Sanders - when to use what type?

Hi Guys

I have a very simple and basic question that I hope somebody can answer for me.

When do you use the following types of sanders?

1. Random Orbital

2. Orbital Sheet

3. Belt

Thanks for any help you can provide.

Regards
Greg

Hi Greg,

3. A belt sander is great for table tops, coffee table tops, i.e. any thing long and flat. You can then also turn the belt sander upside (making sure it is secured!) and then run smaller pieces across it.

2. I'm not a fan of the 1/3 sheet sanders - too many 3/4 circle marks to get out of the timber, but they are good for basic sanding.

1. The random orbital is a much better sander, IMHO, than #2. Use it for just about everything.


Cheers
Wendy

ROS is the best for general and finishing work

Orbital is now neglected to the bottom shelf

Belt is for quick removal and rough work

Greg

As the knowing DarkSide Sister says - but even more than with hand sanding it is critical to choose the right grade (and type) of sandpaper for the job you are doing regardless of the tool.

The first question you need to answer is how much material do I need to remove and then to work out what series of coarse to finer you need to use to get to the finished stage you want. This might vary from quite rough (40 or 60 grade), say for rough-sawn external timber on walls of a shed or garden furniture when you just want it to be splinter free, or maybe you want to remove saw marks, down to 120 or 240 for a final finish with 1200 for a smooth as a baby's derriere surface - for fine furniture or other cabinet making.

As general rule a belt sander will remove more material for each grade of paper and the random orbital less. Belt sanders are powerful beasts and can be hard to control - they tend to dig in a little at the sides so forming long grooves on large flat surfaces. Maintain firm control and as with all tools let the machine do the cutting - do not try to force a faster cut by heavy pressure - a recipe for swirls and marking.

If in doubt start with a finer grade paper than you think it needs and then go coarser if the material is not cutting down as much as you want (and it can take). Start always with the coarsest grade paper (which might be 80 or 60 grade) then move to 120 then 240 etc. The coarser you start with the more it will take to remove the marks with the next finer grade. For soft woods or thinner pieces start with a finer grade - 120 might be suitable and on some fine thin pieces or very soft timber 240 even.

As with many things it is always better if you can test by using an off-cut or similar wood type first to see the rate of cut and what sander type and paper type is best.

I always finish with a hand rub with a block (I use a cedar hand block with 'caneite' glued to it) and the finest grade for the job. Always along the grain (if possible).

Thanks for the great replies guys!

That's why I luv this forum!

Regards
Greg

I've got a Triton 125mm sanding attachment for an angle grinder. Compared to a similar sized random orbit sander, it has a lot more power and I find it is inclined to dig in on broad surfaces if you aren't careful. Then again it has a lot more power and can sand a lot faster than a normal random orbit sander, even with a medium-fine sandpaper in it.

Speaking of random orbital sanders...

I've just been reading the section in Neil's book about the applicability
of different types of sanders. I took away the message that an ROS can
be used for fine finishing on curved (convex) surfaces. Have I got that
right?

So far, I've always been sanding them by hand along the grain
with paper cupped in my bare hand - for fear of introducing swirls
and other marks across the grain. Is it really ok to use an ROS for
this instead?

I have used a ROS for curves with great success - same story though - depends on wood type (especially hardness) and grade(s) of paper. Also on cross/end grain work so long as you start with finer paper than you think to be sure you do not mark the work.

I have been using a cheapo Ozito ROS fine work & corner sander, which uses the triangular pads, for some furniture work on curves and it has been great. Final finish always with hand block though as above.

I use a foam spacer (between the base and the abrasive) on my rotex for curved surfaces, they come in different densities depending how drastic the curve is, I got mine from Gills Tools in Coburg and they were about $18.
These were the 6" with the alignment holes for Festool but I assume that there would be others.

Belt sanders have a reputation as a butchery impliment:D yep they do that well. if you want to remove a lot of material fast.... oh yeh
However if it has been tuned up and fitted with the appropriate abrasive a belt sander can do some jolly fine work. If kept under control It is capable of doing a better job of keeping or making a surface flat than any other hand held sander.

My random orbit gets more work that any other sander these days, because
the dust extraction is excelent
it works fast
gives me a finer finish with any given grade of paper
and
is less angry

however
on timbers with hard & soft parts in the grain it is prone to cutting the soft faster than the hard leaving a less than flat finish.

I sold my larger orbital becaus I baught a ROS, but I baught a small... the little bosch pad sander. I use it for doing edges where the ROS can get unstable and its good in tight spaces.

the last one not mentiponed in the original post is a detail sander...... one of those triangular things.
you may not use it a lot but when you do they are the only option other than hand sanding.

cheers

I'm sure most of us have a sander or sanders to do general jobs as they come up but may be unaware that there are more choises available if you have the need for them.

Some random orbital sanders come in different speeds ranging from about 7000rpm to over 12000rpm and with diffrent circle patterns which can be down to about 5mm dia up to 12mm or more. This can make a big difference to the final finish.

Iain: you can not only get those sanding discs in various diameters they also come in various configerations with different holes and no holes. You can also buy discs with sponges in various densities already attached to the sanding disc and with a velcro backing. Actually the back is a felt and the disc has the actual velcro on it.

Two of the brands I have in the sandpaper drawer are

Mirka : which comes from Finland and is distributed by PPG

Siacar: made in Switzland.

These are both top quality papers

One of the latest sanders around is a small air driven one with a disc diameter of only about 30mm dia. Its meant for small work removing faults on large surfaces but may be just the go for someone doing little jobs like toys etc.

One sander not mentioned which I always go for if I have a large flat area to flatten is a "reciprocating sander" (one where the paper moves back and forth only, ) All the ones I've seen are orbital with a lever which changes them to recirocating. These sanders work just like you are hand sanding with a block going back and forth along the grain and they don't dig in like the belt sanders do. As mentioned by others often the circles left in the surface show up as you are sanding across the grain.

Thanks for the replies and great information guys !

Regards
Greg

I have found the Bosch detail sander useful for cleaning up awkward corners - getting rid of glue stains etc. Subject to this, agree with all the above. I don't think I have used a standard orbital sander in 12 months - since I bought my ROS. I do use a 4" belt sander a lot 60, 80 and 100 grit belts.