Random Orbital quirks??

[Brent]

Hi Folks,

My first post to the group...

I have recently purchased a random orbital sander and am happier than a hog in mud. It gives an incrdible finish and handles beautifully. However I have noticed some funny things on my latest project out of white oak.

Using a 60 grit pad hardly removes wood at all. It almost burnishes the surface giving a small ripple but not removing much stock. I tried some

180 grit and it cuts like a hot knife through butter! I smoothed the whole surface (80cm *60cm) that I am working on in a few minutes! Took out multiple small planing tearouts at least twice as fast as the 60 grit pad??

Has anyone else experienced this?

On a previous project out of a local African hardwood 'Kiaat' I also noticed that the cutting rate with 180 seemed incredibly fast... Happy woodworking Brent

[Leon]

There are different kinds of sand paper and some will load up quickly. If the 60 grit is not an open coat type sand paper it may be loading prematurely. Also are you sure the 60 is not really 600? :~)

[Brent]

I'm really sure that it is 60 ;-)

the 60 grit is the dark red/brown paper which does seem to have a rather heavy binder to hold the grit in place. The 180 I used is a white paper. What are the differences and what is better to use?

I've only ever used a normal orbital and used 1/3 sheets of standard waterpaper. Never used the hook-and-loop stuff before...

Brent

[Lew Hodgett]

Sounds like Leon hit on your problem.

SFWIW, I use Klingspor PS33, an open coat paper they sell to the furniture industry.

It is H&L.

Lew

[Leon]

Hook & Loop should not make a difference over PSA other than being able to reuse the paper after changing grits. Open coat sand paper is usually Aluminum Oxide and tends to do better when sanding wood. Open coat sand paper is usually white in color and is likely what you are using in the 180 grit. Also keep in mind that sand paper wears out before it looks worn out. The easiest way to check is to feel the cutting surface with your finger and compare to new paper. Typically sand paper will only last about 10-15 minutes with constant use.

[Brent]

Thanks for the help guys! Makes sense...

Brent