Cutting perf board cleanly? How?

Lately I've been building some prototype circuits on perf board (is that the right name?)... those experimenter's boards you can buy in Radio Shack, that have little copper pads around each hole for easy soldering. But as I learned the hard way last night, I have no idea how to cut them into pieces without making a big mess. /ubbthreads/images/graemlins/frown.gif

Last night I thought some quick cuts with my Wiss aviation snips would do the trick, but instead the board cracked and flaked with each cut, destroying lots of board real estate in the process. There's got to be a better way!

But how? /ubbthreads/images/graemlins/confused.gif

Dremel with cut-off wheel, if you have one. I'm thinking that a small saw (e.g. X-Acto) might work as well.

If the cuts aren't too big, a pair of dikes (that's diagonal cutters /ubbthreads/images/graemlins/icon15.gif) will cut through without any splitting/cracking.

For longer cuts, a hacksaw is the way to go. Follow a line of unused holes on the vectorboard like they are perforations to keep the cut straight. The aviation snips will crack the fiberglass since there is no opposing support in its scissor-type cut.

Table saw with plywood blade /ubbthreads/images/graemlins/smile.gif Dremel works well too.

Score each side along a row of holes(through the centre) with a sharp knife, give it a snap. A touch on the belt or disc sander cleans off the remnants of the holes.

Duane

I use this: web page . The blades don't last long cutting glass filled boards, but it's perfect for what I use it for. I used to do a limited run of 30 or 40 small (2" x 4" ) PCB's, makes it easy.
Rob

I use a dremel with a cutoff wheel. Then I sand the sides down.

For those who missed 'the secret', trailhead just put you wise. Put it down on the deck, use a steel rule as a straightedge, use a utility or x-acto knife to score down a line of holes, flip it over, back it with the rule and snap it off. Dress with a MB or 2nd cut flat file (two or three strokes typically) and you're done. You really only need to score one side (the 'outside' one, where the fracture starts), it doesn't take very much if you use the rule properly, if you scratch from both ends into the middle, you can bear down hard enough to scribe in deep enough in one pass without the chance of loosing control going off the end. The knife 'clicks' from hole to hole.

Another way is put it scratched side up, right at a sharp edge on the bench, back it with the rule right up to the line and push the overhanging part down.

Far easier and faster to do than tell.

Doug Owen

Hello again,

I've used the sharp knife several times in the past.

One of those heavy duty sheet rock knives work pretty
good. You'll need a sharp edge and it will get dull
after a few uses, but you can grind it sharp again.
Like the above posts were saying, you lay the
board down flat on the table and using a straightedge
(like a ruler) to guide the knife blade you press down
lightly making a light score, then follow up with
several more passes with the blade pressing harder and
scoring deeper and deeper. Score each edge where the
score line meets the edges so it makes a marking point
on the other side of the board, then you can flip the
board over and using the marks align the straight edge
and repeat the scoring on that side too.
Once done with both sides, the board snaps quite
easily along the line and then you can file the edge
clean.

Also used those cheap razor knives with the snap off
blades too, but you cant get as good a grip as you
can with a regular sheet rock knife.

Take care,
Al

Yup, but again, you don't have to score one side. A crack starts at the score on 'the outside' of the bend and propagates through the sheet to the other side. In fact, I one time notice it missed the score line on the inside. If you're careful you can freehand it as well. We used full sheets at a place I worked, the bench had a rough edge and the sheets were over a foot long (longer than the steel scale can back up). However, if you did a good score right to the edge you could hold the sheet at that end, carefully flex it until the crack started at the edge, then sort of peal one piece away from the other. something like you'd tear stiff paper. If you keep the score on the high side and concentrate the most force where the crack is running, it goes from end to end down the row.

Fun stuff, really.

Be careful of the dust, it is full of fibers.

Doug Owen

Yeah, especially if you are using cut off bits or sanding bits. I always wear a mask.

Uh oh. To fix the mess I made with the aviation snips the other night, I used my trusty Dremel with a cutoff wheel. It sliced through the board nicely but did spew a bunch of dust into the air. And no mask! I tried not to get a great big whiff, of course, but no doubt some got into my nose and lungs anyway. What sort of damage could occur from that?

Search "silicosis" on google... /ubbthreads/images/graemlins/eek.gif

Yet another reason to use a file.....

Doug Owen

[ QUOTE ]
milkyspit said:
... What sort of damage could occur from that?

[/ QUOTE ]

I'm not an expert, but fiberglass (glass fibers) are classed by OSHA as a "nuisance fiber". Supposedly not the right length to embed in lungs and cause problems the way, say, asbestos does.


Edit:
I just checked and apparently there is some controversy in this area. Google gives lots to read about. I think you'd have to do a lot more than cut a few boards though (I hope /ubbthreads/images/graemlins/icon15.gif)

Duane

I think the best idea is to not get involved. If you don't generate a bunch of dust and blow it all over the place with a bunch of power tools when you don't need to, you don't have to deal with that aspect. The very small amount (relatively) made by filing is very easy to control, file it over the wastebasket......

Thousands of guys worked on asbestos brakes without problems, huge exposures potentially, yet only a small fraction (those with poor hygiene habits for the most part) got in trouble. Much like those that work around lead.

The key is to understand and respect the threat I guess?

Doug Owen

If using a cutoff disc, just use a small desk fan off to one side of the work area to blow the dust away. Should reduce the risk to a small fraction of what you might inhale otherwise. Advisable with or without a mask. Probably wouldn't hurt to vacuum the work area frequently as well.

The fan helps too if you're soldering. A slight breeze is enough.

[ QUOTE ]
PhotonBoy said:

The fan helps too if you're soldering. A slight breeze is enough.

[/ QUOTE ]

As does slowly exhaling as you get your face too close to the work. After a while, gently blowing the smoke the other way becomes an unconscious habit. Neat adaptation, not much against use of fire, and getting down out of the trees, but fun how your mind adapts. It's like when you drive to work and can't recall every getting to a specific place in the route you went through 'on auto pilot'.

So give it a try, try blowing softly. After a while, you too can be a blow hard.....

Doug Owen

Quick and dirty, use diagonal cutters. For a smoother cut use a band saw or scroll saw with a medium fine tooth. For some wild fun use a pc quality carbide router bit in your Dremel. You can sometimes find reconditioned ones at places like Harbor Freight. They have 1/8" shanks and come in a variety of sizes, I use around a 1/16" for printed circuit material.

As some have said, use a good quality dust mask when cutting board material. Vacuum only with a very fine particle filter, gortex or hepa if possible. Those paper filters used in some shop vacs just don't catch all of the dust.

trailhead said:

[ QUOTE ]
milkyspit said:
... What sort of damage could occur from that?

[/ QUOTE ]

I'm not an expert, but fiberglass (glass fibers) are classed by OSHA as a "nuisance fiber". Supposedly not the right length to embed in lungs and cause problems the way, say, asbestos does.


Edit:
I just checked and apparently there is some controversy in this area. Google gives lots to read about. I think you'd have to do a lot more than cut a few boards though (I hope /ubbthreads/images/graemlins/icon15.gif)

Duane

Click to expand...

i use the knife to score both sides and a sheet of backed sand paper, closed coat? stuck to a sheet of lucite and 2 passes each side and its perfect, please no machines, life is to short please?