I worked in a aircraft parts plating company . We had a round vat that sat on the floor in the paint & parts stripping area. It was about 2 feet tall. If you tripped you would fall right in it. It had something really bad in it. Black nasty smelly stuff. I forget n ow but I think it was called black oxide .... All I know is if you got any on you it would eat a hole right on through if you did not stop it. The only way to stop it was to pour sulphuric on it and then hit the rinse water tank to get rid of that. Never got any on me but that is what they told me to do if I did.clearsteam said:
fingers and other plated boards
- Thread starter markk
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Clearstream,
As a moderator, one of my responsibilities is to help prevent injuries to our members. It's obvious that you don't know enough to advise anybody on this forum about anything. If you continue advising people about anything involved with refining or the use of any chemicals, I will ban you.
As a moderator, one of my responsibilities is to help prevent injuries to our members. It's obvious that you don't know enough to advise anybody on this forum about anything. If you continue advising people about anything involved with refining or the use of any chemicals, I will ban you.
The main chemical in a black oxide solution is lye or sodium hydroxide.markk said:
Yep , I think this must have had something else in it also as I cant think of any reason one would need sulphuric to neutralize lye unless of course it was the only acid available in that area of the shop I suppose.goldsilverpro said:
I tried to keep my distance so I would not find out.
Since you've mentioned it again, I can't imagine putting sulfuric acid on my body intentionally. HCl or acetic maybe, but not sulfuric. Perhaps the information you were given was wrong. Perhaps there is something about the bath I don't understand, as I've never worked in a plating shop.
My only point in making this post is to caution anyone who may read it in the future that sulfuric is one of the most destructive acids to human tissue, and that they should not intentionally use it to neutralize a sodium/potassium hydroxide bath.
If I'm wrong, I hope that GSP will let me know.
Dave
My only point in making this post is to caution anyone who may read it in the future that sulfuric is one of the most destructive acids to human tissue, and that they should not intentionally use it to neutralize a sodium/potassium hydroxide bath.
If I'm wrong, I hope that GSP will let me know.
Dave
The acid would obviously neutralize the sodium hydroxide. As I've mentioned several times, I used to keep a bucket of about 2% HCl to neutralize any cyanide I might get on my hands. After rinsing well with water. I dipped my hand into the weak HCl and then rinsed again with water. I would think one could do the same with sodium hydroxide and a very weak H2SO4 - say, 1% by volume. Of course, very weak HCl could also be used.
With either cyanide or sodium hydroxide, it is very easy to determine whether or not you have neutralized or removed them completely. If, when you rub your fingers together, it feels "slick", there is still some of the chemical remaining. When I used the HCl on cyanide, this "slickness" was immediately gone.
With either cyanide or sodium hydroxide, it is very easy to determine whether or not you have neutralized or removed them completely. If, when you rub your fingers together, it feels "slick", there is still some of the chemical remaining. When I used the HCl on cyanide, this "slickness" was immediately gone.
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Also the "slickness" Chris refers to is the action of the alkaline solution on the skin i.e. Dissolving it. Think of how they used to make soap.
Vinegar would work fine - I just don't care for the smell.markk said:
Surely you're not refining in your house!
I like vinegar . I drink a good swallow now and then. No, not refining in the house . Just the lye for the solder mask. I am thinking of buying the little system shor has with the filter on it. But I think from looking that filter system is nothing more than a column of charcoal. Can make that myself .goldsilverpro said:
Dont have a place to refine at here besides in house or outside on porch.
Thinking I would make a hood in my utility room to vent everything out the roof during cold weather . But then I will have to be going back to work soon and I drive a truck so I might not do anything until summertime anyway maybe during a holiday. Not home when driving except on weekends for a few hours. I'm just sitting around now for a few months or six being lazy.
kernels
Well-known member
One thing that is probably worth mentioning in this thread is that unless you are processing very special boards (out of old electronics test gear for example), that gold 'plating' that you see is almost non-existent. ENIG is roughly 4 microinches thick, as a comparison, a gold bond wire (which is pretty much invisible to the naked eye) is 500 microinches.
Gold plating on 'fingers' like RAM or PCI cards is much thicker (in the 50 to 300 microinch range) and is obviously worth recovering.
It is really not worth the risk or hassle to recover ENIG gold as a home refiner. But, probably worth trying for yourself once, because no-one ever believes it when you just tell them the answer.
Gold plating on 'fingers' like RAM or PCI cards is much thicker (in the 50 to 300 microinch range) and is obviously worth recovering.
It is really not worth the risk or hassle to recover ENIG gold as a home refiner. But, probably worth trying for yourself once, because no-one ever believes it when you just tell them the answer.
Actually, I think it's a little worse than that. If I remember right, gold bonding wire is either .001" diameter (1000 microinches) or .0007" (700 microinches). One troy ounce of the .001" wire is 2 miles long and a troy ounce of the .0007" wire is 4 miles long.kernels said:
A plating website for the immersion gold (IG) part of ENIG, for general purposes, gave a thickness of between 3 to 5 microinches. For soldering applications, it can be as thin as 1.6 microinches. A 4 microinch gold coating is worth about $0.05 per square inch.
I have used a lot of real gold leaf (usually 23K) for signmaking purposes. It's about 3.5 microinches thick. When they are applying it on windows, you can see light through it.
kernels
Well-known member
Absolutely, I made the mistake once of paying good money for 'gold plated' telecoms boards, the boards were about the size of an A3 sheet of paper and fully 'plated' on one side, almost couldn't see the gold drop from that solution! Money wasted, lesson learned.
Immersion plating is essentially a cementation process and its thickness is self-limiting. Unlike the cementation we do as refiners, there are other chemicals in the IG solution that insure adhesion of the gold to the base metal. When the gold deposits, some of the base metal must dissolve. When the surface is 100% coated, the plating stops. This is because the solution can no longer penetrate to the base metal.
I've read that the maximum thickness of immersion gold (IG) is 10 microinches. In another place, they said 20 microinches, although, from my experiences, I would doubt that. When they call out a thickness of 1.6, 3, or 5 microinches, it makes me wonder how they are measuring that thin of a coating. Is it based on actual thickness or is it based on what the thickness would be if the mass of the gold per unit volume were 19.3 g/cc? Probably the former. By definition, IG is an extremely porous coating. Therefore, a measurement of 5 IG may only contain the same amount of gold as an electroplated gold layer of, say, half that thickness. In other words, there may only half (or, whatever) as much gold as you think there is, based on the specs.
I've read that the maximum thickness of immersion gold (IG) is 10 microinches. In another place, they said 20 microinches, although, from my experiences, I would doubt that. When they call out a thickness of 1.6, 3, or 5 microinches, it makes me wonder how they are measuring that thin of a coating. Is it based on actual thickness or is it based on what the thickness would be if the mass of the gold per unit volume were 19.3 g/cc? Probably the former. By definition, IG is an extremely porous coating. Therefore, a measurement of 5 IG may only contain the same amount of gold as an electroplated gold layer of, say, half that thickness. In other words, there may only half (or, whatever) as much gold as you think there is, based on the specs.
Yes that plating on them LNB is very thin on some as it actually looks kind of silver , I guess the copper underneath is making it look that way. Them boards seem to have lost their gold plate in the very strong lye solution.
I was going to use these LNB's and such just to add in to my fingers and other good gold but am thinking of just selling the boards on ebay along with all of my pins and perhaps the Ic's, flatpacks, memory... Not sure yet but looks like just as much money to be made by ebay as refining it.
but I do like to experiment and do things like refining even if I do not make a profit so I might just refine it all with the exception of the thin LNB as it seems like that is more of a waste of chemicals unless perhpoas you had a whole lot of them.
I was going to use these LNB's and such just to add in to my fingers and other good gold but am thinking of just selling the boards on ebay along with all of my pins and perhaps the Ic's, flatpacks, memory... Not sure yet but looks like just as much money to be made by ebay as refining it.
but I do like to experiment and do things like refining even if I do not make a profit so I might just refine it all with the exception of the thin LNB as it seems like that is more of a waste of chemicals unless perhpoas you had a whole lot of them.
Nickel. Gold is rarely plated directly onto copper in electronics because the gold will migrate into the copper over time. Usually, the copper is plated with nickel first, then gold. The gold has a much more difficult time migrating into the nickel. That's why very thin plating can look silver.markk said:
Dave
That would explain the silver look. I have taken up selling my boards that look thin on ebay for a couple bucks a pound after I depopulate and strip the solder mask. I figure someone can practice on them or just add them in with their other stuff to refine without having to do the crap work first. Heck I paid 2 bucks a pound for them.
Hi!
I'm stepping into this thread since it is about boards and fingers.
I have finally been processing fingers and boards in AP for the first time and lo and behold I ended up with a couple of "mistakes" even if reading here for a long time :wink:
I started with a mix of fingers and whole depopulated rams and small PCBs.
Whole PCBs since a few seamed to have gold plating not only on the finger area, mainly ram sticks.
First error, forgot to weigh them
I'll weigh them after so no big deal.
Added 30 percent HCl and water 1:1 + appr a dinner spoon or so with 10 percent H2O2.
After a week there was still no green color, so I added another spoon peroxide
and the solution turned green within 10 minutes.
This is where I realized "mistake" number 2.
I had not dissolved the solder first, maybe that is why it was slow to start?
Or perhaps the temperature slowed the start down since it was below freezing outside?
Now a month or so later the solution was getting more transparent even if some of the foils was still sticking. Mostly it seems because of through hole plating.
But there are also foils that seems embedded/locked by solder mask, which reveals "mistake" number 3.
I should really remove solder mask before processing.
Now I have mostly filtered and separated the PCBs from the foils.
They have been put back into AP to clean out the rest, but they seem stubborn.
Which leads to a couple of questions:
1. The foils is surrounded by a black fine powder and some solder mask remnants.
What is this black powder? Is it solder or copper powder?
It is going to have a second leach in pure HCl before beeing washed and cleaned according to forum recommendations.
2. If the PCBs are leached to end and kept wet, will substantial losses be expected if the remaining gold on
PCBs are leached with AR or HCl/Cl?
I'm stepping into this thread since it is about boards and fingers.
I have finally been processing fingers and boards in AP for the first time and lo and behold I ended up with a couple of "mistakes" even if reading here for a long time :wink:
I started with a mix of fingers and whole depopulated rams and small PCBs.
Whole PCBs since a few seamed to have gold plating not only on the finger area, mainly ram sticks.
First error, forgot to weigh them
I'll weigh them after so no big deal.Added 30 percent HCl and water 1:1 + appr a dinner spoon or so with 10 percent H2O2.
After a week there was still no green color, so I added another spoon peroxide
and the solution turned green within 10 minutes.
This is where I realized "mistake" number 2.
I had not dissolved the solder first, maybe that is why it was slow to start?
Or perhaps the temperature slowed the start down since it was below freezing outside?
Now a month or so later the solution was getting more transparent even if some of the foils was still sticking. Mostly it seems because of through hole plating.
But there are also foils that seems embedded/locked by solder mask, which reveals "mistake" number 3.
I should really remove solder mask before processing.
Now I have mostly filtered and separated the PCBs from the foils.
They have been put back into AP to clean out the rest, but they seem stubborn.
Which leads to a couple of questions:
1. The foils is surrounded by a black fine powder and some solder mask remnants.
What is this black powder? Is it solder or copper powder?
It is going to have a second leach in pure HCl before beeing washed and cleaned according to forum recommendations.
2. If the PCBs are leached to end and kept wet, will substantial losses be expected if the remaining gold on
PCBs are leached with AR or HCl/Cl?
patnor1011
Well-known member
1. It also can be gold. Many plated items are just flash plating which can break down as a brownish/blackish powder.
2. Not good idea. Firstly you are chasing pennies while spending dollars. That plating remaining on boards will be only few dollars worth while you will need quite a lot of solution to leach it out. Not to mention that you will not leach it out anyway unless you dissolve all other metal present what in case of pcb is not possible unless it is finely shreded. Pcb contains layers of copper, nickel and substrate which will suck up any dissolved values as soon as they dissolve.
AP is not throw and forget type of leach. In order for it to work the best agitation is the key. Most of the folks achieve it by using aquarium air machine and introduce air in solution which helps to oxidize and keep leach in motion. Much better than having to agitate solution several times a day.
2. Not good idea. Firstly you are chasing pennies while spending dollars. That plating remaining on boards will be only few dollars worth while you will need quite a lot of solution to leach it out. Not to mention that you will not leach it out anyway unless you dissolve all other metal present what in case of pcb is not possible unless it is finely shreded. Pcb contains layers of copper, nickel and substrate which will suck up any dissolved values as soon as they dissolve.
AP is not throw and forget type of leach. In order for it to work the best agitation is the key. Most of the folks achieve it by using aquarium air machine and introduce air in solution which helps to oxidize and keep leach in motion. Much better than having to agitate solution several times a day.
