My tape is leaving some sticky residue on my PnP which in not an issue unless I am saving it for later use. I forget it is there and the sheets stick to other sheets. Will try bobledoux suggestion and use laser printing labels the next time. I guess this proves that all tapes are not created equal.
if anyone has any interest i did some molar calculating with this cemical reaction: **broken link removed**
(takes some time to load all the eqasions)
dodn't want to convert all of that to latex either...
i was trying to get the amunt of copper i can ech with 1kg of HCl. maybe in some time i'll make this amount in kg into amound in m^2.
PS the mw file ontop of the page is a maple worksheet if someone has maple
My tape is leaving some sticky residue on my PnP which in not an issue unless I am saving it for later use. I forget it is there and the sheets stick to other sheets. Will try bobledoux suggestion and use laser printing labels the next time. I guess this proves that all tapes are not created equal.
Usually I apply the tape at an angle so it is only covering the very corners of the press-n-peel piece (which is also beneficial in that I only need to cut my PnP piece slightly larger than the pattern, often 1/8" border or so), and then instead of trying to tear the tape off after printing, I simply use a razor knife and just cut off the corners of the PnP sheet that are covered by the tape. fast, easy, and no residue.
There was a guy on eBay awhile back selling like 10 lb and up bottles of solid Ferric Chloride lumps.
Easy enough to turn that into etchant. At first I thought a pound of that stuff would make a lot of etchant. However, I did some calculations and saw that the ferric chloride is actually a very substantial part of the etchant's weight. It was still significantly less $ than buying etchant, but not a miniscule fraction of the cost.
One of the transfer sheet companies has been advocating dumping the etchant tank entirely in favor of applying the ferric chloride etchant with a sponge (while wearing gloves), literally rubbing it on. They say this etches a board far, far faster and in the end uses less etchant.
There was a guy on eBay awhile back selling like 10 lb and up bottles of solid Ferric Chloride lumps.
Easy enough to turn that into etchant. At first I thought a pound of that stuff would make a lot of etchant. However, I did some calculations and saw that the ferric chloride is actually a very substantial part of the etchant's weight. It was still significantly less $ than buying etchant, but not a miniscule fraction of the cost.
One of the transfer sheet companies has been advocating dumping the etchant tank entirely in favor of applying the ferric chloride etchant with a sponge (while wearing gloves), literally rubbing it on. They say this etches a board far, far faster and in the end uses less etchant.
The solubility of ferric chloride is about 92g/100ml according to wikipedia. That's just a hair over 2 pounds per liter, and if you do the conversion that means that 10 pounds of solid ferric chloride only makes about 1.3 gallons of etchant, which isn't as much as I would have expected! that guy must be selling that stuff for a pretty good price, because 4 liters of pre-mixed ferric chloride solution is about $22 from web-tronics.com for example, and 1.3 gallons is only 5 liters, so he'd have to beat $27.50 for 10 pounds... best price I see on there right now is $11 a pound, but that's 97% pure and might be fancier than the cheap hobbyist-grade stuff.
I will attest to the sponge method. A friend of mine etched a board at work with ferric chloride (I don't use it much myself, in favor of ammonium persulfate) and used a wadded up paper towel as a sponge, and the board did etch quickly and evenly, since you can see the progress and focus on areas that are etching more slowly. And of course, it doesn't require much etchant, which is very convenient if you prefer to just mix/pour out a batch of etchant, use it once, and then dispose of it, (instead of having a large tank of etchant that you keep filled constantly) since you will only be going through a small amount at a time that way. According to the CuCl etching page mentioned previously:
insoluble copper(I) film formed with ferric chloride or cupric chloride as being the limiting factor on etch rate. Persulfate on the other hand do not form insoluble surface films, and so etch rate is limited only by solution kinetics
Bobledeux:
I have a question about the pulsar etching system. Does it work that great? I have some of the paper, and I can't get the toner to transfer for crap! I've tried a dozen different copiers, and I've tried a clothes iron, and two differents heat laminators. Suggestions?
A good way to remember this is use the alphabet...A to W not W to A...
The explanation is simple..if you have a high concetration Acid (let's say sulphuric acid 10 mole) which would eat through any type of metal, if you would slowly dump the acid into water, the reaction can be controlled by the pouring of the acid into the water.
Let's say you dump the water into acid, then you would have a little bit of water reacting with a large amount of acid as the pouring process starts.
This is very dangerous because of the large amount of concentration of acid is going to react with every molecule of the water, giving off much heat.
I am no scientist but this was 8th grade bio-chem, which is basic reaction control.
Use this rule for adding acid into pretty much anything, espcially water.
-Jim
Bobledeux:
I have a question about the pulsar etching system. Does it work that great? I have some of the paper, and I can't get the toner to transfer for crap! I've tried a dozen different copiers, and I've tried a clothes iron, and two differents heat laminators. Suggestions?
I know this is a bit stale but if the poster is still here.
I use the Pulsar system and it works very well.
Some simple questions?
What is the problem you are having.
Is the toner not attaching to the paper?
Is the paper not letting go of the toner?
Is the toner not sticking to the copper?
What is the substrate PCB material ?
Some are more prone to breaking then others. Fiberglass would be good.
Use a sharp bit.
Do not push, let the drill do the cutting. Small bits heat quickly. Forcing them makes it worse. Hot drills go dull quickly. May only last a few holes.
Carbide bits stay sharper longer but break easily unless you use a drill press or drill stand. You should be using a drill stand or drill press.
What is the substrate PCB material ?
Some are more prone to breaking then others. Fiberglass would be good.
Use a sharp bit.
Do not push, let the drill do the cutting. Small bits heat quickly. Forcing them makes it worse. Hot drills go dull quickly. May only last a few holes.
Carbide bits stay sharper longer but break easily unless you use a drill press or drill stand. You should be using a drill stand or drill press.
Having tried many methods over the years, including printing onto magazine pages,photo-resist etc. and I would say Press-n-Peel is one on the best I have found. It is quick, easy and fast and I have had spectacular results for my SMD work and double sided boards, with achievable edge definition and fine track widths far better than using paper. I use laser labels to stick correctly sized pieces of P-n-P to normal A4 sheets and have not had a 'jam' on my laser printer yet. As for cost, a 20 sheet pack shipped to Sheffield UK from Techniks in the USA is US$64.50 or about £33.00 which compared to Maplin where you get 5 sheets for £15.52 which is almost twice the price at £3.10 per sheet ! and you have to collect.
Even with straight 38% HCl, the ink I use, Brother brand, does not dissolve. What kind of ink are you using? I would try out another type if you can. When I was using OfficeMax to make the copies I did not have that problem either. I use a small amount of solution and immerse it while wiping gently with a sponge, and the only problem I had was the ink from OfficeMax chipping. I can rub pretty hard without the Brother ink coming off.