Finish sanding issues; orbital and random orbit sanders

[trumpetmonkey]

Up until now I kept struggling to get a good finish on pine that is to be stained, after sanding. After thorough sanding the pine can seem silky smooth, and clear varnish would fine, but staining reveals swirls and scratch marks.

I have finally got a random orbit (just a cheap £30 titan one from screwfix) and using this from 80 grit through 120 to 180 grit, then hand sanding along the grain with 180 grit has given an acceptable finish. Used rustic pine colored briwax (was going to use a separate stain then Finpol but had to save time)

The problem has been orbital sanders I used up to now- why do I keep getting swirl-scratch lines? What is the benefit of ever using an orbital as opposed to a random orbit which seems to avoid this issue? What is the recommended sanding procedure to take planed edge-glued pine planks up to a good finish? And any advice on recommended models of sander (belt/orbital or random orbit)

 

[mailee]

All I use when I am making up edge jointed panels is a belt sander with 80g to level the joints then move on to a Random orbit sander moving through the grits from 120 down to 320. A final hand sanding with 320 to 400 and then on with the sealer and finish. This seems to work well for me with pine. HTH. :wink: I use the Metabo ROS which is a good sander for this type of work.

 

[goldeneyedmonkey]

+1 for the Metabo ROS. It's excellent, it's a got a lot of praise on here as well. _Dan

 

[Hudson Carpentry]

Yep another for the metabo.

I used to get just what you described with a cheap orbital. Sometimes i still see it with my Bosch palm sander when using 60 grit but its not often i use 60g with a palm sander.

Try circulating your sander while sanding.

 

[trumpetmonkey]

Ah, the metabo, I have borrowed one in the past off an old joiner and it is wonderful! Looking in Google shopping now there are various different metabo models, what is the model number you are all raving about?

So belt sanding - I tend to get grooves that take a lot of further sanding to remove, what am I doing wrong? (I found this particularly with my metabo BAE75 belt sander, which is quite heavy - not so bad with a second hand bosch scintilla I now use - same 3" belts)

Again, can anyone say what benefit there is to even owning an orbital when you could be using a random orbit? Is it just that they're cheaper and have rectangular bases?

 

[petermillard]

Ah, the metabo, I have borrowed one in the past off an old joiner and it is wonderful! Looking in Google shopping now there are various different metabo models, what is the model number you are all raving about?

There was a thread on this recently, a quick search might bring it up; I used to have a Duo 450 - nice machine, I found it a bit top heavy personally, and the change between orbits was a bit awkward. Current models are available in two sizes, *450 is the 150mm, *425 is the 125mm.

Edit:- This thread

So belt sanding - I tend to get grooves that take a lot of further sanding to remove, what am I doing wrong? (I found this particularly with my metabo BAE75 belt sander, which is quite heavy - not so bad with a second hand bosch scintilla I now use - same 3" belts)

Keep the sander moving laterally, and let the sander do the work i.e. don't press too hard; belt sanders are for rapid stock removal and it's easy to make big errors very quickly...

Again, can anyone say what benefit there is to even owning an orbital when you could be using a random orbit? Is it just that they're cheaper and have rectangular bases?

Random Orbit Sanders are by their nature, circular, which doesn't suit every application. Orbital sanders can be had with different shaped (and sized) bases and abrasives - detail sanders, delta sanders, 1/4 sheet palm sanders, 1/3 and 1/2 sheet sanders; weight can be an issue too. Also remember that not every piece of sanded wood is destined for a stain finish; I use sanders extensively in paintwork prep. and I use my linear and rotary sanders just as much as the orbital and ROS.

HTH Pete

 

[trumpetmonkey]

Keep the sander moving laterally, and let the sander do the work i.e. don't press too hard; belt sanders are for rapid stock removal and it's easy to make big errors very quickly...

So it is good to move the sander side to side as you go forward and back? Like a sine wave if you looked at the motion from above? That's what i figured, to save digging a trench!

Maybe I'll hang on to my 1/3 sheet work orbital, was thinking of taking it back to B&Q but you're right it still has it's uses.

 

[Hudson Carpentry]

Second the belt sander, try not to rock it, not force it down, keep it moving. You can move it side to side as long as the belt is sanding with the grain. Infact a belt sander is more efficient if tilted about 5deg from the grain. Don't confuse more efficient with quality of finish in this case, if you down to 80 or 120g belts then keep it straight.

Are you using non pieced/punched papers with your sander and punching them yourself. The punches that come with some sander don't punch but piece and tare the paper which can cause the issue you described. I use paper off a roll for sheet sanders but never punch them for this reason.

 

[doorframe]

123

 

[trumpetmonkey]

I have a WORX orbital. It's cheap but well balanced with an ally base. Nice to use with low(ish) vibration. If I use the 'punch' that came with it (a really crude piece of plastic with some raised crosses as the punches) it will make a mess of the holes AND the work. Got a very cheap and nasty S/H ROS from ebay and having used it I wouldn't be without it!
Roy

Sounds like you have the same WORX orbital as me, is it this one?
http://www.diy.com/diy/jsp/bq/nav.jsp?a ... egories%3C{9372015}/categories%3C{9372047}/categories%3C{9372206}/categories%3C{9392097}/specificationsProductType=palm___detail_sanders&tmcampid=4&tmad=c&ecamp=cse_go&CAWELAID=656841234

I like the feel of it too and the alu base. Yes, I can see the problem with punching the holes, it can leave little spikes of bent sandpaper round the edges.

Another good thing about the worx sander is that the holes also extend sideways to the edge of the baseplate, so should still suck up a bit of dust without punching.

 

[doorframe]

Sounds like you have the same WORX orbital as me, is it this one?
http://www.diy.com/diy/jsp/bq/nav.jsp?a ... egories%3C{9372015}/categories%3C{9372047}/categories%3C

No.. mine's not as aero-dynamic as your's...

http://www.auctelia.com/images/sitefr/photo_gde/25/Ponceuse-Orbital-sander-worx-WX26FS-147-1.jpg

Another good thing about the worx sander is that the holes also extend sideways to the edge of the baseplate, so should still suck up a bit of dust without punching.

Yes.. same here... still collects without punching... even better with my albeit make-shift hoover adapter.

Roy

 

[p111dom]

I used to suffer from swirls. I had a cheap ros from lidl, Parkside I think. Every now and then they also offered a pack of 100 mixed discs for a couple of pounds which I thought was great. After about two years of fairly hard use it gave up the ghost. I bought the metabo 450turbo which is a great machine but when I got home it seemed a shame not to use up the old discs so stuck with the lidl ones. I was pretty disappointed to find the metabo left swirls as well and tried all techniques to avoid them to no avail. Eventually I tried the better quality sanding discs that came with the new machine which weren't perfect but the swirls decreased by about 50%. At that point I realised that swirls are all to do with crappy abrasives. I've since moved to Abranet discs and get no swirls at all plus the added benefit of ultra good dust extraction means IMO these are the ones to have. The metabo is great but in retrospect I think the expensive abrasives on the cheap ros would have been a perfectly acceptable combination.

 

[trumpetmonkey]

p111dom this is a very helpful insight, thankyou. I expect what's happening is the cheaper abrasives have high spots (eg bigger or more stuck-out grains). I've been using basic ones from Screwfix.

So abranet, I've been thinking of trying those...