Monday, April 21, 2014

Day 75 - Shoulder slats

In my previous entry, I briefly described that I had cut some 1/2" MDF lengths for eventual shoulder slats.  I got up on Easter Sunday and spent the morning cutting those to length on the table saw: thirteen long pieces at 24cm each, four pieces at 14cm each, and the wide slat also at 14cm.  Note that these sizes are longer than in the plans—this is because my shoulder section wound up being slightly taller than normal.

I didn't have a band saw for this next part, so I improvised.  I kept in mind the eventual addition of both 4.5mm HDF side pieces when locating where to cut these lines, basically subtracting 4.5mm from each side, and still having a 3cm middle section to cut out.  To get that middle section of each slat removed, I first cut lines on the table saw, raising the blade as high as it would go to get as "straight-on" of a cut as I could.  I also placed a mark on the wood roughly 4cm from the top, and a corresponding line on the guide (in photo).  I flipped the slat over, made another guide mark on the wood like before, and cut the other line.

Then, using the cut lines themselves as a guide for my ruler, I drew the line the rest of the way with a pencil, and made a corresponding perpendicular line 4cm from the top.  I took each piece to the scroll saw and cut the groove to that line.

Next, I took the slats to my drill press, and bored two holes on each interior side, so that I could return the piece to the scroll saw and finish cutting out the middle, which I then did.  This gave me the 3cm space in the middle of each slat to place a slanting length of HDF board.

I cut up a bunch of HDF into the correct width, and dry-fitted them into the slat grooves.  A minor bit of sanding was necessary, but soon I had all the pieces I needed.  I decided to try them out on the short lengths first, including the wide front slat.  I used a sponge brush to apply some Liquid Nails glue on the HDF, used my fingers to slightly pry the sides of the slat (being careful not to snap them off), then slid the HDF piece into place, angling it as necessary.  Then I clamped it tight.

I took a long break and allowed some time for the pieces to dry before continuing.  Once dried, I chopped the remaining length of the HDF off with the miter saw.  Satisfied with my experiment, I glued up the rest of them, clamping them overnight to dry.  I will finish trimming them with the miter saw once they're set.  Looking at the picture, I'm not too happy with the length of the wide slat, so I may trim it (and the other short ones) down 5mm or so.  Hmm.

One thing I will also need to do is glue a reinforcing piece of HDF onto the lower back of the slat in order to accommodate the countersunk hole I'll need to drill for the attaching bolts.  There's room in the middle of the groove to put another 4.5mm piece in there, so I'm not too concerned.

Monday, April 14, 2014

Day 73 and 74 - The Dome Mk. II

Saturday was perfect Dalek-building weather in the Pacific Northwest.  I flung open the garage door, got the table saw positioned, and cut some strips for the eventual shoulder slats.  The plans call for all but the thick slat on the front to be 6.2cm, so I cut several lengths of 1/2" MDF at 5.3cm wide.  This will account for the 4.5mm sides made from my thin HDF that I will be attaching to give the slat depth against the shoulder bevels, for a total of 6.2cm ((2 x 4.5mm) + 53mm).

I also made a few more hemis.  A hemi a day keeps the Doctor away.  Wait, what?

Now for the "fun" stuff.  Since my last dome had so many air pockets along the sides of the grooves and the panel recesses, I went back to the drawing board, and took a second look at AdamSt's diary.  And I noticed that he had accounted for exactly that situation by adding glass strips to along the sides of every groove.  So I set to work to cut some.

Subcusick also mentioned earlier that thick chop mat can be separated into thinner layers, so while I was setting to work tearing off pieces of that, I made sure to take advantage of that tip.  It gave me some really great results, and a lot more material to work with, coverage-wise.

After that was complete, I took my silicone spray release agent and gave the mold a few good passes with that.

Next, I donned my respirator mask and mixed up some gel-coat.  I didn't add any dye to it this time, mainly to differentiate Dome Mark II from Dome Mark I.  I had already prepped the dome with the inserts and wheel trim a little over a week ago, and had covered it with plastic so that dust wouldn't get inside.  Then I left to go play some video games while that set for a bit.

And, well, damn—tragedy strikes again.  I went to check on everything about 30 minutes later, just to keep an eye out, and it was a good thing I did.  The larger panel inserts had come loose and had slid down the wet gel-coat.  In a panic, I removed them, and considered scrapping the whole thing.

But when that almost-weepy sensation subsided, I gathered myself up and washed the rubber inserts with acetone.  With some effort and some paper towels soaked with acetone, I also cleaned up the area on the mold where the inserts had been.  I re-applied the spray adhesive to the inserts, let it sit a bit to get tacky, and pressed them back onto the dry parts of the mold.  And there I sat, for like 10 minutes, with my fingers splayed out along the length of the inserts, making damned sure that they were going to stay on this time.  Once that was done, I re-distributed some of the gel coat onto and around them—only to remember that I forgot to apply release agent to them first.  Ah well.  Back to the video games ... and checking on this ruddy thing every 10 minutes or so.

After a few hours, when the coat was nice and set, I took the strips of fiberglass I had cut earlier, and added them alongside every groove and insert.  I mixed up some resin and used a bristle brush this time instead of a sponge brush.  I think I prefer the bristle brush, as it gives me a lot more control over the resin, and allows me to take care of air bubbles as I see them.  After that initial resin-ing, I added pieces of chop mat on top of what I had done, make sure to stick within each section of the dome.  Once each section was built up, only then did I place layers of glass over the top of the trim and inserts.

By this point, the daylight was pretty spent, so I called it a night.

The following day, I checked up on the dome, and everything was looking great and setting well.  But I wanted to give it a full 24 hours to cure, and not a minute earlier.  So, Sunday, ultimately, was a light-work day.  I suppose I could have made another skirt panel's worth of hemis, now that I think on it ...

That night (after watching Cosmos, naturally), I went down to the garage and began hammering in my plastic spreader inserts, just like last time.  After I put in enough to surround the dome mold, I started hearing those pleasant popping noises, and, waiting patiently, the dome politely popped itself out.

And I was grinning from ear to ear!  This time, the dome grabbed all the inserts and trim with it, leaving nothing behind in the mold.  Whatever I did, those grooves had quite the grip on that trim!  I think I might have made the dome a little more solid, this time!  I began to peel the trip and the inserts.  The trim was very difficult to get out.  It isn't exactly half-round; it's more like half-round plus a little extra, curving back up on itself ever-so-slightly.  There were some chips in the gel-coat along the groove as I was removing it, but I'm going to sand that smooth anyway.

What I was really afraid of were the inserts that I had to re-attach (and had forgotten to add release agent to).  But, look!  They came right out!  I was well pleased, to say the least.

All four sides of the dome look superb, and I am super happy.


There's only a slight bit of damage near one of the front panels, where some release agent had been wiped away by my acetone-covered paper towel, so I'll need to repair that spot with some Bondo, and also sand that part out of the mold for its next use (which could very well be a dome for ChristmasDalek's Imperial).  Also, I still got those weird "ridge ripples", which I was secretly hoping for, as ccain mentioned they look like a really nice weld line.  Adding weathering to that will make them look great!

Friday, April 4, 2014

Day 72 - Random progress

Not really much of an update for the amount of time that I've been away, but Rainier now at least has potential motivation!  Based on a tip from Slothman86, I trolled craigslist and found someone selling an electric wheelchair for $140!  I drove the 45 minutes to his house to pick it up, and it works pretty nicely!

It's got a simple controller; essentially, there's a velocity dial, and a joystick.  I have yet to strip it down.  Once I do—and since I can't weld—I will likely create a bolted metal framework on which to attach it to the fender, much like this post in Variable's build diary.

The other update is that I wanted Karen Gillan (Amy Pond) to autograph one of my Dalek hemis, so I prepped a few to take to Emerald City Comicon where she was attending as a guest.  I primed and painted four hemispheres with the Valspar brilliant gold, about three coats, and let them dry for a day.  She recognized them immediately, signed one, and wanted me to tweet her a picture of Rainier once he's finished!  I was a little gobsmacked, and said "certainly"!

I also repaired and prepped the dome mold for another casting after getting some more chrome wheel trim, and am waiting for some decent weather to start again.

Also, each night, I'm trying to get at least four to eight hemis glued to their bolted disks so that I get all 56 done.  I want to start cutting the 1/2" MDF soon for the shoulder slats soon, too.