Hi,

I am considering the LS 130 to sand the inside of some drum shells that I am making (i.e., need convex shapes). I am interested to know how much flex/softness/yield/wiggle room there is in the custom DIY blank foam block. I could buy a new block for every single diameter I make (that would add up to about 8 blocks if not more). But for example if I have to sand a shell with a 13" diameter (after all is said and done, the inside would be 6 3/16" radius) and then a 14" diameter (which comes to a 6 11/16" radius), could I simply get a mold to conform to a 13" one, and then just push a bit harder to get it to conform to the 14" diameter one?

If no, I guess that makes the solution simple but cash consuming.

If yes, then how much would you want to drift from the original radius and still feel good? Would the 13" mold work for a 16" shell (radius 7 11/16")? For an 18" shell? For a 48" shell . . . OK , maybe not that one:)

thanks much in advance,
wm_crash, the friendly hooligan

welcome to the fog.

the ls 130 homemade block is very dense. its almost rigdit.
it will sand its own profile and thats it.
thats both good and bad .


i think an ro90 would be better . if you put an interface pad and a soft pad together it should do tighter radiuses than that.

I have made a few custom sandpaper holders with the Festool kit.  Recently I had to make something for a 5+ inch ogee bracket foot.  I'll make a tutorial some day on this, but basically here is what I  did.   I bandsawed an 1 1/2 inch basswood blank to a dimension slightly greater than the profile of the molding as the molding came out of the molding machine.  I attached this basswood shape  to the LS 130  via one of the simple flat connection pads Festool sells with some metric screws and then drilled some dust holes.  Then I put a course stick down sandpaper  on the molding and finished out this reverse profile by sanding the basswood block against the course paper.   Then I placed velcro on the reverse profile and attached the finishing sandpapers to the velcro and finished sanded the moldings.   Although I do not have alot of footage "under my belt", I do think this is going to work very well.  I will probably do this on smaller custom shapes also. The reason here was the width of the molding exceeded the kit Festool sells

My friend suggested that a collection of assorted round shapes, both concave and convex,   could be scavenged  from assorted styrofoam packing materials.  I have not idea if this stuff would hold up or not when subjected to vibration

Do remember that this is a straight line sander so it is not very aggressive.  Have a wide variety of paper grits available so you can more readily achieve what needs to be done

Thanks everyone for the help. Just to give a better perspective as to what I am doing, here are a few shells I was building as well as the rounding of one of them. I did the rounding with a Stanley #40, a Lee Valley Pullshave, and finally with a microplane. After the photo was taken, I made a round mold out of a piece of 2x4 and wrapped some 80grit Dura-Grit tungsten carbide on it. It sorta worked. There was a great deal of sanding because the hand tools aren't really perfect (more like the hands using those hand tools aren't perfect).

I enjoy hand tools, so shaping the larger drums by hand won't be a problem. But sanding by hand is another story, there is just no joy in it.

cheers,
wm_crash, the friendly hooligan

I agree with Alan, the LS130 would be painstakingly slow. You need at least a Rotex sander for this. Considering the fact that you also want to do small drums the Ro90 seems the best choice. On the larger drums a Ro125 would be quite a bit faster but it probably won't fit the smaller drums.

in the FT line, the RO90 is closest...  But for something closer to the right-tool-for-the-job on curved surfaces, you can take a look at the automotive sanding...  Lot's of curved surfaces there...  Of course, if your convex shave is nice and sharp, do you really need machine sanding at all?  I've never coopered a bucket, but have done several 6-piece and 8-piece coopered curved surfaces and the shave took care of 80 percent.

==> Perhaps a gooseneck (or custom) scraper would be useful before sanding.

+1