The Talking Machine Forum — For All Antique Phonographs & Recordings

When I was molding blanks yesterday, I took a photo of a bad casting, this was caused by the molding temperature not being right. Also baremetric pressure, and humidity. It seems the wax itself is not the problem, you can use a batch that gives this effect, and waite a while later andy you see a record come out like the second, one without the star effect, a normal casting. Even dipping the mold in wax will still produce this effect at times. The acceptabe rate is about 40%good to ,60% defective, blanks from 15 to 45 min each is the molding time, wax takes about four hours to make. Blanks sit a day before they are cool enough to trim and ream. The only real wax cylinders are the 1888 white cylinders, all non celluloid records, brown and black are a metallic soap, either lead or aluminum.

60% is quite a rejection rate. I can easily see that many might consider this to be mold but AFAIK a cylinder with a such a wax structure has the blotches underneath the surface. Can you recycle a faulty cylinder and make a blank of merchantable quality from it?

Making blanks, is very odd and strange, it seems to me humidity, and athmospheric pressure are key to make good blanks, the conditions have to be right. The mold effect I believe is the different components cooling at different rates and seperating or humidity getting trapped in the wax as it cools. The blank can be melted again and the effect not there. Some of this effect is stearic vapor, you have to add it periodically as some of it vaporizes, the old stearic I do not think breaks down like the new kind does, the old formula literature says they used the same batch of wax for a week, cooling it and re meting it . Diamond. Disc master wax was re cycled too! This problem comes and goes, and has always puzzled me because you can fix it, but it is not the same fix all the time, in fact nothing is constant, I have made over a ton of wax literally,in the last 10 years and there is still mysteries. I have noticed this effects in some of the new UK blanks, when you shave dwn a few layers as well. I have never seen this effect on original records I have some wax making movies on youtube username edisonworks

Interesting this, and shows why the boys in the various wax departments were valued for their experience.

Jim