Howie Did It - An Experiment in 3D Printing

many years ago before noah was a lad we needed to come up with a method of successfully extending the arches on the mini to cover the significantly wider track of the seleka running gear a set of cheap pattern arches were subjected to some experimentation to try and come up with a way of adding 50 ml width but retain all the contours and features of the original sports pack arches the pioneering lycra reinforced plastic did the trick to a reasonable extent but we never finished them properly because it was obvious that these arches weren't going to cut the mustard you can see the 50 pence shape where it should be a smooth curve so the job needed doing all over again now that we know the process worked this whole situation is due to my unwillingness to spend 400 quid on a set of genuine arches just to cut them up for an experiment so instead what we ended up with was these much cheaper 40 pound pattern arches unfortunately they're made out of a much less stiff rubbery type stuff and they won't hold the shape these genuine arches are unnecessarily expensive but they're fiberglass reinforced polyurethane for good reason having now refined the method and obtained a used set of genuine arches it was time to go through the whole laborious process once more or was it in the autumn of 2019 i had a chance meeting with a mad spaniard by the name of ivan miranda he has his own youtube channel where he takes 3d printing to the extremes the giant nerf gun and drivable tank are just two of his mad cap projects being a binky fan he asked if there's anything he could do to help and of course when it became clear he was capable of pretty much anything we wondered if he could 3d print the arches for the mini technically possible he assured us but there wasn't a 3d printer around big enough to produce the parts so he made one and quite appropriately the first thing ivan printed to test it out was a massive spanner [Music] of course having a custom built 3d printer large enough to make our arches is no good without a design so we enlisted the help of our friend antonio carrazza better known for building championship winning british touring cars he also does a fine line in laser scanning and 3d modelling lasers freaking laser beams yeah that's so cool this simple shape gave tony a headache trying to successfully complete the scanning because there are virtually no features on it lining up the multiple passes to produce an accurate 3d shape was very tricky but after a few failed attempts he eventually got it spot on the next task was to use another bit of software to slice the arch down the middle and extend it by the requisite amount then it was just a case of adding in the missing section from the center and smooth out the profile we gave tony carte blanche to make all the corner radii whatever he thought looks best at this stage knowing that we need a test print to make sure they fit and at that point we could make some changes if we wanted to the main profile went through quite a few iterations in the design stage before nick was happy with it but once it was settled tony turned the design into a file that could be emailed over to spain for ivan to work his magic a few weeks later at the beginning of february a box arrived not pandora's box no this was ivan's box of assorted arch-shaped delights these were purely test prints in fairly low resolution and intended only to ensure the shapes were right the fixing bosses were in the correct place and they actually fit the car we took the opportunity to try some paint on the red pla to see if it reacted some primers and different colors were tested and it all seemed great ivan even did this one in a different material to see if we thought it was any better we didn't to simulate a stone strike a large phillips screwdriver was dropped from two and a half meters onto a sample of the plastic it escaped unharmed leaving tony to his own devices had left us with a couple of radii not quite as nick wanted so we batted it back to our tame designer for a few tweaks before settling on the final version a few weeks later the world went mad and so did ivan who having learned a lot from building the first giant 3d printer decided to build another better one because reasons if you'd like to see how ivan did it there's links to his channel in the description anyway with the design finalized and the new printer up and running we weren't going to let a global pandemic get in the way despite the obvious logistical challenges [Music] foreign [Music] uh [Music] foreign [Music] [Music] oh [Music] after the excitement of the print being completed dies down the task of removing the excess material starts you can't print into a void so this stuff that's being broken off just allowed ivan to print all the main shapes and the surplus plastic is just discarded if you're wondering each of the arches had to be printed individually obviously and each of the prints took 60 hours to complete 60 hours that's almost 80 hours two and a half days to complete one of our four arches the arch is then finished off with some sandpaper and a little elbow grease once ivan had finished his part he packed him into a large box and shipped them over to blighty for us to take the next steps which begin with finding a suitable method of attaching them to the car this is the oem m5 stud which when it's new is fine however once they're bolted up to the car it leaves all of this thread exposed to the elements with the inevitable consequences yep they get so corroded that you can't actually undo the nuts so you just end up winding them out of the arch leaving the stud in the wing if you're any good you can actually get those back out of the car with the um bonus that you end up with twice as many fasteners the aftermarket have now got around this rust problem by producing these studs in stainless steel but they are an eye watering 80 quid a set that but even they don't get around the main problem which is that these holes here only have one thread engagement which means they always pull out they really are just a bit crap and you'd think by now that someone would have come up with a better solution these m5 threaded inserts are made from brass which doesn't rust and they have five threads of engagement meaning they're less likely to pull out of the arch it does mean however that our 4.2 mill hole printed in the arch bosses needs drilling out to seven mil to accept the inserts winding them in properly is key to this so a cap head and a couple of nuts that act as a depth stop make the job dead easy they are specifically designed to self-tap into plastic so using these inserts should make for a considerably more skookum installation the brass insert is in and nicely flush with the edge of the boss the rest are done in exactly the same fashion the fasteners that we're using are these flanged m5 button head screws it's a bit more fat fitting this way as there's no stud poking through but there will be no exposed threads to get corroded so it should be easy to remove them should we need to the plastic printing process has resulted in a surface that isn't exactly smooth but between the red test prints and these final versions we increased the thickness from one millimeter to three millimeters so they're much stronger and there's plenty of meat for a damn good sanding that's resulted in the perfect key for this first coat of filler primer to adhere to so the first coat of paint is on and we're well on the way to completing our new arches the next stage is to sand back the thick primer to get a really smooth flat finish this is aided by the use of something called a guide coat which is just a black spray that helps to detect low spots scratches or other minor imperfections as the part is being sanded the majority of the sanding is taken care of with the air powered d a or dual action sander but they still need finishing off by hand and who doesn't occasionally [Music] we did this entire procedure twice on each of them to come up with a beautifully smooth surface ready for the next stage of the paint process which is another primer this time though it's the wet on wet primer which will be the final stage before spraying on the color the paint booth is heated to approximately the temperature of the surface of the sun it doesn't take long for the primer to flash off and be ready for the next coat remember this is very much an experiment we don't know how robust these 3d printed arches are going to be once they're on the road but we do know that they're more than good enough to produce a mold from and have them made in fiberglass or even something composite and exotic never mind all that they're ready to put the color coat on and tony is tooled up and ready to go you

Channel: Bad Obsession Motorsport

Views: 327,673

Rating: 4.9632211 out of 5

Keywords: binky, project binky, bad obsession motorsport, mini, austin mini, mini 1000, toyota, toyota celica, gt4, 4wd, gt-four, 3sgte, turbo, turbocharged, restoration, shrewsbury, shropshire, episode 32, 3d printing, ivan miranda, giant 3d printer, bodykit, wheel arches, experiment, body kit, arch extensions

Id: XM5z6DSsQzU

Length: 14min 48sec (888 seconds)

Published: Thu Dec 24 2020

Reddit Comments

[u/NSFWfordaysanddays]

That mini has been like 5 years in the making

[u/Captain_barbarossa]

Surprised to see some binky love on reddit.