DIY Bakelite moulding?

[Kiwi BlokeParticipant @kiwibloke62605]

As part of the restoration of an old accordion (sometimes I wish I hadn’t started – and there are three more…), I wish to make some smallish moulded components, ideally keeping the material used ‘period’ – 1940s -’50s. The originals seem to be a thermoset ‘plastic’, probably Bakelite, or possibly ebonite. One has a blind, threaded hole and fractured along it, revealing what looks like a moulded-in thread. The bits are small feet (like instrument feet) and a handle, fixed to a flat plate (which takes most of the load) by a couple of screws into blind holes. All are self-coloured black.

It wouldn’t be difficult to make female moulds: the shapes are such that split moulds wouldn’t be necessary. Is DIY Bakelite casting practicable? All I know is that heat and pressure are required – but how much? And where could I get a couple of ounces of powder?

Any suggestions for alternative materials welcome. I’ve thought of casting epoxy, but I suppose a hard, yet easily machined black plastic might be OK. I’m attempting a quality restoration, so it’s all about look and feel…

[Alan CharlestonParticipant @alancharleston78882]

Hi,

Bakelite is made by heating phenol and formaldehyde together using acid as a catalyst. It’s not really something you can do at home.

If your after a black, hard and brittle plastic, what about perspex, which is readily available in black. You can easily machine it to the shape you want.

If you want to cast the parts, I would look at perhaps using Bond O Fill mixed with black pigment.

Regards,

Alan C.

[DiogenesParticipant @diogenes]

Hmm, I think it possible that some ‘potting compounds’ might be suitably dense and ‘black’.. ..but it’s not something I know anything about.. ..anyone else?

[JasonBModerator @jasonb]

Corian is not hard to machine and I have used it to replicate old switch gear, you can also get a range of “Fake” materials made from various resins from the likes of GPS Agency

Also look at the resins and pigments used for woodworking that can be tinted with pigments if you want to cast, possibly into a RTV silicone mould taken from an existing part. Teranti for the RTV who also do resins.

[Michael GilliganParticipant @michaelgilligan61133]

This article on Britannica is worth a look, Kiwi

https://www.britannica.com/science/Bakelite

… it appears to be technically and historically robust

[a refreshing change from some of what a Google search will find]

MichaelG.

[John HaineParticipant @johnhaine32865]

+1 for Corian

[gerry maddenParticipant @gerrymadden53711]

Kiwi, I remember doing bakelite moulding in my engineering practice training courses back in the 70s. The material was a dark gravelly powder which we poured out of bags into the moulds. I don’t recall that it needed much force on the mould-halves other than that needed to ensure the powder filled the moulds properly. I cannot remember the temperatures we used but do recall that virtually everyone on the course went home with an defect-free ashtray. So it wasn’t a difficult process !

A quick look at the web suggest the powder might still be available, as bakelite still has some advantages, possibly for electrical components, including relatively easy mouldability.

[Roderick JenkinsParticipant @roderickjenkins93242]

As a guide, Bakelite granules as used for mounting metallographic specimens need pressing at about 250bar and a temperature of 180C

Rod

[Ex contributorParticipant @mgnbuk]

I saw thermosetting plastic terminal boards being made during a “Friends & Family” visit to Brooke Motors some years ago. The raw material was (IIRC) a dark soft pasty compound ( a bit like soft marzipan in consistancy, but not as tasty) & the operator weighed out the “shot” before putting it the heated mould (which already contained the contact studs). After putting the compound in the mould it closed & was held under pressure for a predetrmined time before the mould opened & the hot, hard, shiney part was ejected.

Unfortunately both Brooke Motors and my friend who was the employee who took me in are no longer with us, so I can’t follow up on the compound or the parameters of it’s use – but I don’t recall anything particularly special about the basic process or the tooling used. Bakelite are still in business and have two addresses in the UK, so maybe reach out to them ?

Nigel B.

[Robert Atkinson 2Participant @robertatkinson2]

I’d use a Methyl Methacrylate adhesive. These basically make acrylic “perspex”. Use an RTV or two part silicone mold.
If it’s just black you need:
https://www.easycomposites.co.uk/vm100-black-methyl-methacrylate-adhesive (Not used this supplier do your own due dilligence).
For other colours use the standard white and add pigment to get the colour you want.

 

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