How to smooth out your 3D printed E-11

[justjoseph63[Staff]]

                                                                                                 THIS IS NOT A BUILD THREAD... per se.

 

Now that resin E-11 kits have all but disappeared, many are going to the 3D printed version.  3D printing has some advantages over resin builds, especially the fact that you can have MUCH more accurate finished product.  This tutorial will show you how to get all those print lines out for a smooth-as-glass finish before assembly without as much work as you would think, especially if you are aiming for Centurion level approval as there can be no print lines on your blaster.  I spent a total of 3-4 hours (not including drying time) on this project, so it's a lot faster that you may expect!

 

                                                                      This tutorial is for a classic E-11, but the process will work for any 3D printed weapon.

 

 

For this purpose, I am using a kit made with Bryan's (trooper96) awesome files (link).  Know in advance that it contains basically every single part of a real Sterling, down to the nuts and bolts... literally, and is in my opinion the most accurate ANH blaster kit out there.  The fully functioning folding stock is a nice touch!  When it comes time to put it together all those little parts can get confusing, so I suggest checking out Glen's @gmrhodes13 thread here.  I couldn't have done this build without it!

 

IMPORTANT!  Printing the kit (or having it printed) in PETG will decrease the time you spend sanding dramatically compared to PLA.  Trust me.  You can also have it printed in resin, but that can be a costlier option.  Another advantage to PETG is that it contains minimal "threads" as opposed to some PLA prints.

 

NOTE:  I did not include the power cylinders or Hengstler counter.  I am using a real counter and making my own cylinders/assembly, but the same process would apply to the printed ones.  More on that at a later date. 

 

                                                                                                                  LET'S GET STARTED!

 

To begin, you will need the following supplies:

 

1.  Filler Primer-  This is a great option for filling super fine lines but requires a lot more fine sanding prior to use.  I didn't use it on this build, but I have in the past.

 

2.  Bondo Glazing & Spot putty-  This is miracle stuff.  Unlike regular Bondo which requires mixing, it is a paste that you can simply apply with your fingers or a craft stick.  It fills fine to medium lines like magic, dries hard in less than 20-30 minutes or less and is SUPER easy to sand! 

 

3.  XTC 3D epoxy coating-  Since this was the first time I had used this, it took some experimenting but the final results speak for themselves.  It also provides some additional strength to the pieces. 

 IMPORTANT:   Mix this in very small batches.  I can not stress this enough, as it sets up fast.  Be SURE to read all instructions before using.

 

4  1" (2-3cm) Foam brushes-  These are used with the XTC coating.  You will need at least 5 or 6, as the epoxy only lasts a few minutes after mixing so you cannot re-use them.  

     Link here.

 

5.  Sandpaper-  80, 150 and 220 grit.  320 grit optional. (No photo... we all know what sandpaper looks like).

 

6.  Spray paint-  I suggest Krylon Fusion.  You will need flat black, gloss black (for the grip).  Silver is not needed if you plan on painting all areas black.

 

7.  Super glue gel-  Get the gel type.  It doesn't run.

 

8.  Super glue accelerator-   Optional.

 

9.  Mask (PPE)-  I strongly suggest wearing a mask.  Dust from sanding and the fumes from the XTC can be harmful.  

 

10.  Small plastic medicine cups-  The ones that show the exact measurements work best.  These are only good for ONE use for each batch of XTC epoxy and are good if you don't have a precise scale.  Link here.

 

11.  Wood craft sticks-  For mixing the epoxy.  Can be found at your local hobby store

 

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I am not including photos of me sanding down the parts.  That would be pointless, and I did NOT sand down the interior parts as they will not be seen.  

 

I started with 80 grit to get the larger print lines down.  After that, 150 and then 220.  There is no need to go crazy with the sanding, as it does NOT have to be perfectly smooth.  For the T-tracks I used a foam sanding block wrapped in the various grits to get into the crevices.  Like I mentioned PETG sands down FAST and EASY.

 

Hints: 

Do NOT use any filler on the bottoms of the T-tracks, just sand them down fairly smooth.

Sand the interiors of the holes using sandpaper wrapped around a pencil to remove burrs.  Do this BEFORE gluing the 2 parts of the barrel together.

The more you sand down the parts with the 220 the less filling you will have do. 

 

                

 

After wiping down ALL surfaces with a damp paper towel to remove residual dust and letting them dry, I applied the Bondo paste pretty liberally.  Like I said, this stuff sands VERY easily so you can go fairly heavy when applying it

 

Dry time is less than 30 minutes or so, but make SURE it's completely dry.  It already looks/feels a lot smoother, but after that I went back to the 220 grit sandpaper.

 

                                                                                                               After final sanding: (Only some parts shown)

 

                                                                                                                                                                              Note original print lines

                                  

 

                                                     

 

Special notes-

 

1.  In order to keep the details in the interior part of the grip, after the Bondo I used a dental pick to clean them out.  When using the XTC later I went VERY lightly as not to fill them in.

2.  The textured part of the grip was actually perfect and required no sanding. filler or epoxy coating so I left it as is. 

 

                                                                                                1.                                                                                  2.

                                                                  

 

Due to the fact that most 3D printers cannot print long objects some parts will need to be glued prior to applying the paste/filler. The folding stock comes with 2 tabs which I glued to the U shaped stock part and then filled.  

NOTE:  The arms have distinct curves-  there is a left and right so make sure you have them on the correct side before gluing.

 

                                                                                                                                               Finished look                                Real Sterling 

           

           

The barrel jacket/exterior also comes in two parts.  The print came with tabs to help line them up, but before making them one piece I added/glued in extra plastic tabs for increased strength.  I suggest that you do this as well, but be SURE the added tabs are flexible and conform to the interior as seen in the last image below.  Sanding the added tabs down before gluing will help with adhesion.                                                                                                                                                                               

 

              

 

The main body has not been epoxy coated or primed, just some Bondo paste where needed.  Being a PETG print it came out ultra smooth with just sandpaper, and I didn't want the epoxy dripping through the holes and puddling.

 

Be VERY careful when handling the assembled barrel.  Until you get the T-tracks glued on it can be somewhat fragile at the joined seam, so use minimal pressure when sanding after you apply the Bondo.

 

NOTE:  Because of the added tabs and because it fits flush you will need to sand down the rear end of the interior barrel insert in order to get it to slide all the way in.  DO NOT FORCE IT, or you can knock off the tabs.  (Sorry, I forgot to take a picture beforehand).

 

                                                                                               

 

For even MORE added stability, the T-tracks should have a bit more glue on those seams when doing your final assembly.

 

                                                                                      

 

OK, time for the messy part, lol. 

 

HINT:  Don't try to coat too many pieces at one time!  After your first batch you will be able to tell how long you have before it starts to set up.

As mentioned, the XTC epoxy filler dries fast.  Really fast.  You should figure on about 5 minutes (or less) of working time per batch, so plan accordingly.  

You can mix this by volume or weight.  If you have a scale that measures grams that is what I would highly suggest using.  The mixture needs to be precise.

 

IMPORTANT:  The fumes are harmful.  Use a mask and apply/let dry outdoors.  I suggest doing this in an area where there will be no dust/insects/debris that can stick to it while curing.  

  

After wiping all parts down with damp paper towels and letting them dry, I added the first coat of the XTC.  Since I hadn't used this product before I went light, applying a very thin coat. 

 

                                                                                                   

                                                                                                      You can see a big difference immediately! 

 

 HINT:  Always go in one direction when applying.  If you apply it too fast you may get bubbles.

 

 If you go too heavy, you can end up with "puddling" of the epoxy as it not viscous and will settle quickly while drying in the flat areas/crevices.  I wiped out as much as I could with the sponge brush immediately, and in the end they came out pretty nice.  Again, GO LIGHT!

 

                                                                                                                

 

          After 4 hours I hit some of them again a bit heavier as needed.  No need to sand between coats.  Cure time depends on heat and humidity.  Read the instructions for details.                             

 

                                                                                                              After drying... smooth as glass.

           

 

Yes, there are a few miniscule bubbles, but they won't be noticeable and can be lightly sanded out.  To ensure paint adhesion, you will need to sand everything down.  I used the 220 grit.  You can go with a finer grit but in looking at the finished product below I don't think you need to.

 

 

When applying the XTC to the breach block I did not coat the numbers to keep them from being filled in.  These pieces have been painted.

                                                                                

 

A few notes on painting-

 

To make sure you have proper adhesion for the glue, before painting apply blue tape over the areas where you will be attaching the various components.  An easy way to do this is to put the piece where it goes on the body and draw a line around it with a thin Sharpie marker.  When applying the tape, keep it about 1/8 inch INSIDE the lines.

 

                                      

 

Although the paint may SEEM dry after a few hours, be aware that it takes a lot longer for it to completely CURE.  I know it's tempting, but after final assemble try to let it sit in a dry place for 5-7 days for a much more durable finish before you run around the house with it yelling PEW PEW at your pets.

 

                                                                                           

                                                                                                                     Assembled product

 

I am adding the scope rail, Hengstler counter and power cylinders later, but I wanted to show how smooth the parts came out.

 

                                                        

 

                              

                                                                                                                                                   I forgot to cover this area before painting, so it will be sanded 

                                                                                                                                                    down prior to gluing on the power cylinder assembly.

 

                                                                                                                                     Finished!

 

                                                 

 

    

 

                                                                                                                                Final notes

 

Yes, you will notice that some areas I have left silver/metallic.  I may paint these black at a later date, but as seen below on these screen used blasters some were left "au naturale" (or the paint rubbed off during filming).  It's a matter of choice.

 

I will add some light weathering as soon as I attach all the various components.

 

                       

 

                                                             If you have any questions about anything included here (including assembly) always feel free to ask.

[trooper96[501st]]

Nice work, Joseph! Excellent tutorial!

[justjoseph63[Staff]]

Thanks!  I wish I had known about Bondo paste, XTC epoxy and PETG printing before I did my DLT-19 a few years ago.  It would have taken 5-6 hours instead of 40!