For those indoor-builders: Acrylic Resin w/ Iron Man Pepakura Helmets

Here's the info sheet on it. I paid about $25 for a tester kit. He didn't have the big kit size but I'll get that if I can.

Free Form® SCULPT Epoxy Putty

As for sanding - most hand sanders come with a small bag for particles - I picked one up with a vacuum attachment - I'm able to connect it to my shop-vac and it captures almost all the dust etc. I still use a mask etc but it really helps keep the area clean. I don't have a choice at the moment as it's winter and it's bloody cold here in Calgary and living in a condo I don't have many options.

matt

NovaDom said:

Talshadar - what's the approximate price for the Smooth-on epoxy dough you mentionned? I'm curious to know if it's in the same price range as bondo? or if you are paying a premium for the benefit of working with something non-toxic?!

Dirtsen - please keep updating your thread! I`m new to pepakura, but I am VERY interested in finding alternate ways to strengthen and finish Pep parts.. especially if it's something that can be worked with indoors! Thank you for experimenting, for the sake of all of us! :thumbsup

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SriLanKING said:

could you do a tut for how you made the mold with silicone caulk? and I've been using aqua resin, it doesn't go on a cleanly and polyester resin, but a bit of sanding never hurt anyone!

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NovaDom said:

Do you mean that the MOLD was made with silicone caulk, or is the actual part CASTED in silicone caulk?!

.. and, just to be totally certain, are you talking about silicone caulk in a tube, kinda like this here?

I'm very interested either way.. :thumbsup Keep up the good work

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I am surprised nobody asked about that before.
Yes I made a mold using silicone caulk since i wanted to make a test casting. It is possible to do that with the cheap silicone caulk available in tubes, but the mold you get will never be as good as a mold made from a premium silicone. Depending on the silicone caulk used the mold is not as flexible and durable and will tear easily. Also: this technique is not usable indoors because of the smell it produces so it is kind of disqualified for this thread. But I'm going to share this either way.
What I did:
1. Put some silicone caulk in a glass jar with a lid.
2. add some mineral spirits (Xylol works good, some people use Naphta which did not work for me) to the silicone caulk. I do not recommend more than a 1:1 ratio. Less mineral spirit is usually enough.
3. put the lid on the jar an shake until the silicone and the mineral spirits have mixed. It might take a few shakes.
4. Use a brush and brush the silicone-mix onto your object that wou want to make a mold of. Wait until the silicone becomes tacky and repeat the process 2-3 times. I recommend using layers of cheese cloth or something similar in between to improve the durability of the mold.
5. to thicken the mold: get a bigger bowl and add a good amount of silicone caulk (half a tube). Add corn starch (2 teaspoons) and mix well (that can be really messy). Apply that onto your mold until you have the thickness you want.

Corn starch is hygroscopic which means it attracts and holds water which helps the silicone caulk to cure even in thick layers. That is why this works.

Attention: Not every silicone caulk is the same. Make sure you use the kind that smells like vinegar. That means it cures using the water in the surrounding air. The reaction produces the acid that smells like vinegar. Also: the mineral spirits and the silicone caulk do not smell great and are not so good for your health either so do this outside or in a well ventilated area. Another thing: Like every silcone that reacts with water there will be some shrinkage.

EDIT: flopped completely

Dirtsen said:

Put some silicone caulk in a glass jar with a lid.
...
add some mineral spirits...
...
add corn starch (2 teaspoons) and mix well

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:lol wow, you sir are an inspiration.. Your willingness to try new things (like this cake recipe here ) is awesome

On a somewhat related note, I used that type of silicone caulking to seal my house windows, last winter, and I agree that it smells really bad.. ("probably" not toxic, since it was its intended use, but the smell was very strong and lingered for about a week! and, at that point, you can't really open a window since they're all sealed shut)

I'm pretty certain I'll try your method for casting, in the future..
Every time I considered buying some molding silicone to try simple casting, the cost kept me from pulling the trigger

It looks like a LOT of silicone is required to produce even the smallest and simplest of mold and, in my unexperienced eye, it looks like a lot is wasted too.

I already have a couple of tube of silicone caulk in my garage, I will definitely give this a try..
I just need to find something to cast that I can use in my many projects :thumbsup

I just found out about another product that I think should be mentionned here..

Durham's rock hard water putty (Credit goes to AnthonyStark)
11$ for a 4 -pound can, on amazon! (link)


Original thread: Iron Man Mark VI WIP - polyethylene and rivets - solo build by a 13 year old

AnthonyStark said:

using Durham's rock hard water putty as a non-toxic and non-hazardous alternative to bondo.
[...]
If you're wondering how the putty compares to bondo, the putty is easily sandable, very hard, and is very tough. It takes quite the number of hits (about 40 really hard hits) from a mallet to make it crack and fall off from the helmet. Why was I bashing away at my helmet with a mallet? Well, I just wanted to see how tough the material was before I redid the top of my helmet.

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I know water based products and Pep are normally not friendly to each other, but when you're at the stage of applying bondo, I guess (hope?) the Pep wont suffer..

I've been reading the reviews and questions for that products on amazon (Durham's rock hard water putty)
and somebody pointed out that it doesn't absorb paint very well so you need to use some kind of primer first..

I don't think it's a deal breaker as most people prime everything first anyway, but it's just something to be aware of

also, most people there seems to be using it as a wood filler (like to fill the gap left by a knot)
and everybody agrees that it dries rock solid

especially at that price, I think it could be a very nice option

That sounds pretty cool. Does it have shrinkage? That often happens with water based products.

another thing: The website of the Bioresin I was talking about is [url]www.entropyresins.com.[/URL]

The only downside is that is isn't made for slushcasting. I really want to try this out for a helmet. So I need to come up with an idea for injection molding a big piece like that.
I let you know how that goes.

NovaDom said:

I just found out about another product that I think should be mentionned here..

Durham's rock hard water putty (Credit goes to AnthonyStark)
11$ for a 4 -pound can, on amazon! (link)


Original thread: Iron Man Mark VI WIP - polyethylene and rivets - solo build by a 13 year old




I know water based products and Pep are normally not friendly to each other, but when you're at the stage of applying bondo, I guess (hope?) the Pep wont suffer..

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I wish it (water putty) was sold here in the states it sells for 2 dollars a pound can (homedepot)

what best way for indoor acrylic resin for iron man helmet mk42

I had some success making small prototype molds using silicone from the hardware store. The key is to buy the tube that is labelled as 100% silicone. I mixed the silicone with some acrylic paint until it had the texture I wanted and applied it to my model. I have never tried using mineral spirit and corn starch like Dirtsen said earlier but I may give it a try to see how both recipes compare.

spidey20091 said:

what best way for indoor acrylic resin for iron man helmet mk42

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If you read through the thread you can get that information buddy. But in my experience the best way to do this is use cardboard paper, resin it with some fumeless epoxy resin and apply the acrylic resin on the inside first to stabilize it more and then use it like bondo on the outside later if you have some thickener. I usually use woodfiller on the outside.

Kormier said:

I had some success making small prototype molds using silicone from the hardware store. The key is to buy the tube that is labelled as 100% silicone. I mixed the silicone with some acrylic paint until it had the texture I wanted and applied it to my model. I have never tried using mineral spirit and corn starch like Dirtsen said earlier but I may give it a try to see how both recipes compare.

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I guess this technique is best when used for small items. The acrylic paint is a good idea. It adds enough moisture to the mix. The paint also is a good indicator for the mixing process. I tried that once but it produced a crumbly mess since I used the wrong paint. Another option that works other than corn starch is glycerin. But I had the best results with the starch mix.

Nice process of elimination there, I'm definitely going to have to try out some of your ideas

Just wondering if you have tried PVA on the single side laminated paper yet?

Dirtsen;

if it's not too personnal, I`m curious to know your general background? did you study chemistry or something related?

The things you tried and the experiments you do amaze me.. I never would have thought to add glycerin to the mix..

keep it up!

p.s. I ordered Durham's water putty, so I'll be able to experiment too in a little while

NovaDom said:

Dirtsen;

if it's not too personnal, I`m curious to know your general background? did you study chemistry or something related?

The things you tried and the experiments you do amaze me.. I never would have thought to add glycerin to the mix..

keep it up!

p.s. I ordered Durham's water putty, so I'll be able to experiment too in a little while

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You flatter me Sir

I didn't study chemistry but I am always curious how things work and I am not afraid to read a lot and experiment. I guess that makes me kind of an autodidact... which is why I love this forum so much. You learn so much watching other builds and thinking of ways how to improve your own build.

I used the silicone caulk/Testor's acrylic model paint/glycerin mix and molded 2 shins, the ankle cover plates, knee plates, all the screw and bolt heads and both shoulder bell parts on my Mk III suit. The larger pieces needed mother molds to retain shape. The mixture worked well by spreading the silicone in thin layers and using different color paints to distinguish the layers. The mold were made over two years ago and haven't shrunk so far.

NovaDom - I used the Durham's on my Sith Acolyte mask. It's very easy to work with. I found the edges to quite brittle and prone to chipping. However since was only doing a half mask it could be just because that there was extra flex on mine. The main part of the mask is solid though. If you decide to use Durham's be prepared for lots of dust. I used a latex low VOC primer with mine so paint adhesion wasn't an issue.

There's a link on the second page to my build thread.

If your gonna mix acrylic paint in with the silcone caulking, why not just buy a good siliconized acrylic caulk, and be done with it. If you go to a professional paint store they can order you in gallons of said caulking. So you don't have to waste money, time, and effort dealing with tubes, and mixing containers.

Kormier said:

I had some success making small prototype molds using silicone from the hardware store. The key is to buy the tube that is labelled as 100% silicone. I mixed the silicone with some acrylic paint until it had the texture I wanted and applied it to my model. I have never tried using mineral spirit and corn starch like Dirtsen said earlier but I may give it a try to see how both recipes compare.

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MaddMaxx82 said:

If your gonna mix acrylic paint in with the silcone caulking, why not just buy a good siliconized acrylic caulk, and be done with it. If you go to a professional paint store they can order you in gallons of said caulking. So you don't have to waste money, time, and effort dealing with tubes, and mixing containers.


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I found that the acrylic caulk alone resulted in a more crumbly mold. By adding paint myself i find that I have better control over the final product and can get a more flexible and resistant mold. But as I mentions I only used this method a few times and for smaller projects. That's just me though.

Hi

It s the best thread i ve seen since i m looking for indoor building.

i m searching for woodfiller for a while now and i cant find one cheap, could you give me your brand Dirtsen ? i saw you re in germany and i m french so the shipping should be more interisting for me as i making a full armor and i probably need lot of it, we had "sinto" here but it s like 20-40 euros for 1kg when i saw same price for twice the weight in U.S, it s sad for us.

Also, i can't find toxic fumeless epoxy in french store. (should explain lots of things ^^)

I would really like to start your method, i got my full armor pep ready for a month now and i m still looking and looking and... a way to start without all those toxic resin, now i found this, i need to try.

Advice for a full plate (i mean large items) ? moulding ? reinforcment ? it's 190g/m2 paper with hot glue, i tryed to soak two pieces on the outside with acrylic resin and sometime it s litteraly unglue some flaps like if i never glue it, i dont get it...

All helps are welcomes.