Wednesday Workbench 30 November 2022

 

I've been doing a few things since Saturday, mostly slicing files for 3D printing and then printing them. As you can see, I'm also in the middle of deep-cleaning one of my airbrushes.

You may recall that I'd primed a piece "grey" and then hand-brushed a dark grey into the panel lines. I've airbrushed two different colours onto that piece to see how it looks:

It looks OK under the pale blue, but is far too dark under the yellow - I think that for lighter top colours I might need to use a lighter grey for the panel lining. I might also use the airbrush to add a diffuse line of a lighter grey around the panel lines so that the edges of panels are slightly darker than the centres. I'll need to test that in the next few days.

I also tested a couple of colours on the internal partition pieces:

I think I prefer the pale blue grey (top).

3D Printing

I've mostly been printing cargo. I printed another of the shipping containers that you've seen before. I then sliced a load of "Traveller" crates and shipping containers. I've been printing them for the last couple of days and have a few more days of printing to go.

1/4 Ton Crates

Liquid, gas cylinders, reinforced

Bolted, locked, plain

1/2 Ton Crates

Back - gas can, gas cylinders
Front - locked, bolted, plain

6 Ton Containers

Sealed, controlled environment

I've got another 6-ton container to print, then 2- and 4-ton versions. My plan is to eventually have more than enough to fill the 82-Ton hold of the Beowulf class Free Trader which will be next year's big printing project.

Paint Table Saturday 26 November 2022

 

Apologies for the lack of posts recently. I haven't really had anything worth posting about until now.

Over the past few days I've been testing out priming, pre-shading and paint schemes for when I paint up my Type S Scout Courier. 

The piece on the left was primed "grey" (more of an off-white, actually) and the panel lines were shaded using a dark grey with the airbrush; the piece on the right was primed black, then the panels were gone over with the "grey" primer avoiding the panel lines as far as possible. I think that darkening the panel lines over the "grey" primer works best, but might be better done by hand rather than airbrushed. I've primed another piece and done the panel lining by hand to test this out:

I primed a couple of other pieces that hadn't been sanded to test out different colours for the paint scheme:

This was just to see how different colours work together. The brighter colours will be for accents/details; I think I'll go with one of the yellows as the main colour.

I've also done a zenithal prime on a couple of interior pieces to test out colour schemes:

I went with a dark grey primer as the base rather than black as it should be less stark. It also shows up over the black plastic, which all the ship parts have been printed in.

3D Printing

I finally got around to printing the last of the 1:270 scale Traveller ships:

I had to reprint a few parts to replace ones which broker or didn't quite fit. I also had to switch filament spools as I didn't have enough of the black to do the top half. The little bags in front contain a radar dish and various antennae to add later on - I'll need to drill out the holes the antennae go in as they are too snug at the moment. All told, that took about four days to print.

As well as the ship I've printed some more shipping containers (you can never have enough after all) and some air raft variants - the original 2-seater, a 4-seater coupe, a 4-seater saloon and three pick-ups (2-seater, coupe and saloon).

I decided to take advantage of the Black Friday deals on Amazon to stock up on filament, so I've got plenty to keep me going.

Paint Table Saturday 12 November 2022

 

At the back of the photo above you can see what I'm currently working on:

These are two ship parts which I'd run off while testing print speeds. After mishaps while applying the first round of spray putty, I printed the parts they are sitting on.

Before the first coat of spray putty I did an initial sanding pass with the coarse and medium grit pad. I then did a second coarse & medium pass after the spray putty had dried, followed by re-scribing the panel lines. I think the initial spray putty coat was a bit too heavy - it took a lot of sanding and the panel lines were well and truly clogged. after washing the parts down to remove sanding dust and letting them dry completely I gave them a second, lighter spray putty coat which hasn't clogged the panel lines as much. I'll be sanding them with a medium & fine grit pad tomorrow.

I'll be using these to test different priming and pre-shading methods. One will be black primer, followed  by dry-brushing; the other will be light grey primer, heavy black wash, then dry-brushing.

3D Printing

After doing several more tests, I've finally worked out why I was getting such bad stringing. It was a result of the lower ambient temperature and/or higher humidity. I've been able to resolve it by placing the in-use spool in my filament dryer and running it directly from there to the printer:

There are only two potential issues with running it like this:

1. It's not possible with this dryer to see how much filament is left on the spool

2. Whilst it's being used for the in-use spool, you can't dry the next spool

Anyway, here are a couple of  "before and after" comparison prints:

With that issue finally solved, I've started printing the last of the 1:270 scale Traveller ships. I'd left it until last as it's huge and will take a few days to print. I suspect that I'll have to switch spools as I've used so much of the black trying to sort out the stringing. As I've got a few other bits that I want to print in black, I'll probably do those before  do the main body sections.

Wednesday Workbench 09 November 2022

 

I've been doing some more experimentation. Along with the new hotend and fan for my 3D printer, I also ordered a can of spray putty - I've been told that it is better than filler primer and wanted to try it for myself. I used it on another scrap piece from my Type S. I applied one coat all over, then sanded it down. I was simultaneously testing the cheaper own-brand sanding pads from Wilko. For the first pass I used the coarse/medium pad. With that done, I applied another coat of spray putty to half of each face, then sanded it down with the medium/fine pad.

As with the filler primer, the main problem is that it does fill in the panel lines - I need to get better at cleaning those back out. It's particularly difficult with some of the less recessed details. It also has to be done after sanding as you can't see them clearly until then.

I will say this much - it does do a better job of filling in the layer lines than filler primer; each coat was about the equivalent of two coats of filler primer. It's also cheaper - I'll definitely be using it when I prep my Type S.

As for the painting afterwards, the priming went well as did the recess shading and drybrushing I did. I hit a problem when I went to airbrush the pale blue colour - the paint came out much faster than expected, so I ended up having to do several thin coats over the top to even it out and that obscured all the pre-shading/highlighting work I'd done. I decided to gloss varnish it and apply an oil wash for the panel lining (just the varnishing done so far).

3D Printing

I installed the new hotend and fan on Sunday and then had a bit of an issue - for some reason the auto-leveling probe wasn't working. I took back apart to check the wiring, put it back together - still not working. After asking for some advice, I re-flashed the firmware - still not working. I took it apart again, looked to see if anything was up with the wiring that I hadn't spotted the first time, didn't see (or touch) anything, put it back together and...it was working.

Reflashing the firmware meant that it was reset to factory defaults. I therefore needed to recalibrate it. Before doing that I ran a couple of test prints - it's just as well I did as I could tell from the surface quality that I'd knocked a few things off kilter while replacing the parts. After making adjustments and running test prints after each I got to a point where everything was good again.

The problem was I was still getting stringing. I ran more test pieces with different retraction settings, to no avail - I would need to increase the retraction distance and speed to a point where it would then cause under-extrusion when it started printing again. So I tried a different tack - printing at a lower temperature. Dropping from 210C to 190C seems to have done the trick. It was also a good excuse to print a couple of models I haven't printed before.

210C

200C

190C

Different dragon, 200C and 190C

I'm still not sure what is causing the stringing at 210C - I'd been printing at that temperature for months without issue. It wasn't the hotend (although changing it was worth doing as it was well and truly gunked up). I could probably have got away with just changing the heatbreak, but wasn't sure which one I needed to buy.

With that done, I decided to return to testing speed and acceleration values for my starship printing. I also wanted to see how parts like the cabin partitions would come out at 0.16mm layer height (I'd previously printed them at 0.12mm). I got the first two prints done today:

Left 250 mm/s/s; right 500 mm/s/s

One was printed at 250 mm/s/s, the other at 500 mm/s/s. Both printed the details OK, but I think for the higher acceleration (500 mm/s/s) I might need to increase the flow rate slightly as there was some under-extrusion at the start of some layers. I'll need to do another print at 250mm/s/s acceleration, this time at 190C to confirm that it's the acceleration rather than the temperature causing that under-extrusion.

Once I've got these test prints done, I think I'll print out the last 1:270 scale Traveller ship. After that, I'm not sure what will be next.

Finished: 3D-Printed 28mm Celt Warrior

 

You may remember me telling you that I'd been printing some sample figures for the guys from the podcast to try out. I decided that I might as well paint up one of them myself, and picked the Celt warrior (the other options were a Roman legionary, a Greek hoplite and a Persian kardakes). There is a separate shield that goes with the figure, but I decided to leave that off.

Oh, and I didn't notice the blue paint on his left wrist/hand until I was resizing the photos for the blog - not when I was painting it, not when I varnished it and not when I was taking the photos!

The figure was printed at 0.1mm layer height. If you look closely you can see the layer lines, but at a typical gaming distance they wouldn't be visible.

Because of the layer lines, washes weren't going to be an option - they'd tend to pool in the recesses. With that in mind, I primed the figure black, then did a white zenithal prime to help me identify the highlights and shadows for the next step - applying a purple pre-shade to the shadows and pale flesh to the highest highlights of the flesh.

I then built the flesh up using thin layers. I did also do a bit of wet blending to smooth out the transitions from the deepest shadows.

The trousers were also done by layering. For the metals, I decided to have another go at non-metallic metal - it didn't come out too badly, but I need a lot more practice to get it right; the steel certainly looks better than the gold/brass/bronze.

Overall, I'm happy with how it came out but the fact that you can't use washes, contrast paints, etc does mean that they will take longer to paint.

For anyone who is interested, the figure is a free sample from 3D Breed's "March To Hell" range.

Paint Table Saturday 05 November 2022

 There has been a little bit of painting done this week. One bit will get posted tomorrow or Monday, the other you will have to wait for - it's a gift for someone who might read this blog and I don't want to spoil the surprise.

3D Printing

I mentioned that I'd been doing some test prints. These (the items on the front left) have shown that I can increase the speed to 60mm/s without any problem. I did try printing at 80mm/s but that seems to have been too fast. Now I need to test whether I can increase the acceleration value. I did test a higher acceleration at 80mm/s - the results were worse, but I want to check if that is also the case at 60mm/s.

For the 28mm spaceships, increasing the print speed to 60mm/s will save me 10-25% on the time required; increasing the acceleration will save another 10-15%. Now that I'm more confident with my printer I'm happy putting multiple items on the same print bed which should save a bit more time.

I've printed a couple of dice towers this week to see how they come out.

This month's freebies for Tribe members from 2nd Dynasty included two 28mm starfighters:

Starfire:

Talon Interceptor:

I've been having some issues with the printer for the last week or so - "zits" and nasty stringing. I suspect that the fix I did a couple of months ago when I had similar problems hasn't lasted. I've ordered (and received) a replacement hot-end which I plan to fit tomorrow. At the same time I ordered a better fan for the processor board which will also get fitted tomorrow - the one that comes installed is an el cheapo job that is very noisy when the printer starts to heat up (it only seems to do that when the ambient temperature is under 25C or so; it was fine during the summer!).