Rust Stains

[Dean]

I cured my soap on a rusty cookie sheet (I know...ghetto) covered in wax paper to separate the soap from metal. The rust came through the wax paper and stained the soap. I was able to remove the stains but wonder what made this happen.

 

[KiwiMoose]

Uh oh! Luckily you could salvage the soap. Get yourself a new cookie sheet you silly billy!

 

[Dean]

Uh oh! Luckily you could salvage the soap. Get yourself a new cookie sheet you silly billy!

Nope! U know I’m a cheap ...
I just put bk the bamboo skewers under the soap.

 

[Misschief]

I cured my soap on a rusty cookie sheet (I know...ghetto) covered in wax paper to separate the soap from metal. The rust came through the wax paper and stained the soap. I was able to remove the stains but wonder what made this happen.

Hmm.. what made it happen??

A lifetime ago, I went to a conference with my husband. One event in the spouses' program was a visit to a pulp and paper plant. We participated in an experiment to see which kind of paper was the most water resistant. If I remember correctly (I was dealing with a massive migraine that day), we had four different kinds of paper and had to guess which was the most resistant. There was plain copy paper, wax paper and a manila envelope, along with another which I can't remember right now. The most water resistant was the manila envelope.

Conclusion? Wax paper isn't very moisture resistant. And fresh soap contains moisture. I'm not surprised the rust came through the wax paper. You need something that raises the soap away from the surface of the cookie sheet.

 

[Ivanstein]

Wax paper is paper coated with a wax. Chances are any free lye in your soap will react with the wax much the same way as it does with oils to make soap. This would let the water permeate and microscopic rust particles transfer by capillary action.

I would suggest parchment paper which is basically wax paper but treated with silicone instead of wax. More heat resistance and less likely to interact with lye. I know there is a huge difference when gluing model airplanes together with CA glue between wax paper and parchment paper. CA has some pretty strong solvents in it and they don't seem to pass through the parchment.

And...if it doesn't work for soap, it's great for cookies!!!

 

[penelopejane]

I don't think the skewers are a good solution either.
Soap can react with wood too.

 

[lsg]

You can line soap mold with freezer paper. I would use something besides metal for a mold, though.

 

[Dean]

Thx all for the recent replies. I will ditch the skewers per @penelopejane and replace the wax paper with parchment (since I have some) per @Ivanstein. Interesting tidbit bout parchment and silicone.

 

[Ivanstein]

Thx all for the recent replies. I will ditch the skewers per @penelopejane and replace the wax paper with parchment (since I have some) per @Ivanstein. Interesting tidbit bout parchment and silicone.

See here, under "Bakery Release Paper":
https://en.m.wikipedia.org/wiki/Parchment_paper

Although, I learned it from Alton Brown, who is infinitely more interesting than Wikipedia.

 

[dixiedragon]

Nope! U know I’m a cheap ...
I just put bk the bamboo skewers under the soap.

Ditch the cookie sheet. Go to Costco or Sam's Club and get a bunch of the cardboard produce flats. If you get the same kind, they will fit together. I personally like the blueberry ones.

 

[Dean]

I just passed an empty one of these:

...and wanted to steal it for curing. Fortunately, my conscience kicked-in. I don't know what's mo' ghetto...my rusty cookie sheet or my thieving impulses.

 

[JanelleTrebuna]

I just passed an empty one of these:

...and wanted to steal it for curing. Fortunately, my conscience kicked-in. I don't know what's mo' ghetto...my rusty cookie sheet or my klepto impulses.

Bread trays! You might check with local bread delivery places and see what they do with worn out trays.

 

[jcandleattic]

You're probably lucky your soap didnt' get DOS. I had a metal curing rack that had a teeny tiny spot of rust on it, and the soap bar that was nearest to that spot got DOS. It's the first, last, and only time I have ever gotten DOS.