Random Orbital Sanders - Is it Just Me?!

[OPJ]

I've been working on the lid for the blanket chest today but I can't seem to keep the thing flat...

Fresh out of the cramps, it was looking surprisingly good and flat! :wink: Mainly thanks to the biscuits, I guess. So, I began the flattening process with my 4" belt sander; working across the grain and the diagonals, which gave a great result and a lovely flat panel!

As I only have 120g belts, I decided I would use my Metabo SXE 450 random orbit sander to remove the scratch marks and finish with 240g paper... Now, I can feel the surface isn't flat when I run my hand across it! :x Checking with a straightedge only proves it is going up and down in places.

This is something that's never bothered me before as I've only ever done jobs like this for myself. I'm not sure how happy I'd feel giving someone a blanket chest with a (slightly) "wobbly" top. :? I've tried it using the dual and single orbit modes with only the same results.

Do other people have the same problem? Is there a knack to using to using these sanders? I try to work it slowly and evenly across the surface without forcing the tool; letting the disc do the work.

Just looking for some thoughts on this. Thanks for looking,

Olly.

 

[Mr Ed]

Whats wrong with your plane Olly?! :roll:

Joking apart, thats the best way of finishing surfaces and keeping them flat in my opinion.

Cheers, Ed

 

[Chems]

Get your plane sharpened up, its pine that will smooth out beautifully. Make sure its really sharp thou.

 

[wizer]

I could never get on with my 450 SXE. Far too aggressive IMHO. My DeWalt orbital sander is much nicer to use with similar results. I think i'd only use the Metabo again if I was working on a surface that was meant to be a bit fluid\uneven.

 

[Doug B]

Think i`d have to agree with Ed, Olly

I wouldn`t have approached this with a belt sander & ROS.

Best of luck sorting it out.

 

[OPJ]

Okay, thanks guys. I do have a Veritas scraper plane somewhere (is that a subtle gloat? :wink that I've only used once so far; might be time to break it out again!

I thought the DeWalt and Metabo sanders were identical? (As is the Mafell and maybe one other...)

Yeah, I've got the planes it's just the workbench that bothers me! :roll: There's no easy way to hold something 1200x500mm, until I can get started on a brand new one...

 

[wizer]

Sorry I meant Palm Sander:

http://www.screwfix.com/prods/83256/Pow ... alm-Sander

Tho I am tempted to try the smaller 125mm ROS such as the Triton. Lighter to use and seemingly less aggressive.

 

[paulm]

I could never get on with my 450 SXE. Far too aggressive IMHO.

Not sure how it can be too aggressive Tom, that's why it has a large and a smaller orbit setting, and if you want it less aggressive still you use finer paper surely, or perhaps I'm misunderstanding ?

I find mine excellent to use, one of the best on the market I would have thought.

Cheers, Paul

 

[wizer]

Maybe it's just me. But I can't keep hold of the damn thing, in either mode, it's got a mind of it's own.

 

[OPJ]

Tom, don't get me started on palm sanders after the Bosch episode!! :shock: :wink:

 

[wizer]

Honestly I love my little DeWalt. I got it 2nd hand off here and it's been great. Nice and light and leaves a perfect finish with Abranet.

 

[Chems]

Olly, planing isn't to messy, take it inside if you have too!

 

[pren]

Just a thought: Every time I use my belt sander to flatten timber, I notice the wood gets warm from the friction. I think belt sanders are worse for this as the belt heats up the metal sole that it rides over, turning it into something similar to an iron.

Could this heat cause the panels to expand?

Just my tuppence

Cheers.
Bryn.

 

[JonnyD]

Does the hollows follow the summer / winter growth rings on the timber. I have found in the past that the difference in hardness between the summer and winter growth can produce a slightly uneven finish.

Jon

 

[jhwbigley]

Does the hollows follow the summer / winter growth rings on the timber. I have found in the past that the difference in hardness between the summer and winter growth can produce a slightly uneven finish.

Jon

i've had that happen, knots also can stand proud. i find my Metabo SXE 450 random orbit sander works 10x better with proper bosch discs

John

 

[Rich]

The ROS I bought from Aldi for £20.00 works just fine.

Rich

 

[promhandicam]

Olly,

snip . . Fresh out of the cramps, it was looking surprisingly good and flat! . . . . So, I began the flattening process with my 4" belt sander. . .

Why on earth if, as you say, it was flat 'out of the cramps' did you use a belt sander on it? Even 120 grit on a belt sander is very aggressive.

Does the hollows follow the summer / winter growth rings on the timber. I have found in the past that the difference in hardness between the summer and winter growth can produce a slightly uneven finish. Jon

you don't mention what wood you are using although from what someone else has said I infer that it is a soft wood / pine. If this is the case then I had exactly the same problem as Jon describes when I made something from Douglas Fir and I sanded it with my metabo 425. I've not noticed this on any other timber as I usually work with Oak or tropical hardwoods, so suspect it is as Jon says the varying hardness between the rings. Only way that I can see to overcome it would be to use a plane as others have suggested and finish off with a cabinet scraper if there are any problem areas.

Steve

 

[Ironballs]

This is definitely a job for a plane, I found when using my ROS on pine doors that there were ridges with the early/late growth. Most planes will give a great finish that's flat as long as they're sharp when used on pine

 

[BradNaylor]

I never have any problems getting things flat with my belt sander...

:wink:

Cheers
Mr Smug

 

[mailee]

Unlike Dan I have the smaller 4" belt sander. :lol: I have used it excluively on Pine and flattened boards with it. I move from this to the Metabo SXE450 and go down to 320 grit with it and my panels are all acceptable enough. I don't have the time for hand planing as you can prpobably tell so use the RAS exclusively. Just make sure you are keeping the platten of the sander flat to the surface and don't use any weight on it. Same applies for the belt sander and keep it in line with the grain. Always keep both sanders moving and never stop with it running. HTH. :wink: