BA Baracus Build Thread

Laminating some solid wood for the nose cone blank. Finally. It'll hit the lathe sometime this week.

qquake2k said:

What kind of wood is that?

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Mahogany. I went to the local boat shop and got the cheapest 2" thick block that was solid and dense enough to machine on a lathe.

qquake2k said:

Sounds expensive. I've only ever turned basswood for nose cones. It's easy to turn, and finishes well.

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It normally would have been. I got a bit of a friend discount, especially once I explained the project. Boat builders don't sell rocket building materials very often lol.

Odds are good it'll be pretty, but I doubt it'll see light of day. It'll be the plug for the nose cone mold.

Lathe day. Still a ton of work before this is ready to make the mold, but... it's nose cone shaped.

That is going to be one nice nose cone.


Composite Addict

Thanks Sinful. I have to say, I'm really pleased with the progress on it. Now to bring it down just a bit more, seal, then get it down to 600 smooth.

The look of wood on CF is pretty cool. I know it's just the plug, but I'd be tempted to troll TRA FB with that photo as a finished product jistnfor giggle .

That camemout reslly cool

For scale:

I was happy when it came off the lathe, but I'm truly happy now that it's down to 600 grit smooth. Small logistical issues, but it'll be sealed with west tomorrow night, brought back to true with 600/1000 on Tuesday, and if all goes well the melamine/wax/PVA should be available for Wednesday evening for the first part of the mold.

Nice work Chris, is that an Ogive or VK or something in-between? BTW, did you ever back that tube?

Last night's work:



Mounted a dowel in the base of the nose, and drilled a hole in a scrap piece of wood to stand it up. Will make sealing and wet sanding much easier. Also, I got some hardboard, roughly cut it to nose cone shape and glued on supports. Once the nose is sealed and true I'll fit the nose in the hardboard and use modelling clay to fill any gaps.

mpitfield said:

Nice work Chris, is that an Ogive or VK or something in-between? BTW, did you ever back that tube?

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RE shape, it's more VK than Ogive, but basically splitting the difference. Re the tube, I've unwrapped it, but other than that it's untouched. I still need to pretty it up.

Update. Brushed on the last coat of West last night, so I'll hit it with the 320 dry/ 400 wet/ 600 wet tonight and we're good to go. (After 10 coats of wax lol). Tip when sanding to a finish with epoxy soaked wood - if you know the grain is saturated, mix food colouring with a little bit of acetone, then brush it on the work. It shows all the deep spots and grooves, so sand until the colour disappears, then move to a finer grit and repeat. It's not necessary, but for sure it gets to the right finish at your spec.



Next is to make the board a perfect fit to the plug, then get to work on the molds. Unlike John Coker's video, I'll be making a 3 piece mold so that there's a flange for the join of the two nose cone parts. In my opinion it's a much stronger seam than taping the inside of the finished nose. (Briefly considered an external recess for external taping, but an internal flange made a lot more sense.) I also use furniture feet to help the molds nest correctly into each other.

Mini update. Nose cone is absolutely beautiful in my eyes, parting board formed and cut to spec. Furniture feet on the parting board make lining up the molds for the finished part quick and easy, so clean everything up, lay the feet and start waxing. The wax says 3 to 5 coats - no way, I'll do probably 15 to 20. Don't touch the wax with your hands, as even clean hands have oils that can mess things up. When both NC and parting board are nicely waxed, place the NC in the parting board and use the no cook modeling clay to fill any voids, then wax the whole thing again.



Off this weekend to Buffalo to get my truck fixed and to introduce a well known TRFer to something called a mojito. I doubt we'll just have one each. Next update when it's time to drop thickened epoxy on the corners then drape cloth.

Man thats going to be one sweet nose cone.


Composite Addict

Wow, that is beautiful!

Sent from my SAMSUNG-SGH-I337 using Rocketry Forum mobile app

I demand my blanket.


Those mojitos were good.

DavidMcCann said:

I demand my blanket.


Those mojitos were good.

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For sure, a good time was had by all.

Dang, that looks really good!
I like how the grain stands out.


Thanks,

Another mini update. I uploaded the pics from my phone, so sorry they aren't rotated.

4 coats of wax done on both the nose and the parting board. I have 3 little cradles to support the nose when it's in the parting board, so a dab of hot glue to hold it in place, use the clay in the seam, then resume waxing. At this point I'm applying wax, then sanding my tube while waiting for it to glaze.

If I had to do it again I'd have put the furniture feet a bit further away on the right side of the board. But... it'll work.



Wet sanding carbon over my kitchen sink. Just a hint of spiral left, and 240 wet is just enough grit that the epoxy will stick when I touch it up with another thin coat. After this, apply the high temp epoxy, then wipe it off, leaving just what's in the voids in the weave.

I hate when projects stall, but month long corporate audits will do that to you.

I got aggressive with the waxing, and the hot glue released the nose from the wooden supports. The modelling clay gave way when the nose lifted, and because there was so much wax I couldn't get the clay to stick. So... hot glued the NC back down to the supports, Bondo in the seam, then back to the wax. With the waxing now done I can lay up the mold. (Finally).

Will put white pigment in the epoxy and brush it on without glass fiber and let it green. It fish eyes on you because of the wax, but just keep spreading it out until it starts to kick. Then do it again, and let it green again. Then lay up the mold. Epoxy thickened with Cabosil around the outside feet and the NC/parting board seam, build up laminate on the shoulder, more thickened epoxy with Cabosil at the NC/shoulder joint, then load on the ply. The plan is for 15 ply of 6 oz glass. I'm still a bit concerned that my feet with separate from the parting board because of the Cabosil, but we can dig those out later if they come off.

Forgot to mention, I'm planning on a 3 part mold. Top half, bottom half, and joining flange. Pigment just makes the initial pure epoxy layer easier. The finished glass nose will have black pigment, so white for the mold.

So I finally got off my ass. Time and build space have been an issue, so you'll see I laid up this mold in my kitchen. I suspect I'll be single forever if I keep this up.



Really happy with how it turned out, but the rebate feet stuck in the mold (came off the parting board). Tried to pop them out with a knife but it only bent the tip.



So, I needed to get creative. This proved successful.



So now soften the rebate holes a bit, wax like hell and lay up the other side.

Corkscrews.... solving problems for centuries

Sometimes builds stall, and they're all the better for it. I think this is the case. Here's the updated .ork file, and I should have the finished 3 part nose molds this week. New plan is head end deployement, dispensing with the whole forward section, and adding a downward facing Raspberry Pi V2 video camera (and thanks to Random Flying Object for the tip).

View attachment BA Baracus 76 chopped.ork



Edit to add, if I can reduce the size of the lump for the camera shroud I absolutely will. This design is still a work in progress. And yes, I'm going to fair the camera shroud into the BT with carbon/high temp epoxy.

Barkley said:

(and thanks to Random Flying Object for the tip).

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What was the tip?

Jim

JimJarvis50 said:

What was the tip?

Jim

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I was looking for good 1080p video options. The Raspberry Pi V2 camera with the Pi Zero board is lightweight and his go to for his latest Spikey build. If he's recommending it, I'm going with it.