It's been a while since my last update. Things have been amazingly busy, and I may be starting a new job. I'm going to hear back tomorrow, fingers crossed.
I received a new Shapeways shipment so I thought I would make a short article about how to properly build a printed model. I've been getting a few questions on the matter, and hopefully this will clear things up for people.
The first thing you always want to do is inventory your parts. Shapeways does their best, but sometimes they miss things. On occasion you will get extra parts. My theory is that they printed extras for parts which they were worried may not print well, and they came out fine so you got the extras. No confirmation on that, but I have a few extra parts for the Arrow pattern for that reason.
The models are printed using either a laser sintering method, which involves laying down a bed of powder, then tracing it with a laser to melt the powder into a final structure, or a UV cure method in which resin is placed and cured under UV light, and a waxy support structure is used. In a sintering process, the unused powder is left behind as support structure to hold up the model as it is printed and prevent it from warping or collapsing in on itself.
After printing they are put into a sort of bath. I believe it is a sonic oil bath to break up the support structure trapped inside. They also go in with hand tools to clean up the inside. They don't always get everything though, so you'll need to check any crevices and holes for a slimy mixture of unmelted plastic powder and oil. I use my airbrush cleaning needle since it has a very fine point and just clean the needle thoroughly afterward. In a pinch a toothpick will work. Small brushes like those used to clean an airbrush can be useful as well, but it depends on the structure of the print.
The oil residue left after the print can be harmful to your primer and paint. It can lead to bonding issues much like uncured resin spots on a Forge World model. I have had varied results with models over the years with some arriving with no residue, and some arriving in a bag which is easily 25% oil. I'm not sure why, there seems to be little rhyme or reason. Either way I always clean them. The model I sent out for our challenge I pre-cleaned and inspected before mailing out, making sure I sent out the best prints as a prize.
Here is my cleaning method: I have two bowls of warm (not hot, it can warp the print) water. One is mixed with dish soap, and one is just water. I soak the parts in the dish soap for about 15-30 minutes, then scrub them with a soft bristle toothbrush and then move them to the clean water for a rinse. I'll clean the toothbrush and scrub them a second time before placing them on a towel to dry. I like to let them sit overnight in the air if possible to let any residue I may have missed crystallize and turn a chalky white color, which I can then scrape off and repeat the cleaning process if necessary. If you are thorough with your scrubbing the first time this will not be an issue.
The next part is the fun part: test fitting. Depending on the model, things may be just dry fit, or they may be tacked in place. I always like to test things before final gluing. Sometimes measurements are wrong, so the print doesn't quite line up and you have to improvise. Depending on the material, modifications may or may not be easy. Frosted detail plastic from Shapeways is very brittle, and may shatter in unexpected ways when you try to cut it. I find it easiest when I need to modify these to clip them large, then sand to shape gently. It definitely takes a while, not unlike working with pewter models back in the day in its slow pace, but you have to do what you have to do sometimes.
White strong and flexible is easier to work with by far, but has a surface finish which I guarantee will require some work to get it where you want it. Moddler LLC has a great detail plastic which is about as easy to work with as resin. I used it on my Riptide conversion and would still be using it if the price was competitive. For big prints, such as Hollywood props, Moddler does some great work. Their smaller prints are definitely high quality but not close to the price of other printing services. There are a couple others I plan to try out, including one suggested to me by our own Paulson
, which I simply haven't had the time or money to check out at the moment. I'm planning to rectify that in January.
There are some small gaps which I will adjust with greenstuff to make a seamless model.
Here the pictures are a bit washed out. In real life this is a seriously cool looking test fit. I have some better shots later. I also realized just how dusty this model is from sitting out without getting worked on until I had weapons for it. I need to do a little cleaning before I paint this guy.
Once things are test fit and modified satisfactorily, I go ahead and prime them. This was my first time printing these particular parts, so I wasn't sure what to expect on the surface. It's hard to tell when they're still translucent just how smooth they are. It looks like these were printed oriented vertically, so they were printed with the back at the bottom, up to the barrel at the top or vice-versa. The orientation of printing can have a serious effect on how smooth the print is. Features which are printed all in one layer will tend to be smoother than features printed in several layers. I would have preferred if these had been printed on their side, so things would be smoother in more places but that choice is made by the Shapeways technicians, and how they feel the product will print best. Don't be afraid to make changes at this point in the game. You can still sand and scrape to get smooth faces if you desire. The primer will actually fill in the gaps to a point, which makes your job easier, but I still recommend a filler like liquid greenstuff.
In about a week I should be back to my projects full force. I can't wait to show you all the finished Arrow Pattern, my turrets, and the 11 XV15 suits I've been working on in a scheme based on Macknight
's. Cheers for the tip that the transfer sheets fit the shoulder pad circles.