It is, and I may well use opaque resins because they’re so easy to work with.
I value a transparent medium not only because of its aesthetic appeal, but because it would be easier to diagnose internal problems. I could use an optical thermometer to read the temperature of an internal component, to name just one advantage.
My current favourite idea is to use plastic and metal boxes. An external plastic box holds 10 litres or so of water at an initial 40C or more. It can be filled using a hose from the kitchen tap. A smaller box (probably metal) floats inside and holds the moulds loaded with items to be cured. Both boxes have ventilated lids. It’s best if the large box has a transparent lid.
This assembly would be used outdoors in a well ventilated location. Perhaps a rigid insulated cooler is best for the external box.
Vitrine test 4 ep 4, 5 ep 2: success.
I made this video about half an hour ago. In short, test 4 has satisfactory results after 49 hours but test 5 outperformed all expectations by curing well in 24 hours. Toolshed temperature at the time of this video was measured at 15C, on a windy day. The tripod blew over and deposited my phone on the concrete yard shortly before the test, so I count myself lucky to get a good 4’30" take with decent sound and reasonably good picture.
Here is a picture of the assembled vitrines. These are layer 1, each of them will now get a second layer and spend a while in the toolshed.
Layer thickness here varies between 8mm and 15mm. I haven’t been too concerned with levelling as I consider it an unnecessary factor for my purposes. As long as the components are covered I will consider the result a successful vitrification.
Note the three paper labels in front of the smaller items. They are different geometric shapes drawn with blue Crayola Super Tips washable marker (triangle), black Sharpie fine point permanent marker (circle), and Staedtler HB school pencil (hexagon.) I plan to embed the labels between the first and second layers as a test of different marking methods.
I should have used a 2B pencil, clearly. The HB line is faint and indistinct compared to the markers.
Edit: having limited time I chose to start the second layers on test 4, complete with the embedded paper labels. Test 5 will have to wait until I have time to add another layer to it.
Edit 2: I lost track of time during the layer 2 potting. I’ll take zero hour as 2100 on 28th just to have a figure to work with.
Vitrine test 4 ep4: I’ve Looked At Clouds From Both Sides Now.
Vitrine test 4 is complete, at least for now. After just 16 hours in the toolshed all three vitrines were solid enough to remove from the ice cube tray and the video shows that they have excellent definition and handling qualities.
An unexpected effect is that the second layer is cloudy. The two possible causes of this are contamination of the mixture and bonding with the polypropylene in the upper part of the ice cube tray. I’m so happy with the new silicone 5cm ice cube trays that I probably won’t want to use these old ones again anyway.
Edit: another obvious possibility and one I now think is the most likely, is low temperature. The toolshed has a temperature gradient from floor to ceiling of 15C to 16C but this is only when I measure it. At night time especially with the heavy recent winds the resin may be too cool for optimal curing.
The vitrines still look very beautiful, and the underside of each label is still clearly visible through the first layer. It’s not what I’m after though.
First view of the second layer.
The tray is now inverted on the concrete and I have a toy mallet ready.
One of the vitrines (triangle) is out of the tray and looks pretty good. The Swiss army knife shown here was used only for probing the surface prior to removing. I didn’t risk using it to remove the vitrines. They came out cleanly with a few light taps on the soft green underside of each ice cube cup.
Here’s a 15-second video demonstrating the good handling qualities and appearance of the triangle vitrine.
Finally I got circle and hexagon out by banging the underside of the tray with the toy mallet, just as with triangle above. Here’s the line up shown with layer 1 on top. You’re seeing through about 10mm of clear layer 1 resin and the thickness of the printer paper to the marks made by the HB pencil, black permanent marker, and blue washable marker respectively, seen from left to right. I’m surprised the pencil mark is visible at all.
I’m really excited about this. The vitrine à sandwiche method works very well. It seems that thinner layers cure disproportionately faster than thicker layers. It might be possible to design more convenient production processes involving multiple thin layers each curing within an hour or two in daylight conditions which are typically warmer and easier to control. A full batch of vitrines could be constructed in a single day, with a carefully designed process. I’m now planning carefully controlled thin layers of varying degree, and brief curing tests, in order to measure the effect of layer thickness on curing time. The use of ice cube trays suggested by Sandy (@Farabide) is proving its versatility
Vitrine test 6: a new method.
I’m trying to remove the mixing vessel from the process and also to use hot water (around 50C/120F so safe to work with) to keep the final pour as warm as possible.
For this I mixed a very small amount of resin, around 22ml, in a graduated cylinder kept warm by standing it in a bath of warm water. I used a wooden stirrer and as well as stirring I inverted the entire column twice though I refrained from shaking it vigorously.
This is what it looked like after five minutes of continuous stirring.
Then I let it stand in the bath for 15 minutes. This was in the hope of bubbles rising to the surface and clearing the resin.
Meanwhile I transferred the mould to the sink to keep it floating in hot water.
I don’t think the 15 minutes made very much difference to the bubbles, but here’s a photograph anyway.
At this point the resin had become very thick, but it still poured. I took these photographs with the flash in the hope of showing the bubbles more clearly. One cup had resin up to the line between green and white, the other is about half as deep. I poured a very small amount into a third cup. The centre cups of the ice cube tray were chosen because they are the most likely to be level with the concrete floor.
At 1830 I transferred the mould to the toolshed, where the ambient temperature was 15.5C. I’ll check it after 3 hours to see if there are any clear signs that depth makes a difference.
Edit: after three hours I couldn’t really detect any difference. The ambient temperature was around 14C.
An old baby bottle warmer or a yoghurt maker (warm water bath in a square thermos) might make a cheaper warmer or one of those snap chemical hand warmers under the tray may help.
It might be worth remembering that your circuit will cover several layers. So dipping the circuit into water in your measure will let you guesstimate the remaining volume for each layer and packing out with clear plastic beads or suchlike may save curing time and resin.
Mignon a rice crispy treat?
(Sorry I’m catching up on the posts. Been asleep while everyone’s been so busy)
Really great ideas there.
From Friday the 31st of July I may have a lot less spare time as my caring duties take centre stage. This is likely to last at least for most of August. After that whenever I have any time for these experiments I’ll have to deal with the cold and the shortening daylight hours.
Still, that’s all part of production engineering. The process will have to be weatherproof.
It took me a few minutes to realise what you meant, you genius. I just ordered a pack of 5000 clear “scattering diamonds” for £4.50. Smaller sizes may work better but this will be a relatively painless way to prove the concept.
Vitrine aux diamants? I’m working on it. Part of me just wants to call it tarte aux cerises.
Edit: these are said to be 4 x 4 x 3 mm and made of acrylic. At that size they also provide a useful armature for supporting the circuit during construction. On the downside they occupy valuable space, but I can always build upwards with more layers.
Edit 2: tarte aux cerises stuck in my head, so that’s the Bitnik name for that construction method now. But obviously call it whatever you like as long as it’s reasonably acceptable French.
Vitrine test 6 episode 2: no clouds.
Well I checked test 6 at around 1115 today, nearly 17 hours since potting. All three pieces had cured well, but there were still lots of bubbles. Gentle warming in the bath after mixing had not helped noticeably at all.
Toolshed temperature was around 15.5C at the time I checked it.
Here’s a profile view with a rule to give a rough idea of scale. The markings on the right hand side of the rule are centimetres and those on the left hand side are standard inches (2.54cm.)
I’ve just taken delivery of a heat gun, the kind of device used to activate heat shrink. I’ll try using that to encourage bubbles to come out of the mix after potting.
You can try this : https://www.youtube.com/watch?v=hwMDTME8VVY
I like the method she describes there. I’m going to go back through my posts and try to isolate why I’m no longer getting problems caused by unmixed epoxy.
The reason I would be cautious before adopting the method shown here is that I see it introducing a lot more work. I’ve just eliminated my mixing vessel for that very reason.
What you don’t see is the amount of cleaning involved after each pour. I mean I’m mixing a very powerful adhesive here, so of course it’s a real pain when you need to clean up. Reducing the amount of unnecessary work involved is a large part of my research. Reducing the amount of vessel surface area that makes contact with epoxy resin is a key factor in that.
Here’s the graduated cylinder I used in test 6 yesterday evening. Notice that I inverted it and stopped the mouth lightly with kitchen roll. The remnant of mixed epoxy has flowed down to the mouth and formed a plug. This is intentional, because if it remained in other parts of the cylinder I couldn’t clean it off. It will still need some serious work to clean this up before I use it next, though, and I haven’t had the opportunity to do so.
Use disposable plastic cups for the mixing (if they are big enough depending on how many minions you’ll pour at once)
And use a pocket scale to get the mixture proportion right :
https://www.amazon.com/s?k=pocket+scale
No more cleaning…
Glass is sustainable, disposable vessels are not. I’ve had no problem pouring the right quantities, but the viscosity of this fluid is such that there will be cleaning.
I’m also making an effort to collect my waste and keep it out of the water course. This project is supposed to make the world a better place, not worse.
The 1Kg of polyester resin has arrived. Even though it’s well packaged, I decided to put it out in the yard immediately on opening. There are two parrots and two budgies in our living room at the moment; even stuff that’s okay for humans such as non-stick coatings on frying pans are forbidden as an unacceptable health hazard in our house. We use ceramics that have been declared safe for birds.
That stuff really does have a powerful smell. It hit me as soon as I unwrapped the parcel.
Elements of typical polyester casting are shown in this video. Note that I don’t endorse the method used here. Gloves, protective clothing, respirator and protective eyewear are essential when working with polyester resins.
The difference is the method of setting (a very small amount of catalyst is used) and even quite deep cast resin sets in a matter of hours given appropriate temperatures. The toxicity means this stuff must be treated with respect. You can get away with a lot more when you’re casting epoxy.
Edit: the toolshed is actually under our stairs although it is only accessible from outside the house. By this evening the pungent smell of uncured polyester resin had become noticeable in our stair well, so now it’s in the garden shed where I should have put it in the first place.
Following on from the tarte aux cerises idea (big thank you to Sandy) the scattering diamonds arrived. Depicted here on my slightly chaotic bedroom work surface because I’m not quite ready for the breakfast table yet.
These items are very reflective in air, but I hope the optical qualities will be different in resin. Ideally they should be quite transparent, as their function is simply to occupy space and make resin curing times shorter.
Incidentally this is a product marketed for the wedding industry. Apparently some people think it’s a neat idea to scatter them like diamonds (hence the name) on tables at the wedding banquet. I had no idea.
Kids, speaking as one who has been happily married for longer than many of you have been alive, I say no amount of money and show expended on a wedding will help to make a good marriage. Be poor and in love, but don’t deliberately squander money you could be saving up for things that really matter. If you want to do cosplay, get an Instagram account and some glitter and have fun for much less money, at a time that suits you. Look, if Tom Lenk can make a career out of being Tilda Swinton the sky’s the limit.
Here’s a quick refractive index check. Here’s one of these cerises resting on top of the results of vitrine test 1 (our old friend the 1K resistor) both immersed in water. Compared to their appearance in air they both seem to be quite muted.
The cerise is perhaps a little more reflective but that’s mainly because it’s gem cut. I don’t have time to do any resin work today but this test makes me feel more confident about the optical properties of the acrylic cerise. It seems like a good match to the epoxy resin. We’ll see how that works in practice when I start sprinkling them in my test castings.
We had a simple ceremony with friends before it was legal here. Once it was time, we just went to the courthouse.
Dunno how Tom Lenk got in there. My daughter is obsessed with him, I suppose. It seems that I may have picked up a secondary infection.
