Okay I've gotten the help I needed. Thanks guys.
Okay I've gotten the help I needed. Thanks guys.
Last edited by Joshalots; Feb 28, 2011 at 7:57 PM.
Did you make it out of card and brushed on urethane, or did you make it from sheet plastic?
I am not an experienced pepakura maker. I have made only a 3PO head a few years ago. I reinforced it with papiér maché (newspaper soaked in glue) onto both the inside and outside, sanded the outside and then added papier maché on the outside to reinforce the smoothened paper model. Then I brushed on fiberglass resin and fixed the rest using auto-body filler.
Unfortunately, I had rushed the papiér maché. It had not dried well enough, so I had to scrap it.
Sheet styrene (HiPS) and ABS can be sanded. Use plastic adhesive (that has solvent such as M.E.K in it) to glue reinforcing plastic strips on the inside. Fill any remaining cracks with ABS slush. You make ABS slush by putting scraps of ABS into a jar, cover it with solvent (acetone or other) put an airtight lid on it and let sit overnight.
I used cardstock with 2 layers of Smooth-cast 320 liquid plastic on the inside and out.
The second layer on top I didn't use a brush. Isntead, I used my hands(with latex gloves) and just smeared it acrossed the top. That seem to fill it in well and smooth it out alot more than it was previously in the picture above.
it still not that smooth though
I'm thinking I could get alot of spot putty to make smoother and cleaner. perhaps another light coat of plastic to seal it on.
If you have an HVLP spray gun and compressor, you can spray multiple heavy layers of a high building sandable primer (sanding between each layer). The best primer to use would be one you have to catalyze so if it is heavy in areas it won't stay "gummy". Utec is the best urethane primer for plastic.
go to the 405th.com. They have a whole database about it!
since when is bondo considered hard to sand?
Actually Bondo brand filler is fairly hard to sand compared to others for sure. I would recommend getting some automotive grade filler, it will be way easier to sand than the Bondo brand filler. Only way you will get your armor smooth, and it works perfect. Here this is pic of my build using auto grade filler all the way.
thin rondo? (not bondo)
There are a lot of easy-sand body filler products on the market, I always tend to use those. I ususally use Upol easysand body filler, it's not hard to sand. Unfortunately though, by it's very nature a scratch built item like this will always require quite a bit of elbow grease and sanding.
The other alternative is an epoxy putty like Milliput, but that is fairly hard to sand once cured - harder than bodyfiller - and it will be more expensive than body filler.
You could also apply a coat of Rondo, as said a few posts up. It's a mix of Bondo and Resin at 1:1 ratio (more or less) and can be applied with a brush.
"Rondo" as you guys like to call it will actually be harder to sand than the standard Bondo brand filler. The more Polyester resin added to the filler the harder it will be to sand. That's the reason the Bondo brand filler is so hard to sand, basically a thick polyester resin designed to be solid/stronger not easy to work with.
Goodluck with the sanding and I'd have to agree with everything Finhead has said!
I'd just like something clarified, if you don't mind me asking. When you say it's hard to sand, are you meaning it's hard to sand by hand? I ask because I use a power sander with 60 grit sandpaper it tears right through Bondo brand filler.
^^^what he said
Sure you could tear through it with a power sander no problem, still would be hard to finish correctly after it is roughed out. You don't do finishing work with a power sander, hand sand with a block.
so far almost everyone on here has given you a correct answer, I use bondo brand myself, but I would love to see the brand that you use Finhead. If I remember you do all your work by hand, where I do most of mine by machine (sanders, dremels, etc.)
anyways I mean its hard to sand even with a power sander, it takes a long time and bondo really makes the parts heavy. I don't have a dremel for doing small detailed areas though.
And I have question about bondo. In the past I've been smothering it all of the parts, is that bad? Should I only do one section at a time? Because when ever I do bondo I can never sand it down to have nice crisp edges and rounded areas, it just becomes a pile of mush.
Pic of my old mark 4 back piece with bondo
Pic of my new mark 3 chest before adding bondo
For my Pep projects, I just slush mold a fast kicking plastic on the inside of each piece until I get the thickness I want. Then you just sand the outside smooth!
I really wish I had a dremel but they cost $50
I just barely put on a light coat of bondo on my chest,back,and abs pieces but I don't have any sandpaper right now so I'll have to hold off on that.
The truth here is, you get nothing for nothing. There are no shortcuts.
There's no easy way to make a silk purse from a sow's ear, pepakura promises that initially but actually demands a whole lot of graft. But it can be done with blood, sweat and tears. I've mocked up quite a few sow's purses in my time so I know what I'm talking about. You really have to work at this thing if you want it to be great. That means having the right materials, like sandpaper, putting in the sweat and doing what's required. A bit of dedication and extra effort.
That's the only way it can be done.
Then you will have the piece you want to make.
Contrary to popular belief... Smooth Cast 300, 320, etc... are toxic. Just because it doens't give off offensive odors does not mean it's non-toxic. I used to think the same thing and I use it all the time. I was informed and also found the "Material Safety Data Sheet" which put in plain english that it is not good to inhale this stuff.
So out of your own safety please wear a respirator.
I'd recommend investing in tools that would be suited for working with those materials. In general, a craftsman's abilities are linked to his available equipment. Even if it gets used for this one single project (being that it's Iron Man, that's a pretty sizable project) and you never pick it up again, a simple palm sander will probably be worth the investment just in time alone. Whatever means you seek for finishing work (as previously discussed) is up to you, but if you're wanting to smooth out major areas quickly and efficiently, do yourself a favor and get a power sander. Your hands will thank you. LOL.