Stearic acid in Pine tar

[gdawgs]

So I started using the pine tar soap I made a couple months ago, and I'm really liking it, so I'm thinking it's time to try another batch.

I bought some stearic acid a while back for making shaving soap and I'm wondering if this would be something worth while to add. ???
Will it help bring the hardness up or will it just set it up faster than it already does? I have no idea how much to use, any suggestions? Or should I just skip it?

I was thinking of starting low, like 5% since I'm winging it(unless anyone has suggestions).

Something like this.
60% Lard
15% Pine tar
10% Olive
5% Coconut
5% Castor
5% Stearic acid

 

[The Efficacious Gentleman]

It would set up faster, but it would depend on how you do it - for example, many people mix the oils with the lye and then add the pine tar, rather than having the pt in there from the start. That might help.

 

[Steve85569]

It will speed up an already fast soap.
Doing all oils and lye prior to adding the PT helps but only some. Gave me an extra 45 seconds to get it in the mold. Stearic might be an interesting experiment.
Keep us posted.

 

[KristaY]

Definitely keep us posted if you give it a go. When I make PT I add it last and stir in as fast as I can using a whisk. I just barely have enough time to get it thoroughly mixed and into the mold. Even at 5% the stearic is going to speed that up.

Other than hardness, what are you hoping to accomplish by adding in the stearic?

 

[gdawgs]

Other than hardness, what are you hoping to accomplish by adding in the stearic?

Well I'm not exactly sure. I was down looking at all my soap making supplies and saw the rather large bag of stearic acid staring back at me. So I'm thinking of ways to use it. My first batch of pine tar soap was kind of soft(although it did harden over time) so I was wondering if it would harden it up a bit.


My plan was to mix the pine tar with the olive oil, and add the lye to all the other oils first. Then add the pine tar and OO at the end. I think I'll give it whirl. I'll let you know what happens.
Ok, I'm rethinking my recipe. In reviewing my first batch, my recipe was;

70% lard
20% pine tar
5% Coconut
5% Castor

I'm thinking I should stay similar to this rather than using the other recipe I posted, otherwise I won't know what the stearic acid does.

So maybe I'll cut back the lard to 65% and add in the 5% stearic acid from that.

Or maybe I should leave the lard and cut back the pine tar to 15% :think:

 

[doriettefarm]

If I wanted to see exactly what stearic brings to the party, I think it's a good plan to stick close to the original recipe you used. I'd probably take 5% from the lard and see what happens . . . might also do it in a crockpot in case you end up having to HP. If the stearic doesn't work out you could also try adding some beeswax for hardness but totally understand wanting to use supplies already on hand.

 

[gdawgs]

Done deal. No major issues. I didn't notice a big difference with the stearic acid after I added the pine tar. But this is only the 2nd time I've made it, so I'm not all that familiar with it. The one thing I noticed with the stearic acid, is that is was at trace as soon as I got to emulsion. Almost instantly when I gave it a little stick blend. Once I added the pine tar, I just did maybe 20-30 seconds of quick stirring with a whisk, then dumped and scraped in the mold.

I don't recall how fast it hardened after that last time. But this time, it was a brick within a few minutes. I scented it with a hodge-podge of EOs I had laying around. Eucalyptus, frankincense, patchouli, and peppermint. I kind of like it. It should get even better once the stench of the pine tar fades a bit.

 

[KristaY]

Looks good, gdawgs! I wasn't surprised to hear how quickly it came to trace with the stearic in there but I'm glad you had enough time to get the PT/OO blended in. Now I'll be waiting to hear how these bars compare to your last batch. I love experiments!

 

[gdawgs]

Well I can say with certainty that this batch is much firmer than the first one I made.

I posted in this thread that my other stuff was still pretty soft at the two week mark. I remember trying to remove it from the mold the day after I made it, and it was still pretty gooey.
http://www.soapmakingforum.com/showthread.php?t=59720&highlight=pine&page=3

I unmolded and cut this batch last night and it was already pretty firm at the 8 hour mark. No sticking to the mold. This morning it is quite firm.

The one possible problem is the appearance of white specks. I'm suspecting undissolved stearic acid. I heated the oils up to 115°F before adding the lye. Normally my oil mixture would be clear at that temp, but this was still kind of white, but appeared to be fully melted and dissolved. I looked up the melting point of stearic acid and it is 156°F. So that probably puts it into the hot process only category. I guess I'll try that next time.

Here are some pics. It even showed up on my mixer, which I didn't notice until this morning.

 

[gdawgs]

I rebatched a couple bars the other day to see if I could get the white spots to go away. I cut the bars into chunks, put them in a bowl with a little water and microwaved it and got it pretty hot(190°F) which was hotter than I intended to take it. But the white spots are now gone, so it has to be the stearic acid not dissolving.

I did another little experiment. I put a little olive oil and canola oil in a coffee mug, and threw in some flakes of stearic acid. I then microwaved a little at a time to see when the flakes would dissolve. They completely dissolved at about 150°F. Then I let it cool to see when things would get chunky. It actually looked good down to about 95°, that's where I just started to think I saw some solids. At room temp, it now has the consistency of room temp bacon fat after you cook it.

So for my next batch, I think I will try the same recipe, just heat the oils up hot to that 150-160° range to be sure the stearic acid is completely dissolved, then let it and the lye water cool to about 110 or so, and soap there. I'm guessing that it's going to setup real quick since all the stearic acid would be ready to react with the lye.

If that's a total failure, I'll try hot processing.

 

[DeeAnna]

If I were making this type of soap, I'd mix the stearic acid and the pine tar with about 1/2 of the oils and heat until the stearic melts. Put the lye solution in the remaining fats and bring this plain batter to emulsion. Stir in the melted stearic-PT-fat mixture into the soap batter and stir by hand. That would make the process as streamlined as possible as well as eliminate the stearic bits in the finished soap.