Yeah color is such a great plus.... today I have been dreaming of printing a new body for my glasses. I just grew tired of the ones I have and thought how cool it would be to have many different sets to juts wear for whatever mood you have. Ok, so here are the first results! A mix of 2g Agar Agar with 100g of water results, once cooled down, in a rubbery gel, quite more stiff than regular Gelatby spota - Plastic Extruder Working Group
Adding color would be very easy indeed, like easy to get food colorants. I'm currently making some tests in my kitchen, keep posted, in 10 minutes I'll have some thrilling updates!by spota - Plastic Extruder Working Group
Ok, my curiosity was such that on the way home I went to a nutrition shop and got me 200g of Agar Agar for 11by spota - Plastic Extruder Working Group
I have thought for a while about a cheap and easy to use support material that might be used. There have been several materials proposed but my approach to this is that it should be as easy to obtain and prepare as possible, as well as easy to work around and remove once the piece is finished. Also, being non-toxic would be a plus. The first thing that came into my mind was Gelatin, but It has tby spota - Plastic Extruder Working Group
Wellcome back Mike! As of lately I have been very busy with stuff unrelated to RepRap. I'm trying to get my ass back to R&D at work, wich takes a lot of my time. The only developpement I have been able to keep up and finalize is the UV-curing resins, the results which you can find in the Fabrication forum. As for the Furfuryl Alcohol/Furfural resins, I have no new developpments yet. I haveby spota - Polymer Working Group
@nathan: I have tried out the upper UV-catalyzers with rectified linseed oil I got from an art-shop and it didn't work out. Looks like the double bonds available in the linseed are not available to the radicals created by the above catalyzers. sorry... @viktor In some other posts abouy phenolic resins i was trying out an organic acidic solid, solved in ethanol, called Tolueneparasulfonicacid thaby spota - Plastic Extruder Working Group
Hello Nathan! There seems to be a real lack of online sites that sell an of-the-shelve acrylic casting resin. I have been looking for it for over an hour now and have found nothing that would be usable. If I recall well, there was a page i found some time ago that talked about a MMA (methylmethacrylate) and BMA (butyl methacrylate) mix that was used to produce glass clear castings of objects. Youby spota - Plastic Extruder Working Group
It really depends on what material you are using. If you use spontaneous or triggered catalyzer hardening resins, you can apply many different types of building strategies. Stopping and restarting in the middle of a printout is just one. Another that comes to my mind is to print out compartments, later to be filled out with casting resin.by spota - Plastic Extruder Working Group
@Paul: Here a couple of sites for epoxy resins I have found online: @Adrian: All of the shelve UV-resins you will find are hugely expensive. Refer to the post above if you want to have a cheap version that you can mix yourself and are between 10 to 100 times cheaper (sometimes 1000 times cheaper for rapid prototyping mixes, they are really ripping people off)by spota - Plastic Extruder Working Group
What about creating a light underpressure in an airtight volume to accelerate evaporation? I envision some kind of a vacuum pump sucking air out of the reprap and condensing/recycling/disposing the solvent out of the air.by spota - Polymer Working Group
It could be usefull if we solve some major problems: the bubble formation of evaporating solvents and to get the evaporation to be uniform. Also, we need to get rid of all the acetone from the room, so ventilation will be necessary. It would be desirable to remove all the acetone in the mix to get a solid body. This would probably shrink the printed layer in some way, as we reduce the volume of eby spota - Polymer Working Group
Great! I'm curious about other resins too. Will get me some epoxy soon. Yeah I read upon the polystyrene and acetone, I will type an answer in the other thread now.by spota - Plastic Extruder Working Group
OK, no problem! Whenever you have time. I also guess the mechanical dispenser is probably easier to build and maintain, as well as cheaper. Will you be using Polyester or Epoxy resin?by spota - Plastic Extruder Working Group
I discovered by keeping the resin mixes in the dark that the pot-life they have is mainly dependent on light exposure. For three weeks I have had a mix isolated from light and it hasn't changed in any way. Good news, as keeping the resin unexposed to light until usage is pretty easy to achieve.by spota - Plastic Extruder Working Group
I think there is a previous thread on this issue in these forums. Dunno if a search will pop it up. Bottom line is that it's not easy to synthesize, it's more of a factory process. Check out this for a hunch:by spota - Plastic Extruder Working Group
What's the brand of this conductive paint you are talking about? Is it available in shops or online? if we can get a conductive path painted with this and improve conductivity by electrolytic deposition of copper this would be the easiest solution. I have made some conductive resins loaded with copper powder filler, but the resistance was in the order of 1 Ohm, which is to much for circuit boardby spota - Plastic Extruder Working Group
Yup, that's great! I somehow wanted to have everything together in one place. Before you start mixing away with the chemicals I sent you, we should first discuss it here. I am sure the mixes I mentioned above can be made more economical, like 3g+3g+1.5g or such. One question for you: do you have access to a chemical products store next to where you live? You will notice pretty fast that once youby spota - Plastic Extruder Working Group
Well the only ways i know of to reduce Copper 2+ to elementary copper is eitjer by electrolysis or by deposition on a less noble metal, as zinc, iron etc. deposition usually results in an uneven porous surface that won't conduct well. As for ascorbic acid, or any reducing agent, you will most likely only be able to reduce Copper sulfate only to its Copper 1+ form, just a different salt, really.by spota - Plastic Extruder Working Group
4) Recipes Here I will list a number of possible recipes for UV-curable resins. The list below is just a start and I'm sure a wild variety of different ones will emerge and evolve in time. I have created a small spreadsheet to calculate the prices of these mixes. I will show the price as well. Pot-life of all these resins can greatly be improved if they are kept away in dark places and in opaqueby spota - Plastic Extruder Working Group
3) UV lamps Here I will discuss the source of UV lights that can be used for curing the resins at hand. The wavelength necessary for activating the photoinitiators is dependent on the chemical nature of each photoinitiator. In our case, Benzophenone, Benzil and Benzoinisobutylether are all especially sensible to 2 wavelengths: 256nm and 365nm. 256nm UV-light is in the UV range generally describby spota - Plastic Extruder Working Group
2) Catalyzer Chemicals These are the names of the chemicals used: Benzophenone, CAS: 119-61-9 (+/- 44Euro kg) Benzil, CAS: 134-81-6 (35Euro 500g) Benzoilisobutylether, CAS: 22499-12-3 (36Euro 100g) MDEA, CAS: 105-59-9 (31Euro 1kg)by spota - Plastic Extruder Working Group
1) Resins * Polyester resins These are cheap, very commonly available resins. They are, when not mixed with fillers, clear and have the consistency of syrup, the viscosity depending on the Styrene monomer solvent content it has. The resin sold in shops usually comes with a dual component catalyzer, generally Benzoylperoxide or MEKPeroxide. This catalyzer is of no use for our UV-catalyzed mix. Theby spota - Plastic Extruder Working Group
What do you need for using UV-curing resins? In this thread I will list a number of materials you will need to make use of UV-curing reins. I have decided to post this information here in the forum for now, as it seems the place where it's guaranteed not to be deleted and I can always link to in the future when asked these questions, as well as being able to receive comments from people engagingby spota - Plastic Extruder Working Group
Zach asked me on the builder's blog what the shelf-life of these resins was. That's quite an important issue as nobody wants resins to harden in your gear overnight or even worse, while you are printing. I have found out that on my standard, high reactivity resins (composed of high amounts of any of the new catalyzers, between 4-5 weight% of new catalyzers along with 4-5w% Benzophenone (BP) andby spota - Polymer Working Group
Maybe I'm funny that way but Walter jon Williams is one of my all time favourites. "Aristoi" is a great book about self-replicating machines set in space opera setting. But I'm a complete fan of hard sci-fi, such like Kim Stanley robinsons Red, Green, Blue Mars, and anything of that typeby spota - General
I made some tests with pressure pots a while ago and I can confirm that the repeatability of these devices is very tricky to achieve. But if you want to use that simple and cheap device for testing UV-resin extrusion, you can go ahead. The Polyester resin is OK with polyethylene plstic this pump syringe seems to be made of. There are some plastics that do not respond well to PE resins. These areby spota - Polymer Working Group
It has more of a honey like viscosity, yes. Probably acrylic resins could be made less viscous. But those resins remains to be tested yet as I have only tried out Polyester for now.by spota - Polymer Working Group
Ah, if you could get me plans for a syringe based RepRap I'd rush in and start buying and building myself one. I am confident enough on the resins I found to start printing some very neat stuff as soon as I have a robot for it. Maybe you could tell me what are the modules I can start with and that will support your newly designed syringe head. I will probably not have finished the building beforeby spota - Polymer Working Group
Well, I know the products needed for visible (blue light) radiation curing and they are all very expesive, sadly. This application, for now, is out of our reach, unless I manage to get fulltime in a research-lab with all the means necessary to find out some cheap chemical that would do this. This means if I win the lottery or some philanthropist to pay for my billsby spota - Polymer Working Group
I think Viktor has answered there quite exhaustively. I would add that I have no idea what an optical robot with precision mirror parts means as a development challenge, and if it's manageable, what the price tag would be. I would rather carry an optical fiber with a lens at the end on a cartesian robot arm, which would make things easier to implement. Also, I wager the UV laser needed for theseby spota - Polymer Working Group