PSM’s resin update set for the ICM Unimog also contains 3D printed coil springs for all wheels that look incredibly much better than the kit parts. The ones for the front wheels, however, have a printing support rod in the center that I think should be removed – just how? The base plate is of hard, brittle material about like clear plastic, so I’m afraid to destroy the springs. Any suggestions are very welcome.
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It does look like the bar in the middle should not be there:
(source)
No idea how to remove it, though. I must say that I do think the 3D-printed spring looks rather flat, however, like it’s not made of round cross-section material
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I tend to use a Ultra-sound knife for such jobs. It makes possible to cut the material without exerting any significant force.
Mine is a Proxxon. It was quite expensive, but worth all the money I paid for it to cut delicate 3D-printed or laser-cut parts.
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Yes, Jakko, the bar must go, as otherwise, the spring on the prototype couldn’t be compressed. And I intend to thicken the 3D part with thinned white glue - once the bar will be gone.
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Like you said, Alexandre, those supersonic cutters are quite expensive. Considering that this is the first time in more than fifty years of plastic model building that I’m unsure how to cut (plus my statistical remaining life expectancy) I’m not (yet?) willing to shell out that kind of money. Thank you for the suggestion, though.
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I use UMM-USA micro saw blades because they have more teeth than most micro saw blades I have seen. I usually end up bending it too much and breaking them. I would take one of those bits and put them in a pin vise to cut out the rod.
Usual don’t try this at home and wear eye protection, etc.
Because a picture says more, one of my scraps in a pin vise.
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Not very keen on detail/correction sets that must be corrected…
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The following process is more applicable for making straight coil springs such as those on the HEMMT and MRAP.
From the Archives:
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I haven’t read the linked post yet, but is the method there to wrap two (or three) wires together to get the spacing right? That’s how I would do it, anyway.
Unimog springs have a problem here that the upper and lower coils are smaller, though. I think I would try to make them from copper wire, all to the larger diameter, and then bend the end coils a bit more tightly.
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“What a drag it is getting old” sang the Stones, and I can confirm that: It took the search for something entirely else in my tool drawer to stumble on this set of saws. Bought them a few years ago and never needed them, so I didn’t remember. Their teeth are even finer than the fine-toothed side of the razor blade saws we all know, plus they come in very handy shapes:
That made removing that strut easy enough, so I could start ”rounding” the coils.
I like to make test builds with white glue; after disassembling them, it is only too easy to overlook transparent residue, so I always have a little bottle with a few drops of white glue, thinned with water and dyed with a drop of black Gouache. This thin liquid could be applied to the flat coils in tiny drops on the cutting edge of a #15 knife blade - several times, until it had built up sufficiently.
For me, that’ll look good enough under a coat of OD.
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