Disk sander with or without backing?

[Patrice Lemée]

I have some cork backing on my aluminum disk and I sometimes feel that it gives me less than a perfect flat finish. So what do you guys like better? Feel free to elaborate.

 

[go mike]

I've seen that a backing (I used rubber instead of cork) seems to help the grit cut faster, and hold up longer. My pieces also look very flat with it, but the finest I have gone is 800 grit. Perhaps a mirrored finish would show more imperfections.

 

[MadBug]

How thick is the cork backing you are using? I use the 1/16" thick cork, and like it. Stops the chattering, but isn't mushy like the 1/8" stuff.

 

[Robert Mayo]

I have always ground my blades with just the plate and sandpaper i get good flat grinds and no chatter but i use a push stick to apply my pressure. I have ground a couple of finger tips off and it hurts!

Bob

 

[Josh Dabney]

Pat,

I got a 9" tapered disk from Rob on a VS motor with a cork backing.

My take is this- The cork allows a smoother finish at a given grit. Thats all. If you muff your grind with a cork backing you would've muffed it on a bare disk.

I dont try to grind bevels on the disk just make them FLAT so it's just even pressure over the entire height of the bevel. NO uneven pressure towards the spine or edge. If I need to do that I'm not ready for the disc.

Do understand that you can wash out a grind line with a cork backed disk but also understand that you can make a grind line CRISP on a cork backed disk.

I think the real answer lies in technique and skill.

There are men alive who can step up to a 2x72 they've never seen before and lay a wicked symetrical grind on a blade ( not me) in short order. It doesn't work that way for me ???????????? Why

I think Chris LeDoux said it best- " it ain't the years boy, it's the miles"

-Josh

 

[Patrice Lemée]

My backing is about 1/16th. I guess the vote is pretty much split so like Josh said, it's a question of preference and practice if you can obtain good results with either option.

Thanks once again for your feedback guys.

 

[A C Richards]

I use both. I use the plain disc to do any hogging left from the belt, cleaning up my ricasso, and establishing the final bevel shoulders and anything I want to be FLAT. I use the cork back to sand to 400 grit, and do a final clean up of the shoulders. If you don't have 2 units the changeable faceplate unit from http://www.nielsendesigndiscgrinder.com/Welcome.html would be the answer. You could have 4 faces, one flat with and without backing and one 1 degree bevel with and without backing. It will give you the best of both worlds.

 

[Ryan Minchew]

Its never made sense to me for a soft backing to make something flat. It maybe minute but the leading and trailing edges of the part are not going to be flat compared to the rest of the piece.

 

[Patrice Lemée]

Thanks for the link Chuck, I'll take a look since I only have one disk sander.

 

[gixxer]

Its never made sense to me for a soft backing to make something flat. It maybe minute but the leading and trailing edges of the part are not going to be flat compared to the rest of the piece.

Word Ryan. There is always gonna be that minute bit of compression of backing and hence not perfectly flat at the leading and trailing edges. The only way to avoid that is VERY light pressure as not to compress the backing.

Guess how I voted???


-->edit<-- HOWEVER that is not to say that using a backing is WRONG per se, it all depends on what you are trying to accomplish. Respect to the others...

 

[argel55]

I have a double disc set-up. I use straight disc with 60 or 80 grit and on other side 120.220.400.600.1000,etc with 1/8inch rubber backing.