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Hi - I am looking to get a Mars Pro 2 printer, mainly to manufacture low strength engineering components to supplement my traditional lathe and milling machine capability. Some components may need an element of flexibility, for example, a pipe clip needing to flex enough to clip over a pipe without fracture etc. Are there resins available to give some flexibility? From what I have read, most resins, when cured seem very brittle and break easily. Generally, are the Elegoo printers good for engineering tasks or would an FDM set up be more suitable?
Many thanks
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Experimenting with different mixes, one runs the risk of ruining a tankful of resin. Given the cost of even the cheap stuff, and the fact that I'm a cheapskate, I'm not yet at the point of that kind of experimenting. At least not until I can get consistent results with the parts I'm making.
Then it occurred to me that it's not necessary to mix up a whole tankful. You just mix up a very small amount, pour it into a mold and cure it under the curing lamp. That, in turn, got me wondering how much of an adulterant could be added to the resin before it would no longer cure properly. The only material that I have readily available, and that has been used industrially as a plasticizer is linseed oil. So, last night I mixed up a small batch with varying amounts of linseed oil, poured it into disposable plastic spoons and cured it under the UV light. I included a control sample with no linseed oil. The sample with about 2 drops of linseed oil per teaspoon cured completely, but took a bit longer than the unadulterated sample. I didn't measure the time difference, because at that point, I didn't know if the adulterated sample would cure at all. When it did cure, I did a third sample with considerably more linseed oil. I didn't measure exactly, but I'd guess that it was as much as 15% linseed oil. Even this extreme case cured, though taking longer again. There was an oily film on the surface of this cured piece. So some of the oil had separated out.
By curing a thick liquid sample all at once, they all developed a fairly large hollow in the middle, when the surface hardened almost immediately and then lifted, allowing air to get underneath. However, they were all identical in this regard. So, that doesn't seem to be anything that can be attributed to the linseed oil. In fact it's hard to tell the difference between the three different samples.
I haven't given them the hammer test yet, because I don't know how long it will take the linseed oil to polymerize (by oxidization), and I think I should wait for a while to allow it to happen. I'm not expecting the linseed oil to improve the properties. I'm more interested in how much it degrades the properties.
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FWIW I have mixed resins as diverse as Elegoo's water washable garbage and Siraya Tenacious and have yet to come up with anything that could net be "printed". That was a fingers-crossed long-shot, but I was too cheap (my mother's family are Scottish) to toss out the 1/2 litre or so of the WW crap that remained unused and not likely to be used. Turned out this stuff is more miscible than i had any reason to expect.
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That figures, a soon as I find an affordable resin I like it goes away...