Reviving Old Recipe For Faraday Wax Keeps Vacuum Experiments Going

Science today seems to be dominated by big budgets and exotics supplies and materials, the likes of which the home gamer has trouble procuring. But back in the day, science was once done very much by the seats of the pants, using whatever was available for the job. And as it turns out, some of the materials the old-timers used are actually still pretty useful.

An example of this is a homemade version of “Faraday Wax”, which [ChristofferB] is using for his high vacuum experiments. As you can imagine, getting a tight seal on fittings is critical to maintaining a vacuum, a job that’s usually left to expensive synthetic epoxy compounds. Realizing that a lot of scientific progress was made well before these compounds were commercially available, [ChristofferB] trolled through old scientific literature to find out how it used to be done.

This led to a recipe for “Faraday Wax”, first described by the great scientist himself in 1827. The ingredients seem a little archaic, but are actually pretty easy to source. Beeswax is easy to come by; the primary ingredient, “colophony”, is really just rosin, pretty much the same kind used as solder flux; and “Venetian red” is a natural pigment made from clay and iron oxide that can be had from art suppliers. Melted and blended together, [ChristofferB] poured it out onto wax paper to make thin strips that are easily melted onto joints in vacuum systems, and reports are that the stuff works well, even down to 10-7 mbar.

We love this one — it’s the perfect example of the hacker credo, which has been driving progress for centuries. It also reminds us of some of the work by [Simplifier], who looks for similar old-time recipes to push his work in DIY semiconductors and backyard inductors forward.

[David Gustafik] dropped us the tip on this one. Thanks!

24 thoughts on “Reviving Old Recipe For Faraday Wax Keeps Vacuum Experiments Going

    1. Technically, Trawled and Trolled are both correct.

      Troll: carefully and systematically search an area for something
      Trawl: an act of sifting through something as part of a search

      Though if you mean fishing,
      Trawl: an act of fishing with a trawl net
      Troll: fish by trailing a baited line along behind a boat

      oh wait.

  1. I love when people find ways to resurrect old recipes for industrial compounds, there’s so much out there that could make a lot of things more doable for hobbyists if some more of that stuff was resurrected.

    This is a particularly useful and cool thing he found for sure

    1. “Henley’s Formulas” is one of the best books out there for those hard-to-find old recipes. The old version can be had used for <$10. There is a "Twentieth Century" version also, but I have never looked through the newer one.

  2. There are lots of different grades of rosin. They differ in melting point, hardness, color. I suspect that softer grades may have residual turpentine which would be bad for vacuum seals. Any natural product will have differences based on origin and processing. Beeswax is refined by melting in a water bath, filtering, and cooling to separate wax from water. So, you need to be very selective to get material that won’t outgas for vacuum use.

    1. When its only in use as a sealing compound it doesn’t really matter if it does outgas unless what it outgasses in some way harms your experiment, as there is so little of whatever you mix up in use – all it really means is it takes a little longer to get to your desired vacuum.

  3. For people building their own apparatus (for personal use, or as their day job) my two go-to books for this sort of thing are:

    Henley’s Twentieth Century Formulas Processes and Trade Secrets, and

    Procedures in Experimental Physics (John Strong)

    Looking in Strong’s book:

    “Beeswax and rosin compound is prepared by … It’s outstanding property is its adhesiveness to cold metal. It is not very strong, but its strength is adequate for sealing vacuum systems and for fixing apparatus, as for example fastening a prism to the prism table of a spectrometer.” It continues with how to apply, how to remove, and other useful info.

    The two books above give a wealth of information on how a lot of really useful scientific stuff can be easily made at home.

    If you ever get a free moment in a library, flip through a copy of Henley’s and see if it doesn’t capture your imagination.

    Strong’s book is available online as a .pdf. If anyone knows of a copy of Hemly’s online, please post a link.

  4. It seems that Faraday borrow the old formulas for Enchaustic Painting and jewlry “holding wax”
    Both were common and use the same components.
    Enchaustic medium is beeswax and damar resin, and cheap versions are beeswax and rosin.
    I don’t know if would be cheaper to buy that medium or make it yourself

    1. Usually jeweler’s dop wax is shellac mixed with beeswax. Shellac is harder than rosin; I suspect it’d work in a similar fashion but I think it’d be a lot more brittle.

      1. Well, that makes sense – Faraday wouldn’t have come up with this out of thin air, he’d have started with existing compounds and adjusted the ingredients until he got the right properties for his specific application.

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