Cutting phenolic PCB. Suggestions for square cuts?

[large_ghostman]

Thinking about this I remember doing a post a while back on alternatives to ferric chloride. One of them was to use copper chloride, this is often use in something called the fish and chip gold recovery system. A little known fact is that Copper Chloride will dissolve copper, actually its the Chloride Ion doing the work but my point is they use COPPER CHLORIDE.

If you add Hydrochloric Acid and Hydrogen Peroxide togther and stick a pcb board in why does it etch? Simples you have made copper chloride!! So dont throw the stuff away, use it again and again until eventually it will no longer be acidic or have much chloride Ion left. There is also a neat trick to this..................Once fully used up chuck a bit of rebar or other iron part like a large nail in, the copper comes out of solution and collects around the iron. I might look for the post later as it has a video with it.

One last word on using Hydrogen Peroxide and Hydrochloric acid mixed together.............Everybody is going to tell you they done it for years and years and never had a problem. Concentrated Hydrochloric Acid mixed with Hydrogen peroxide is not something you should mess with without a proper fume cupboard. Chlorine is a Halogen, ok its one of the nicer ones (its relative) but its a nasty nasty chemical. Take a big whiff of chlorine fumes and the water vapor in your lungs instantly turns it into hydrochloric acid, takes surprisingly little Chlorine to do enough lung damage to cause Pulmonary Odema and irreversible lung damage.

This is a forum so few will agree, but use ferric chloride or something else, using Hydrochloric acid and hydrogen peroxide mixed for etching pcb's is like using semtex to dig a whole to plant a lettuce

 

[shortbus=]

What would the result be if ferric chloride (powder) was mixed with hydrogen peroxide instead of water? Would it etch faster or not? Not a chemist or chemical enthusiast, just a thought I've had for a while.

 

[large_ghostman]

What would the result be if ferric chloride (powder) was mixed with hydrogen peroxide instead of water? Would it etch faster or not? Not a chemist or chemical enthusiast, just a thought I've had for a while.

You would destroy the ferric chloride depending how much you had added, hydrogen peroxide is an oxidiser so basically you would oxidize the ferric chloride into iron and chlorine (roughly), dont do it, to speed up ferric chloride warm it a little, people chuck it when it goes blue but at the stage where it wont etch anymore people say how do I get rid?? You dont! When it will no longer etch at warm temps you basically have copper chloride! add a small amount of 3% strengh of hydrogen peroxide and warm to 30C it will etch, takes a bit longer but the traces should be sharper and cleaner edged

 

[shortbus=]

Thanks LG, Don't know enough about this kind of thing. Was just a thought and didn't want to start a separate thread to ask.

 

[large_ghostman]

Thats ok, people think of swimming pools when you say chlorine, because of this kind of connection the tendency is to greatly under estimate just how dangerous the Halogens are. Chlorine is the best of a very bad bunch. The worst is fluorine, yes the stuff in toothpaste comes from it, and yet so does Hydrofluric acid, 2% strengh of which will eat through pyrex glass in minuets. 4 cm area of skin covered with 20% strengh hydrofluric acid is likely to kill you without very fast treatment, you wont get a massive burn or much pain for a while, just a little white patch on your skin. But it gets into your system and dissolves all the calcium in your body!

Normally treated with Calcium Gluconate, anyone working with Hydrofluric acid over 10% must have a tube of the Gluconate near to them at all times. Really nasty stuff, then you get fluorine itself, not many people have really seen it or worked with it, its so difficult to contain and exposure never ends well, look at some chem vids on fluorine. lastly Bromine a very very poisonous red liquid often in gas form at room temp, next to impossible to contain in anything but a sealed glass vial, will rust everything in 5 mins within a 20 radius if you undo a bottle of it.

Chlorine the harmless sounding often mishandled little green genie with a killer bite. thats how my Chem teacher describes it lol. Very interesting to work with the Halogens though, but you need good equipment

 

[KeepItSimpleStupid]

The thing with cutting fiberglass is that the stuff is very abrasive. The dust kills brushes in motors.

A Carbide tipped blade should work although most might use a 4" diamond blade on a small saw.

Bromine: the Genie in a bottle. Kinda eerie. The stuff "just escapes" Where I worked, we kept it in a jar with a ground glass stopper in the hood.

 

[large_ghostman]

The Halogens once you know them are scary and yet fascinating at the same time, in chemistry terms they are a wonder and really exquisite. To most most people they are just chemical names, like I said people think Chlorine is put in water. Chlorine as such isnt put in water, but chemicals like bleach contain the chlorine Ion. Bleach is pretty harmless so the assumption is 'whats all the fuss about chlorine', mix strong bleach with any acid even strong wee if you put enough bleach down the toilet and you get a little chlorine, normal room temp its a green gas. In its pure form like this its has some amazing properties and some really interesting chemistry can be done, but its not to be toyed with.

It was used as a war gas to great effect for a reason, and Chlorine is the least harmful of the halogens, which is a bit like saying the little boy nuclear bomb is the most harmless of the bombs in the Nuclear arsenal .

One day I want to see and use Fluorine just once, but I doubt it will ever happen, sure you can make it easy enough but controlling and containing it is the problem, wear as much safety gear as you like but very little withstands an attack from it.

Most people who have to keep Bromine in a bottle keep it in a fume cupboard, modern practice is small glass ampules completely sealed with say 1-10ml of Bromine in. its just alot less hassle that way

 

[shortbus=]

I don't know how true it is, like I said not up in chemistry but was told you could make a pretty dangerous fire bomb by mixing pool chlorine powder and brake fluid. Supposedly makes chlorine gas and a fire when mixed.

 

[large_ghostman]

I don't know how true it is, like I said not up in chemistry but was told you could make a pretty dangerous fire bomb by mixing pool chlorine powder and brake fluid. Supposedly makes chlorine gas and a fire when mixed.

Depends on the powder to some extent but there is one in particular thats pretty nasty, Strong industrial bleach is around 12% chlorine the tablets from memory are around 40% chlorine. I would need to check to be sure, but mixing them with brake fluid is a pretty bad idea, pool shock i think one brand is called. Not many pools in Scotland so dont quote me lol.

The chlorine tablets should always be treated with respect, never mix with acids etc or brake fluid. You could in theory make make table salt from Sodium metal and chlorine gas, I have no idea if anyone has had a pair big enough to try it

 

[large_ghostman]

wow looks like there are some mad enough, the water is needed because the sodium oxidizes quickly, looking at the chlorine colour there isnt much chlorine gas in the vessel, Still he is braver than me

 

[BobW]

Pool chlorine in dry crystalline form is sodium chlorate. It is an extremely powerful oxidizing agent. If it comes in contact with anything flammable and just a tiny bit of moisture, then watch out! The same chemical plant that I mentioned in my earlier post, also manufactures this product as well. Lots of fun times there.

 

[ronsimpson]

Look how it is solved

Very interesting.
And all there years I have been using a round drill bit and then a triangle file to get the corners.

 

[atferrari]

Very interesting.
And all there years I have been using a round drill bit and then a triangle file to get the corners.

After reading your comment, I realized that I answered the OP thinking he asked for square holes. My bad, he asked for square cutting of PCBs.

 

[fezder]

The thing with cutting fiberglass is that the stuff is very abrasive. The dust kills brushes in motors.

Buddy told this too, he used to sand fiberclass stuff with angle grinder...

After reading your comment, I realized that I answered the OP thinking he asked for square holes. My bad, he asked for square cutting of PCBs.

Yes, cutting smooth factory-looking square-shaped cuts is what I'm after, not square holes (I don't start cutting in middle of board hehe).

 

[fezder]

As for potent acids, I would have probadly sued them too, but pretty much all proper acids, HCL, sulfuric as well as nitric acid and hydrigen peroxide when 30% need all either tons of searching where to buy, or be prohibited alltogether, as some stupid kids made bombs. Yesterday I looked on local store if any cleaning stuff contains HCL, nope. Of course, there is pharmacy, but boy those prices and all that questions.....

 

[KeepItSimpleStupid]

Besides "household" chemicals and some "electronic chemicals", I have Methanol at home. It's great for ink stains in the laundry and removal of permanent marker stains and won't harm plastics.

I bought "stuff" that contained 3% hydrochloric and 3% hydrofluoric acid because of some etched windows that was attacked by this stuff: https://www.supercleancanada.ca/MSDS/EN_SuperClean_Degreaser_MSDS_03-10-11.pdf

It saved replacing the windows. The 3%/3% thing was designed just for that. For now, I use it to clean the bottom of a glass ice tea container.
I have a gallon to use up.

Commercial Pesticides/Herbicides are other nasties. Need a little and have to buy a lot. So, use like 4 oz per year of one herbicide and have to buy a gallon.

 

[JonSea]

Shears for cutting floor tile like the one pictured work great and cost about $50. It's fast and easy to get square cuts, without the dust resulting from sawing.

Someone mentioned that the dust is hard on bearings. It will also damage your lungs! When sawing circuit boards, wear a dust mask.

 

[fezder]

It will also damage your lungs! When sawing circuit boards, wear a dust mask.

No worries, I have lack of alpha-antirypsine (protects lungs & liver againts infections, so I get infections easily and I've gotten habit of using respirator very often. I don't want any fungus or cancer on my lungs, most likely it would be deadly for me. And these cause also that mine (can't recall what those are called, what cause trouble for some folks and after operation It's popsicle/ice cream) really is not wise to remove. Luckily I didn't get any infection of removal of wisdom teeth (none left)

 

[spec]

How do you guys cut phenolic pcb's? this pcb is what I use: https://www.taydaelectronics.com/hardware/prototyping-boards/copper-clad-board-pcb-single-side-6x6.html

Hy fezder,

I know you didn't ask this question, but fibre glass FR4 is generally considered as the best material for PCBs. Not only is it electrically superior, but mechanically too. You would probably find it better to machine, but the dust is a hazard. The other advantage is that it can be repaired well with resin. You can also make boxes etc with it.

From Wikipedia:

• FR-2 (Flame Resistant 2), phenolic paper or phenolic cotton paper, paper impregnated with a phenol formaldehyde resin. Cheap, common in low-end consumer electronics with single-sided boards. Electrical properties inferior to FR-4. Poor arc resistance. Generally rated to 105 °C. Resin composition varies by supplier.
• FR-4 (Flame Resistant 4), a woven fiberglass cloth impregnated with an epoxy resin. Low water absorption (up to about 0.15%), good insulation properties, good arc resistance. Well-proven, properties well understood by manufacturers. Very common, workhorse of the industry. Several grades with somewhat different properties are available. Typically rated to 130 °C. Thin FR-4, about 0.1 mm, can be used for bendable circuitboards. Many different grades exist, with varying parameters; versions are with higher Tg, higher tracking resistance, etc.

spec​

 

[fezder]

Thanks spec, no worries, I was in fact wondering differences between phenolic & epoxy (fr-4) PCB's. I might buy few 6"-square sheets next time I buy from tayda. OR, now that I checked my favourite local dealer, 20cm * 30cm, is about 5.5€, and same price about for same size DUAL SIDED too. I'm moving more into SMD now, making holes is so time consuming and boring for DIP-components (altought they can be SMD mount too, but still take quite much space compared to true SMD).

I make PCB's with vinegar, I don't have cnc, yet....