By Christopher O'Connor
I've always loved R2D2 and though I considered tackling a cardboard build of the little astromech once... that idea didn't last long as the build wasn't looking too good. Now I have access to 3D printing and the very generous works of Mr Baddeley (look for his patreon if you want the files... you can get the files without joining... hence "very generous").
I had planned to keep this as a project to do "a little further down the track"... but for some reason I decided to do a "test print" of part of the dome and once that was done I kind of figured "well that's done... I might as well keep going".
The starting place... if I can't get this right then there won't be any point doing the rest. Fortunately, following Mr Baddeley's plans... it's actually not too hard. The dome model is split in to two versions, one for large build plates and one for small. Due to my current build plate limitations I had to use the small version but it's designed in such a way that each part matches it's neighbour and bolt holes have been incorporated (as well as holes for small pieces of filament to be used to help alignment of the top (pie) portion. The larger portions took around 6 hours to print at the recommended .3 layer height and Mr Baddeley was quite right in that he stated he designed it to not loose too much detail at that layer height, but it does shave a lot of the print time. Having said that... a lot of sanding, filling, sanding, filling and so on was required to get a finish I was happy with (well at least willing to accept).
Painting is another issue. I ended up using an aluminium colour with Rub'n buff silver leaf on top... it turned out ok but part of me prefers and earlier version that used the same colours but due to having some of the black plastic exposed and a touch of the orangey/brown filler ended up looking kind of like brushed steel.
With the main part of the dome printed and prepped... it was time to move on to the panels and greebles :D
I have been told it's tough to sand PLA... but like many things you can't just be told that... you have to learn it for yourself first hand. Now I should clarify here... it's not that it's "hard" to sand... it's more that it's hard to get it to a point at which adding paint over the top won't show the layer lines etc.
I managed to get many pieces to a point where they felt quite smooth to touch (typically using sandpaper from around 120 to 240, 400, 1200 and even 2000)... but inevitably it would still show at least a faint hint of the layer lines beneath when paint was applied. I even went down the path of using spray filler... but found that it was not overly effective... it really is more for small... and I mean Small imperfections. Putty does do a good job but can end up costing quite a lot (ergo always buy the "economy" size tubs.).
To that end (ie I have a very tight budget) I thought I'd try some multi-purpose filler I had left over from a roof repair job I did last year. Now it is meant to be used on plaster... but I wondered if it could be used on 3D prints.
It turns out yes it can. Now I would add a caveat to that, namely that the finish seems a bit more grainy (though to be fair I haven't tried the wet sandpaper finish that I did on the dome on the pieces that I've tried so far... I may give that a go and see how it comes out). I also don't know if durability is likely to be the same... so they are issues to consider.
As of typing this I am planning on at least doing a test print of one of the panels at either .15 or maybe .2 layer height to see if that might improve the result sufficiently to swap all the pieces I've already done... well that and changing the print orientation... so I will probably be "back tracking" somewhat... but I do find myself getting very picky with the results on this build. Either way... sanding is something you just have to get used to... but at least the plaster intended filler sands very easily... I mean really really easily.... so I do suspect that it's too good to be true because it took a lot less time to get the pieces to a reasonable level of finish than it has with any other approach.
So while I wait to print/reprint some parts... I have started ordering some bits and pieces to give R2 life... that and my dad actually sent me an Arduino Uno, a servo motor and a few other bits and pieces... turns out the servo is the exact same one mentioned in Mr Baddeley's plans for use with the holoprojector so I should be able to test that mechanism once it's printed :D
I had ordered most of my bits and pieces from Aliexpress so it will take a while to get here (hence dad sending me the advance kit)... but I recently sold a review set of discs on ebay and figured I was entitled to use that money for more supplies... but this time I made sure it was from Australian suppliers.
So I should have a bunch of LED's, some prototype double sided copper circuit boards (they call them breadboards... are they technically?) I figure I may be able to use these for the LED arrays in some of R2's front displays.
I also have my ultrasonic mist maker and a little fan plus food storage container for my mist making machine... I'm still waiting on my mini MP4 player to arrive to take apart and see if I can convert it into a mini projector... the theory is I may be able to make a "mist screen" and project onto it... it's a big if and I've only seen other people mention the idea but haven't come across anyone who has pulled it off yet... so fingers crossed I can manage it.