On 7/21/2014 4:57 PM, Mike Marlow wrote:
Leon wrote:
On 7/21/2014 1:53 PM, Mike Marlow wrote:
dadiOH wrote:


It has nothing to do with randomness, nor orbital for that matter.
It has to do with the movement of the sander itself, not the motion
generated by the sander.

I happen to agree with that statement and that's what I had said in
my reply. But... I do defer to those who do finer work than I do
(like Leon and Karl), and I do accept their opinions since they go
way beyond the level of acceptance that I do.



Actually that is pretty much what I said and you disagreed.

What I said,

Actually the direction that you move the sander, ROS or finish sander,
is more important.

What you said,

I have to disagree with this statement Leon. It has nothing at all to
do with direction. I would say that it has something to do with the
speed at which you move in any direction - so as to allow the orbital
action to do its thing, but most certainly - not to do with the
direction.

So - you are correct Leon. Allow me to explain if I may. You are correct
in calling me out on this but my point is that the negative affect of cross
hatch is going to be more driven by how the sander is used than by its
direction. I know - that is a complete contradiction to what I said above,
and I apologize for that. The direction is somewhat irrelevant because it
is an orbital sander. What really plays into the finish is how long one
keeps the sander in any given area - how slowly or how quicly they move the
sander to minimize the effect of crosshatch. I know - I said it completely
wrong the first time - my bad.


Basically if the ROS's direction of movement is against the grain you
are more likely to see scratches than if the direction of movement is
in the direction of the grain.

But ROS isn't really "against" or "with" the grain - it's always both.

That is correct. BUT if you move it across the grain you are
introducing a non random direction as is with the grain. Now if you
move very slowly the effect might be less. Move fast enough so as to
not sand through the veneer on a piece of plywood and you see scratches
across the grain. I;m going to leave this where it is. I understand
the principal behind the random orbit, it creates scratch patterns that
are irregular. The moment you move the sander in any direction the more
that irregular pattern begins to leave a particular pattern.
When I bought my first ROS I thought differently too. 25 years of
experience is what I go by and going with the grain gives me better
results. Remember I am the guy that likes to sand, If I was not getting
good results I would not like it so much.

Ultimately do it the way you like.