RedDwarfIV

If I'd bought the 3D printer for the sole purpose of making a business of it, then I'd have included it. But I bought it back when I was just interested in making things for myself. I paid that off with my real job some time ago. Time spent designing and prototyping could also be written off as something I would have done whether I started a business or not, as I mentioned the original idea was just to print off coaches for myself. ABS plastic can be smoothed using acetone and sanding. Both would be rather complicated as I don't want to melt/sand off things like the window rims. Would also significantly increase production time. Thanks for reminding me about the second power car. None on sale on eBay at the moment, but looking at my purchase history I got one for £40 including postage. H'mm. Maybe I should design and print off dummy power cars.

It's also probably worth noting that DJM are probably planning on building entire new sets, yes? They would have to be to be making N-gauge ones as well. I was including the £80-£100 cost of an existing APT set from eBay in my calculation. A 1KG roll of ABS fillament costs £12. For each 14 car rake, it takes about one roll and I would be making 10 intermediate coaches. So that's £1.20 per coach in materials. Electricity cost is negligible. A 236ml pot of grey paint was £6, a 500ml pot of RAF blue grey paint was £9, enamel paints for the 1st and buffet stripes £6 altogether. The paints last for ages so cost there is also negligible. An A4 sheet of clear acetate sheet for the windows is £2. Painting parts takes a while, assembling each coach is quick. These are not expensive for me to make. Most of it is time spent working on it, plus however much people are willing to pay for it. So let's run that through again, using conservative estimates. £100 for a pre-owned 5-car APT. £12 + £6 + £9 + £6 +£2 = £35. £135 materials. £185 to cover labour and profit. £320. If you're a company that has to cover overhead costs, £1000 makes sense. I'm not, so I don't. I'm a guy who decided to make some APT carriages for himself, posted images of the progress on the internet, then got an offer from someone to make more for them (for £220, which is where that number comes from) that made me think about how I could do it for other people too.

I didn't delete it because that would imply I wanted to hide my wrongdoing. I accept that I said something incorrect, but what happens if someone makes the same assumption I did? Either they post about it and this all happens again or they don't post about it and they'll go away with the wrong impression. If I did something worth banning me from the forum over, I'll accept responsibility for that. As for £320, I'm already doing it. Note the 'budget' part of the immediate next sentence. If you're willing to lose some detail, you can absolutely sell a 14 car APT for that much. (Being the person making it, it cost even less.) Not mass-production, mind you.

You're absolutely right, I didn't have a clue what I was talking about when I made that post. Reading the linked thread, it looks like a crowdfunding project. Makes everything else make sense. I was basically writing the post as my first reactions, and they weren't particularly good ones. Added a disclaimer to my above post.

14 car set, £1000? I could do that for £320. Pretty sure there's still room for a low-quality budget version. And that site doesn't even seem to have pictures of the whole train (I'm not even convinced those are pictures of OO gauge APTs rather than the full size thing). Maybe they're legit but that would concern me if I were thinking of buying from them. (Edit: Seeing as both the OO gauge and N gauge pages show the same images, they're definitely of the real thing.) The thread will go on! (Edit: Please disregard my questioning DJM's legitimacy. It was unnecessary and based on incorrect assumptions.) (Speaking of, I'm still working on mine. Got 1 complete buffet car, a second almost complete buffet car, two almost complete coaches that could be 1st, 2nd or unclassified depending on what insert I put in them, half a coach, a load of painted coach bodies and three sets of unpainted coach bodies. Certainly enough for at least one rake when its done.)

Honestly this was one of the big motivators for me to do this. Cut-and-shut means buying £40 worth of carriage with no guarantee that you won't botch the work when trying to put them together. Buying enough carriages to make a 14 car rake, or even two 14 car rakes would be a massive investment. With a 3D printer, if I break a carriage beyond repair, I just print another one off, no biggie. And I say this having actually botched two attempts and got a sub-par result out of the third.

Buffet and second class coaches. It may not be obvious, but both of these coaches have clear acrylic sheet for windows. I modified the body design so that the windows can be placed underneath the strakes, and between the roof supports, with no cement required to hold them in place. This should significantly reduce workload and time to build each coach. Please note that the join will be less visible when I actually cement the two halves together. I haven't done that yet because I may want to work on the inserts more and add interior lighting. Also, the old bogeys were added for demonstration purposes, I didn't have the time or the 240v wire to fit 3D printed bogeys right now.

Attempt 2. I may do what I did with the strakes and add a groove to show where the red and grey paints should go. Would keep the red stripe more in the right position. Honestly though, it looks fine from a distance. I'll probably use this one for my own APT.

A few things to note. I've extended the strakes by 2mm, so they are now the same length as the carriage. I also moved the window holes so that they line up properly with the roof supports - previosly the windows were not symmetrical for some reason. I also made a slight redesign to the body shell around the edges of the windows to reduce the amount of space between the strakes and the roof. It might not be obvious in these photos, but it makes it look a lot better. As for the paint, you may have noticed some blue smudging... and that the red stripe went everywhere. I'll be working to improve my painting technique to avoid these. Making a cover for the white stripe should fix the blue smudging, while the red stripe should work better if I spray paint it rather than trying to use a brush. I haven't done the silver spray on these strakes yet. Also, the glossy look is mostly due to my camera's flash. I'll probably use matte varnish on it when its done.

Update: I've been having to work out how to paint the window strakes. They require three different colours - white, (unidentified bluish-purple), silver - and they all need to be applied carefully or they'll look sloppy. But doing it carefully means taking ages to do each one, so I've been coming up with ideas for how to do it fast and right. For the silver I used a metallic silver spray paint can. For the bluish purple, I think RAF Blue-Grey (BS381-633) works better than Dusky Parakeet. Neither is the exact right colour, but blue-grey is closer. For white... I'm undetermined whether I should just use the unpainted white ABS surface or actual white paint. I'll decide which looks better when I actually try putting white paint on it. The strakes I printed off with the window frames removed work quite well for constraining the silver paint to the rims if I put the frameless strake on top of the framed one while spraying. But because it was part of a defunct plan to print the strakes and frames separately, the window holes are slightly too large and the result is overspray. I can fix this by just printing off new frameless strakes with the correct window size. The silver can be sprayed on top of the blue-grey paint. So the painting process will probably go like this: Step 1: Use tape to cover the area that will be white Step 2: Paint everything else blue-grey Step 3: Cover strake with frameless stake Step 4: Spray silver through window holes Step 5: Remove frameless strake Step 6: Remove tape Step 7 (optional): Paint white band across bottom I've yet to work out how to add the red buffet or yellow first class strips. I have paint for this, but it seems quite runny.

Inserts for 1st class and unclassified carriages.

Thanks to Dagworth for providing APT blueprints, without which this wouldn't have been possible. This is the insert for the buffet/restaurant car.

Huh. I'll look into that, I know Halfords sells some. I knew water displacers didn't work as lubricants, but for some reason I thought GT85 counted as a lubricant.

Been doing a bit of spraypainting. Looks like Dusky Parakeet is a bit too light. Can't tell if Inky Prose is right because of how it reacts with the bumps between print lines on the surface of the window strakes. I may be forced to redesign the strakes with that in mind - print the wall and the window frames separately (the side of a part that faces the hotbed is always flat thanks to the ABS cement I use to stick the parts down. That should make a perfect surface for paint.) Would probably also require printing some sort of cover to go over where the frames would be so paint doesn't get in the way of sticking the window frames on after painting. In any case, a surmountable hurdle when I get the motivation to do it. Currently in the process of buying a plot of land as well as repairing the bike I use for work. Bit stressful.

You think you know all the issues your 3D printer might have, then it goes and socks you in the face with a new problem from left field. Tried printing nine of the short shell parts at the same time. Printing time: nearly 9 hours. Print failure: 40 minutes from end of print. Cause: Extruder freegear clogged with debris, causing increasingly loud and worrying grinding noise. Fix: Remove freegear, clean freegear and mount, spray mount and gear with GT85 lubricant, return gear to mount. It's no longer making the grinding noise, and I will no longer be doing 8 hour prints unless absolutely necessary.