I’m still exhausted from my caring duties earlier this week, but it does look as if I’ll have more spare time for the next few days at least.
Here’s my failed attempt to destroy the hexagon vitrine, so called because that’s the shape I drew on the embedded label. This is one of the three vitrines (test 4) which I completed last week in two layers. I’m still not sure I know why the upper layer is white.
These things are tough enough. I really thought the whole thing might split apart across the layer boundary, but there’s no sign of that. This is far more punishment than synth components can reasonably expect to undergo (except ones that may get dropped on airport tarmac) so I’ll leave it there.
Epoxy is used to glue vital parts of some Airbuses together…
So, even if you have a kind of epoxy optimised for it’s optical properties rather than it’s adhesive properties, and have not made any special preparation of the first layer before pouring the second, I was quite conviced it will never separate at the layer boundary.
This boundary IS the weak spot, and you can make it separate there, but not by throwing it at stuff with your bare hands… that will need more energy than that.
I deliberately didn’t prepare the first layer before pouring the second. It was dry and smooth. The result here, while not entirely unexpected, tells me that I don’t need to take special steps in pouring layers.
I still have layer 1 of test 5, and if I have time today I’ll pour a tarte aux cerises layer on top. This is where I use a mixture of acrylic scattering diamonds and freshly mixed resin. I’ll be looking at the optical properties of the finished item (which I really hope will not turn out white like test 4.) Test 5 is the two large items on the right in this photo. The three on the left are test 4 before I poured the second layer.
Okay, my current plan is to use 5-core insulated cable and devise a keying system to prevent polarity reversal or worse. I plan to use colour coded wires, and to make connectors with male headers and heat shrink.
Kinda wondering now why I don’t just use 5 pin mini DIN. Whatever I end up with, it will be fantastic.
Edit: damn, this sounds so cool. Aviation connectors! The price is keen, too. Less than 50p each for a connector pair.
Edit 2: I misread the item text. You get 6 connector pairs, not 18. Still looks good to me.
Edit: sorry this entire connector discussion was supposed to go to Fast prototyping, where it would have made a lot more sense in context with my earlier posts.
Ok ok, point well made. I once found a TRRRRRR jack and socket and built an entire project around it just so I could use it.
Go have fun but you may have to seriously reinforce your mounts.
8 pin din and 5 pin din are also cheap.
As good an excuse as any to buy that second hand Sea Harrier (one careful owner, 300,000 miles on the clock.) Suddenly my bookcase design is looking a little tame for my aspirations.
Back to potting. I’m still exhausted, and the heat wave isn’t helping with that. Tomorrow in principle I will be able to complete that tarte aux cerises layer I talked about. The bright side of weather like this is that it’s as good for curing as it’s ever likely to get in Northeast England.
Neve is panting. I’m going to try to get a through draught in this bedroom.
Not potting really, but I did get a chance to use the epoxy putty today to mend the loose bracket in the middle of my daughter’s curtain rail. It was easy to use, though I took the precaution of wearing disposable gloves while handling it. I’ll probably eventually get around to designing a line of mignons that exploit the versatility of this material. It handles like plasticine and sets like stone.
If you use wet fingers or take a wet brush to it before it sets you don’t get fingerprints on the surface. You can also copy a surface texture with plasticine and press it into the wetted surface of the epoxy putty (before it’s set). Works with wood filler too.
I used the gloves because I’ve used epoxy resin and I don’t want to risk getting stuff like that on my hands. It feels horrible and it takes a lot of scrubbing to remove. For my application here it didn’t matter whether the putty ended up with fingerprints. It was out of sight between the fitting and the hole in the wall.
With the recent fuss I didn’t get any experimenting done. I’ll soon revive that work. However I’m close enough to being ready for production, so I’m going to need to concentrate on my sapin de Noël circuit construction technique so I’ll have something to pot.
The circuit I intend to use first is a simple transistor voltage level trigger convertor. The design comes from the open source (GPL v2) schematics for Bela Salt, which needs to shield a delicate 3.3V system from scary Eurorack voltages. As I’m using surface mount parts I ought to be able to fit at least two of each circuit into a single vitrine. But first I must validate my half-baked ideas about how to solder these parts.
Once that task is out of the way I’ll produce a tarte aux cerises as promised nearly two weeks ago.
That’s the beauty of French. It’s full of great words and phrases. I would continue to use tarte aux cerises because most non-native speakers would be able to understand the metaphor, but for people familiar with French cuisine clafoutis would work to describe the technique of embedding a transparent solid armature of inexpensive acrylic gems in the resin.
That was in late July. The polyester resin is supposed to have a shelf life of three months so I’m going to have to make a move soon. It’s unfortunate that the autumnal weather has come so I’ll need to use artificial heating to keep it warm enough to set outdoors. Polyester resin isn’t the kind of stuff you can work with indoors.
I’ve got some plastic containers and a mains water heater, and I aim to run a mains line into the yard to heat up a water bath on which I can float my ice cube trays. If the temperature is kept reasonably high the curing time is supposed to be an hour or two, it sets much more quickly than epoxy resin.
And I’ll be using strict safety procedure for this stuff. It’s nasty to work with, much nastier than epoxy. Respirator, eye protection, gloves and overalls.
I was unable to use the polyester resin. This was a couple of years ago. I concede that I would have found this idea easy to implement if I had had the foresight to live in a warmer climate. There are some issues that I never resolved to my own satisfaction, the most important of which is how one can provide reliable power distribution to systems of potted electronics. But also problematic was the question of heat dissipation.
Most epoxy resins handle heat very well. I’m going to have to re read this thread to remember what you were doing.
Just been using clear photo cure resin. Sets when exposed to UV.
