cutting Garolite

[bob p]

Easy-to-Machine Electrical-Insulating Garolite Sheets and Strips
1/32" -0.004" to +0.004" 9322K11 $2.65 9322K21 $3.94
1/16" -0.005" to +0.005" 9322K12 3.25 9322K22 4.06
1/8" -0.007" to +0.007" 9322K13 4.76 9322K23 6.38

https://www.mcmaster.com/#garolite/=1ax0gf1

Thanks for posting that. There is a bewildering number of specifications when it comes to garolite. The G-10/FR4 that I had mentioned previously (MIL-I-24768/27, UL 94V0) is only available in 1/16" thickness as large sheet stock, with the smallest piece being 6" x 6".
https://www.mcmaster.com/#garolite/=1axeafo

It's available in the narrow bar format, but only if you're willing to buy it in 1/8" thickness or thicker.

The product that you referenced is a different type of garolite known as Garolyte XX. The basic difference is that XX is a phenolic resin and paper laminate, while G10 is an epoxy and fiberglass laminate. The difference in composition means that XX is easy to machine, while G10 is not. XX is also less impact resistant, and doesn't have the fireproof rating that G-10/FR4 has. As a result the military specifications are also different (if that matters to anyone but me). The 1/8" G-10/FR4 that I buy from McMaster is very difficult to machine. I have to cut it with carbide tooling. I've smacked it hard against the metal edge on my table saw table and it bounced off. It's hard to imagine scoring and snapping it.

Juan, looking at your photos would I be correct in assuming that you're using a phenolic/paper laminate, something along the lines of Bakelite? I've never tried scoring and snapping my 1/8" G-10/FR4 boards, but I don't think it will snap as easily as the product you're working with. Maybe I'll buy some of the thinner 1/16" G-10/FR4 sheet and give it a try, but if I had to guess I'd expect that the epoxy/fiberglass won't snap like the phenolic/paper.

[J M Fahey]

I mentioned in the post it was Phenolic/Paper copperclad, but it also works fine on standard PCB thickness epoxy/fiberglass.

Never saw or had 1/8" thick (3.2 mm) G10 so canīt elaborate on that.

I think in such case I would still score and snap it if all I had was a Dremel type tool, would probably run cutting disk spindle top along a piece of wood so scoring is even and more passes eat the same spots, but would bnever even try to actually cut with that, I guess Iīd break one disk every inch or worse, and with high danger of being hurt by flying debris.

ONLY attempt I would make to actually *cut* it would be using a table mounted tile/brick/ceramics cutting machine and disk, diamond edged if possible.

In fact I think that is what PCB fabricators do.

Would even use wet cutting techniques, go figure.
I am paranoid about glass/asbestos/marble/ceramics/brick dust ... for good reason.

Any heavy/sharp mineral particle which gets inside your lungs never gets away, just gets encapsulated and slow but steady diminishes pulmonary capacity ... ugh!!!!

[bob p]

Sorry, I missed your comment about composition.

I have a cold-cut saw, which is a low-speed wet metal cutting saw. It produces chips rather than dust, and it uses water to keep the workpiece cool and to prevent suspension of any dust into the air. Works great. Big money.

Prior to getting the cold cut saw I used a table saw with carbide tipped blades. Works great. Not too expensive. But there's the dust and debris problem. In my workshop I have a gigantic cross-ventilation fan that I use as a fume/particulate extractor. My shop is shaped like a long tube with an open window at one and and a huge exhaust fan at the other. I'm able to get a high enough crosswind with my fan system that all of the hazardous particulates get moved outside (which I admit, isn't a perfect solution because eventually I have to mow the lawn). With a carbide tipped table saw I can get nice clean cuts on G-10/FR4, where the kerf products are primarily chunks rather than fine particulates. (example pic attached)

I haven't tried using a tile saw. Good idea. The wet-cut would help to keep fine particulates out of the air. Never having tried it, I wonder if a diamond-type blade would be better for cutting, but worse for particulate generation. I'm thinking that the diamond cutting blades work by generating a lot of powder, and that's a problem. IME with the table saw, a carbide blade does a pretty good job of getting perfectly clean cuts without generating a lot of fine dust -- most of the kerf extraction comes out in chunks -- even moreso if you're capable of cutting at slower speeds, like with metalworking saws.

[Randall]

What kind of carbide blade should be used, as in how many teeth? IOW, is fine tooth better than coarse?

[bob p]

In the example pic that I posted I didn't use a fine-toothed finishing blade like you might want for Formica. The blade that I used probably had a thick kerf with a low tooth count. I don't know the exact tooth count offhand, but I could take a look. IME the tooth count isn't critical for G-10/FR4 because the stuff is so impregnable that it won't chip apart the way wood does if you use a low tooth count blade for fine cut finishing work. I recall specifically using a low tooth count blade with big carbide inserts.

Suffice it to say that if you already have a carbide tipped saw blade then I would just use whatever you have. I wouldn't even consider buying a new blade with a high tooth count if you already have a carbide tipped blade that has a lower tooth count. A high tooth count carbide finishing blade isn't necessary. IMO carbide tips are what's important, tooth count not so much. but then I'm cutting 1/8". On 1/16" maybe the tooth count could matter.

[nosaj]

In the example pic that I posted I didn't use a fine-toothed finishing blade like you might want for Formica. The blade that I used probably had a thick kerf with a low tooth count. I don't know the exact tooth count offhand, but I could take a look. IME the tooth count isn't critical for G-10/FR4 because the stuff is so impregnable that it won't chip apart the way wood does if you use a low tooth count blade for fine cut finishing work. I recall specifically using a low tooth count blade with big carbide inserts.

Suffice it to say that if you already have a carbide tipped saw blade then I would just use whatever you have. I wouldn't even consider buying a new blade with a high tooth count if you already have a carbide tipped blade that has a lower tooth count. A high tooth count carbide finishing blade isn't necessary. IMO carbide tips are what's important, tooth count not so much. but then I'm cutting 1/8". On 1/16" maybe the tooth count could matter.

I've turned the blade backwards before to reduce chipping on formica.

nosaj

[Randall]

I'm not sure that helps at all.

[Chuck H]

Well I started with a slightly irregular 2x4 sheet I bought as scrap from an industrial shop in Santa Clara, Ca. I cut my first piece with a diamond embedded fiber disc blade on my Skill saw. I wasn't much worried about waste. I fined up the edges with a sanding block, drilled holes, tapped in eyelets and built an amp on it. Sure there was some waste. Not a lot. I like Juan's score and snap idea. Though with a large piece it forces you into a two or four foot length at a given, snapped off width. Probably useful(?), but not necessarily if, for example, the next board you want to make was two and a quarter inches rather than the two inches of your snapped piece. Still, a good technique if you make many boards of the same width. Otherwise you can just use a fiber disc on your Dremel and fine up the edges with a sanding block. It amounts to lumber really. Building material. Maybe there's a little waste.?. Do you save the two inch end cuts from course lumber projects, or do you toss them? The 4x4 sheet I'm working on now has lasted forever. It has a very irregular profile and I'm pretty sure some waste material will result from that. Six in one hand and a half dozen in the other. Cut the stuff with the tools suggested, whatever you have on hand, and get to work! This minutia is the worst part of amp building. It's the design aspect that is the fun part. If you bury yourself in the crummy stuff you won't have any fun

[bob p]

I've used the big sheets but I really don't like ripping them. too difficult to store, to handle, too much waste, too much cutting. so far my preference has been to buy the 1/8" thick bars that come in 2", 2.5" or 3" widths in 4-ft sections. I just make a single cut to cut off what i need from the bar. by buying the short-width bars i get to avoid all of the tedious long length ripping and the particulates that go with ripping, and I limit myself to quick short cuts, just cutting off what I need.

for F and M type circuits the 3" width works great for PSU boards and the thinner pieces work well for preamps. if you want ultra compactness for a Vox circuit the pre-built generic turret boards from CED are great. they allow you to fit lots of parts in a tight space.

as i mentioned earlier with G-10 chipping isn't a problem. i think that if you reversed a carbide tipped blade on G-10 two things would happen: 1) it couldn't cut the G-10 and the G-10 would knock the blade's teeth out. It's that hard.

happy new year.

[Dave H]

I used to chop it up with the large guillotine we had where I worked. It produced a nice straight cut and no dust.

[Chuck H]

I used to chop it up with the large guillotine we had where I worked. It produced a nice straight cut and no dust.

That must have been a hell of a thing! Sort of creeps me out just considering what sort of guillotine it would take to make clean cut/snaps through G-10 of even 1/16" at circuit board lengths or greater.

[Dave H]

That must have been a hell of a thing!

It was an industrial guillotine for sheet metal like the one below. It could easily chomp through 1/4" mild steel (and fingers)

[g1]

It was an industrial guillotine for sheet metal like the one below. It could easily chomp through 1/4" mild steel (and fingers)

I think that's what I would do, just take it to the local welder/metal shop. Actually we have a welding school where they only charge for materials, all the labour is done n/c for students experience.

[Chuck H]

Scouting local resources for anything is fun and rewarding on many levels. Maybe because resourceful and generous people also make good friends