cutting expresspcb boards?

[robkeeler]

What do you guys use to cut expresspcb boards if you have multiple circuits on them?

[trjones1]

I use tin snips or a hacksaw.  Tin snips are faster, but I like the results with a hacksaw better.  I hear Dremel cutting tools are good for that too. 

Just remember to wear a mask and gloves.  That pcb dust is nasty.

[Paul Perry (Frostwave)]

I score the line I want to cut with a hand-held tile cutter , then snap. Worked for me.. about 100 times, after my PCB maker forgot to do it

http://diy.abcaz.co.uk/5_430321/tile-and-glass-cutters/screwfix-tungsten-carbide-tipped-tile-cutter.html
That's a "tile cutter", just a chunk of carbide tipped steel that you scratch the surface with. I got a $5 wooden handled one from the local asian hardware. Advantage: less dust, and harder to cut yourself.

[Peter Snowberg]

Table saw with a fine cabinetry blade, followed by a belt sander with fine grit belts.

The edges look almost like factory routed.

I've also used hack saws and tin snips. They all work just fine, but tin snips will leave stress marks by the edges.

I leave 0.2 between sub-boards for these cuts and put a 0.007 copper line down the edge of each sub-board. With a fine belt in the sander it's actually quite easy to sand down until that 0.007 line is partially sanded off.

[Brian Marshall]

I highly recomend not using anything that is a saw.  the saw will spew fiberers in to the air that are almost the same as asbestos.

I used to cut boards this way, and wish i hadnt.  i suppose ill find out in 20 years how much dammage i did this way.

Tinsnips will still release some fibers, but typically much larger (whish is good) and not forced in to the air like with the saw.

I also highly suggest not drinking drano.

Brian

[bwanasonic]

If I had a proper workshop with good ventilation, I would might saw and sand. But I don't, so I just use tin snips. OK for the relatively small circuits I have done. Bigger boards might get ugly. But I work around kids and pets, so the toxic dust is not an option.

Kerry M

[Penguin]

dremel cutting wheel, slightly damp. keeps from spewing the dust in the air.  also yes for god's sake use some heavy ventilation i found out the hard way it stinks and if it stinks this bad it can't be good foryou. lucky we have heavy duty exhaustfans at my place for now.

[Connoisseur of Distortion]

is it seriously as harmful as asbestos? if so, exactly what kind of board? are epoxy based boards ok?

[petemoore]

  Why not just clamp a straight edge on it, and run the razor knife across it a number of times to score it, then snap it? Lay out newspaper, maybe have a wet paper towel.

[Peter Snowberg]

The big health danger is from the fumes created by burned epoxy. That stuff is SUPER bad.

The big danger from asbestos is that the crystal fibers can be in the form of needles a few molecules wide. These can rip into a cell and damage the DNA without triggering apoptosis which is the process that cell use to end their lives if damaged. If the damaged DNA replicates, you have potential for cancer.

Glass fibers are not quite as sharp, but they're bad to inhale none the less.

Never create board dust without a vacuum system to keep it pulled into a bag, or better yet do it all outdoors, and ALWAYS wear a respirator when working with stuff that causes damage. That is why they make them.

[FunkyGibbon]

This from

http://www.safetyline.wa.gov.au/pagebin/pg000096.htm#book6

in Australia:

"DOES FIBREGLASS CAUSE CANCER?

The International Agency for Research on Cancer (IARC) changed its classification in November 2001:

Fibreglass is now not classifiable as carcinogenic to humans and is no longer considered “possibly carcinogenic to humans”.

The reasons for the change are:

Studies of occupational exposure during manufacture of fiberglass show no evidence of increased risk of cancer; and
There is an increased use of “biosoluble” fiberglass, which has been tested and found to be non-carcinogenic."

It just seems to make you really (painfully) itchy, so it's still a good idea to cover up with long sleeves, goggles, mask, gloves. Also, do your cutting outside (where possible).

"SAFE WORKING PROCEDURES

Employers must provide safe working procedures to minimise hazards. However, in cramped or enclosed spaces where fibreglass insulation is generally installed, dust may exceed recommended levels and may be difficult to control.

Here a class P1 or P2 dust mask should be worn. Protective overalls should be worn to avoid skin irritation, and these should be washed regularly. Suitable gloves, tucked under overall cuffs, will prevent hand irritation. Goggles should be worn.

Safe working procedures for glass filament are different. Handling continuous fibreglass filament before it is bonded into hardened plastics does not usually generate sufficient dust or airborne fibres to cause even short term irritation.

However, once it is in a solid form, irritating dust may be generated by cutting, grinding or sanding, and ventilation or personal protective equipment may be required."

Cheers!

[bwanasonic]

  Why not just clamp a straight edge on it, and run the razor knife across it a number of times to score it, then snap it? Lay out newspaper, maybe have a wet paper towel.

The expressPCB boards are fibrous (FR-4 laminate), and although the *score and snap* will eventually work, it takes a lot more than a few strokes of the utility knife.

Kerry M

[Mark Hammer]

Yes, it takes a LOT more than just a few strokes of the utility knife.  I know because I spent a half hour cutting one up on Saturday night.  On the other hand, this method does not result in dust being spread all over.  You can easily keep a moist paper towel on hand, and wipe the particles off the surface after each scoring action.

Just make sure you score it well before attempting to snap.  You will want the breaks to uccr precisely, and not wander from the target area.

[spudulike]

Old guillotine I got from a car boot sale cheap. Big curved blade and a built0in workpiece clamp. I get the blade resharpened by my local butcher

[Paul Perry (Frostwave)]

Spudulike, are you actually cutting the green fiberglass PCB with that hand gullotine, or just the brown phenolic stuff?

[spudulike]

Both. I use thin (1.6mm ?) and regular fibreglass, and also some older thicker phenolic stock. No dust, no shards, just a clean cut. I always wear a mask over my nose and mouth though ...

[Mark Hammer]

Bench shears are wonderful things.  Their chief drawback is that they assume your PCB is going to need straight cuts only, and not cuts that go straight to there, hang a left for 3/4" and go straight again.  Sadly, getting the most out of an expressPCB "composite board" will often necessitate  rectangular jigsaw-puzzle arrangements.