So ive been printing a lot of parts this last couple of weeks... Ive printed off the base and the frame for the base, and been doing the resin parts for the gate itself. Here are the parts, nearly ready for for silicone casting. Still a couple of bits to touch up and close off...
First cast pulls.... not perfect. not usable... and a few bad bubbles. but was informative and shows what i can improve in the next cast. Need to make a few more air holes for bubbles to come out of. And need to come up with a fast degassing. Also less filler this time too. These are a little.... fragile.
This looks amazing MangyDog. The details are bang on. I commend you for this. I tried to make one back in 2004 at 1/7th scale but stopped part way through. Wish i had CAD and 3d prints back then. The ring did move but the materials i used were not up to the job.
Those photos are are 2011, i think it is still in storage somewhere but never got around to finishing it. Looking forward to seeing yours completed. Keep up the amazing work. All the best.
Most of the parts done... Nearly ready to start assembling... Gonna print the inner ring edge now as I ran out of casting resin and silicone and didnt want to have to spend even more money on this... That's going to take 2 more days...
And then for to print the chevron wings and frames... And the chevrons too....... Hopefully will be ready to start making part 2 of the series of videos in a week or two...
The resin parts all need some cleaning up, flashing and fixing some bubbles. I had a couple more than i needed to try and pick the best of the bunch. But they all have some bubbles in detailed areas which isnt fun. Its the kind of bubbles that degassing wouldnt have solved as it was corners and liquid tension areas....
A pressure pot might have fixed it but then I didnt degas the silicone so who knows what horrifying mess that would have created.
So like I say im going to make a part 2 video at the assembly, prepaint stage... With part 3 being paint and electronics and finished I think...
The resin is Easy Composites tough resin, mixed with graphite... The pure white parts are a pure resin test... The black ones are graphite mixed. The graphite helped with bulking out the resin to make it go further as frankly I have NO money... this silicone and resin process has been far too expensive as it is. :/
Anyway downside is the graphite has made the resin a tad brittle... should be fine for the model. Its just weaker than pure resin. But it does look more like Naquadah on its own (it will get painted) also it adds a kinda added bushing effect so with the likely hood of the dialing ring rubbing up against the gate part, it shouldnt cause any real issues.
So finally getting round to final prep before assembly. The outer greeble ring needs painting first as it would be harder to paint it properly after its assembled.
But the primer really has shown off just how bad some of the bubbles are. I made 10 outer ring segments and i only need 7 and 2 halfs. ive picked the best of the bunch to go on the gate but theyre all got some bubbles... I tried putting in some spot putty but its not really worked out.
i might just have to accept im going to have bubbles :/
Also i dont know if its warp or not but, I didnt give the parts enough tolerance when designing and had to use the dremel to make them fit better. I might still need to do some more as they still dont quite meet. That or theres some shrinkage too :/
But as bad as it might seem, its actually fitting... soooo might be ok, just maybe a few gaps where i didnt want them :/
i fixed the bubbles in the resin by dripping 3d uv resin and then setting them... primed and painted dark grey and just dry brushed some "chrome" on... i might take back some of the brush brush as its a little too much in a few spots. But nearly ready to assemble... might even do it tomorrow
Ok so heres whats going on........
And why theres been a huge delay in this project...
I casted all the resin parts as mentioned above, but Ive been having real issues with bubbles being caught in the details. Surface tension bubbles. While I managed to repair most and hide them for the greebly bits, i was getting very very bad bubbles in the corners of each squarish thing on the main faces and in a few other spots.
i tried repairing them but it just didnt work.
Looking around online some one mentioned using talc on the mold. brushing it in and using air to blow out all the excess.
I tried that and it actually worked.
Problem is, it also pulled some of the silicon with it :/ AGGHGHHh!
I did notice when I went back to the mold, that the detailed bits kinda felt dry. Its only been a few months since I last used it to make the first batch. But I guess 12 pulls and a humid summer has kinda made it a little brittle. I dont know. Anyway mould ruined.
So I am now making a new mould to try and make a new batch of these using the talc method... Or was talc a mistake? Is that why the mould ripped off?
Also what about mould release agents? Are there any save to use for detailed parts like this? Would they help with surface tension bubbles? Obviously cant use a release agent AND talc at the same time. Release agents ive seen before tend to leave a kinda lumpy texture to the part... I dont want that. I did buy some but it turns out it cant be used with polyurethane resin :/