Savage's Fusion Generator

[savagecreature]

Man, I thought there'd be twelve of these things out there by now.  Guess I'll just have to do it myself.


I've been asked for instructions for assembling one of these a few times, so I figured that doing a build log for one might be a good way to answer some of the questions folks had, including some of my own.

I started by getting the pieces I had already cut and test fit off of the shelf in the lab, figuring I would just start gluing those pieces together, only to discover that a significant number of those pieces have gone missing in the time since I did that first dry fit.  So I guess I'll start from the beginning again.

There are a lot of printed parts in this build, so the first thing I did was get some parts on the printer. Which brings us to question no. 1 ; why did I chop the top into so many pieces? well, firstly, I hate supports. They make a mess of the printed surface and significantly reduce print quality in my experience, so I avoid them whenever I can. The shape of the top of the generator doesn't lend itself to a good way to minimize supports unless you cut it into sections and put the sections on edge like this.

Secondly, as you can see from the above image, it needs to be cut into pieces to fit on the most common size print bed.  The bed in the image is a Flashforge Creator Pro which has the same print volume as the Replicator 2, CTC, Flashforge orginal, etc. Which is to say all of the most common printers a print volume similar to this, so that's what I assumed people would be using.  I segmented between major features in the hopes of making surface finishing easier once all the segments had been assembled.

For this build, I also went back to the CAD and added some features, one of which is numbers on the bottom of the segments so you know which is which, and assist in getting them put together in the right order.

kresty has asked in the past question no 2;  why are there so many different segments instead of it being just "print five of these and one of these?". The answer to that is I cut the segments by eye, not with math, so I don't at all trust that any two of the segments are actually alike.  I figured it was better to just include a file for each segment to be sure the finished product turned out the way it should.

In addition, I finally implemented  the system to keep the lid on the top. (hopefully it'll work)

[kresty]

Wait, I saw that first photo in person like.... forever ago!
BTW: I overlayed yours and they're all the same within small printing tolerances, I guess it's good that you were consistent?
I toyed with a system to hold the top on for mine. I fear my measurements got wrong though.

Glad to see you posting it! I probably won't get to continue my build 'til October.

[savagecreature]

I printed in PLA (sorry for the gross color, but I got a good deal on the filament and figured I was going to paint it anyway) with 3 shells all around and an infill of 30%, layer height of .3.

So, after a bunch of printing . . . .

    I got a bunch of the primary parts of the top of the reactor completed. I also seem to have managed to get my finger into frame in every image I took of the parts.  Sorry. :/  But it's just a pile of parts showing that progress is being made, so I figured all of you would forgive me.

Now that I had the parts I needed I could get started on actually assembling.  I did a dry fit on all the pieces and cleaned them to get the best alignment possible. I used a small file to remove any burrs or stringing that printing had left. I glued the slices of the lid together one at a time, starting with no. 1 and working my way counter clockwise when looking at the lid from the bottom. Looking at the bottom of the lid (the only way you can see the numbers) they're arranged like this:

I applied a bead of Gorilla Glue (this is what I used)

along the entire edge of the first segment, . . .

. . . then flipped it over and placed the rim of the piece flat on the table. Then I slid the adjacent piece over into position using the table to maintain alignment between the two pieces.

I then shot it with Zip Kicker to instantly harden the glue.

This Gorilla Glue super glue is stronger than just the regular ole stuff (or at least it seems to be to me), which is why I use it. I'm not patient enough for epoxy. If you're concerned about gluing the parts to your work surface, try putting down some wax paper. That's always worked well for me. It repels super glue and even if it sticks it's not difficult to clean up. When I  lined things up on the table I shot the zip kicker only on the outer edge which would lock that in place but leave the inner seam adjustable to make sure I got the best alignment.

When I had worked my way all the way around the lid I ended up with a gap (and somehow fingers, again, too) and it looked like this:

Even though the gap was fairly large, it wasn't difficult to pull the two sides together to get a proper join.  I applied a bead of glue to the edge again, pulled them together  and placed the whole lid on the work surface to make sure everything aligned and shot it with Zip kicker again.

Ultimately, I had a fully assembled top to go on my fusion generator

I should mention that while I was dry fitting things together I would occasionally grab the wrong piece and put two of them together that weren't in sequential order. (putting 4 and 6 together, say) and I did notice that they . . just . . . didn't . . quite fit the way they were supposed to. I'm sure whatever discrepancies could be sanded out or corrected with filler, etc, since some of that is going to have to be done, anyway, but I stand by my decision to make each slice a distinct file because there was a noticeable difference.

[savagecreature]

The printed pieces of the lid had some roughness here and there caused by Z wobble in the 3D printing process. It's due to how thin the lid segments are. It's not terrible, but I try to do work I won't be embarrassed by, so I decided to hit it with some glazing putty to fill in some of the larger flaws. It'll also remove some of the visible layers. I use this stuff that I buy at the auto parts store.

I apply a squiggle of glazing putty to the surface, and then, while wearing a nitrile glove, I smear it around on the surface making it fairly smooth.  This stuff starts to harden absurdly fast, and once it's started hardening it will no longer stick to the surface you're trying to smooth out, so make sure you apply it in small enough sections that you get it done in time.

     

Don't fret too much about it getting into the holes and slots for the other parts and such, it won't be difficult to remove later.  Just try to get it in any surface irregularities that you don't like and don't put it on super thick.  After I had done that, I set it aside for an hour or so to harden up and I grabbed some of the CnCed parts so I wouldn't just be sittin' there.

I decided to glue the ribs/rings that wrap around the center of the generator so I'd have them ready for later.  In the CAM files (the files the machine uses for cutting them out) the rings are all spit into two halves to reduce the amount of waste, but they have to be reassembled into continuous rings now.  I slapped a piece of wax paper on my work bench so I didn't glue the rings to it, applied some glue to the edge/end of one ring half, put two of them on the paper, lined 'em up and pressed 'em together. Then just I just flipped it around and did the same thing to the other seam.

Depending on what type of glue you're using you can either just hold it while it sets or wrap the wax paper over the top of the seam and set something heavy on top of it while it sets.

I did this about 300 times (or 18. whatever) and  a couple of more times for the top ring, which goes on the inside of the barrel opposite these outer rings. That top ring has a slot cut into it for one of the cylinders that rests on top of it to fit into.  I cut these pieces some time ago, so I don't remember exactly how this happened, but that slot didn't get cut quite to specification.  There's a pretty noticeable mess that I'll have to clean up later. The piece should still work, though, so I'm not planning on cutting another one.

When it was all said and done I had a nice set of rings that'll I'll set aside for now and come back to later

This took just about enough time for the glazing putty to harden up. I cut a piece of 150 grit sand paper, grabbed the generator lid and a piece of plywood I had that's got holes cut in it. There's a hook on the bottom side of this version of the lid that helps keeps the lid on the finished piece that prevents the lid from lying flat on the table.  I used the holes in the plywood to allow the hook some pace but still let me put the main body of the lid flat on a hard surface.

This is the hook on the bottom of slice no. 2. It's gotten dirty and has some glazing putty on it, so it looks ugly, but . . . no one will ever even see it. (stop judging me!)

I took that piece of 150 grit sand paper I had cut and, using the plywood to support the rim of the lid, started sanding by hand around the outside working my way up to the top of the lid and back out again. This glazing putty sands very easily, and it's not difficult to take more of it off than you'd like to.  I often start with 220 or 320 grit to prevent having to reapply after I've sanded off all the filler, but in this case it seemed to me to me that it would have the desired effect.  I continued sanding until I ended up with a surface I was content with when I ran my hand around the surface. It isn't perfectly smooth, but I think it's smooth enough that the filler primer will take care of the rest of it when I get to that point.

[Dyne]

Looking good. Gonna have to build one of these eventually.

Minor question though. Why use glazing putty for such a large area? Wouldn't filler primer do the same job and be easier to apply? I suppose, given the piece isn't flat, filler primer would have a tendency to go on thicker near the bottom. Or is it that the blemishes are too much for that method? (Can't tell from photo.)

[savagecreature]

yeah, it's difficult to see because of the plastic, but the defects are too large for filler primer. The glazing putty goes on so fast and easy and sands so quickly that I figured I might as well do at least one application, just to get it closer before I start spraying.

[savagecreature]

As you may or may not have noticed in the previous images, the top portion of the lid has some issues .  It's difficult to see in this image because of the color of the plastic, but it's not what one would call smooth.

 

For this repair I went to something a little more durable. I used Milliput epoxy putty. Nifty stuff. I've been using it for years. (okay, okay. Decades. But decades are made of years, right?)

You use this stuff by cutting off equal sized segments of each stick and mixing them together until it's a uniform color. I knew I wasn't going to need much so I only cut off about a quarter of an inch of each. The yellow really overpowers the grey, color-wise, so you're mainly focusing on making sure there are no streaks and color is even.

  

Once it's mixed, smear it as best you can into/onto the areas you need to fill.

Once I had done that, I got my fingers wet in a small bowl of water and smeared it as smooth and flat as I could.

I had some putty left over after the what I've been thinking of as the "cap neck", so I went ahead and filled in some places on the main lid that I didn't think would easily smooth out.  from here I just let it harden for a few hours (overnight is usually best) and then it's ready for another round of sanding.

[kresty]

Looking good! You do realize you're going to have to stop at some point, otherwise you'll be in danger of completing the project?

[Rhyno45]

He can send it to me and I'll finish it for him.

[savagecreature]

Once I had the milliput sanded smooth I figured it was time to hit it with some filler primer to see how much work I had left to do to come up with an acceptable surface.  I also decided to throw in some of the other lid parts so I could get started on them as well.  I had printed the heat sinks with supports on the bottom to accommodate the peg on the that inserts into the main lid piece. They came off easily, I just grabbed the support structure with my thumb and index finger and twisted it and it came right off.

      

I grabbed an old piece of plywood that was lying around and drilled some holes in it so I could stick the pegs on the back of some of the detail pieces into them, so they wouldn't blow off the board when I was spraying them.

Then I just placed all the rest of the pieces I was spraying around on that same piece of plywood and sprayed it with a coat of filler primer

All in all I was happy with the results. There are still some areas that I need to hit with more glazing putty and re-prime, but that was to be expected. The process is pretty much always; fill, sand, prime, repeat.  I've never had it just come out perfect the first time.

The tops of the coil sockets was one of the particularly bad places. I'll definitely have to do something about those.

And of course, just to keep myself motivated to keep working on this project, I had to fit all the pieces I currently have together to see how it would look

I think it's gonna be pretty cool when it's all said and done