Thread 2946817

>I've made a table and kinda fucked up the finish. It's built into a nook and in active use, so I'm trying to fix it without completely nuking the place.
>Tried doing it by hand, but the stuff clogs up a p120 paper within seconds.
>Thinking of buying an orbital sander and blow a pack of p120 and a pack of p240 on this to fix it, but I have no experience with sanding power tools.
What to watch out for, what are the general guidelines when buying/using this stuff?

RO sander is a critical tool if you're doing anything beyond rough framing. In a perfect world you want to cut or scrape your way to exactly what you need, but at the end of the day the sander goes brrrrrrr.

The RO sander is almost idiot proof. Sometimes the velcro can drop the paper and I'll accidentally sand away the velcro before I notice. Other than that, you start with a low grit to cut away more material. Then you work your way up to eliminate swirls. I don't go under 80, that's belt sander tear shit up territory. 120 and 240 give good finishes. Past 320 can impair stain absorption. You're getting into paint polishing and blade sharpening grits in the high hundreds and 1000s.

Think about what you're doing when you're sanding. 60 grit belt sander is ripping away whiskers of wood like shredded wheat. A hand plane carves away shavings. RO is always cutting circles or spirals into dust or fine powder. Proper technique is to use a finish sander to final sand with the grain, especially when you build something from scratch or need perfect stain and finish. Most jobs and people will never know the difference, RO is plenty.

>>2946817 (OP)
Buy a stick-on type instead of the velcro type. You can buy giant rolls of circular stick-on pads at the local auto paint shop for a fraction of the cost of the velcro ones (which are extremely overpriced).

>>2946911
went with a bosch for 90 bucks, its not that big of a deal, atm convenience(available near me) is a bit better
>>2946832
what is the lifespan on these papers? should i just throw them once the gunk from the varnish covers it or is it cleanable in some way?

>>2946925
The discs have low lifespans. They're only good when they're cutting away dust. Finish and filler will cake them up quickly, so it's beneficial to scrape that first. They dull on their own in short order as is.

The RO isn't for correcting a 1/4" difference. It's for bringing 1/16" flush. Smash filler into the recesses and let the sanding dust bond to that hiding all of your gaps.

>>2946925
>gunk from the varnish
>p120
youre wasting your time. Remove the varnish with a glass shard or card scraper (no need to get autistic, filed burr is good enough)
then clean it up with a normal grit progression

>>2946817 (OP)
get a finish sander so you can get into the corners, RO is nice for sanding big things, they aren't nice for sanding things with other things around them

>>2946832
>I don't go under 80
I put 40 on mine and it's fucking great. Especially combined with the turbo mode which rotates more.
Saves so much time, even taking into account the 60 pass you need to do.

>>2947617
Sandpaper is cutting valleys or more intuitively reverse mountains into the surface. The higher grits cannot reach the peaks without removing bulk to get to the last cut of the low grits. Too high of a grit and it will never reach, only burnish the surface and chew up piles of discs.

Using progressive grits generally works. An example issue to me is trying to sand away too tall of a speed bump. A planer would only hit the bump because it's held parallel at that distance. The sander is going to curve around the bump or rock as I use it. The sander will then cut away areas beside the speed bump and also leave a gap in the middle. The low grit will dive into the material and I'll need to sand a lot of the broad surface to clean up the work.

There are all sorts of methods. I think it's good to put some mental effort into eliminating dust and consuming discs. Most experienced workers are going to naturally do something that makes sense, but early on I think most of us can create unnecessary work.

What you need is Festool Rotex for them agressive grind (forced rotation) and Mirka Deros for finishing sander. I know, i have em all, all pad sizes. But automotive mostly.

>>2946817 (OP)
Whatever you do, don't get a cordless one because they run down batteries something fierce.

>>2946911
the stick on ones will become unusable eventually.
The pad will get coated with sawdust-glue

>>2946817 (OP)
I'm currently using a 220V orbital sander for most of my wet works on a car. Is it against sharia law? Should I transition to a 12V version or pneumatic one?
Standing in a pool with the thing plugged in grid sounds retarded. But i can't stand epoxy dust either.

I refinished a coffee table last year. Hand sanding was not going to cut it. Too much time and not consistent enough results. This worked well, and takes 1/4 sheet of sandpaper (fold in half twice and cut on the folds) so it has to be the most economical. I stabbed the dust suction vent holes with a pencil.