Captain America Shield - Could use advice

Ok, so the pepping didn't work as well as I'd hoped. It just isn't rigid enough for something this big and flat. That's alright though, because we are on to plan B: big foam circles.

foam%20at%20angle.jpg


foam%20with%20overlay.jpg


Only the top five circles are for real. The bottom one is thirty inches, and is just there to tell me where to stop. The darkened area in the second picture is where there will actually be shield.

To give you a better idea of the shape, here is the picture I threw together in Photoshop to figure out how big to cut the circles.

layers.jpg


To build it up, I'm thinking the paper-mache material from this video: YouTube - Easy Paper Mache Clay Recipe. Has anyone used something like this? Would it be suitable?
 
Great idea!

You could use bondo or some type of sculpting material to smooth it out.

I'm hoping that I'll be able to sand it smooth enough that I can just put on a few coats of polyurethane or resin or even just a crap-ton of the release wax to get it smooth enough to make a good mold.
 
I did a test with that paper mache stuff, and several days (and 20 minutes in the oven) later it still isn't completely dry.

I'm going to experiment later today with the quick-drying drywall mud, but in the meantime, does anyone have any advice of a good material to build the foam up into a curve?
 
You could use that spray expanding foam... Trowel it around before it sets. It does expand, of course, but then it can be carved, sanded, etc.
 
On the expanding foam, how much time should I expect to have between when it stops expanding and when it starts to harden?
 
Quick materials update. In my test I found the expanding foam to be too unruly. Not fun to try to form into any kind of shape.

Right now I have a quick-drying drywall filler and toilet paper mixture drying. Hopefully it will be dry enough early enough to get a good read on it tonight.
 
I did some tests, and came up with a mix that I like. It's pretty easy to work with, but it does start drying out pretty quickly.

I have gotten started building up the shield with it. I had to stop because I was getting the foam wet (the mache is about 1000x easier to work with the wet hands), and the the paper-mache-stuff wasn't sticking to it.

Here are some pictures of where I am right now:

buildup%20start%20angle.jpg


buildup%20start%20side.jpg
 
Quick materials update. In my test I found the expanding foam to be too unruly. Not fun to try to form into any kind of shape.

Right now I have a quick-drying drywall filler and toilet paper mixture drying. Hopefully it will be dry enough early enough to get a good read on it tonight.
that's what i was gonna say.... wall spackling/joint compound is great for filling in large areas like that. easy to sand too.
 
Not a huge update, but here's where I am right now. I'm hoping to be able to finish this stage of it tonight when I get off work tonight.

Buildup%202%20angle.jpg


Buildup%202%20close%20side.jpg
 
OK, so I was out of the country for a week, hence the lack of updates, but I'm back and I'm working again. Right now I'd say the plug is about 80% there. I have the shape and I just finished the first pass of spackling. With any luck after I sand it down I'll be ready to put some primer on. I was going to try to prime it today, but the humidity is crazy high today, to the point where I had trouble getting pictures taken without my camera lens fogging up, and that makes me a little nervous.

Anyway, here's where I am right now:

spackled%20top.jpg


spackled%20side.jpg


Also, if anyone is keeping score at home, the joint-compound/toilet-paper mix works great. It holds together, and is a lot less brittle than the joint-compound by itself. Problem is, the toilet paper keeps it from sanding smooth. Not that big of a deal, but it is a bit of a pain and is why I had to use so much spackle.
 
Yeah, this is just a plug for a mold. The final shield will be fiberglass.

Over time I would be worried about cracking, but this only needs to survive long enough to make the mold.
 
I'm going to start making my mold this weekend. I'm going to try the foam disks to build up and use filler. I will post pics as I work them out.

Thanks for the idea.
 
I'm going to start making my mold this weekend. I'm going to try the foam disks to build up and use filler. I will post pics as I work them out.

Thanks for the idea.

Glad my 3/4 dead thread could serve as a bit of inspiration for you. Once you get started make sure you put up a link to your thread. I'd love to see what you come up with.

I don't think I posted any info on how I made the disks. I basically put a bolt through the end of a 2x4 to turn the foam sheet around, and mounted a hot-wire foam cutter the correct distance down. It worked beautifully. Here is a picture of the rig.

cutter.jpg


You can see the various holes I drilled to mount the cutter at different locations.

To get the joint compound in a curve I bent a flexible piece of inch-wide trim over the top and twisted it. Horrible description, I know. Here is a crude sketch of what I mean. The black is the shield plug, the red is any sort of long, thin, semi-rigid thing.

sketch.jpg


This thread went silent when I picked the wrong primer and almost ruined the entire thing. The primer peeled in places, and I jacked the plug up pretty good getting it off. Plan B, which I'm currently working on is just to cover the now rough surface with Bondo, and sand smooth. Seems to be working well so far, but probably isn't ideal.
 
That's awesome.

Now, I don't have a lot of experience using fiberglass. I was thinking of after putting bondo on the plug, a few layers of resin and then after it cured, a lot of release wax before making my final fiberglass mold.

Does this sound like the correct route?
 
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