Cutting Stainless Firewall for Recess?

[Ironflight]

We are about to cut a square out of the RV-3 firewall to rivet in the standard Van's recess (for the prop governor), and I was wondering how folks like to cut the thin, soft stainless. I have used punches for round holes, but this is going to require some long straight (8 - 10 inches) cuts, and I know that if we heat it up, it'll be next to impossible. Already installed on the fuselage, of course, but very accessible.

Tools? Techniques?

Paul

[Vlad]

Paul the Dremel thing might work good. Fits perfect and cuts clean. To prevent overheating and burning just go slower or heat sink with a bucking bar.

[Phil]

Paul,

According the wiki page, a Fien Multimaster will cut it. (and straight too)

http://en.wikipedia.org/wiki/Fein_Multimaster_RS

The good thing about it is that it doesn't spin and generate heat from friction; it vibrates and the removed material falls straight down.

There is some heat obviously (from tearing molecules apart) but its nothing like a spinning disk.

The next problem is cost; they're expensive. But I happen to have one and you're welcome to it if you'd like.

If you're out looking for a joy ride this afternoon, come on up to Williams and I'll meet you out there with a cold drink and the saw...

Phil

[L.Adamson]

I think I'd start trying right and left tin snips. The red and green type. Start with starter holes, and don't cut near to the final cut, until you've made a rough cut close to that point. That way, it doesn't go for the big metal streach. Finish the edge with a 2" angle die grinder. You won't have much of a mess to clean, as from a grinding type operation.

I use these snips all the time by trade, but I admit to not cutting stainless steel too often.

L.Adamson --- RV6A

[rv7charlie]

Harbor Freight has a very inexpensive imitation Multimaster now.

FWIW, I've cut much thicker stainless sheet (unknown alloy) using a 4" cutoff wheel with minimal problems by cutting a bit, waiting a bit, cutting, etc.

Charlie

[gasman]

Originally Posted by Ironflight

We are about to cut a square out of the RV-3 firewall to rivet in the standard Van's recess (for the prop governor), and I was wondering how folks like to cut the thin, soft stainless. I have used punches for round holes, but this is going to require some long straight (8 - 10 inches) cuts, and I know that if we heat it up, it'll be next to impossible. Already installed on the fuselage, of course, but very accessible.

Tools? Techniques?

Paul

Paul, The cut off wheel that Van's sends out to cut the canopy will work just fine for cutting the stainless. Drill the corners so you will have a clean start and finish. Use a guide, and the speed of your drill motor is plenty for this thin material. Cut it just like you did with the plexi.

Don't worry about heating it up........ (you won't with your drill motor).. the cut off wheel could care less in something this thin.


Warren

[G-force]

I work in the marine industry, as such, I fab and weld tons (literally) of stainless every year. I would drill each corner so you have a start/stop point and round corner, then cut it with a straight die grinder with a 3" cutoff wheel. I would use as thin as one as I could get, I buy ones .035" for work. Keep the RPM and travel speed up and you should be able to cut a pretty clean edge that would just need some touch of with a 2" or 3" sanding disc on a right angle die grinder.

[Ironflight]

Thanks everyone - and thanks Phil for the offer of the tool!

I was actually hoping that "cutoff wheel" would be a popular answer, as that is my favorite tool for cutting squares and straight edges (after drilling the corners), so that's what I'll use. Just didn't' want to start with it on stainless and discover that all I was doing was making the stainless mad....

Paul

[RV6AussieNick]

Hi Paul,

You could also try a plasma cutter, fast, clean easy to use, may need a little filling after.. I'm sure there is a sheet metal shop near you that would be able to help you out, a plasma cutter is almost standard equipment for a sheet metal shop.

Nick..

[Mel]

The cutoff wheel in a die grinder is what I use. Works great.