Category Archives: Body

Magnetic connector for dome (version 2)

I’ve always wanted an easy and affordable magnetic connector for the dome to body connection.  I’ve used the DB25 connector with FlthyMcNsty’s board since the beginning and it works great, but it takes two hands to make the connection.

Here is version 2 of the magnetic connector that I’ve designed.  It uses conductive magnets for the voltage and then a 8 pin millmax connector for the data.  This mirrors the high current board I previously used.  Basically 4 wire for the slipring carry each leg of V+/V- times two as I run 5V and 12V to the dome, and the 8 remaining wires carry data.  Each wire is rated at 2A, so that gives a max of 8A per power leg, each magnet is rated at 8A, but I doubled up just to be safe.  So 2 magnets per power leg.

Here is a list of parts, again this is NOT perfect and will take some builder experience to get it working.  If I have time I may fix the things to make it easier to put together, but mine works so it won’t be a high priority.  Warning – the millmax connectors are tiny and difficult to solder as they are brass pins that heat up great but also melt their own housings.  Tried the solder verisons of them and just melted them all the heck.  So went with the pin mounts and provided a separate pcb board, much easier to solder these.  SO USE AT YOUR OWN RISK.

Parts:
3D Printed Female end
3D Printed Male plug
3D Printed Male back piece
8 sets of conductive magnets
Male Millmax connector
Female Millmax connector
PCB Board for female end (brd file)
PCB Board for male end (brd file)
PCB Board for Millmax connector X2 (brd file)
5.0 pitch 2-pole screw terminal x2
2.54 pitch 4-pole screw terminal x2

(obviously you’ll need a slip ring and a way to connect it to the dome – this is only for slip ring to body connection)

Here are pictures of the connectors

U 

Video of the mating, sorry for the shaking video as I had one hand on the dome another on the camera.

 

Shoulder Hub fix

Had a problem with the shoulder hubs falling out as they were only held in by friction.  Decided to JB Weld a piece of 1/4″ threaded rod to the back of each, I drilled a 1/4″ deep hole in the back center of each hub to help hold the threaded rod.  Once the JB Weld dried, I inserted the hubs into the legs and used a strap strip of styrene (drilled a 1/4″ hole), a washer and a wing nut to hold it all in place.  Definitely not going to fall out this time.

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Cost:  $x for 1/4″ threaded rod and wing nuts

Details, details and details

Didn’t someone say the last 10% takes 90% of the time, that’s how I feel as I am now working on the details.

IMG_2659Izzy ordered a skirt for me as the styrene plans were awfully intimidating. I didn’t like the hollow feel of the skirt so I put in the door/window expandable foam (it doesn’t exert pressure when expanding). It worked great, but it sucks up water. So if you wash your R2 body, like I did before painting it, make sure you don’t get water in skirt or it will take days to dry – trust me — days!

 

My resin parts camIMG_2661e in from Brenda/Calvin and I’ve been cleaning, sanding and painting them over the past few weeks. Here is the cylinder details on the center ankle. Looks great, although when I masked off the silver to paint the blue, the silver painted dulled a bit. I ‘polished’ it with fine steel wool and really like the look. The grooves on the cylinders are still the shiny silver and the rest is more like a brushed finish.

Costs:
Skirt: $

Holder for R2

Once I got the skins on I realized I needed something to hold R2 horizontally so I could work on the various pieces and parts that I had to attach.  Someone on one of the boards had a pvc holder that they build so I headed to the local hardware store.

Using 3/4″ PVC, elbows and 3/4″ foam pipe insulation I build my own rig to hold R2.  I built my at 11″ wide and 25″ long which worked out well.

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These photos were taken after I finished R2, but it demonstrates how the rig sits on R2 without any of the body components like the center vents sticking out past the holder.  You can lay R2 flat without working about scratching the body parts.

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PVC pipe, elbows and insulation: $

Costs:
PVC pipe: $
PVC elbows: $
Insulation: $

Skin me

I’ve been working on cutting out the pre-scored skins I purchased from Greg for $60, he had previously ordered these and won’t be using them.  Cleaned up a lot of the openings with the file so they were square, if the mis-cut was too much its now battle damage.

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Spent last night taping the skins into place, but it was too late and I was too tired to actually glue them.  Woke up early and just had to glue them in place.  I bought the skins from Greg who had bought them from Izzy who bought them from a run on Astromech.

The glue applicator from ePlastics seemed fine for gluing the 2mm and 3mm sheets, but it put out a lot of solvent which made the 1mm warp.  I went to my local hobby shop and picked up a small needle applicator to use on the skins, dome and various parts that are wrapped with 1mm.  The needle applicator was $6.

Needle applicator

This is just the inner skin, I have a lot more work do to on the outer skin before its ready to be glued into place.  I mistakenly cut out the center vent piece, the entire rectangle on the inner skin, oh well again thankfully styrene is more forgiving than aluminum.

My first pass at gluing the skins, I was very judicious in the use of the glue not wanting to warp the skin.  However, as I usually do I couldn’t leave well enough alone and thought that most of the inner skin would be covered by the outer skin.  So I applied more glue along the frame members as I know the skin is part of the structure of the body.  Problem is that the four back panels are only the inner skin, and I could warping along several of the members.  Oh well, a little sanding, weathering and heck that side faces down most of the time – you’ll never notice.

Tip:  Be careful on the back inner skin as most of this is exposed, unlike the front.  If I was to do it over, I’d add another inner skin so those areas are just as thick as the rest of the skin and you’d be able to cover up any warping easier.  Or just use less glue, but you really want this to be strong.

Not sure if it was my cutting, gluing or if the pieces were just off, but I had a few pieces of the frame protrude into openings.  The one below is on the center vent, but had similar issues on both side vents.  Again, styrene is very forgiving so I’ll be able to fix these fairly easily.

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Oops!

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All taped up

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Inside view of my mistake

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Rear inner skin

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A new tradition?
I work in the construction industry, and part of our tradition when we build a new building is to place inside a wall cavity something with the year the building was built.  Usually its a dollar bill or a quarter.

With this in mind, when attaching the skins I realized there was going to be a small area that would be completely sealed by the skins.  I put a shiny 2013 penny into this area right below the side vents before gluing it in.  Now when you move my R2 if you listen closely you can hear the penny move back and forth.  You’d never notice it if I didn’t point it out, but I felt it was important as someone in the future may dismantle him – and there will be a piece of history from when he was built.

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Costs:
Laser cut skins: $60
Needle applicator: $6

Resin parts ordered

Ordered the following resin parts today.

Worrparts
Utility Arms
Under Shoulder Details
Octogon Ports
Shoulder Hubs
Power Couplers
Pocket Vents
Side Vents
Leg Struts
Shoulder Hydraulics
Coin Slots
Knurled FIttings

Wayne uses aluminum particles in his pieces so they look like aluminum, decided to go this route for the silver parts instead of using Rub-n-Buff that Izzy keeps saying is easy to use…….we’ll see.

Costs:
Resin parts: $267

Back from vacation

Spent two weeks at the beach, and now the family is spending the 4th at my folks so time to work on R2.   Izzy and I stopped by Greg’s on 7/3 to work on a few droid things.  Again, I’m amazed at how much Greg and Izzy are helping me, Greg is spending countless hours working on the cad files to maximize the pieces he can fit on a sheet – thus minimizing the cost.  He is also tweaking some items.  My R2 will be the first one built from parts off his CNC setup so I’m the guinea pig but a well watched guinea pig – I could never have done this without both their helps.  For all those handcutting the styrene, you have my admiration – this would not have happened if I had to do those cuts.

In looking at the shoulder support plates, again my engineering kicked in and thought that a single piece of 3mm would not be enough, it flexed when I pushed on it and if this was going to support a good part of the load I needed to beef it up.  Again, of course I didn’t really read the instructions.  The styrene sheet I received had two of the shoulder support plates so I assume one on each side and totally missed that you needed to laminate two 3mm pieces together.    I beefed up one of them, then went back and re-read the directions – doh!

Ended up picking up the other set of plates from Greg and had to do some creative cutting to get the second piece of 3mm to attach correctly to the one I beefed up – should actually say butchered.  Here is a picture of one of the many mess ups…..but styrene is very forgiving.

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Screwed up shoulder plate

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What it should look like

 

Shoulder Hubs and Center Ankle

Spent the long weekend working on the shoulder hubs and center ankles.  Here are pictures of the near completed items, unfortunately I was too excited about having some free time that I didn’t take progress photos.

I decided to buy a laminate trimming bit for my rotozip to cut the 1mm skin flush.  Worked like a charm, but you need to practice and turn down the speed so that you don’t melt the styrene.  Cost was $20.  Also purchased the Loctite for the bolts in the shoulder hubs for $7.

trimbit2

Tip:  Make sure you mark the left and right hubs as they are different.

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Laminate Trimmer: $20
Loc-Tite: $7