Cutting 1/8" Plywood Fins

[opcon]

I don't have many tools anymore for cutting wood. I picked up a carbide wood cutting disc and the required mandrel for my cordless Dremel. Has anyone gone this route before? I figured I would clamp the 1/8" to a large piece of 3/4" 7 ply as a work surface and use the 3M-Scotch Spray Mount Repositionable Adhesive to hold a pattern to the 1/8" plywood. (That stuff is pretty expensive for what it does)

I ran a test cut on a scrap piece of wood and the carbide disc cuts through wood like a hot knife through room temperature butter but it's a little wonky to cut nice straight lines. Should I setup a small jig fence or just go large and sand them together to get symmetric fins with straight lines?

Anyone have any suggestions?

 

[mbeels]

For straight lines, I'd consider using hand tools like a razor saw, or fine toothed Japanese style pull saw. It might be a bit slower than your Dremel, but they'll get through 1/8" plywood fast enough, and with much more control.

 

[mikec]

I just use a small cheap coping saw and clamp the plywood to my work surface. Trace the pattern with a pencil and clean up by sanding as a stack.

 

[scsager]

I struggled to find a good solution for cutting 1/8" plywood. (I kid you not) - That expensive Dremel attachment I bought just sits in the case gathering dust.

For the 1/8" lite "poplar" 3-ply plywood (the no-name plywood from Balsa Machining) - a sharp utility knife and a straight edge works great for me.

For the heavy 1/8" Baltic Birch 5-ply plywood or anything thicker than 1/8" - I use a small power trim saw and one of those $20 Folding Clamping Workstands from Harbor Freight.

 

[jqavins]

LASERS! (Pew-pew.) Some cutting services aren't prohibitively expensive and maybe you have a nearby maker space with one.

 

[Lynn McCall]

If you want to use the Dremel, I would mount it to a jig like a drill press. Then use both hands on the wood.

You could even do multiple fins at once, clamping them together.
You will probably still need an electric sander to make the fins even.

That is how I would do it.

 

[Lynn McCall]

I think it would be easier to stabilize the tool and have both hands on the wood.

 

[Lynn McCall]

Thinking about it, that is what I will be doing only with a table to jig saw later this week.

 

[prfesser]

I've cut 1/8" plywood old-school style, with an X-acto knife and multiple passes. Yes, it's a royal PITA, yes, it takes a long time. But you do get very clean edges. A good ruler guides the first few passes, after which the groove is usually good enough to guide the cut. For later cuts hold the knife at a higher angle, it seems to cut through the cross grain better.

That's a last resort, or if you're lacking other tools (which was the case with me at the time); usually I cut them rough with a 5" fine-tooth circular saw and sand on a disk sander to shape.

Best -- Terry

 

[GaryT]

If the shape dosent have many curves use a Jig Saw with a Hack Saw blade in it, still cuts nice without chopping up the wood or splintering. clamp a straight edge on the wood for the saw to follow and put a piece of heavy duty 2" tape on both sides of the wood. I've done it many times. I made a scratch upscale of the old BSD Diablo in 7.5" 1/4" Baltic Birch cut this way, came out beautiful.