Melt and Pour Soap Guide
Whatever you are doing, the most important thing to remember is not to overheat your soap base. You need only heat it until it melts and no further (exceptions to this rule are the Natural or Organic bases which should be heated to 75degC to avoid 'blooming' in the finished soaps). Cutting the soap base into small chunks will help this, especially if using a microwave, although small chunks will melt far easier with any method used, so it's worth the time in doing this.
If using a microwave it is unlikely that you will be able to melt enough soap to make more than 3-4 bars. Most mass produced moulds for bar-sized soaps will contain about 70g of soap, so use this as a guide when weighing out your soap base for melting if you are going to be using a mould. With the soap cut into small chunks and put into a suitable sized microwaveable container, simply use the microwave on full power for a few seconds at a time, checking to see when the chunks have melted fully. Around 15 seconds for a single soap bar batch using a typical domestic microwave is a guide, but check yourself, as microwaves vary considerably and overheating is easy using this method.
Once melted you need to work fairly fast, as a skin will start to form quite quickly on the surface of the soap. It is whilst fully melted that soap colour, fragrance and any other additions such as irridescent powder or dried flower petals etc. are added.
Simple food colours can easily be used, as can liquid soap colours and other water-soluble liquid colour bases. Obviously the depth of a particular colour is dependent upon how much is used. Don't be tempted to over-colour your soaps, especially if using clear soap bases, as the transparency of the finished soap will be affected if too much colour is used, plus, coloured lather in use is off-putting. Fragrance can be added either using essential oils or simple fragrance oils, which are available in a huge range of tempting fragrances these days. Again, strength of fragrance is dependent upon the amount added. For a meaningful fragrance, around 20ml fragrance per Kilo of soap (2%) is sufficient, so a few drops per single bar is fine. As a guide, a maximum of 3% fragrance addition is generally advised. Irridescent powders or glitters may float or sink to the bottom of a mould depending on their make-up, so a suspending base may be helpful if you want to avoid this. Also, glitters and sheens can become lost if too much is added, so be sparing for best results.
You will need to stir in all these additions fairly quickly and pour into whatever mould you are using before a skin forms as this will spoil the finish of the final bar. There is nothing to stop you from quickly re-heating the mixture whilst it is still in its microwaveable container, but remember that a few seconds is all it will need. Too much heat will evaporate the fragrance, so avoid this if you can.
Try not to intoduce bubbles into the soap mixture as this will also spoil the final appearance. The mixture starts to set quite quickly, trapping any bubbles or other imperfections, which is especially problematic when using a clear base to make a transparent soap. If you are able to obtain any form of denatured alcohol (rubbing alcohol is available from some chemists) you will find that 'spritzing' the surface of the soap with alcohol immediately after pouring will disperse surface bubbles and give a better finish. To obtain TSDA (trade-specific-denatured-alcohol) which is the correct product, you will require a license from HMRC. This license is free but requires correctly applying for.
If making larger numbers of bars or maybe a loaf, it is much more suitable to use the direct - heat method. That is to say, heat the required volume of soap in a suitable pan on a hob. There is no need to go to the trouble of using a double-boiler, but you must ensure you don't overheat the soap, otherwise there is a risk that it could burn, although you'd probably have to have a lapse of memory and leave it for some time for this to happen. Use a thick-bottomed suacepan over a low-medium heat
Cut the soap into small pieces to help it melt quickly and evenly. Gently heat over a low-medium setting until the mixture is completely liquid. At this stage and whilst still over a low heat, add the colour and fragrance desired. It is at this stage that irridescent powders can be added also, together with other additions for texture, such as oatmeal or desiccated coconut, which are 2 examples of useful and easily availble additions to give an exfoliating texture if desired.
The addition of extra ingredients is more leisurely using this method, as continuous low heat is available to keep the mixture from forming a skin. Again, be careful not to introduce bubbles if at all possible. Fragrance should be the last addition, as heat will cause some evaporation. Again, work on around 20ml of fragrance or essential oil per Kilo for a meaningful fragrance.
Once all ingredients are added, pour carefully and slowly into the mould and allow to cool. Larger quantities of soap will require longer time to cool. The filled mould can easily be refrigerated to speed this up. Support large moulds in a bed of sand or rice to prevent distortion. Do not store your soap in a fridge or cold conditions once it's set. Soap should be stored at normal room temperature and humidity to minimise any 'sweating', which can spoil the surface of your soap.
Removing individual soaps from moulds is perfectly simple. Be sure to leave the soap to cool completely. If using a suitable mass-produced mould, which will have a shiny surface, the soap will release with slight pressure. More complex or larger moulds can require some force. To help remove a soap from a large or complicated mould, ensure it has fully set and put it in the freezer until quite cold throughout (don't actually freeze it), When you remove it from the freezer the change in temperature on the surface of the soap will help it release from the mould. This method can be especially useful when making large loafs or slabs, which are to be cut by weight or into bar sizes later.
There are a great many household objects that can be used for simple moulds without having the expense of buying specific ones. The best material is slightly flexible, smooth surface plastic, like sandwich containers and beakers. Small freezer containers are often a perfect bar size. Also, if you want to pour the soap into a sheet for cutting into shapes, a fairly rigid non-stick baking tray is fine, as plasitc trays tend to warp with the heat when the soap is poured, causing an uneven thickness in the soap sheet.
Very popular with soap-makers these days are Silicone Moulds. There are a huge selection of shapes and sizes of silicone baking moulds available, which are non-stick and very flexible, so ideal for creative soap-making.
Having mastered the technique af actually shaping, colouring and fragrancing soap, there are a great many simple techniques to make your soaps more interesting.
Melt-n-pour is so simple it lends itself to experimentation. My first simple experimental soap was a 'Jam Tart' soap, which was well received by small children and a great way of adding a little fun to a childs bathtime. The simple techniques of combining sheets of soap which can be separately coloured and/or fragranced and easily rolled or shaped whilst still slightly soft, with a separately coloured/fragranced soap poured into or around the shape can result in a huge variety of colours and appearances. Use opaque soap within a clear soap to show off the colours and shapes within to their best.
The simplest technique is to colour a small amount of opaque soap base and pour it into a shallow mould. Once set, cut into small chunks or flakes. Make up a complimentary coloured batch of clear soap base. Place the chunks in the mould for the final soap and pour the second, clear soap into the mould over the opaque chunks. This gives a simple and effective appearance to an otherwise plain bar.
Pouring opaque coloured soap into sheets and then slicing into thin lengths is easy to do. These thin strips of soap can be easily shaped whilst still soft into many different shapes, like spirals and barley-twists, which again can be put within a mould before pouring a clear and complimentary coloured soap over it.
'Swiss Roll' loafs are also easy to achieve. Find a suitable loaf mould and measure the length. Pour a sheet of coloured soap and cut it to the same width as the mould is long. Let the sheet set for a while and whilst still soft, roll it up loosely (or lay 2 or more different coloured sheets on top of one another and roll together). Place the roll into the loaf mould and carefully pour the clear soap base into the mould, slowly, allowing it to flow between all the gaps in the roll. Let set and slice for best effect.
My 'jam tart' soap was simply made from a sheet of opaque white soap, coloured very slightly with yellow soap colour to achieve a cream colour. The sheet is cut using a pastry cutter into tart rounds and pushed into the recesses of a non-stick baking tray that would normally be used for real tarts or maybe Yorkshire puddings (you know the type). This is left to set completely and then a second batch of clear soap is coloured red and fragranced strawberry. This is then poured into the cupped shapes in the baking tray and left to set. The result is quite convincing.
Soaps can be poured in layers of colour within either a large or small mould. Picking out the detail of a delicate mould by pouring an opaque soap base into the surface irregularities, letting it set and then pouring another colour over it will leave a detailed 'picture' on the surface of the soap bar. This is especially useful in enhancing soaps with raised flowers or animals etc. on their top surface.
Melt & Pour soap can be whipped into a smooth mousse-like substance whilst still quite hot, using an electric hand-whisk, then used as a convincing 'icing' on soap cakes or other toiletries like bath bombs. Simply spoon the whipped soap over the area to be covered and spread if required. Make sure to do this before it starts to set-up. The 'iced' surface can easily be decorated before it forms a skin, with glitter or flower petals etc..
There are soft forms of Melt & Pour soap bases available (often known as bath butter or 'ice cream' soap), which can be piped like a cream icing when warm, which can be used to great effect when 'decorating' soap 'cakes'.
Tip... To avoid 'bleeding' of colours into each-other, use a 'pigments' rather than dyes. Pigments have a larger particle size and are generally not water soluble, so will not bleed their colour. Alternatively, choose a specific colouring system like Zenicolour 5, made for the purpose.
Tip... To help layered soaps stick together better, wipe or spray the surface to be poured on-to with either Alcohol or Witch Hazel.
Obviously, this is a brief article and is intended as a guide to get you started. Experiment yourself and you'll soon be making beautuful soaps.