I would like to share some information concerning the melting and rendering of beeswax. As a fairly new beekeeper I have not had access to very much wax, and have therefore regarded every bit of it as precious, even old brood comb.
Most of the information I have found, both on this forum and on other websites, has referred to repeated renderings of the wax, and the use of cheesecloth, or stockings, or coffee filters to capture the fine particles of dross which can be made to settle out of the wax. Some of the people who have used these types of material have referred to the fact that this method of filtering causes some loss of wax. Some of the comments in this discussion thread refer to methods which can be used to recover wax from the filtering material.
The information I want to share is that I have been able to get very clean wax as a result of a single rendering of quite dirty wax, without the need for any fine filter material. I hope that this may be of interest to other members of this forum.
The first requirement I have found is that plenty of water should be used in the saucepan or pot, in comparison to the amount of wax. I have used about three times as much water as wax, when I have purified my wax. If the wax has any residue of honey in it, I would suggest that the wax should be washed in cold water to remove any honey residue before commencing the wax rendering.
I have made a sieve which uses a fine wire screen, similar to one which you may have in your kitchen, but my sieve has a long handle about 18 inches (45 cm) long. This protects me from reaching too close to the pot of boiling water and wax mixture. While the water is boiling, I repeatedly scoop my sieve through the water and melted wax mixture, to remove every bit of course debris, whether that is dead bees, or silk cocoons, or any other foreign material. It is very easy, with this method, to collect the debris, allowing wax to drain back into the pot, and to shake the sieve it until it is virtually free of wax.
After removing this coarse material, I then transfer the saucepan into a large insulated box. The purpose of this is to shield the saucepan from any breeze or draught, to allow the mixture of wax and water to cool as slowly as possible. If a close fitting lid is fitted to the saucepan, and the box is well insulated, it will remain quite hot for a number of hours. The fine particles of debris which are still in the hot water and melted wax mixture will only settle slowly, so we want an environment in which the wax remains molten for a long time, providing the opportunity for the dross to settle down to the water level. The chief reason why people have had problems of impurities remaining in their block of wax is that the wax has cooled and congealed before the dross has had time to settle down to the water level.
When my wax block has cooled down, and I have been able to shake it out of the saucepan, it has been easy to scrape the dross from the underside of the block of wax. I have found it helpful to actually shave a thin layer of wax from the bottom of the block, to get back to really clean wax, and to set aside those shavings for the next batch of wax which I wish to clean. The saucepan which I use has tapered sides, because this makes it so much easier to shake the wax block out of the saucepan.
Using this method I have been able to get wax clean enough after a single melting, to then be able to use the wax to make wax foundation sheets with my silicone mould paddle, using a process similar to that used by Tim Rowe. I have been able to do this without the use of any cloth, or gauze, or other fine filter material.