Tricks and Tools: Home-made Dremel sanding drums

Hello again!  I've gone a while without any updates, so I figured I'd pop in and share a cool new trick I found on Instructables on how to make your own sanding drums for your Dremel tool.  This was a great find for me, as I just bought a big pack of wet/dry sandpaper sheets and am already incredibly sick of trying to sand everything by hand.  My Dremel only came with very low grit sanders, which aren't exactly useful when your prints don't come out looking like hell, so I'm eager to try these out.  It's too late for my coasters, but I'm gonna put a few of these together for my Dragon Priest mask in the hopes that it'll speed up sanding significantly.  My little arms are tired!

Disclaimer: making your own sanding drums might be dangerous, as they could fall apart and get flung towards your face or otherwise injure you or your Dremel.  Please use this tip with caution.  I'll report back if something terrible comes from this experiment!

Fallout Pip-Boy: Lessons Learned

Hi again!  As the title suggests, I've put together a custom Pip-Boy.  This was a gift for a special someone who was unable to get a pre-order for Fallout 4 before they stopped offering the edition that came with a wearable Pip-Boy.  Luckily for me, someone else had the same idea, so I'll be using this guy's models instead of trying to design the entire thing by myself.  It sure was nice of him to make this available for dorks like me to use-- I hope to do the same when I finally design something other people will want to print!

Considering the number of parts that come in this kit, as well as the fact that many needed to be cut into pieces to fit my printer, this was a very long project that consumed much time and filament.  I'm pretty sure this took me a good nine months of off-and-on work!  Instead of trying to do a chronological set of posts about it, I opted to be lazy and just use this one post as a general "what I've learned" style of summary that I updated over time.

Quick notes: I 3D printed the parts with PLA and a Printrbot Play printer.  A combination of XTC-3D and sand paper were used to smooth the prints.  The paper decals were printed from my normal paper printer, glued to a piece of cardboard for extra strength, and then wrapped in a cut of plastic baggie to give a shiny "behind plastic" kinda look.  Much of this was assembled using screws and toothpicks.  The black cable was salvaged from an old headset that no longer worked.  The "blank screen" and screen surround are the cheap craft foam you can pick up for like a dollar at a hobby store.  Bondo was my filler of choice, and I used Krylon spray products for the paint and sealant.  I did not include any LEDs this time around, but the guide mentioned at the top does show you how to set them up if you're so inclined.

For the complete Imgur album of the completed Pip-Boy, please look here!

Samsung Galaxy S5 not included

Things I've learned from trying to make a Pip-Boy:

• ModPodge sucks.  There, I said it.  I know all the other arts and crafts blogs have at least one entire post ranting about how awesome they think ModPodge is, but I've yet to have a good experience from using it.  As a sealant?  It never fully dried and left my figurine sticky.  As a glue?  It's pretty much the same junk we give kids, except I don't have to go to the hobby store for regular paste.  As a filler for 3D prints when you're attaching two pieces and have gaps?  Holy hell, no.  It doesn't exactly "harden" as much as dry into a rubbery substance.  I thought I could live with that at first... but then I tried to sand it, genius that I am.  It simply turned to gum that clogged up my sandpaper.  Never again.
• XTC-3D will pool if you apply too much and don't wipe it up.  Sure, trimming an edge with your Dremel isn't too bad, but the part where you get covered in a fine dust that the packaging marked as "do not inhale" is a bit of a pain.  And if it happens to pool on the model itself, you'll lose any surface detail that's under it.
• On a related note, XTC-3D dries clear when there are no bubbles.  This means a spot can look terrible but still be silky smooth.
• Spray paint and primer can be finicky, especially when you're in a hot, dry environment like I am.  Both too much and not enough humidity are things that can affect your results.
• Generic super glue seems to have a minimum surface area requirement.  If you don't meet this requirement, the two pieces won't stick together and the glue will take its sweet time to cure.  This will not keep it from instantly fusing with your finger, however.
• If your prints are warped or crooked, they'll result in a disfigured final piece.  Go figure.
• Painter's tape is the least elegant solution to filling large holes caused by said warped prints, and will not be covered completely with primer and paint alone.  Works well enough for parts you won't see, though.
• Dropping PLA prints can break them, especially if they're heavy but still manage to land on the most delicate part.
• Screws do indeed obey the same laws as every other physical object, in that they cannot exist in the same space that other matter currently exists in.  In other words, if you try to force a screw into a solid print that doesn't have room for a screw, you're likely to pop a couple layers of the print apart to make room.  Next time I'll use my drill to clear out a proper pilot hole.
• The level of craftsmanship a person puts into a prop does not necessarily correlate to how much effort they'll put into the tutorial explaining what they did.  The "tutorial" provided by the guy who made these models is pretty lack-luster, especially when it comes to assembling the crazy number of pieces that go into this build.  I was able to figure it out, but it certainly wasn't easy.
• If you're in the US, your local Ace Hardware is probably the best place to find screws and nuts.  For that alone I've started patronizing them more frequently as a thank-you for being so helpful!
• When cutting pieces to better fit your printer, straight down the middle isn't always the best idea, especially when the center has nooks and crannies you'll have trouble sanding later.

This thing took an eternity, but I'm so glad to have it done!  Hopefully my next project will be a little less complicated... until then, happy crafting!

Ocarina of Time Coasters: Part Two

Click here for Part One: Modeling

Welcome back!  I'm slowly but surely making progress on these damn coasters, and am now at the stage where I need to give the originals a good finish so they'll actually make good-looking molds.  This should be a shorter post than the previous one, as the process isn't super exciting... except for maybe the parts of it I messed up, of course.

Part Two: Finishing My Originals

Due to the wonky ways I've been printing my parts, they don't exactly come off the printer looking fabulous.  In fact, the edges that touched the supports can get pretty jagged.  This is where my dear friends sandpaper and Dremel tool come into play.  Pardon the lack of pictures-- the sanding process makes an absolute mess, and I don't want to get plastic dust all over my shiny new phone.

To give a rough overview, I've been using a sanding drum of unknown/ very low grit on the Dremel to hack off the more jagged pieces.  After that, I had no problem scrubbing away with a sheet of 220 grit sandpaper attached to a foam sanding handle, which it came with in a small kit from the hardware store.  Once I can't feel any jagged pieces with my fingers, I've started giving it one more go-over with a wet/dry sanding block that I bought years ago to use on clay sculptures.  I have no idea what grit it is, but it's pretty fine even compared to the 220.  Iterations Three and Four have benefited the most from this mystery sanding block, as I can actually reach the inner surface of the coaster and sand it until it's nice and smooth.

Oh, something important I learned!  Don't rely on your eyes when trying to sand 3D prints, as the thin walls will let light through in some places but cast shadows in others.  This'll cause a lot of weird discrepancies between what the surface looks like and what the surface feels like.  I thought I had a big gouge in the middle of my Forest Medallion print, but it turned out to just be a thin part on the backside of the wall.

Now, as to the matter of the prints I ruined...

Ugh, this again?

So while I was getting started in home printing, I came across a neat product by Smooth-On that's meant specifically for smoothing out 3D prints.  It's called XTC-3D and is a gooey resin that's supposed to self-level after you brush it onto your prints.  Although it's a really nifty product that can turn a crummy print into a smooth, shiny print, I've had mixed results in my attempt to use it.  Most of my applications have at best still been kinda bumpy, at worst... well, again, the lumpy mess you see above.  Smooth-On recommends working at room temperature, which I'm willing to bet is causing my issues-- I'm working outside in the Arizona desert, where it's still getting up to 100F during the day while most people are enjoying cool autumn weather right now.  Since exposing a heat-curing plastic to heat makes it cure faster, my working time decreases faster than I can work when I try to finish a large batch of prints.  I'm pretty sure that's where I slipped up with Iteration Two.  I went back to do a second application and smooth things out a bit more after coating all six coasters, and by then the resin was starting to set up.  If I had left them alone, they probably would have just been a little bumpy like the time before.

On a related note, if you decide to use this product on your own prints, resist the urge to use cheap chip brushes.  Seriously, they've caused me so much grief that I kick myself every time I use one instead of throwing them out and getting foam brushes instead.  XTC-3D is a little tacky, and gets increasingly more tacky as it starts to cure.  Tacky plus cheap brush equals so many bristles getting pulled out and stuck to the resin!  Ahem.  Naturally, this causes you to either end up with bristles stuck in your print, or take the time to pull each one out and redo the section of resin you just screwed up by digging it out.  In my case, you're likely to have both occur and get really mad at yourself for being dumb.

At this point, I'm hoping sanding alone will suffice for Iteration Four.  However, gluing the two pieces together has left a small gap around the inner edge of the Forest Medallion prototype, which showed up as a thin rim sticking out of my new test mold.  I trimmed it as best I could, but my X-Acto knife didn't exactly slice the rubber too well, so it ended up looking sloppy.  If it shows up in the final cast and can't just be filled in with some sealant spray, I'll have to give XTC-3D another shot.  I'll be sure to post an update if that happens.  Until then, may the super glue be with you, not on you!


UPDATE 10 October: After the above-mentioned mold was used, I've discovered that whatever grit my wet/dry sanding block just doesn't cut it for mold-making-- I was left with obvious layer lines in the mold and test cast even though my fingertip couldn't feel them.  After a bit of Googling, I've found people recommend getting up to 1500+ grit, so I bought a variety pack of wet/dry sandpaper sheets.  My current plan is to do a coat of XTC-3D and follow it up with a good sanding from each grit of sandpaper I got-- if I still can't get a good mold, I'll be sure to come back and update this page again.