Template sanding bumps

bradleyheathhays · Oct 5, 2023

I'm brand new to making templates and I'm finding out making a good one is not as simple as it looks. Luckily I've got the Ridgid oscillating edge belt/spindle sander to make it easier for me. My problem is making smooth inside arcs. After about an hour of practice my outside arcs or curves are nice and smooth, but my inside curves feel lumpy when you run your finger down the edge.

What I figured out that got my outside curves smooth out was that almost all sanding passes must be made as long as possible. I zeroed in on flattening down the proud parts by doing long passes and keeping a steady speed, but then doing a gradual application of pressure at those sections. I applied this technique to my inside curves but because I have to work on the curved part of the sanding belt I'm not able to get the same effect. I'm sure it's because the flat part of the sander is more forgiving than the curved part which has a much smaller sanding 'foot,' or contact patch I'll say. I've tried to lessen this effect by keeping my approach angle as shallow as possible but this still isn't producing the smooth edge I'm after.

So what am I missing? Do I just need to keep refining my sanding technique to be even lighter and sneak up on the template edge even slower doing more long and shallow passes? Or is there some kind of technique out there I haven't run up on yet?

I'm using 3/4 melamine for making this piece. Paper template is on the bottom side for the pic.

jttheclockman · Oct 5, 2023

Can you post a photo of your project? What you run into when doing inside or outside corners like that is end grain VS flat grain. Flat grain sands faster. Light touch is a must and you need to get a feel for entering and exiting the curve. I would draw a witness line on the top of the piece so you can see where you need to sand more or sand less by watching the line.

If that white piece is your example the problem you have is you are worried about hitting the end piece and ruin that part. The best tool for a job like that is a straight spindle drum sander with a 4" drum. Would make the job alot easier. If you are going to use that tool then sand more toward the back side of that large spindle to avoid the flat portion of the sander.