Positive lead test

[Craig Allison]

My CS&T mortar and pestle did test positive. Thanks for the warnings from y'all.

Now my question is, is the lye bath and e-tank contaminated and needing replaced?
My thoughts are probably not because obviously the lead is still on the iron, and the lye and the other pan that was hanging in there should not be affected.

What do the experts say?

[Jim Glatthaar]

I did some quick research on dissolution of lead into lye.  It appears that the lye bath will dissolve the lead albeit very slowly.  I could not find anything specific about how quickly the dissolution takes place.  Nor could I find any expert opinion about whether the lye bath can transfer the dissolved lead to another piece of cast iron. 

During that research I saw that electrolysis will not dissolve lead.  But after thinking about it, if there is lead in contact with rust particles, removal of the rust particles from the iron would mean that lead particles could be roaming around your e-tank.

Given that you have made a significant investment in your cast iron, I would not take any chances and would dispose of your lye bath and e-tank contents.  Sorry you have to go through this.

[Neal Birkett]

I agree with Jim on disposal of the likely contaminated lye bath.  However, before you do, you may get some lead-stripping effect by letting your mortar and pestle sit for a while, perhaps a long while, in a hot lye bath (not boiling) before you do.  The longer and hotter, the better the likely effect.  Lye won't hurt the iron.  You may even wish to add water everyone in a while so the hot bath lasts longer.

If you do, please let us know if the apparent contamination is reduced, and so what extent.  We would also like to know which test kit you use to get those results. 

Good luck

[Neal Birkett]

And now that I think about it, the lye bath is probably "toxic waste" now, and that should be taken into consideration for disposal.  You may wish to combine this with my earlier comment, and let the bath sit hot until the water evaporates and the lye crystalized.  But take out your iron before the surface level exposes it.  Weird things happen to iron when exposed at the liquid-air interface.  But there will then be a smaller about of waste, now in solid form, to ge4t rid of.  You may wish to let go of the lye bath container also.

[Craig Allison]

I'm currently looking for a test for the lye that doesn't rely on a strip that changes color since the well-used lye will quickly turn it black. No luck so far.

Thanks for keeping me from making a bad situation worse.

[Neal Birkett]

You could neutralize a sample of the lye bath with some pool acid, added very slowly.  You need pH test strips to tell you when you are close to neutral (pH 7).  Anything 5 to 8.9 is probably close enough to neutral for this purpose.   The result of the titration is a salt solution with a slight excess of H+ (a little acidic) or OH- ions (a little basic) or equal amounts (ph 7.0).  Then you could test with with test strips for lead (I did not know of such a product).

[Jim Glatthaar]

Craig it is unfortunate you have to go through this, but at least Neal gave some good ideas on disposal.  And I didn't think of the toxic waste potential for the lye bath.

[Craig Allison]

Time for an update.
The first lead tests I used were kinda sketchy at best and the positive test results were questionable. Twice. But I trusted them. And then I didn't.

So I ordered some new test swabs from Amazon.
https://www.amazon.com/PRIMED-Lead-Test-Kit-Pre-Activated/dp/B0CDJ9DL88/ref=asc_df_B0CDJ9DL88/?tag=hyprod-20&linkCode=df0&hvadid=675645180186&hvpos=&hvnetw=g&hvrand=15124219839237259814&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9024324&hvtargid=pla-2247815620977&mcid=7f39d3e5fb793aff9a077df9da889f9d&gad_source=1&th=1
Tested negative four different times.
Still not comfortable, I tested a lead fishing weight and instantly got a very positive response.

So I think there's nothing to worry about.

Thanks for all the advice and the education on what to look out for in the future.

[Jim Glatthaar]

I think this was an education for all of us.  I have been looking for evidence of lead or paint on any cast iron I buy, but I will be checking more thoroughly now.

When you said "Tested negative four different times" were you referring to the mortar, the lye bath or the e-tank? 

[Craig Allison]

The mortar.
I never found a way to test the lye itself but was still looking. It would be a good thing to know if this ever pops up again.

[Neal Birkett]

I think this was an education for all of us. 

Agree. I learned as well.