Balsa for stropping?

[stitchawl]

OK... you guys who are using balsa as a substrate for stropping compounds...

Which cut of balsa is working best for you; tangent cut, quarter grain cut, or random cut? As each has differing surface structures there must be a real difference in your results. Which do you prefer?
(Please... not which company you purchased from. )


Stitchawl

 

[Jason B.]

Didn't know there was a difference I just get mine from the hobby shop.....

 

[stitchawl]

Didn't know there was a difference I just get mine from the hobby shop.....

Big difference!
Tangent cut has a much softer face than the other two, with quarter grain cut a bit harder. Making a strop out of random cut would make a rather non-yielding surface compared with tangent cut. Quite like a soft mouse pad compared with a telephone book.

To me, this is a very important factor in edge fabrication. It's why we use the firm grain side of tooling leather to strop on rather than a thick piece of suede.


Stitchawl

 

[Ben Dover]

Stitch,

I haven't tried it yet, but intend to do so in the near future.. Which cut do you prefer?

TIA!

 

[oronocova]

I didn't realize there were different cuts either...

Are you getting them somewhere special or just picking through what is available at your hobby shop?

 

[stitchawl]

Stitch,

I haven't tried it yet, but intend to do so in the near future.. Which cut do you prefer?

TIA!

Frankly, I haven't seen any real difference between balsa and leather. but then, I'm not looking at the edge microscopically. My gauge is how the edge cuts. The edges finished on both are perfect mirror finishes to the naked eye, and for me, cut just the same as edges stropped on compound-covered leather.

I picked through a couple of different bins in three different shops and was able to get a sample of each cut. The quarter grain cut and tangent cut pieces were flat boards 3"x1/4" and the random grain cut was a 3"x2". All were 30" long that I cut down to 10" for my test. (For this test I did NOT finish the edges on bare leather. The compound was the final step.)

The quarter grain and tangent grain boards felt as if I was stropping on a piece of paddle-mounted leather. The random cut, when turned so as to give an edge grain, felt a bit firmer. But as I use almost no pressure when stropping, I don't feel that the substrate, as long as it's flat, gives me any pro or con result when using compounds. (Unless deliberately using a very soft substrate to create a convex edge.)

For me, it's only a surface to carry the compound, and the blade only contacts the top of compound. The little abrasive points that are sticking up are what's doing the job. The abrasive grit size is far too small to make a difference based on the substrate. A single smear of rubbed-out compound, thick enough to actually see, is still stacking the grit perhaps 25-50 layers deep. If the bottom layer is digging down into the substrate, that will have virtually no effect upon the top layer that is contacting the edge.

EDIT: This could be the substrate to use with powdered compound as it's possible to get a much thinner coating with that stuff. Some of the grit could embed itself into the balsa while remaining powder blows away. That could create a different finish. I didn't think of that at the time. I'll have to pick up some CrO2 and try that...

Another interesting experiment, worth my time, and letting me form my own opinion about what works for me. Give the test a try yourself, and post the results. I'm sure many of us will have different answers.

Stitchawl

 

[cziv]

I just got a 24" piece of very flat smooth balsa today and cut it into 3 8" strops and saned them to 600 sand paper -- very smooth.

I put 2 micron paste on one, sprayed a coat of HA 1 micron on another and .5 micron on the 3rd.

I screwed up though and forgot which one I put the 1 micron and .5 micron on. They both look the same dammit!

I guess the only way I'd know is if I can see one of them getting darker than the other and it would be the higher micron. Sound right?

 

[stitchawl]

I just got a 24" piece of very flat smooth balsa today and cut it into 3 8" strops and saned them to 600 sand paper -- very smooth.

But... how was it cut? Quarter grain cut? Tangent grain cut?

I put 2 micron paste on one, sprayed a coat of HA 1 micron on another and .5 micron on the 3rd.I screwed up though and forgot which one I put the 1 micron and .5 micron on. They both look the same dammit!

Some of civilizations best discoveries came from the discoverer screwing up!
We may be on to something here!

I guess the only way I'd know is if I can see one of them getting darker than the other and it would be the higher micron. Sound right?

In theory, it sound right. You said you got flat boards, so I'm going to guess they were either quarter grain or tangent grain cut. Try picking up a block instead of a sheet, rotate it so that you can use the end grain and compare that with the flat sheets.

Stitchawl

 

[Jason B.]

Stitch, I think you just have more selection. I've never seen a selection like you speak of and as it seems now I will need to go back to the store to see if the balsa type is labeled at the hobby shop. The sticker on the balsa didn't say.

If it feels like a bench strop then that's what you want.

The difference you should notice is a faster cutting rate and larger visible scratch pattern for compounds above 1 micron.

 

[stitchawl]

Stitch, I think you just have more selection. I've never seen a selection like you speak of and as it seems now I will need to go back to the store to see if the balsa type is labeled at the hobby shop. The sticker on the balsa didn't say.

No... no label. You have to look at the end of the piece, same as when you go to a lumber yard. The displays of balsa that I have here look just the same as the displays I used to see in the US. A collection of different thicknesses and widths but all the same lengths. The stuff sold for making model airplanes and boats. Flat sheets, blocks and dowels.

Perhaps this will help you. It's what I used to choose my test pieces.
http://pldaniels.com/flying/balsa/balsa-properties.html

If it feels like a bench strop then that's what you want.

That covers everything from pine, maple, balsa, MDF, telephone book, National Geographic magazine, garrison belt, tooling cowhide, and horsehide. The questions is; which works best for me when covered with compounds.

The difference you should notice is a faster cutting rate and larger visible scratch pattern for compounds above 1 micron.

For me, above 1 micron means a stone or polishing tape, not a strop. These days I use a strop only for .5 micron and finer, with most of the really finishing work done with bare horsehide at .01 micron.

Stitchawl

 

[Jason B.]

You probably won't see a difference then except price.

The feel I am talking about is the "pull" like leather has.

 

[stitchawl]

You probably won't see a difference then except price.

The feel I am talking about is the "pull" like leather has.

Once you cover it with compound, how do you get any feel from the substrate? The edge is no longer even touching the base, only the surface of the compound? I don't understand.


Stitchawl

 

[Jason B.]

Maybe I'm just more in tune

For me I can feel the difference between all my leather and wood strops. Its also partly the reason I use compound on leather, the feel and the finish is to my liking. With leather as a substrate it makes the compound finish finer and gives the edge a smoother feel.

My switch to balsa as a strop was to save on leather and cost and make my compounds above 1 micron work more effectively. 1/2in balsa is also the exact thickness of my diamond plates so when I use the aligner clamp I don't have to freehand the polish steps

 

[stitchawl]

Maybe I'm just more in tune

That must be it.

For me I can feel the difference between all my leather and wood strops.

Well sure, but the knife edge can't. It's riding on the compound, not the substrate. My hand can feel a difference in the way the knife rides over the strop, the same way knocking on a block of wood will tell you if it's hollow or solid, but it's not making any difference to the resulting edge.

Its also partly the reason I use compound on leather, the feel and the finish is to my liking. With leather as a substrate it makes the compound finish finer and gives the edge a smoother feel.

I like it just cuz it's cool.

I didn't find any difference in the resulting edge using different substrates with compound. Right now I have roughly two full sides of veg tanned leather in my leather working area as well as about 40 wallet sized blanks of tooling veg tanned leather, perfect size for strops. While I don't see any real reason to use leather as a substrate other than 'I can,' there is no reason not to either, other than waste. But I'll still finish on bare horsehide. Nothing give an edge like a .01 micron strop.

1/2in balsa is also the exact thickness of my diamond plates so when I use the aligner clamp I don't have to freehand the polish steps

Now THAT makes sense to me. :thumbup:


Stitchawl

 

[cbwx34]

I don't understand... first you say this....

Big difference!
Tangent cut has a much softer face than the other two, with quarter grain cut a bit harder. Making a strop out of random cut would make a rather non-yielding surface compared with tangent cut. Quite like a soft mouse pad compared with a telephone book.

To me, this is a very important factor in edge fabrication. It's why we use the firm grain side of tooling leather to strop on rather than a thick piece of suede.

Then you say this....

For me, it's only a surface to carry the compound, and the blade only contacts the top of compound.

The abrasive grit size is far too small to make a difference based on the substrate.

If the bottom layer is digging down into the substrate, that will have virtually no effect upon the top layer that is contacting the edge.

Once you cover it with compound, how do you get any feel from the substrate? The edge is no longer even touching the base, only the surface of the compound?

Well sure, but the knife edge can't. It's riding on the compound, not the substrate. My hand can feel a difference in the way the knife rides over the strop, the same way knocking on a block of wood will tell you if it's hollow or solid, but it's not making any difference to the resulting edge.


I didn't find any difference in the resulting edge using different substrates with compound.

(Bold added by me)

So, you seem to be saying there's a big difference, then you say it doesn't matter?

Also has anyone used both MDF and balsa, and if so, how do they compare?

cbw

 

[stitchawl]

So, you seem to be saying there's a big difference, then you say it doesn't matter?

I'm happy to clear up your confusion.

There is a very big difference seen when the substrate is hard or soft, i.e. mouse pad vs MDF. That should be obvious.
But it doesn't matter which hard substrate or which soft substrate, so no difference between different soft substrates and no difference between different hard substrates. Within reason, of course. Stropping on a soft substrate made from fresh Playdough will be quite different from stropping on a soft substrate of mouse pad.

This can be seen clearly when using a soft mouse pad as a substrate and creating a convex edge compared with using something hard such as MDF, and creating a good stropping surface for a beveled edge. Instead of the mouse pad one could use a a soft thick suede leather. It doesn't matter as long as it's soft. Instead of the MDF one could use firm leather, a paint stirring stick, etc. It doesn't matter as long as it's hard.

Also has anyone used both MDF and balsa, and if so, how do they compare?
cbw

I have now. I don't find any difference. As long as one is using normal light stropping pressure, only the surface of the compound is being contacted so there is no difference between the substrates.

If someone strops with a very heavy hand, and uses tangent grain cut balsa, they will compress the wood. If they use quarter grain cut they will compress the wood to a lesser degree. If they use end grain or random grain cut adjusted to a grain-on surface, they will need a very heavy hand indeed to compress the wood but it can be done. But then, that's not how to properly strop an edge.

Stitchawl

 

[cziv]

Maybe I'm just more in tune

For me I can feel the difference between all my leather and wood strops. Its also partly the reason I use compound on leather, the feel and the finish is to my liking. With leather as a substrate it makes the compound finish finer and gives the edge a smoother feel.

My switch to balsa as a strop was to save on leather and cost and make my compounds above 1 micron work more effectively. 1/2in balsa is also the exact thickness of my diamond plates so when I use the aligner clamp I don't have to freehand the polish steps

I would agree with knifenut 100% after touching up 2 knives with my 3 new balsa strops. The only good "pull" feedback (I felt it too) I got, was from the 2 micron paste strop.

The 1 micron and .5 micron sprayed sections gave no feedback "feeling" from the blade when stropped. They did remove metal, as seen by the black streaks on them but it was guesswork compared to my leather strops loaded with low micron spray.

The 1 and .5 micron balsa were taken to the leather for comparison and leather gave me the feeling of where my edge was and if I was hitting close to 100%.

The leather also gave a decidedly sharper edge as well. I'm keeping my balsa for the higher pastes and the leather for the finer sprays.

 

[stitchawl]

I didn't realize there were different cuts either...

Are you getting them somewhere special or just picking through what is available at your hobby shop?

I've been buying mine in DIY shops and home centers. I tried three different places to see what was available, but all three carried the same display. I didn't know about the different cuts either before I did some research about them. I figured that if I was going to try and experiment with them I sure better learn something about them before I began. There are too many shops selling the Emperor's New Clothes. I can't blame them for it; there are plenty of folks willing to pay good money for them!

Stitchawl

 

[stitchawl]

I would agree with knifenut 100% after touching up 2 knives with my 3 new balsa strops. The only good "pull" feedback (I felt it too) I got, was from the 2 micron paste strop.
The 1 micron and .5 micron sprayed sections gave no feedback "feeling" from the blade when stropped.

So if you were applying different compounds to the same balsa, and only the 2 micron paste gave you 'pull,' it's safe to say that the balsa had no effect in that feeling. You were using that same balsa with all three compounds. The pull was caused by the 2 mic paste. Or am I missing something?

The leather also gave a decidedly sharper edge as well. I'm keeping my balsa for the higher pastes and the leather for the finer sprays.

I'm going to use my balsa to make a model plane. I'll stick with MDF and leathers for stropping. Interesting experiments though. :thumbup:

Stitchawl

 

[cbwx34]

I'm happy to clear up your confusion.

There is a very big difference seen when the substrate is hard or soft, i.e. mouse pad vs MDF. That should be obvious.
But it doesn't matter which hard substrate or which soft substrate, so no difference between different soft substrates and no difference between different hard substrates. Within reason, of course. Stropping on a soft substrate made from fresh Playdough will be quite different from stropping on a soft substrate of mouse pad.

This can be seen clearly when using a soft mouse pad as a substrate and creating a convex edge compared with using something hard such as MDF, and creating a good stropping surface for a beveled edge. Instead of the mouse pad one could use a a soft thick suede leather. It doesn't matter as long as it's soft. Instead of the MDF one could use firm leather, a paint stirring stick, etc. It doesn't matter as long as it's hard.



I have now. I don't find any difference. As long as one is using normal light stropping pressure, only the surface of the compound is being contacted so there is no difference between the substrates.

If someone strops with a very heavy hand, and uses tangent grain cut balsa, they will compress the wood. If they use quarter grain cut they will compress the wood to a lesser degree. If they use end grain or random grain cut adjusted to a grain-on surface, they will need a very heavy hand indeed to compress the wood but it can be done. But then, that's not how to properly strop an edge.

Stitchawl

I understand all that, but you're original post was on differences in how balsa was cut, saying "there must be a real difference in your results", which you now seem to say doesn't make a difference, unless used improperly. It was not in using different media to strop on.

So, my original question remains, why talk about different cuts in balsa (not different media), if you don't think there's a difference?

cbw