Thread: Melting VDH

The double boiler produces slow and even heating of your soap, you chose wisely. This is the best method for your experiment. A microwave heats very fast and the heating is not homogeneous. The chance of evaporation of volatile components increases, not to mention potential bursts. I would not recommend using a microwave to melt soaps, regardless of their kind.

I agree with livingontheedge, your soap should recover its original consistency at some point but since the glycerin content is high and glycerin is very hygroscopic, this may take some time. This happened to me when I put a lid on the double boiler, this should be avoided. Placing the bowl containing the soap inside a sealed plastic bag can also help. The chemical composition of your soap has not changed, it is still a soap, only more diluted unless, you added other ingredients. You should expect the exact performance as before, just use less water.

Al raz.

Originally Posted by bhinks

I think I may have made a bit of a boo-boo here:

Recently got a puck of the standard VDH soap at CVS, as I wanted something inexpensive to mess around with proportions for uber-lather.

Anyway, I was having trouble with the puck spinning like a top in the mug, so using what I assume is the correct double-boiler method (placed the soap in the bowl and the bowl in a pan of lightly boiling water), I melted it to fit. Stuck it in the freezer for about 24 hours and thought I was set. The soap came out still a bit soft though, and I figured it just needed a bit more time to set and firm up.

Well it's been almost 3 days now, and the whole puck still has about a thick whipped-cream consistency, and I'm wondering if in my newbie zeal, I didn't quite pay enough attention to the shaving & pressing vs. melting method for glycerin- and non-glycerin based soaps. I'm wondering if I'm going to have to toss this puck now (not a huge heartbreak at a whopping $3, but still...), or if there's something I can to do get it back to the right consistency?

+1 With what Al told you already...

One thing to add on the "Double Boiler" method it should really be called the "Double Heating" method
The water does NOT need to be rapidly boiling, the soaps melt at about 160 degrees, so just a gentle bubble will do it.. Also you don't even have to melt the whole puck, just enough to even out the soap in the bowl/cup...

Originally Posted by gssixgun

+1 With what Al told you already...

One thing to add on the "Double Boiler" method it should really be called the "Double Heating" method
The water does NOT need to be rapidly boiling, the soaps melt at about 160 degrees, so just a gentle bubble will do it.. Also you don't even have to melt the whole puck, just enough to even out the soap in the bowl/cup...

It does not matter if it is rapidly boiling or just gently bubbling, the temperature of the water bath is the same, the boiling point of water at local conditions (e.g. 212 deg F at sea level). The additional heat input at a vigorous boil (over the gentle simmer) all goes to evaporating water. This latent heat input does not change the temperature of the bath.

Originally Posted by MasterRolf

It does not matter if it is rapidly boiling or just gently bubbling, the temperature of the water bath is the same, the boiling point of water at local conditions (e.g. 212 deg F at sea level). The additional heat input at a vigorous boil (over the gentle simmer) all goes to evaporating water. This latent heat input does not change the temperature of the bath.

I think perhaps you are missing the point, a rapid boil splashes water in the soap..... the heat factor has nothing to do with it..

Originally Posted by gssixgun

I think perhaps you are missing the point, a rapid boil splashes water in the soap..... the heat factor has nothing to do with it..

Yes, I did miss the point. This only applies, however, if the soap is in an open container. I always used a ziplock bag.

Your a lucky guy. That VDH Soap contains Nitro. A little too much heat and it's adiós muchacho.

Originally Posted by Alraz

The double boiler produces slow and even heating of your soap, you chose wisely. This is the best method for your experiment. A microwave heats very fast and the heating is not homogeneous. The chance of evaporation of volatile components increases, not to mention potential bursts. I would not recommend using a microwave to melt soaps, regardless of their kind.

I agree with livingontheedge, your soap should recover its original consistency at some point but since the glycerin content is high and glycerin is very hygroscopic, this may take some time. This happened to me when I put a lid on the double boiler, this should be avoided. Placing the bowl containing the soap inside a sealed plastic bag can also help. The chemical composition of your soap has not changed, it is still a soap, only more diluted unless, you added other ingredients. You should expect the exact performance as before, just use less water.

Al raz.

+1 With what Al told you already...

One thing to add on the "Double Boiler" method it should really be called the "Double Heating" method
The water does NOT need to be rapidly boiling, the soaps melt at about 160 degrees, so just a gentle bubble will do it.. Also you don't even have to melt the whole puck, just enough to even out the soap in the bowl/cup...

Apparently I use the "deluxe" variety, thanks to a previous post.


Sounds like you've got it covered now but I want to re-assure that if your in a pinch again you can microwave it. It may not be the "best" way. I put it in the microwave for a whole 10 sec. Then check it. I'll go another 10 sec. etc.

I honestly forget how much time it takes, and it'll vary from machine to machine anyway.

The point is I go in 10 sec intervals and allow time for the heat to even out a little between each zapping. I melt it only enough to "glue" the puck to the bottom of the mug.