Stropping compounds

[L2bravo]

With the recent threads of stropping, and what we are all using for compounds, let's start a single big thread. Let's all put in our techniques, and progression that we use. Let's also weigh in on what brands are good, and not so good. I think this will shed some light for all of us, both experienced and new alike. We are all here to learn right?

Here is what I use right now:

I use some yellow Ryobi that I got at Home Depot. It shines like hell, but gets really funky quick.

I also use some green that I just got at a wood working shop. It seems to be some high quality stuff, and works quite well too.


I have a question.
What are you guys experiences with the Porter Cable brand from Lowes? Is it good stuff, or low qual. stuff? What numbers/colors do you use?

 

[Magnaminous_G]

From an earlier thread:

Stropping is more about cleaning up an edge that is already apexed and ready to go, to bring it to the next level. It does make a huge difference, but it works best when you've got an edge that is already pretty much burr-free. As for what angle, that depends entirely on what angle you sharpened at. If you sharpened at 15 degrees, then you should strop at that, too. The medium you are stropping on plays a role, too. If you are stropping on leather, if you keep your sharpening angle (or go too high) and use pressure or go at it too long, you could end up dulling/rounding your edge. So you keep your angle low and use light pressure. Less aggressive and firmer surfaces (for example, newsprint on glass) are much, much more forgiving. Hope this helps.

Best thing to do is get a strop, watch some vids, read the stropping sticky at the top of this subforum, and just start practicing. I second the Strop Block recommendation.

Now then, I have found that stropping, like using your finishing stone, benefits greatly from medium-light pressure at first followed by increasingly light pressure down to a feather-light touch with less than the weight of the knife, regardless of what you're using, medium or compound. Also regardless of what you're using, if you're doing it for more than a few minutes, you're doing it wrong, imho. Your finishing stone will determine what medium/compound you use.

For example, if finishing with my best stone (currently an Arashiyama 6k with natural nagura slurry), I'll go straight to plain leather or maybe denim, sometimes after plain newsprint on glass. If finishing with diamond plates (the finest I have in bench stones is the EF; I have the EEF duofold which I almost never use), I'll follow with 1 micro diamond on leather (I have diapaste and HA spray). I used to follow my Norton Combo India and coarse DMT plate with the Strop Block, but if I want to leave a toothy, coarse edge on a knife, I'll mostly follow up with black compound on HH Washboard these days.

For anything I use, the above usually applies. You need to have a clean, apexed edge that is already good enough for a working edge or better. If you've got a big, nasty wire or burr left from the stones, you're doing it wrong, imho. Needs more stone work: some alternating, edge-leading deburring strokes followed by edge-trailing strokes, lightening as you go until you are just "kissing" the stone, as knifenut says. Then some pressure with the stropping for the first few strokes, lightening up until just kissing the stone. It is important to strop *judiciously*. A few minutes is all it should take. If using a hard, flat surface like glass or the Washboard, you can use more pressure. When I use newsprint on glass, for example, I don't mind really bearing down. If using diamond spray on cow leather, I'll be very careful about pressure.

As for angles, I think I said it all in my quoted text above. There is also a good sticky at the top of this sub.

 

[HeavyHanded]

With the recent threads of stropping, and what we are all using for compounds, let's start a single big thread. Let's all put in our techniques, and progression that we use. Let's also weigh in on what brands are good, and not so good. I think this will shed some light for all of us, both experienced and new alike. We are all here to learn right?

Here is what I use right now:

I use some yellow Ryobi that I got at Home Depot. It shines like hell, but gets really funky quick.

I also use some green that I just got at a wood working shop. It seems to be some high quality stuff, and works quite well too.


I have a question.
What are you guys experiences with the Porter Cable brand from Lowes? Is it good stuff, or low qual. stuff? What numbers/colors do you use?

The porter cable stuff looks a lot like the stuff that Sears is now selling. The black is still very nice, but the stainless is not so good. I do not know if they are from the same source.

The best of the lower budget black emery is made by Dico IMHO, their stainless compound is not so good for stropping but the black does a great job making a satin finish and maintaining toothier edges.

You can thin out the goo factor of the Ryobi yellow with a drop of mineral oil - too much and it will become too fluid to work, so just a tiny bit - let the oil soak into the paper (if using paper) before stropping if it looks like its too thin. Ryobi black is not bad at all.

Best all purpose compound that still leaves a very fine finish is probably Flexcut Gold.

The term "stropping" is a little slippery. Murray Carter uses it to describe backhoning on polishing grade waterstones.

As for technique, if I'm stropping on paper over a stone, or firm leather I use the lightest touch I can manage and still make consistent contact. Less is more, one should use the stones as much as possible to get the edge ready for the strop, and use only enough compound to make very thin preparation on the surface.

That said, I have successfully used fairly high amounts of pressure on softer steels when stropping on paper over a stone. For a number of years maintained all my machetes in this manner - black compound on newspaper wrapped around a combination stone, followed by white compound, used the same. Some rounding, but for a heavy chopper on soft steel this works great - yields a tough edge, yet capable of shaving arm hair cleanly. When used with a lighter touch this method works very well on harder steels with reclaimed stone mud from a SiC stone or waterstone, or regular compounds. Very difficult to round an edge with this method compared to many other options as long as technique is sound. Scandi and full convex can go a long time with a lot (relatively) of stock removal using this method before needing to be put back on a stone. Plain paper or plain newsprint to finish works very well at any finish level.

On my Washboard many of my rules for stropping go out the window. Provided the paper has been pre-compressed I can use greater pressure on the strop than I can on a stone or sandpaper/lapping film, nearly twice the pressure. Have taken a number of micrographs that verify virtually no edge rounding from this practice and a great deal (relatively) of stock removal. So much in fact, it doubles as a finishing hone. At this point maybe not stropping anymore then backhoning on waterstones is stropping?

Link to a video where I go into some detail re this:
http://www.youtube.com/watch?feature=player_embedded&v=SalomUAvMHI

The more firm the backing, the less rounding will occur. One can actually sharpen a knife on an oak board using regular compound cut with a few drops of mineral oil to make a slurry. The definition can be stretched quite a bit...

Many compounds can be whipped up using graded abrasives from a lapidary supply shop or lens grinding supply houses. They can work very well. The proper binder can make them work even better, better than many commercial options depending on application.

Martin