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!