EMRFD Message Archive 14982

Message Date From Subject
14982 2018-08-04 11:25:59 Jim Strohm 3-D printers and missing radio parts
Hi all

I just came back from the Austin Summerfest swapfest, where I saw a gent making 3-D replacement parts for a camera tripod (missing feet, etc.) to show the capabilities of the 3-D printer he was trying to sell. 

When I got back to my truck, I looked at a huge old surplus choke I got for next to nothing because one of its porcelain insulators was broken off and missing.

Now, it's not hard to make replacement porcelain parts if you have an original.  Just make a mold from the original, pour in your porcelain slip, and fire it a few days later.  Then glaze and re-fire.

BUT -- porcelain shrinks unpredictably when it dries, somewhere between 8 and 15%, depending on which river bank it came from.

Now, here comes the cool part -- 3-D laser scanners are coming way down in price, the same way 3-D printers did a few years ago.

So you can scan your original with the 3-D scanner, print the part, make a mold to cast and fire a prototype in porcelain, then fire the prototype.  That lets you measure the shrinkage with the 3-D scanner, determine the EXACT percentage of shrinking, and then up-size your prototype using the percentage you found to make molds that will deliver a perfectly sized finished porcelain piece.  As long as you use the same porcelain, you will have exactly the same shrinkage.

This gent at the swapfest wanted only $400 for his rather nice 3-D printer, and it came with several spools of plastic feedstock.  Here in Austin you can get ceramic kilns all day long for well under $1000 -- and the itty bitty 110VAC kilns often go unsold for $200.  They will fire porcelain.

All you need is that 3-D laser scanner to complete your system. 

If I cleaned out all my Porsche junk, I'd have room in my garage for ... hmmm.  Maybe it's time to post for-sale ads for my '80 924 Turbo and my '87 944S twincam with spare engine.  That would pay for everything I just mentioned.

In the meantime I got lots of cool stuff from the swapfest today.  If anybody else collects ARRL handbooks, I will have my extras available as soon as I sort them all out.