I decided to post this as a re-mix, as I added some items and designed my own files to fit the upsized model.
Printed this great model by YipYip: https://www.thingiverse.com/thing:3086550
Took about 5 months in all from start to finish, working mostly on weekends only. The printing took a while and I sliced the model into sections, due to the up-scaled size of 1/32 to match my other aircraft. The final model, including the afterburners, is 1070mm in length!
The finishing and detailing took the most time, particularly the sanding, sanding and more sanding!
I had no issues up-scaling YipYip's model by approx. 520%, using the original STL model length and calculating the scale needed to achieve 1/32 scale. The print was done at 0.2mm layer height.
Sanded each section with 120/220/600/1200 grit papers in that order, joined the sections together (trial and error with the resized joining pegs, but superglue holds well), filled and sanded the joint lines, spray primed, sanded again with 1200 grit, then 2 final top matt/flat black coats.
The primer and matt black were Rust-o-leum 2X spray cans.
Had to design a "holder", which I used by wedging it onto a plastic pole and inserting it in the space where the stand would usually go - this was so the complete joined model could be held up for the painting work and detailing.
Also had to design a cover to fit over the undercarriage hole where the stand would usually be - as the model would be hung from the ceiling, I wanted to cover the stand hole.
I designed some windows to insert into the cockpit spaces, printed in transparent PLA, 1 shell, painted with Tamiya Smoke acrylic to give them a tinted look. Use the mirror option on the included files to print the opposite side of each window!
I could not source the right size decals locally, so decided to make my own and laser printed them on some old DVD label stickers - they came out really well and also stick well to the model. If I were to do it again, I'd fill all the pre-sunk decal markings on the STL before printing in order to achieve a better decal finish. The DIY decals cover the pre-sunk markings well though.
I used some Parrot vinyl tape (red 3mm) to mark the red stripes - ideally you would need 2mm, but I could not source it where I live. Turned out well though.
Added the nose spike, using some PLA that was heated and starched to achieve the right profile and length, then cut to length. Painted silver.
The afterburners were an after-thought - found a good set of cone/rocket shapes on Thingiverse (https://www.thingiverse.com/thing:3279856) and adjusted the length/diameter to fit the model - they work rather well, although I make re-print them to make them twice as long to match the picture I've seen of the real thing!
I originally tried printing in transparent red and clear PLA, but the transparent orange looked much better in the end. I've actually added similar to my Tamiya 1/32 F-14 Tomcat and Revell 1/30 X-Wing :)
This was a big project and a labour of love, and I'm well pleased with the final result!
Thanks again YipYip!
All the remixed files and additions are included here. The SKP files are also included if you wish to re-size or adjust.
The original SR71 main files can be sourced from YipYip's thing.
I've posted some pics in the comments section of YipYip's thing if you want to see some progress photos/text.
If you want more pictures of any stage, let me know and I'll share them ;)
Black, clear, transparent orange