2013-03-30 by Todd F. Carney / K7TFC
Lye ("caustic soda," sodium hydroxide) is available in many forms on eBay,
in the United States and elsewhere. Dozens of listings. I don't believe the
bit concerning official restrictions on lye because of its use in meth
making. It's used in that process, alright, but take a look at this list of
meth-making materials published by a drug task force in Washington state:
http://www.srdtf.org/pageview.aspx?id=25477.
There's more than a dozen common household chemicals on the list, including
rock salt, peroxide, Ammonium Sulfate fertilizer, starter fluid, etc. No
restrictions on those anywhere. The only ingredient not in thousands of
other common uses is pseudoephedrine decongestant. It's the critical
chemical, and it *is* being restricted. In Oregon, it's a
behind-the-counter product now, and a store will sell it only in
one-cold-at-a-time quantities. This restriction has made a huge dent in
local meth production.
If access to pseudoephedrine is controlled, there's no need to control
anything else to curtail meth-house production. I suppose a store or a
chain of stores might have company policies on lye, but I really don't
think the "associates" on the floor are good sources to consult for those
policies. Frankly, I think what we have here is an urban myth.
73,
Todd
------------------------------------------------------------------------------------
K7TFC / Medford, Oregon, USA / CN82ni / UTC-8
------------------------------------------------------------------------------------
QRP (CW & SSB) / EmComm / SOTA / Homebrew / Design
On Sat, Mar 30, 2013 at 3:13 PM, designer_craig <cs6061@...> wrote:
> **
>
>
> Rick,
> Lye (Sodium Hydroxide) solution will etch aluminum very well. The trick is
> not to make the enchant too strong as the reaction is very exothermic and
> will run away. Use a very dilute solution and give it some time to work.
> The reaction evolves hydrogen gas, the bubbles tend to lift the edge of
> your resist which is another reason to use a dilute solution. Most paints
> and waxes with resist the NaOH but not most photo resists. I would think
> toner would work ok. Brush the surface now an then to keep the hydrogen
> bubbles from blocking the etching. NaOH is nasty stuff, but no worse that
> other strong bases or acids, protect your eyes � your corneas doen't do
> well with lye eye drops. Strong hot HaOH and Al will emit a mist of hot
> caustic mist not good on your lungs and use gloves.
>
> Red Devil too their lye off the market years ago, I buy RamRod drain
> cleaner at Smart and Final, it's a fairly strong NaOH solution. I dilute it
> to clean aluminum parts coming off the mill prior to anodizing.
>
> NaOH is not on the DEA list I or II precursor chemical list yet so it
> should be available, though there is not much call for it any more � not
> many folks make their own soap. It's available on line � I got some food
> grade stuff for baking pretzels. Acetone, sulfuric acid and hydrochloric
> acid are on list II so watch how much you buy at one time.
>
> I saw a nice process for activating plated through holes the other day
> that uses copper hypophosphite. Looks to be a simple reliable way to
> activate the holes prior to copper plating. The process starts with Calcium
> Hypophosphite and Copper Sulfate. Turns out all Hypophosphite salts are
> List I chemicals, which makes it out of reach for home practitioners.
>
> Craig
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "Rick Sparber" <rgsparber@...>
> wrote:
> >
> > Has anyone used lye to etch aluminum through photo resist?
> >
> >
> >
> > As a test, I put a strip of aluminum in lye plus water and after 15
> minutes
> > the strip was half of its original thickness. So there is no doubt that
> lye
> > can etch VERY deep. But the chemical reaction generated a lot of heat and
> > the tape I had on there quickly floated off. Next time I will use more
> > water.
> >
> >
> >
> > I did have the lye and aluminum outside while I watched from inside.
> Nasty
> > fumes!
> >
> >
> >
> > Thanks,
>
> >
> >
> >
> > Rick
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>
>
[Non-text portions of this message have been removed]