the edges... Check it is flush. I removed the clamps and double-checked. Fortunately, wood glue doesn't slide around anywhere as easily as epoxy, so this is not so tricky as it might seem.

Next step is to trim the edge after it dries.

*In the future, I think "remove no more than necessary" is a good principle for repair. My method of take more off, so that it can be cut in one straight line is not ideal. More chance to alter the blade feeling / mess it up.

Finished. Waited around 12 hours then cut trimmed the edge.