Electric Sanders for Finishing: Grits and Pads???

[verhoevenc]

I can't really find anything online about this so I thought I'd start a topic to discuss this. 

If you use an electric sander for finish sanding let's hear your take on orbit size, pads (thickness, stiffness, etc.), and grits.

What tricks you have to avoid sand throughs. What techniques are important when going from hand sanding into the world of electric finish sanding?

How do you handle carved tops? Differently? What about sides? Still hand sanding those?

Lastly, any particular sanders you recommend for this?

Best,

Chris

[Bjorn.LaSanche]

I don't think one should use a powered sander for any step of the refinish job except stripping of an old finish.  It is too easy to sand through any work you have done and destroy an otherwise good job.  I make my own sanding blocks about half the size of ones you can get in the store, and glue a piece of leather smooth side out to it.  I spray glue my sand paper to that, and peel it off to change grits.  It works a lot better than a store bought sanding block. 

The amount of pressure needed to sand the finish coats is so light that a powered sander would eat through them in short order.

[curtisa]

I think when Chris refers to "finish sanding" he's talking about the final sanding performed on the raw timber before applying a finish.

IME buying a good quality random orbital sander changed my perceptions of power sanders. Up until then I had only used generic orbital (non-random) power sanders which always tended to leave tiny little sanding "squiggles" on the surface of the timber, requiring more hand sanding to get them out, which defeated the purpose of using a power sander in the first place. I ended up getting a Makita BO5041KX ($250AU or so). No doubt I could easily spend 3 times the price of the Makita on something by Festool. I believe the Bosch GEX (blue) series sanders are recommended too.

Sandpaper attachment method may be important when buying replacement pads. Some manufacturer's may utilise specific shapes, sizes and securing systems that may require you to buy more expensive sanding paper. One of the reasons I chose the Makita was that it just uses a velcro-backed 125mm circle which can be bought just about anywhere. Buy a big stash of sanding pads in various grits up to as high as you can get them. With the velco-backed stuff, after the first use they rarely reattach to the sander properly when they're peeled off, so they're effectively single-use only. What I've found when using the ROS is that the equivalent grit used on the sander will give a smoother finish than using that same grit sanding by hand.

Have a look at the dust collection port and see if you can hook something up to it. The little dust bags that come with most sanders aren't worth their weight.

Sides and complex carves where the ROS won't fit I'll still do by hand. Just takes time and patience.For really tight stuff I'll cut up some sand paper into 8" strips, place it between the timber and my hand and use the other hand to pull it through in one continuous motion. Kinda hard to explain - a bit like pulling a piece of sticky tape out from a dispenser.

[verhoevenc]

Quite the opposite. I'm actually interested in takes on sanding finishes! I've seen a lot of folks recently on Instagram using poiwer sanders to reduce their finish times. A lot of which is spent leveling coats between days of spraying! Notable examples have been Jauer and Frank Brothers. I've seen the latter using Mirka sanders (high quality stuff from what I've read) for the job. But no info on grits, how much give the pads they're using have, etc.

Chris

[curtisa]

Interesting. I would have thought that'd be way too aggressive to be of any use, although the quick check of the Frank Brothers Instagram feed I did only mentions scuffing the sanding sealer, rather than levelling the finish coats.