Two Color 3D PlaqueWelcome to the latest instalment in my new 3D Printing Beginner Series.

I did so much 3D printing last week that I couldn’t cover it all in one reasonably sized blog post, so this is kind of part two.

There’s lot of good stuff to cover in this post so lets continue right away, starting with multi color printing.

Although I’d heard of using a single extruder printer to create multi color prints I’d never really given it much thought until recently, when I noticed the Pause option on the MakerBot menu.

After pausing a print and resuming a few times I then noticed that you could also change the filament before resuming. Viola, we have basic multi color printing.

Ok so it’s very limited because you can only use different colors for different Z-axis layers but where you want a different color for the upper part of a print it’s great. Typically this could be a plaque/keyring with raised writing on, or even something like a black fishing float with a bright orange top. There are multiple uses for this feature.

A few test prints later and I noticed the “Z Pause Height” option on the MakerBot menu too. This only seems to be available once a print has started, but it allows you to automatically pause a print at a given height in millimetres. This means you can swap colors at a precise height without having to supervise the entire print.

This is a great feature and one which I’ll be using a lot from now on. One thing to note though. When you start a new print sliced with something like MakerWare it’ll start by extruding a line of filament in order to help clear the extruder before printing.

This doesn’t happen after changing filament during a print, so try to ensure there is minimal plastic hanging from the nozzle before you resume printing. It’s not critical and any initial excess can usually be removed from the print afterwards, but it does help create a cleaner print.

Custom Profiles for Fine Tuning Your Prints

In previous posts I have stressed the importance of Measuring Filament Diameter. There are many reasons for this, but the main one is because your software will use the filament width to calculate the exact rate of extrusion.

WakerWare Custom ProfileThin filament will extrude too slowly and thick filament will extrude too quickly. Within reasonable limits you can correct this by telling your software your filament diameter, which you can work out by measuring it in a few different places with a vernia caliper and taking the average.

So, how do you tell your slicing software what your filament diameter is? In most slicing software there’s a field on the interface where you can enter the value. Unfortunately, MakerWare is the exception and there is no such field.

Don’t stress though, when you click on “Make” from within MakerWare you’ll see an option to create a custom profile. When you do this you can manually edit a settings file which opens up a whole new world of hundreds of settings, including “feedDiameter” which you can update with your filament width (to the nearest 1/100th mm).

This file may include a couple of hundred settings but don’t be scared by it, just update the “feedDiameter” setting for now and then take a look at the other Slicer Settings on the MakerBot Website.

There are settings for two extruders by the way, even if you only have a single extruder on your printer. If you have a single extruder it will usually default to the first set of settings, or just update both if you wish.

An Example of When You Need Supports

Whether you’re designing or downloading things to 3D print you’ll need to know when and where your design requires supports.

When designing my own objects I try to design them to not require supports at all but it’s not always possible. When 3D printing things I’ve downloaded I also need to know whether to turn on the support options or not.

Obviously none of this is possible unless you understand when supports are needed and when they’re not, so let me give you some simple examples.

One way to help decide when supports might be needed is to learn the “YHT” rules. Let me explain…

  • Y – external slopes of less than 45 degrees from horizontal may well need supports. Slopes more than 45 degrees from horizontal usually won’t. Think of the letter “Y” where it branches into two slopes.
  • H – bridges between two or more pillars, like the cross bar of the letter “H” usually won’t require supports. Even though your printer is extruding into mid air it will usually do a decent job without supports if there’s a gap to bridge.
  • T – overhangs like the cross bar of the letter “T” will always need supports. Your printer will be extruding into mid air, the cross bar is zero degrees from horizontal and there is no gap to bridge between two or more pillars. Without supports your “T” will fail every time.

Ok so I hope that makes sense but if not, I thought the best way to demonstrate this was to ditch the theory for a minute and to actually do it, so I did…

I printed these three letters, upright and filmed it so you can actually see the “Y” and “H” print well, but the “T” fail exactly as I described above. Watch my 3D Printing Slopes, Bridges and Overhangs Demonstration and it will all become clear…

If you remember these three simple rules of thumb I promise it will dramatically improve the way you design and 3D print your objects from now on.

Tinkercad Broken and colorFabb Filament

On the subject of designing, for some reason my favourite CAD program Tinkercad no longer works on any of my computers. I know Tinkercad is only a very simple CAD program with limited functionality, but I love simplicity and for quick jobs, like my “YHT” design/print above it’s excellent.

I’m pretty sure it’s not the fault of Tinkercad, it just seems that the Google Chrome browser I use has suddenly disabled or become incompatible with webGL, which Tinkercad uses to render the 3D images.

colorFabb FilamentAlways trying to turn negative situations into positive ones, I have taken this as an opportunity to learn a new and more complex CAD package, FreeCAD.

I keep hearing very good reviews of FreeCAD so it’s time I learned how to use it. Best of all and as the name suggests, it’s completely free too and we all like free :)

I’ve downloaded and installed it, but it looks like there’ll be quite a learning curve, unlike Tinkercad which took about an hour to master. I’ll keep you informed and if you have used it yourself and have any tips, please send them to me.

Even though my design capability has temporarily diminished, at least until Tinkercad is working again or FreeCAD has been mastered, I decided to buy some more filament.

If you haven’t noticed yet, most of the pictures in this Beginner Series are of objects in green or purple filament, just because I have lots of it. I have many different colors of the colorFabb filament, but only samples and not much of each.

So it was time to order some more, partly because I found a 10% discount code on Twitter, which unfortunately has now expired else I’d share it with you. Anyway, I ordered another color sample pack of ten different colors and then got carried away and ordered a full spool of Sky Blue, another of Dutch Orange (colorFabb is a Dutch company and orange is their national color), another of Fluorescent Green and finally a spool of Natural White (great for all those Dinosaur and Celtic Skulls).

When this filament arrives expect some much more colorful pictures, especially now I have mastered multi color prints too. I chose the colorFabb filament because it prints so well and the colors are glorious, but it isn’t too expensive. I now wish I’d have ordered some woodFill and bronzeFill too but never mind, next time.

Thanks for reading and feel free to Like, Share and Comment on this post. Also you can Download your FREE Beginners Guide to 3D Printing at Home eBook for more 3D printing tips.


Tyrannosaurus Rex SkullWell, I have so much to write about this week that I might have to split this blog post into two. Maybe I just need to do a little less 3D printing and a little more writing and publishing.

Anyway, last week I wrote about the largest thing I’ve ever 3D printed, a Celtic Skull.

Well, not only did I print another one this week in MakerBots natural (clear crystal like) PLA, but I printed a Tyrannosaurus Rex Skull which was even bigger and far more impressive.

I printed two bottle openers, one in PLA and another in colorFabbs new XT Copolyester, so I can do a strength test. That should be fun, seeing how many beer bottles I can open with each before they break.

I’ve tested colorFabbs bronzeFill filament to see if it conducts electricity. If it did I was going to use it for copper or zinc plating, but it didn’t conduct at all so that concludes that experiment.

Oh yeah and I 3D printed a little Shamrock Shot Glass which goes nicely with the bottle openers. Are you spotting a pattern yet?

That’s enough of the summary, now it’s time for a few details and some pictures.

Crystal Celtic Skull

Celtic Skull with Rafts and SupportsAfter the success of the Celtic Skull I printed in green last week (just because I had lots of green filament spare) I thought it’d be cool to print one in clear PLA.

With Halloween looming it should look pretty good in the window if I illuminate it with a torch or a few LEDs.

As you can see from the pictures it looked like it was made from ice while it was still on the build plate, with the rafts and supports still in place.

The only issue I had with it was the same issue I had with the green version, my filament was in a knot on the reel again and kept tightening throughout the print.

3D Printed Illuminated SkullI thought I’d fixed this but I hadn’t so again it required some supervision while printing to ensure it didn’t tighten too much and prevent extrusion.

I have since checked and untangled all of my spools and I now always thread the end of the filament though the hole in the spool to prevent further tangles.

Hopefully this is the last I’ll see of this problem and I’ll be able to leave my 3D printer alone to print unsupervised. Another lesson learned I think.

Although my photography still needs a little work I did manage a picture of the skull in the dark with a torch behind it, just to demonstrate the reason I printed it in the first place. I hope you like it.

Tyrannosaurus Rex Skull

Now, I’m not obsessed by skulls or anything but I was now ready to print something even bigger and a common theme on Thingiverse seems to be variants (or remixes as they call them) of the Tyrannosaurus Rex Skull.

It seemed like the natural choice for me so I downloaded a four part T-Rex Skull and set to work. The four parts that all fit together are as follows:

  • Main Skull
  • Jaw Bone
  • Rod (for the stand)
  • Base (for the stand)

Although I printed the rod and base for the stand I don’t like them much so I’ve omitted them from the main picture at the top of this post. The main skull and jaw bone clip together nicely though to make the complete skull.

3D Printed T Rex Skull MountedThe print went really well, but I only printed it in low res (0.3 mm layer height) and I used purple PLA. Again, just because I have lots of it. I would have preferred to do it in white so I might buy some and try a high resolution version in white PLA.

There’s also a great looking finish which I’ve seen but have no idea to do yet. You print in white, rub something dark (paint or similar) all over the print then clean it off.

The pits, holes and indents all stay dark but the raised areas are clean white. I’ve seen this done on various prints but am yet to learn exactly how it’s done.

From memory the jaw took around 1.5 hours to print and the main skull took around 5.5 hours. The rod took a matter of minutes and I can’t remember how long the base took because I had a few attempts. It required a few attempts because it is large, flat and rectangular. This is one of the worst shapes for warping and it did Warp up from the Build Plate a few times until I used a raft to prevent this.

The T-Rex Skull is definitely the most eye catching thing I’ve printed so far and if you have a 3D printer I can highly recommend it if you want to create a little show piece to demonstrate what your 3D printer can do.

What’s Your Poison?

I mentioned a wile ago that I’d ordered both of colorFabbs Filament Sample Packs. These consist of lots of colors and some special filaments containing wood, bronze and glow in the dark plastic.

XT Copolymer Bottle OpenerThe only one I’d not tested up to this point was one called XT Copolyester. This stuff is clear, FDA approved (so it’s safe to be in contact with food) and supposedly much stronger than PLA.

Well, a quick bend and break test with the raw filament does prove it’s stronger than PLA and much less brittle, but I needed a more fun test. So, I printed out two bottle openers, one in PLA and one in XT.

Obviously the PLA one was easy to print, that’s one of the main characteristics of PLA. The XT one however required a temperature of 250 degrees which is quite hot. I believe my Replicator 2 can handle this temperature without issues but some printers might start to struggle at such temperatures.

It did warp a little, which PLA wouldn’t do with such a small item. That aside when it had printed some of the outer layers came loose because it didn’t look like it had fused together too well.

Shamrock Shot GlassHaving never printed in XT before I reserve judgement because it is indeed much stronger than PLA. I think with the right settings (temperature, rafts etc) it has great potential where strength is a requirement. I’ll continue to tweak the settings and report back my findings.

As for the Shamrock Shot Glass, I don’t know what inspired me to print this but I saw it on Thingiverse and thought it would be a good little print. Lets be honest I have plenty of green filament so it was a good excuse to use up a little more.

Someone did ask me if PLA was safe to drink from. Well, it’s not FDA approved like XT Copolyester is but I’m sure that the drink you put in it is far more toxic than the PLA itself. I thought that was a fair answer.

I think that’s enough info for you to absorb for now. Thanks for reading and I’ll be writing again soon about some other exciting stuff I’ve been up to in the 3D printing world (there is much more). I’ve already added a video to my YouTube Channel if you want a sneak preview. A quick clue is “YHT” and if you follow me on Twitter you may already know.

Happy 3D printing and as ever feel free to Like, ShareComment and download your FREE eBook: Beginners Guide to 3D Printing at Home.


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