The authoritative public forum
  for Metal Finishing since 1989
-----

Caustic Acid Leaching from Joints in Metal Bed

Hi.
I'm a homeowner with an antique metal bed (cast iron); it's not all that valuable but it has great emotional value to me. It was in bad condition-- I had it welded and then stripped. The stripping company used a caustic soda ⇦liquid caustic soda in bulk on Amazon [affil link] bath. It cannot be disassembled.

Now it is leaching through whatever primers I apply. I have removed the casters and pressure washed the inside (the tubes are hollow) and then let it dry for weeks-- also tried various sealing products-- all to no avail. Within a day or so after priming it the leaching starts again, from virtually every joint. The stripping company suggested drilling holes, but the problem doesn't seem to be that it's holding water-- the water flows through it and empties. When I prime it the surface seems dry and clean-- but then the leaching starts again in a few days.

Any ideas as to how I could solve the problem? Are there primers that seal caustic soda crystals (or whatever is causing the problem)? Please help-- I really want to keep this bed!
Thanks,

Shannon L. Antoine
homeowner/writer - Lacombe, Louisiana, USA
2005

---

caustic soda ⇦liquid caustic soda in bulk on Amazon [affil link] is highly soluble in water and if you are sure it rinses out well and even dries without a residue, then there is no way what you are seeing is caustic soda. I think something else is going on! perhaps you can describe what is leaching out a bit better. is it a liquid or a powder leaching out? is it white, clear or coloured? is the inside of the tube dry after you wash it out? if not try high pressure air blowing through the tubes to dry it

best of luck

Peter Van de Luecht
- Melbourne, Vic, Australia
2005

---

I'm just a country boy with a ton of pro amateur exp dude just soak that stuff in baking soda [in bulk on eBay or Amazon [affil links] find your own combo it neutralizes everything in the right strength all were talking about is soda and water.

Bruce Raymond Witte
- Germantown, Maryland
2006

IF THE FRAME WAS SOAKED WITH CAUSTIC THEN THE BED WAS NEVER DESIGNED TO BE REPAINTED BACKING SODA IS YOUR BEST BET TO KEEP THE METAL FROM BREAKING DOWN THROUGH OXYGEN, BUT YOU MAY HAVE TO WORRY ABOUT IT NOW BREAKING DOWN THROUGH HYDROGEN IF YOU COME UP WITH A MIXED PAINT TYPE OF CAUSTIC YOU MAY BE ABLE TO NEUTRALIZE THE EFFECT BOTH WAYS BUT THERE IS A HALF LIFE ON EVERY ELEMENT SO I GUESS NOTHING LAST FOREVER. OR MAYBE DIRT DOES.

BOBBY
- OCALA, Florida, USA
March 18, 2008