Cloning vintage knobs... This guy posted a cool video.


That was fun. Smooth-On makes good products. He orders from a third party on Amazon. You can order directly from the Smooth-On website or they're distributor Reynold's Materials.

Mold Star is a platinum based silicone. It has a long (approx 20 yrs) library life so your molds will last a very long time. However, it's very susceptible to contaminants. Make sure everything is clean or you may end up with a puddle of sticky goo.

If you decide to go with another silicone make sure it's pour-able straight out of the container. Most silicones are very thick and will require a vacuum chamber to get out all the air bubbles.

If you want colored, clear, or clear tinted knobs you'll need another resin (obviously) which Smooth-On also has and they have tints and colorants.

If you decide to make the entire knob (not just the top with flat bottom on it) that will require a 2 part mold (at least) so don't forget mold release and keys in the mold so both pieces will line up. A pour spout and/or relief holes aren't bad idea either.

He uses a mold release. You don't really need one with silicone most of the time but it doesn't hurt. But, silicone will stick to other silicone - see above comment.

I hope you enjoyed my novel.
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Formerly fullertone
Silver Supporting Member
His work is impressive, but I was thinking that I'd go on eBay to try to find a broken tube tester that has a decent knob or two.


Now I will never be able to be 100% certain that my vintage amp purchases come with all original knobs. Outstanding video.