Question on buffing handle material

hi all

I just recently finished a knife i made with a blaze orange G10 handle. When i went to buff the handle on my 3600rpm buffer just like i have the last couple i ran into a issue. the first wheel i use is a sewn cotton wheel with white rouge. while it did polish the G10 it also smudged the handle with a black or almost purple stain. this smudge is pretty much impossible to wipe off so instead i ground it off and left the handle unpolished

i have never noticed this problem before on the other g10 handles i have done, any ideas??

Sounds like maybe you overheated the material?

I was going very lightly, i mean very very lightly so i wouldnt see how i could unless it is a buffer speed issue and in that case i dont know what to do since i have no way of slowing it down

sometimes i get a black residue on my knife blade when i am buffing or sharpening but it just wipes off. maybe due to the more porous material the residue is embeded and i just cant see it on other darker handles.

i dont know, but i sure would have liked to have been able to have buffed that blaze orange

You might want to try a different rouge also. Im not sure how aggressive the white rouge your using is. Ive got some white called fabuluster that i use on jewelry thats very good for final polishing. I like a slower speed with it also. The pink scratchless rouge on a new cotton buff might be the ticket also? If you got some scrap pcs of the g10 left do some experimenting.

I'd guess that the wheel is glazed/overloaded with compound hit it hard with a comb or try a fresh buff and try on a piece of scrap.

This sounds about right, i will give that a try, thanks all

Lerch said:

I was going very lightly, i mean very very lightly so i wouldnt see how i could unless it is a buffer speed issue and in that case i dont know what to do since i have no way of slowing it down

sometimes i get a black residue on my knife blade when i am buffing or sharpening but it just wipes off. maybe due to the more porous material the residue is embeded and i just cant see it on other darker handles.

i dont know, but i sure would have liked to have been able to have buffed that blaze orange

Click to expand...

Only three things that can be causing your problem- speed, pressure, and abrasive.
All three must be matched to each other for everything to work correctly.

You mention that sometimes you get "black residue" on the blades. I'm not there to see the symptoms, but a very common error is overloading the wheel with compound.
If you're getting a black slick of compound on the workpiece, then you're applying too much compound to the wheel. The workpiece itself becomes overloaded with compound and the black that you see is the excess grease binders in the compound.
The result is that you now have it over-lubricated, and are no longer cutting cutting effectively. Meanwhile, you're still creating friction and heating things up.
When charging the wheel, it's always better to apply a smaller amount and charge more frequently. If you keep the bar in contact with the wheel any longer than a second, you're probably wasting compound and reducing cutting effectiveness.
If you suspect this is an issue, clean the wheel with a rake and start over.

Regarding pressure, I understand that you're going very lightly, but going too light on the pressure can also cause its own set of problems. The reason stems from the fact that, believe it or not, you are actually removing material on a very small scale.
Material removal by any method, whether it be drilling, cutting, sanding, buffing, etc., will call for a certain amount of pressure in combination with a given speed for a given workpiece/cutting agent combination.
If you do not apply the "right" amount of pressure, you're simply "spinning your wheels" (pun definitely intended :biggrin. There may not be enough pressure to do the type of cutting action you wish to achieve, but that wheel is still spinning on the workpiece and heating things up.
A very good example of this is the "drilling problem" thread, particularly posts #8 & #13:http://knifedogs.com/showthread.php?19230-Why-can-t-I-drill-a-1-4-quot-hole
Unfortunately, the "right" pressure is subjective to your other conditions (material, speed, and abrasive), and requires experimentation on your part to find out what works for your particular circumstances.

Regarding speed, I don't know what wheel diameter you are using.
But if you're using a 6" (or larger) wheel on your 3600 RPM machine, you're going a little faster than I would feel comfortable with when doing typical handle material (wood, G10, etc.).
In other postings I have stated how I like high speeds to get the work done quicker, but the higher speeds are for most metals we use (excepting titanium).
If you feel that slowing it down may help your situation, the way to do it with a fixed-speed machine is to experiment with a smaller diameter wheel. If you want to go faster, increase the diameter.
This is one of the reasons we have so many different wheel diameters available.


Good Luck,
Rob

thanks for the post Rob45, i think your right on two marks, the overloading and the speed

your probably gonna laugh at this but when i was setting my stuff up and buddy of mine was helping me and a guy that he works with as a electrician told him that you know when to stop applying compound when it is flying off the wheel. like that means its full lol, so i have been doing that, applying for around 10-15 seconds at a time lol. glad to know now though. what "rake" can i use to clean the wheel, or do i just need to start over with a couple of new wheels??

I am using a Harbor Frieght copy of a baldor buffer. its a 3/4" arbor and i am using 8" wheels. the buffer was listed as a 3600rpm buffer but it did not specify wheel size

im thinking the overloading of the wheel maybe the issue and not so much the speed as on the darker G10 handles i have done i have not noticed the problem as much and only really had a issue with it on the light (orange) . the grease overload may just be that much more apparent on a light color, the previous two were all very dark colors.

thanks
steve

As another little question that some what pertains to this, i am using my buffer to put the final edge on my knives. I am using a flat platen and a 220 belt that is a little worn to cut down the .030" edge i grind to into a initial edge. basically until i fell comfortable with it and i have a decent burr that i can feel. then i am taking the blade to the buffer with the white and pink scratchless rouge with the white on a sewn wheel and the pink on a loose wheel. with it i am able to produce a edge that shaves very easily (another practice i have to stop as my arms and legs are starting to be polka dot hairless lol)

is this a good way? it was how i was shown by another knife maker

thanks
steve

I know folks who sharpen on their buffers and belts, and are happy with it. One worry is rounding over the edge, and keeping a consistent bevel off the buffer, but if it pops hair easily your keeping the edge. I would be concerned about the grit 220 is way too coarse for sharpening which means you have to either spend a lot of time on the buffer or your not leaving a polished edge. Personally I'm a stone and strop guy my self, I feel I can get a smoother more consistent edge that way. For mechanical sharpening I use a Tormek up to a 4k Japanese wet stone and hand strop. I used to work in restaurants, for about 15 years, and I grew to hate commercial sharpeners who used a belt system, which was about all of them. I know there are guys here who take more care so please don't take offense. But those guys, yikes. Way too much tooth, and those teeth would fold over in a hurry. Bottom line there are several ways to get you where you want to go, and the choice is yours what you want is a highly polished edge with a consistent bevel and there are many ways to get there. And each has potential pitfalls and drawbacks.

That is probably my problem too. What is the technical name for the rake to find one at HF or homedepot.

Lerch said:

thanks for the post Rob45, i think your right on two marks, the overloading and the speed

..... what "rake" can i use to clean the wheel, or do i just need to start over with a couple of new wheels??

I am using a Harbor Frieght copy of a baldor buffer. its a 3/4" arbor and i am using 8" wheels. the buffer was listed as a 3600rpm buffer but it did not specify wheel size

im thinking the overloading of the wheel maybe the issue and not so much the speed as on the darker G10 handles i have done i have not noticed the problem as much and only really had a issue with it on the light (orange) . the grease overload may just be that much more apparent on a light color, the previous two were all very dark colors.

thanks
steve

Click to expand...

Every buffing station should have a wheel rake nearby, unless you're well-heeled enough to throw out an otherwise good wheel.
To see what one looks like, check out this link: http://www.usaknifemaker.com/metal-rake-and-handle-for-buff-wheels-p-1901.html
To use it, you slowly and gently place the jagged edge of the rake against the (spinning) wheel. Work it across the wheel face, and the old compound breaks loose and the wheel fluffs up.

Some people like to use the same wheel for different compounds, thinking that it's now "clean enough" since they raked the wheel.
Unless you're wanting to rededicate the wheel to a coarser compound, this is a sure recipe for frustration. The purpose of the rake is only to restore the wheel back to a usable condition.


Regarding the speed, if you are using an 8" wheel on your 3600 RPM buffer, your SFPM (surface feet per minute) is over 7500.
That's the top-end that I use for the carbon steels.
For any of the "softer" stuff that is more suspect to burning, better results are usually obtained with much slower speeds in the area of 3500 SFPM or perhaps even lower.
This would include materials such as lacquers, paint, and other coatings, wood, phenolics, plexiglass, etc.

Perhaps you can "tune" the four variables (material, abrasive, speed, pressure) in to where you can successfully use those high speeds on your G10 material, but it's a fine balancing act to say the least.
I've tried it in an effort to shortcut and save time, but that's the problem- it's a shortcut, and we know how those usually turn out.
There are some people out there who can do it; I'm not one of them. So if you can make it work for you, consider yourself blessed with a deft touch.

Using a 4" wheel on your machine would put your surface speed somewhere around 3700 (I don't have a calculator handy right now). That could eliminate a lot of head scratching.

At least for now you know about the most common mistake (overloading the wheel). Clean the wheel and try it again.
It's all about eliminating the variables one at a time. If you know that overloading the wheel is no longer the problem, but you're still not obtaining satisfactory results, then consider adjusting speed.

Just think, we still haven't discussed compound entrapment that can sometimes appear as tiny burns. But that's another discussion.

Good Luck,
Rob