# Cutting Fiberglass

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#### ActingLikeAKid

##### Well-Known Member
Need to trim a little off a tube. Masking tape and a hacksaw and a steady hand?

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#### Steve Shannon

##### Well-Known Member
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A wet saw works best and captures the dust. A Dremel works well also. Toothed saw blades can result in splintering along the cut edge and a rough edge with glass fibers.

[emoji1010] Steve Shannon [emoji1010]

#### bobkrech

Remember you are cutting glass. As Steve mentioned regular saw blades don't work well and dull quickly. A wet tile cutting saw with a diamond blade is the best way to go. A 4" to 4.5" tile cutting wet saw can be purchased as low as $50 and blades will run from$15-$20. Very good cuts and no dust. The dust from cutting fiberglass is not good for you. Make sure you wear a good dust mask and safety glasses. #### ActingLikeAKid ##### Well-Known Member Remember you are cutting glass. As Steve mentioned regular saw blades don't work well and dull quickly. A wet tile cutting saw with a diamond blade is the best way to go. A 4" to 4.5" tile cutting wet saw can be purchased as low as$50 and blades will run from $15-$20. Very good cuts and no dust.

The dust from cutting fiberglass is not good for you. Make sure you wear a good dust mask and safety glasses.
So I have a bit of leftover fg tubing that I've been using for testing stuff (mostly "OK, let me triple check that this is the right drill bit"). Tried it with a Dremel cutting wheel and masking tape outside & inside the tube. Worked pretty well; the resulting tube-end was rough, but the lumps sanded off.

Now I just need to take a deep breath before I cut the actual rocket.

#### Steve Shannon

TRF Supporter
Remember you are cutting glass. As Steve mentioned regular saw blades don't work well and dull quickly. A wet tile cutting saw with a diamond blade is the best way to go. A 4" to 4.5" tile cutting wet saw can be purchased as low as $50 and blades will run from$15-$20. Very good cuts and no dust. The dust from cutting fiberglass is not good for you. Make sure you wear a good dust mask and safety glasses. And John Coker's website has information on how to use an inexpensive tile saw to make a tube cutter that will give you a square edge each time. [emoji1010] Steve Shannon [emoji1010] #### REK ##### Sponsor TRF Sponsor Try to find a tungsten carbide rod saw at your local hardware store. I use this all the time to cut my carbon fiber laminates. Works just as well on fiberglass Alexander Solis - TRA Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet #### Maxwelljets ##### Well-Known Member This depends on whether you want to keep the little bit at the end (e.g. you need an av-bay collar) or whether you're trimming a tube down to a specific length. If you're just trimming to length, and it's under a half inch you need to take off, I'd honestly recommend using a disc sander. #### manixFan ##### Not a rocket scientist Remember you are cutting glass. As Steve mentioned regular saw blades don't work well and dull quickly. A wet tile cutting saw with a diamond blade is the best way to go.... I've used the same X-Acto fine razor saw blade for over 10 years with no issues. It's just a basic X-Acto saw kit which I guess is not the same as a regular saw blade. I use a properly sized hose clamp to guide the blade and just rotate it when I get to the clamp area. I've cut dozens of fiberglass tubes this way - both glassed phenolic and spiral wound fiberglass. I use the fine blade and it creates nice clean cuts with no splinters or frayed ends. The amount of dust produced is negligible and you can dribble a little water as you cut to keep it down but using a shop vac rigged to collect the dust is better. I've cut from 38mm to 6" FW fiberglass and phenolic fiberglassed body tubes using this method. I'm sure the wet saw works well but the last thing I need is another piece of gear to try and find room for. Plus the setup and cleanup with this method is very simple. Just another way to do it. Tony The sequence below shows cutting a thick SW tube - start to finish just over 5 minutes. Last edited: #### TopRamen ##### SA-5 Unlike garbage like balsa, which I still love, Glass can be made to order. Any of the pre-fabricated glassed parts I've ever used on actual rockets had to be touched with some fitting technique. I never bitch about it because I am already working outside my comfort zone, and require no further I'de much rather prefer to recoup my costs of practicing for so long at the least. A soft piece of balsa can be wrapped with some aluminum HVAC Tape, but unless you cover that carefully, it will make a very poor mold. Everything is possible if you are patient and wait for your mind to catch up. As long as I can observe an axial dimension on a model, I cant create a drawing template. I sometimes wish that others here were using similar techniques for making parts. Last edited: #### EeebeeE ##### Well-Known Member I use my handy dandy miter saw. It is a hand saw so the cut is slower and a lot less FG dust goes into the air. But it is a cross-cut blade for wood and it goes right through FG. Since it is a miter saw, I get a good clean 90-degree cut and a smooth straight line that sands out well. It's a lot more old school to hand saw stuff these days...but it works. I still use a dust mask when I saw FG, though. Don't want to breathe that nasty stuff. #### Pat_B ##### Well-Known Member For dust remediation, I often spread toothpaste on the fiberglass part. It works keeps the dust from even becoming airborne. #### RKeller ##### Well-Known Member I use a fine blade hack saw (32TPI) working my way around the tube and then block sand it smooth. dust mask... shop vac... #### REK ##### Sponsor TRF Sponsor I use my handy dandy miter saw. It is a hand saw so the cut is slower and a lot less FG dust goes into the air. But it is a cross-cut blade for wood and it goes right through FG. Since it is a miter saw, I get a good clean 90-degree cut and a smooth straight line that sands out well. It's a lot more old school to hand saw stuff these days...but it works. I still use a dust mask when I saw FG, though. Don't want to breathe that nasty stuff. View attachment 293536 If only this would accept a tungsten carbide rod saw it would make cutting so much easier. Alexander Solis - TRA Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet #### TopRamen ##### SA-5 For dust remediation, I often spread toothpaste on the fiberglass part. It works keeps the dust from even becoming airborne. That's a great tip!!! Thanks! I often use tapes, but have to construct "Cages" around the part to be machined to catch the stuff that gets loose. I've got Toothpaste and similar items nearly by the gallon. I can see/imagine why the properties of toothpaste make it ideal.:clap: #### ActingLikeAKid ##### Well-Known Member Update: I used the cutting wheel on the Dremel to do it. Rather, I used about three and a half cutting wheels. As expected, the wheels eroded fast. Which was fine. The result was .... okay. A bandsaw or tile saw would have been WAY neater and faster, but you know what they say about doing what you can with what you have. When I got finished with the Dremel, the end of the tube was rough. I'd estimate a variance of 1-2mm. So I just put 80grit on my block, held it flat, and scrubbed it down. When I was getting closer, I took a colored pencil and colored the top. The low points stayed colored until the high points came down to meet them (if that makes sense). When that was done, the NC fit the top of the BT pretty well. But the rim of the tube was rough and nasty. 5 minutes with some 150 grit and it was a lot better. 5 minutes with some 3m "Sandblaster" flexible sanding sheet (350grit) and it was silky and smooth. #### TopRamen ##### SA-5 Update: I used the cutting wheel on the Dremel to do it. Rather, I used about three and a half cutting wheels. As expected, the wheels eroded fast. Which was fine. The result was .... okay. A bandsaw or tile saw would have been WAY neater and faster, but you know what they say about doing what you can with what you have. When I got finished with the Dremel, the end of the tube was rough. I'd estimate a variance of 1-2mm. So I just put 80grit on my block, held it flat, and scrubbed it down. When I was getting closer, I took a colored pencil and colored the top. The low points stayed colored until the high points came down to meet them (if that makes sense). When that was done, the NC fit the top of the BT pretty well. But the rim of the tube was rough and nasty. 5 minutes with some 150 grit and it was a lot better. 5 minutes with some 3m "Sandblaster" flexible sanding sheet (350grit) and it was silky and smooth. Carbon Fiber eats #11 Z-Series X-acto blades for breakfast, and I don't want to know what it has for lunch. I've begun taping all cut lines pre-anything else with painters tapes of various aspects, and cutting cloths with cheap scissors. Certain Epoxies have different effects on certain tapes and pre-adhesives, and I'm still experimenting, so don't go asking for any advice, as my advice based on my environmental conditions such as humidity and temperature, may yield disastrous results in a desert climate. When I have conducted comprehensive research, I will share results, but it is so time consuming that for right now, I can't get involved. #### Pat_B ##### Well-Known Member Peanut butter works for catching dust too. #### manixFan ##### Not a rocket scientist Update: I used the cutting wheel on the Dremel to do it. Rather, I used about three and a half cutting wheels. As expected, the wheels eroded fast... Were you using fiberglassed reinforced wheels? They should last a lot longer than that. I can use one to cut through a lot of 1/4" steel rod before they need replacing. The issue with using a Dremel is it's hard to get a parallel cut since you typically need to hold the Dremel at an angle to be able to cut the tube. Using a saw allows a much cleaner cut. I really like the miter saw that Evan shows in post 11. I may have to break down and get one of those - it seems like with a fine toothed saw it would work very well. The only downside is the one that can take 6" tubes is$200!

And really, simply using a vacuum cleaner hose near the cutting area is much better than smearing gunk all over the body tube. I hope you guys are just kidding about that!

Tony

#### Pat_B

##### Well-Known Member
The issue with vacuum cleaners is that some of the cheaper ones aren't sealed too well and can allow microscopic amounts of fiberglass to escape into the air. I actually use a HEPA filtration unit that I bought on Craigslist. I got lucky- it cost me $80 and retails for just about$4,000. But I was shocked to learn how expensive the filters and activated carbon module was.

#### EeebeeE

##### Well-Known Member
Update: I used the cutting wheel on the Dremel to do it. Rather, I used about three and a half cutting wheels. As expected, the wheels eroded fast. Which was fine. The result was .... okay. A bandsaw or tile saw would have been WAY neater and faster, but you know what they say about doing what you can with what you have.

When I got finished with the Dremel, the end of the tube was rough. I'd estimate a variance of 1-2mm. So I just put 80grit on my block, held it flat, and scrubbed it down. When I was getting closer, I took a colored pencil and colored the top. The low points stayed colored until the high points came down to meet them (if that makes sense).

When that was done, the NC fit the top of the BT pretty well. But the rim of the tube was rough and nasty. 5 minutes with some 150 grit and it was a lot better. 5 minutes with some 3m "Sandblaster" flexible sanding sheet (350grit) and it was silky and smooth.
Another way to sand to smoothness is to insert a coupler tube into the airframe. Periodically slide the coupler up to your edge and you will see what areas need sanded down and what areas don't.

#### flynfrog

##### Well-Known Member
I have the cheapest tile saw from lowes that I tend to use. I also use a portaband in a table mount that I use sometimes.