VielAntrob wrote:
I am presently searching for sources of good material: verneers and glue:
I think I found some companies that supply verneers, but since most/all of them supply their material for furniture building, and may not always be the best supplier choice for TT-blade making, I will greatly appreciate recommendations for companies/websites to buy verneers from!!
In particular, I do not yet know a single source of "endgrain" balsa sheets.
Does anyone have a suggestion where to get "endgrain" ("crosscut") balsa sheets?
I am talking about sheets where the grain direction is perpendicular to the plane of the sheet itself. TSP, now Victas, uses these as cores and I think adyy ( @adyy ) used such cores also.
I would also love to get some advice on which glue to choose for the lamination. I have seen impressing close-up pictures by adyy ( @adyy ) of the porous structure of wood sheets. Glue that seeps into these pores must change drastically to mechanical (playing) properties compared to a situation where it was avoided to have glues seeping into the pores.
Can someone provide advice on:
- Suitable glues for the lamination
- Whether or not it is beneficial to avoid that glues seeps into the pores
- ...and how to avoid it, if it is deemed beneficial.
Finally I have a potentially stupid question, based on really enjoing to treat wood with oil:
What kind of experience is available on the effect of "surface-treating" TT-blades with oil? I believe that all commercial blades are "just wood", without any "finishings" on the wood (possibly apart from the "surface sealing" that some apply before gluing a rubber), so that might be an indication that the wood should better be left alone. Whenever I put oil on wood for funiture I have the sensation to do something good to the wood, think (nourishing, protecting). Is there anything known good (or bad) happing from such treatment for TT-blades? (...or rubber adheasin for that matter...)
Thanks so much in advance in case of any answers!
I am mentioned in a post and somebody wants me to get answers from me ?!!!!
My God, it seems like I have reached a certain level as a home builder
So, here it is:
VielAntrob wrote:
In particular, I do not yet know a single source of "endgrain" balsa sheets.
Does anyone have a suggestion where to get "endgrain" ("crosscut") balsa sheets?
I am talking about sheets where the grain direction is perpendicular to the plane of the sheet itself. TSP, now Victas, uses these as cores and I think adyy ( @adyy ) used such cores also.
Actually I have no source. Like you, I have searched a source in Europe and found none. The only source was on Alibaba at a factory in China, but the minimal order was 1 cubic meter of endgrain. The shipping itself was more expensive than the balsa itself. So, next step was to find an alternative way to make it myself. And I have bought some balsa lumber (5x5x100cm), went to a carpenter and asked him to cut for me slices of 5mm from that lumber. I ended up with something like this:
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Than I glued the "squares" with some cheap paper glue and obtained something good enough for a blade core.
Another alternative way, was to cut manually the crosscut "slices". It can tell you that it works, but you need to build a jig for that and buy a good japanese type handsaw.
I can tell you that it works. But you will spend a lot of time and make a lot of wood dust.
VielAntrob wrote:
I would also love to get some advice on which glue to choose for the lamination.
Glueing blades is like searching Eldorado or the eternal life. Its a constant search for a better glue and a better process. Here I have no clear advice to give you, since I am not happy with anything that I have tested until now.
I have tested many and even threw to garbage a few. They were that bad.
But from my tests, I can tell you that:
- the first glue I have used was
epoxy. From the durability point of view and if you want to use synthetic fibers, that is the glue to go with. Also, performane wise, its a good glue.
Once hardened it never cracks, it is elastic/flexible and some no problems with water and chemicals. Chemically it is almost inert, once cured. One problem with epoxy is that you need to mix the parts properly otherwise you endup with a sticky plastic that never hardens. The other one is that depends how fast it hardens, because there are hundreds of types of epoxies. If it is a slow cure (takes long time to harden) it will go into the wood pores, soak up the wood and make the wood plastic-hard. You will get some sort of stabilized wood that feels and behaves like a plastic laminate, not like wood. If it cures to fast, you will need to work very fast with mixing the glue and put the wood veneers very fast into the press and close the press. Otherwise you will get a badly laminated blade, that may even have blisters of air between the veneers. I have one blade blank that ended up like that. Anyways, after 10-15 test prototype tests I have quit using epoxy on wood-wood bonds.
- the
PVA glues. Here
MalR explained very well the way to go with PVA. I have tested a few and from my tests, this is a simple to use glue, very suitable for DEF and ALL blades.
Cures relatively fast and if the glueing is properly done, it also durable. I have not used the type that MalR sugested. I just checkd if they are D3 or D4 class. D3 means that it is suitable to be used outside and D4 is for marine environments. Yachts furniture basically. Currently I am not using PVA to laminate blades. I use it only to laminate handles and sometimes to glue the handles to the blade blanks.
-
hide glue. I have tested 2 hide glues, one made from rabit skin and one from fish bones.
These glue are water based. Basically, you get some pellets and dillute them in mild water until you get some sort of cream. The biggest no-go for me is the smell. It stinks like crazy. The second is that they are water based and it takes a lot of time to cure/harden. While curing, the water needs to evapore and pass through the veneer some how to get out. This takes a lot of time and you need to keep the veneer under pressure until that happends. Otherwise, the bonds between the veneers will get loose or the blade will curl/bends. In a press like MalR recommended to build, it will take days to harden. For me it took 2-5 days until they were ready. I have built Acoustic and Violin clones to see what I can get and I ended up after a few tests with some good enought blades. Due to this glue, they had better feel than blades glued with any other glue. But in time they curled. Basically they twisted 1-1.5 milimeters away from a straight plane. This glue is still an open territory for me. Someday I want to resume the tests and build a press special for working with this glue, since it has potential to create some very unique blades.
- PU based glue -
pressure activated type. Similar to glues present in scotch tapes and/or glues used in the past to repair shoes or glue leather. The results were interesting and the feel of the blades was close to hide glue.
Anyway, it comes with its own problems. If you add the glue on only one of the veneers you want to glue, you will need to add a thick layer and this is not good for the final blade, since it dampends the feel and cuts speed on hard shots. The better way is to add very thin layers (as thin as you can) on both veneers before glueing. This improves the results but its very hard to get there. These glues are very sticky and while applying them there are very high chances that the veneer will splinter or tear. And it will be hard to join it back and resume the glueing.
-
PU based glue - the type that reacts with the air humindity and expands while it hardens. This is what I am currently using.
It does not stink, its not very sticky when you apply it and its easy to apply. It takes 3-4 hours to cure (depending on the brand) and once cured, is there forever. There are almost no chances of delamination. Also blades do not bend/curl with time, since this glue is not water based.
But the big problem with this glue is that it expands, especially if the veneer is not very-very dry. If the veneer is mild wet or if added in a thick layer it will expand so much that it will fill all the pores of the veneer, go through the veneer and glue the release agent/foil to the blade. And there will be no way to remove it. The way to use this glue is to apply a layer as thin as you can and in case there is some excess, clean it away with some soft paper. This glue changes the feel of the wood a little and makes the blades feel sharper and the dwell time will be shorter. Depending on the veneers used, the ball impact will feel a bit more vivid than with the other glues and on hard shots the blade will feel a bit more stable/powerfull. This "a bit" I am talking about is a 5-10% difference, not more.
Anyways, this is a short knowhow share from me. And as I said I am not 100% happy with any.
Even Mr. Moon@Nexy talked a bit about this topic somewhere (here or another forum).
Depending on the application, some glueing methods will work better and some not. The glueing process, is one of the reasons that similar blades - made from the same veneers and having similar thickness - from different companies feel different. The glue used and the way it is applied participates in the feel of the blade. Sometimes a lot.
My advice is that you should make some tests with different glues and see what works for you.
VielAntrob wrote:
I have seen impressing close-up pictures by adyy ( @adyy ) of the porous structure of wood sheets.
Glue that seeps into these pores must change drastically to mechanical (playing) properties compared to a situation where it was avoided to have glues seeping into the pores.[/quote]
The pictures are from this website:
https://www.wood-database.com/limba/If you want to understand how a wood laminate works, you will need to see what are the Janka hardness, the Elastic Modulus and the pore structure of the woods used in that laminate.
Also that site is good to read about the different types of woods and "learn" how those woods look. You will need that later when you will see pictures like this:
http://www.mytabletennis.net/forum/uploads/New/20100614_040944_IMG_4885.JPGVielAntrob wrote:
Can someone provide advice on:
....
- Whether or not it is beneficial to avoid that glues seeps into the pores
- ...and how to avoid it, if it is deemed beneficial.
The glue process is a trade-off between durability and feel.
No matter which type you use, some glue will anyway go into some the wood pores. You cannot avoid that.
What is important is that you should avoind using too much glue. There should be only a super thin layer of glue between the veneers. Otherwise, the more glue it is, the more will kill the feeling of the wood.
VielAntrob wrote:
Do such cuts (or possibly other measures in/under the handle) have any impact on the "feel" of the blade? (...feedback, etc)
How you tried other geometries / cut-outs / hollow handles etc?
I have tried a cut similar to Re-Impact, but not on a balsa blade. I have used it on a limba/limba/ayous/limba/limba blade. I felt nothing special about it and did not investigated further. Maybe for balsa blades really makes a difference ...
Hollowing out, yes. Most of my blades have hollow handles and some cuts in the blade blank under the handle. Otherwise the blades that are 80+ grams would be 90+ grams. Feeling wise, hollowing out the handle, at least from my tests, makes the blade to feel a bit smoother if its dedicated to a spin based game.
But I have not made any serious comparative tests to be able to tell you exactly what happends. Its just comparing how blades feel hitting a ball on bare wood.
VielAntrob wrote:
One more thing on the balsa core thickness: I argued about something like a "spring effect" of the vertical fibres in cross-cut / end grain verneers.
I am not sure how big that effect is. But judged from basic mechanics, two things should hold:
- The "stiffness" is mostly determined by the strength of the "outermost" layers
- The stiffness increases with thickness
So while Balsa is certainly not stiff in itself, a thick balsa in conbination with strong outer layers should produce a much stiffer blade than a thin balsa core with the same outer layers of "strong" wood. And since (I believe) stiffer blades are typically faster than less stiff blades, this may be the true origin of the correlation between a thicker balsa core and the speed of the blade, ...and not as I argued before the "spring effect" of the vertical balsa fibres.
Its almost like that!
VielAntrob wrote:
Interestingly, MalR, this argument also runs against your experience that a thicker balsa core produces a slower blade.
Are there some other voices that can add to this discussion and possibly enlighten this by additional information/perspectives?
It depends on the type of balsa.
He mentioned - if I have understood well - that he uses the type of balsa that is very low density. The type that is almost pure white. That type of balsa, really absorbs impact. I can confirm that.
Anyway have not made so much tests with balsa, but I would not be amazed if I would see an 10mm thick blade that is slow.