Updated: Mar 4, 2020
I can't say I actually thought I'd ever really use the speed control on my random orbital sander. But today I did. Yes it was even on purpose... And I'm impressed with how well it worked!
Wait a minute... If you didn't think you'd use it, WTH did you buy it?!?!
It was purdy?!
No, well, yes, but... I like it because it has a real handle in addition to the normal palm grip. I find this helps dampen the vibrations from the sander better which is nice when you're using it for long periods of time.
OK, back on topic. Why was the variable speed useful?
Right. I needed to do more sanding than expected on a delicate piece that I laser cut from 1/8" plywood. Using full speed on the sander was causing the wood to bend and flex more than I was comfortable with. Hand sanding (ugghh) would work... but it would take forever and I don't have my patience hat on today.
Enter variable speed control - I need less power captain!
I backed 'er down to 2 and all was good! The sander was no longer bending the piece and it was still removing the pitting in the wood a lot faster than hand sanding. #likeaboss ! OK, not really, but it worked well and I didn't have to hand sand so I'm happy. Go team.
OK, how about a little background info on what happened to cause the excessive staining and pitting on the plywood?
Along with being LOUD (noise dampening post here) another thing lasers sometimes do while cutting is called "flashback." This is where the laser beam goes through the material you're cutting, meets a metal part of the laser bed and reflects back into the underside of your workpiece. This can be mitigated by masking the workpiece with tape and by not using more laser power than needed to complete the cut.
I was planning to stain the piece I was working on, so I didn't mask it because I knew I'd be doing at least a little sanding and cleanup. This should have just caused a little smoke on the edges of the piece and really been no big deal to clean off with a little denatured alcohol.
What I didn't know is that this piece of wood had a knot or some other imperfection in one of the plys... So I had to use full power and multiple passes to get it to fully cut the one spot with the knot. Which caused the excessive flashback on the parts of the piece that weren't near the knot.
Imperfections in the wood happen, it's a natural product. I still like the woodpeckers birch plywood for laser cutting, overall it's been very consistent for me. But... I'll probably mask at least the bottom of the part next time I cut something that's going to be a bit delicate. For masking, there are dedicated products that work well, but I tend to use 3M blue painters tape because I already have a bunch of it for my 3D printers.
Alright, this is the internets, get on with the pictures already!
Gently sanding... You can see the flashback still on part of the "F"