Wasn't sure if this'd go in Technochemistry because of the electroplating, figured I couldn't go wrong putting it in Misc.
Is it even possible to plate something with lead? I'd heard a bit about tin/lead plating, but I'm not sure if the tin would be a good thing (below for
what I wish to use this for). I looked everywhere and didn't find much. Hoping someone here knows a bit more about it than I do... Or at least has
better google keywords . If not, perhaps someone would share an alternative
method?
I'm unable to get glassware, and I read that lead is inert to sulfuric acid. This is good as I wish to produce oleum.
Edit: I'd certainly thought about dipping it in molten lead, but I'm afraid I won't be able to use the threads, etc. Plating would give me a much
finer coat.
[Edited on 24-1-2010 by R0b0t1]bbartlog - 23-1-2010 at 18:46
I've unintentionally plated small amounts of lead onto a stainless steel cathode (from sulfate solution). Don't see why it wouldn't be possible.
Obviously a lot of lead compounds are insoluble so you'd need to think about what to use (lead nitrate seems the obvious choice but I have no
experience with it).
I'm not sure though that you should treat a thin layer of lead such as plating would achieve as an impervious barrier to concentrated sulfuric acid.
Lead sulfate is soluble (slightly). I realize that sulfuric acid was made by the lead chamber process, but I'm pretty sure those were plates of
substantial thickness.
Also, what do you mean 'unable to get glassware'? Do you live in a state where it's illegal?R0b0t1 - 23-1-2010 at 21:21
No, it's just above my budget. I was told it was only the custom glassware that was expensive, but I can't even find straight tubing :\.
I realize the layer is thin, I do, however, plan to plate as much as a can onto it. I will then wrap the fittings in teflon tape and screw them
together (to increase the seal and prevent scratching; I could also re-plate the assembled pipes to fill in any gaps). I think the thin layer will be
sufficient to resist the acid, I wouldn't imagine it'd come up off of it without some vigorous action going on.
But, could you be a bit more descriptive? You plated your steel accidentally with lead sulfate (I imagine you mean this), or you had solid lead in a
solution of some other (please specify) sulfate?
However, I'll try your suggestion of lead nitrate unless another is offered, it certainly sounds plausible. Since it was used in paint, I might be
able to acquire some from an art store (mix your own paints, not sure if they sell it).hissingnoise - 24-1-2010 at 05:56
Quote:
I'm unable to get glassware, and I read that lead is inert to sulfuric acid. This is good as I wish to produce oleum.
I can't see lead standing up to the action of oleum for any length of time.
You could go to the trouble of lead-plating only to find that you've wasted your time.
Glassware is probably essential for what you want to do. . .
And worth every penny you'll pay.bbartlog - 24-1-2010 at 07:44
I'm pretty sure that manufacturing oleum safely would require a budget that can accommodate glassware, but without knowing specifically what you're
ultimately trying to do and what scale you're trying to work on, I'll just leave it at that and try to address your specific questions.
The inadvertent lead plating I did involved a lead anode and a stainless steel cathode in a solution of MgSO4, with a terra cotta membrane. On
electrolysis at 12V, the anode fairly rapidly developed a coating of PbO2 (which however gradually flaked off), while the cathode became surrounded
with Mg(OH)2 as the magnesium was reduced and then oxidised by the water. Over a period of several days, however, the stainless steel cathode
developed a dull gray layer of lead. Whether this was lead that turned to sulfate and dissolved prior to the formation of the PbO2 layer, or whether
the imperfect PbO2 layer allowed some lead to dissolve as sulfate even after it formed, I don't know. Obviously, this is not a practical plating
method as the low solubility of the sulfate makes the plating extraordinarily slow.R0b0t1 - 24-1-2010 at 14:27
Hm, yes. Now that you describe it, it does seem like I won't be able to accomplish this at all. Will, however, still attempt it if I can get a hold of
some lead nitrate.
I recognize glassware would be preferable, but neoprene tubing (gas line) is cheaper and seems to work just as well. I do have glass
bottles/containers I will be using to actually store the acid/oleum, it is just that I was having trouble acquiring glass tubing. If the lead-plated
connectors don't work out, I'm sure I could somehow bond the neoprene together...watson.fawkes - 25-1-2010 at 07:55
[...] neoprene tubing (gas line) is cheaper and seems to work just as well.
I would suggest looking into
materials compatibility more before deciding on this.R0b0t1 - 11-2-2010 at 22:05
I'd like to note the neoprene (I believe that is what this tubing is made of, windshield wiper vacuum line) worked well for me, it is still flexible
and has no cracks/leaks (I checked with pressurized water) after exposure to the H2SO4 vapor, still not tested in actual boiling acid, yet.
I had a few glass jars with rubber stoppers with holes, coming from the flask on the hotplate, I connected 1/4 tubing via latex, then put 1/8 tubing
into the 1/4, sealed with white (as to note any color change) electrician's tape. This went into a large glass jar/bottle via a nylon(?) tubing
connector shoved into the stopper. This was connected to a jar filled with water, to stop any vapor that did not condense, and that was connected to
an empty jar to catch any water, which was connected to my vacuum pump. The pump's output was submerged in sodium bicarbonate solution. Seeing as my
hotplate was a little lacking (it just barely reached 330C), I wrapped the flask in some tape-like insulation and fixed it with some fiberglass tape.
All stoppers were wrapped in teflon tape.
Interestingly, very little vapor actually made it into the flask's outlet and condensed. I had just enough acid condensed to fill the bottom (bottle
was about 4.5in across, with an upwards dimple). This was then flooded with about 1/2 in of Jar 2's water when I turned off the pump momentarily
(oops) to check on the setup for leaks.
Jar 2's pH at the end of the experiment was 4-3, and Jar 1's was 1. The acid left in the flask (pretty much all of it) registered <1 (turned the
paper purple...). As the process progressed, the original light red/brown color of the acid turned into pitch black, and then started lightening up,
ending at a practically clear color with a slight tinge of yellow (which could probably have been removed with more heating). Carbon residue was all
over the top of the flask by the stopper. I guess that's where all the contaminants went, although the pump's output water was orangish.
I know no one really cares, as distilling acid isn't really that cool. I just like monologuing.
[Edited on 12-2-2010 by R0b0t1]Mr. Wizard - 11-2-2010 at 23:34
Why not just use sheet lead? Any threaded portion could be cast around a suitable mold made of steel pipe, and sections of the lead sheeting could be
fastened together using normal sheet metal tools and folding the corners to form seals. I believe you can also weld lead with a oxygen /gas torch
quite easily. I know it melts easily, but you need a lot of heat at once to keep the joint localized and not just burn a hole through it. Also known
as 'Lead Burning'. Sheet lead is used in roofing.
. If not, perhaps someone would share an alternative
method?