Easiest way to cut FG fuselages and couplers?

[Ccolvin968]

I'm new to the whole building FG rockets and the sort.
I was curious as to what the easiest way to cut fiberglass tubes was.
I'm trying to retrofit my current rocket with an avionics bay.
Before any cutting starts, I wanted some ideas on how to cut it, and where to cut it at to add the bay into it.
Thanks!

 

[tim cubbedge]

I've cut fiberglass a few times with dremel and/or hacksaw. I wrap the area with masking tape and cut away on the side of tape I marked. A little sanding with a block afterwards. Some people use chop saws.

 

[Ccolvin968]

Good stuff. I'll give it a go!
Thanks for the reply!

 

[OverTheTop]

I personally use a toolpost grinder in a lathe these days :wink:

I would suggest something like a Dremel with a cutoff wheel. Angle grinder with a cutoff wheel would work, but way to easy to take too much off in a short time.

The most important thing is to make sure you get the cut nice and square to the axis of the tube. I do this by wrapping a piece of paper around the tube, nice and tight, and using the continuous strait edge of the paper to guide the cutter.

If you get it close you won't need much sanding with a sanding block to get a nice cut end.

Don't forget PPE with fiberglass. A good vac sucking up the dust while you cut works wonders, and I usually wear disposable gloves to stop the itch... Some sort of facemask is recommended too.

Don't rush and you will be fine!

 

[manixFan]

I've posted this before but I use a hobby razor saw and a hose clamp. The clamp guides the saw allowing for a very even cut (assuming you get the clamp on the tube square) and the razor saw leaves a very clean edge. It seems like it would take forever but it really goes very quickly. I've used it for everything from 39mm to 6" tubing. The only issue is once you have cut most of the way around you need to loosen the clamp and rotate it due to the bulge of the screw housing. But it's easy to keep it lined up since so much of the tube has already been cut.


Tony

Rather than repost the photos, here's a link to the original thread:

https://www.rocketryforum.com/showthread.php?134612-Cutting-Fiberglass&p=1591203#post1591203

 

[Dave A]

You can cut smaller tubes 4" and under with a mitersaw, always use carbide blades. The cheaper ones at Home Depot work fine.
You may have to rotate the tube then finish the cut,
Larger tubes you can use a pipe fitter trick. Get a piece of thick poster paper with one factory edge. When you wrap it around the tube and the edge is aligned, it is a perfectly square cut. You can scribe the line with a pencil or sharpie.
If you do not have a mitersaw, then start a small cut with a cutting disk on a dremel. Finish the cut with a jig saw and metal cutting blade to go around the tube. You may burn a blade or two.
Lay 80 grit 1st (then later 120 grit) sandpaper and push the end of the tube down on the sandpaper. Twist around and around until the end is smooth.

 

[Dave A]

For sanding the ends of most any size FG tube.
I made this from a grinding disk, 80 grit sand paper and a universal arbor next to the grinding disk.
Can make this for less than $12. I sanded tube ends up to 9", perfectly flat.
I had this setup to make switchbands, the lengths never varied mor ethan 0.010".

 

[mpitfield]

You can use a miter saw, or by hand, dremel, etc. there are many ways to do this. Some require more patience and skill than others. For FW/FG and CF and even phenolic tubes I use an abrasive 14" Rigid cut-off saw. I think I can cut up to a 5.5" tube if memory serves.

https://www.ridgid.com/us/en/14-inch-abrasive-cut-off-machine

 

[Ccolvin968]

Alright. Sounds like I have plenty of options... Some cheaper than others!
Thank you all for your input!

 

[OverTheTop]

Love the tube sander Dave A ! Great idea.

 

[DaveAllen]

After trying different methods over the years, we have found that using a miter saw like this gives the straightest, cleanest precise cut. However, using this method you should always wear a dusk mask as it generates much more fine partials than other methods. Also I highly recommend to do this outdoors. This is a cheap Ryobi miter saw found at Home Depot, with this use a cut off blade not a saw blade.
This also works extremely well with carbon fiber and some phenolic tubes. I've even tried this with paper tubes (but you'll have to wrap with tape).
Also use a very slow feed or you'll burn the fiberglass, carbon, phenolic, paper.



[video]https://youtu.be/3E7wCrcYfs4[/video]