Question/help with casting with fiberglass

[Riceball]

I'm relatively new to the whole costuming and prop thing and don't have any experience with the methods used by the pros here but I know what I want to do and have a rough idea of how to do it but I need help with the details though. What I'm trying to do is to use a cheapy set of vac formed Halloween store grade Roman muscle cuirass as a mold for making one more to my tastes based on the type seen in Rome and Spartacus. To do that I plan on filling all of the details and other unwanted parts with clay and then laying glass in it to create a plain curiass/breast plate that I'll attach my own decorations to. But having no experience with fiberglass or anything similar I don't know if I can apply the resin directly to the plastic with some basic mold release or would I need something more specialized or would I need to fill the interior with another material or clay?

I would also appreciate any suggestions for casting materials, any alternatives/better solutions to regular fiberglass resin or a particular type or brand of resin? Any general tips and/or suggestions for working with the stuff would also be greatly appreciated; things like how to apply the resin to get a smooth surface, things not to do, things to get best results, etc. All help would be most greatly appreciated.

Here's what I'm working with:

And here's an example of what I'm trying to make it look more like:

 

[rollerboi]

That looks like a leather breastplate; you could carve a wooden mold and shape a piece of leather over it instead.

 

[clonesix]

Fiberglass? How about hydrostone? Pour in, let set, form done. If need be, pour in small batches so as not to distort the original form.

 

[Riceball]

That looks like a leather breastplate; you could carve a wooden mold and shape a piece of leather over it instead.

I've thought of that before, taking what I have and making a plaster cast of it and shape leather over it but I have even less idea of how to work leather than I do with plastic & fiberglass, at least going the glass route I can get help from the members here. That and I'm not looking to duplicate the example I posted exactly, it's the style that I'm after; fewer decorations and separate shoulders. Basically I'm looking to make a hybrid between Hollywood and historically accurate; certain stylistic aspects influenced by shows like Rome & Spartacus but historically accurate in that it's not leather which there's (apparently) no evidence to support that this form of armor was ever made from leather.

 

[Riceball]

Fiberglass? How about hydrostone? Pour in, let set, form done. If need be, pour in small batches so as not to distort the original form.

Hyrdrostone eh? Is it easier to work with than fiberglass, it sure sounds like it; simple as pouring in, no need for laying in matting or anything? Will I be able to pour right in and pull out once dry or would I need some sort of mold release?

 

[Riceball]

After doing a little reading up on hydrostone I'm not sure that it's the right medium for this project. Being a form of plaster it sounds it would be pretty heavy and it doesn't seem to ideally suited for making armor. Thanks for the tip though, it sounds like a great material for making vacform bucks and the like.

 

[Darth Mule]

Many many responses.

Fiberglass? How about hydrostone? Pour in, let set, form done. If need be, pour in small batches so as not to distort the original form.

First, I believe Clonesix is suggesting you reinforce your plastic with hydrostone to create a sturdy mold or a buck to then shape your leather on. You would have to create a very sturdy form to do so.

but historically accurate in that it's not leather which there's (apparently) no evidence to support that this form of armor was ever made from leather.

Not exactly true. The style of armor changed from period to period and its pretty well established that (with the non-segmented style at least)the Roman soldier primarily wore leather armor, often with chain mail. The higher born military and politicians would wear in Bronze or Brass. The metal cuirasses were a mark of wealth and not for all soldiers. By that logic, the particular character you posted a pic of should probably be wearing metal as a sign of his social standing, but I find it to be a good stylistic choice designwise, so I'm not arguing. There is some question of whether the particular musculata style was used by anything other than High Ranking Romans, but leather was used on the infantry and its a short leap from a shapeless cuirass to the muscled variety.

Now your question... If you want something more plain that you can decorate to your whim, perhaps you should start off with something more plain. Tobins Lake sells many sets of plastic armor (easy armor) on the cheap (usually less than $30.00 or a chest/back combo) http://www.tobinslake.com/studios/
Trying to eliminate the detail already there would be a whole other issue involving alot of work on your part.

These too are fairly thin plastic, much like your costume cuirass, but can be reinforced. I've reinforced them by gluing a layer of felt to the inside with great success. Sometimes even shellaccing the felt to make it harder and less flexible. You may also reinforce it with fiberglass I'm sure. Be sure to scuff the inside before you apply anything to it though or it may not bond to the smooth plastic.

This method should cut out any need to sculpt onto the armor and recast it.

 

[Riceball]

Not exactly true. The style of armor changed from period to period and its pretty well established that (with the non-segmented style at least)the Roman soldier primarily wore leather armor, often with chain mail. The higher born military and politicians would wear in Bronze or Brass. The metal cuirasses were a mark of wealth and not for all soldiers. By that logic, the particular character you posted a pic of should probably be wearing metal as a sign of his social standing, but I find it to be a good stylistic choice designwise, so I'm not arguing. There is some question of whether the particular musculata style was used by anything other than High Ranking Romans, but leather was used on the infantry and its a short leap from a shapeless cuirass to the muscled variety.

Thanks for the info, I'm only going by what I've read on a Roman history/reenactors forum where they're vehemently argue against the existence and/or usage of leather musculata citing the lack or archaeological evidence for such a thing. They contend that the Romans pretty much wore nothing but metal armor exclusively and feel/argue that not even officers would wear leather armor over metal due protective value for weight and vanity.

Now your question... If you want something more plain that you can decorate to your whim, perhaps you should start off with something more plain. Tobins Lake sells many sets of plastic armor (easy armor) on the cheap (usually less than $30.00 or a chest/back combo) http://www.tobinslake.com/studios/
Trying to eliminate the detail already there would be a whole other issue involving alot of work on your part.

These too are fairly thin plastic, much like your costume cuirass, but can be reinforced. I've reinforced them by gluing a layer of felt to the inside with great success. Sometimes even shellaccing the felt to make it harder and less flexible. You may also reinforce it with fiberglass I'm sure. Be sure to scuff the inside before you apply anything to it though or it may not bond to the smooth plastic.

This method should cut out any need to sculpt onto the armor and recast it.

Your suggestion about the Tobin's definitely has some merit to it but I want to recast from the existing armor that I already have because I want the experience of casting and working with fiberglass. Basically this project is intended to serve as a training project for a more advanced project that I eventually want to do (building a suit of Southern Cross/Robotech Masters armor) and this will give me a little practice with working with fiberglass on something that if I mess up on won't be a very big deal.

 

[Darth Mule]

Then you are looking at reinforcing your current armor to prevent its collapse while working on it. Then doing your sculpting directly on the cuirass with whatever you're most comfortable with (bondo, clay, whatever), then taking a negative mold using silicone or polyurethane with a fiberglass, plaster, or plastipaste jacket. Then using that mold to create your fiberglass cast.

Here's a brief tutorial on the smooth-on site
http://www.smooth-on.com/gallery.php?galleryid=272&cPath=1241

 

[Riceball]

Then you are looking at reinforcing your current armor to prevent its collapse while working on it. Then doing your sculpting directly on the cuirass with whatever you're most comfortable with (bondo, clay, whatever), then taking a negative mold using silicone or polyurethane with a fiberglass, plaster, or plastipaste jacket. Then using that mold to create your fiberglass cast.

Here's a brief tutorial on the smooth-on site
http://www.smooth-on.com/gallery.php?galleryid=272&cPath=1241

So from the sounds of it I can't just make a fiberglass cast right after filling in the details/decorations with clay then, I'll have to make a mold using another material first? I'm guessing this is because the fiberglass resin will just stick to the plastic and no form of mold release will prevent that from happening?

 

[clonesix]

actually, after reading all this, I don't have a clue what you are trying to do.

Yes, you can laminate fiberglass into your plastic chest plate. Give it a few coats of wax first, as a mold release.

 

[mdb]

There are other kinds of leather armour, just that particular type is causing the contention right? I know when I was looking into cuir boille that there was a bit of contention of methods used.
Basically if you soak vege tanned leather in water (hot but up to ta point as you do not want to warp the leather) for a short period and wrap it over a form. It's fairly easy to do but as always the more detail you want the more diffiuclt it is And you'll want to practice tooling as well.

That said the photo shows that it could also be patinaed bronze which would be ok And would explain the leather binding around the arms. I'm most concerned about the lack of undergarments.. chafing!

But back to the casting molding thing:
What you have is a positive master to work on. If that is flimsy then you are best off pouring plaster/cement into the back to make it sturdy and adding details to the top (either to the plaster or the original depending on what the clay sticks to and how much detail you want or do not want). You will then want to make a negative mold from silicon (possibly with a FG jacket if you are skint like me and can't afford lots of silicon). Front there you can fibreglass a positive cast.
I use epoxy resin as I have found my perfect blend of fillers and matting for me to be happy. It takes much longer to set up than urethane resin and has about the same level stinkiness to it Polyester resin is something I avoid like the plague though I admit when using the plastic putty I do (a generic "Bondo") it probably would adhere better being a polyester too

Oh yeah and I find the epoxy pops out of my molds better than urethane but that's me being skint again and not buying the specific mold releases I leanrt all this in my year long Slave Leia project (on my site in my signature). If I can do it, you can

 

[Darth Mule]

actually, after reading all this, I don't have a clue what you are trying to do.

Right there with you now.

I was trying to help, but I Now I'm quite lost.

So you just want to reinforce your existing breastplate with fiberglass and change some of the relief (sculpting) on it? Is that what you're getting at?

 

[twistedxknights]

ok lemme see if i can get this right.. your wanting to take the chest plate in the first picture and basically "erase" the ornamentation and then apply your own ornamentation to make it look more like the second chest plate..

yes reinforcing it with fiberglass will help however you will have to fill in the ornamentation that is there from the back side and then grind it down..

please be aware that not all plastics take fiberglassing well, as some will melt from the heat generated by the curing process .. It is best to either test it in a small area first or buy more then one so that if the first one melts you have a back up to try a different method of reinforcing ...

 

[Riceball]

There's obviously a good bit of confusion as to what I'm trying to attempt so let me see if I can't clarify it up a bit.

What I'm looking to do is to use the cheap plastic armor that I have as a negative mold. I first plan on filling in all of the details/decorations with clay and leave just the musclature, once that's done I want to make a cast of it using fiberglass and then add my own decorations to the casting.

Thanks for all of the input and help so far, even though there's been a bit of confusion over what I'm trying to attempt there has been some helpful tips so far. Keep them coming, the more advice I have the better; it'll (hopefully) keep me from making too many mistakes.

 

[Riceball]

actually, after reading all this, I don't have a clue what you are trying to do.

Yes, you can laminate fiberglass into your plastic chest plate. Give it a few coats of wax first, as a mold release.

On the wax thing, what kind of wax do you recommend? Floor wax, car wax, candle, furniture? And any particular brands? The last thing I want is to spend hours filling in the details, reinforcing the armor, laying the fiberglass only to have it stick to the plastic and not want to come out.

 

[clonesix]

once you laminate the fiberglass into the plastic piece, you will ise THAT fiberglass piece as a new armor plate?

Yes, that can be done. I envisioned that you were tring to make your own vacuform mold (hence solid stone), sculpt new decoration, and then vacuform new plastic over the buck. Sorry, my missunderstanding.

Here is my suggestion: Wax the inside of the plastic form. Support it well, so that it won't distort as you apply the fiberglass and resin. Laminate 2 layers of fiberglass into the form, one layer of 1.5 oz MATT, and one layer of 10 oz cloth.

Why one layer of 10 oz cloth? Because you are wearing it, and it gives a smother finish. Matt will give you lots of sharp points to poke you and irritate you.

Once the fiberglass has cured, you can pull it from the form and sculpt your own ornamentation.

I reccomend Magic Sculpt for the ornimentation. It is a 2-part epoxy clay that will harden within 4 hours. There is no need for a second mold to be made. You have a one-off chest plate.

I hope I understood the problem better this time.

 

[clonesix]

On the wax thing, what kind of wax do you recommend? Floor wax, car wax, candle, furniture? And any particular brands? The last thing I want is to spend hours filling in the details, reinforcing the armor, laying the fiberglass only to have it stick to the plastic and not want to come out.

ANY wax you want. It doesn't matter. You can even use dish soap if you want. Paste wax is fine. Even if you used no wax, you could pull the fiberglass part out, it goes better with it, though.

 

[Riceball]

once you laminate the fiberglass into the plastic piece, you will ise THAT fiberglass piece as a new armor plate?

Yes, that can be done. I envisioned that you were tring to make your own vacuform mold (hence solid stone), sculpt new decoration, and then vacuform new plastic over the buck. Sorry, my missunderstanding.

Here is my suggestion: Wax the inside of the plastic form. Support it well, so that it won't distort as you apply the fiberglass and resin. Laminate 2 layers of fiberglass into the form, one layer of 1.5 oz MATT, and one layer of 10 oz cloth.

Why one layer of 10 oz cloth? Because you are wearing it, and it gives a smother finish. Matt will give you lots of sharp points to poke you and irritate you.

Once the fiberglass has cured, you can pull it from the form and sculpt your own ornamentation.

I reccomend Magic Sculpt for the ornimentation. It is a 2-part epoxy clay that will harden within 4 hours. There is no need for a second mold to be made. You have a one-off chest plate.

I hope I understood the problem better this time.

Thanks for the advice, what you've described is exactly what I'm looking at doing. One more thing, by cloth do you mean any piece of 10oz cloth or are you referring to some sort of cloth used specifically for fiberglassing? And regarding the laminating, you recommend 2 layers of resin; would the order be resin, matting, cloth, resin?

 

[clonesix]

cloth means fiberglass cloth. The fibers are woven, as opposed to random. Visit here: http://www.shopmaninc.com/cloth.html for examples. Mind you, you don't need anything this fancy, just woven cloth. You can get away without it, and you will have the piece you want, it will be cleaner, and safer as a worn product if you do.

Go to You Tube and type in fibergalssing and you will get more information than you want.

The procedure is like this: Wax insde of form. Wear protective clothes, mask and eyewear. Mix a 1/2 litre (500g) of resin with 1% catalyst. Brush in a layer of resin. Tear up pieces of matt (better if torn) and lay them (dry) into the form so that everything is evenly covered. Brush in another layer of resin on top of matt and let it soak in. Use the brush to work in the resin into the fiberglass and work out any air. Lay on one piece of cloth (dry) and let it soak up th eresin from underneath. Use the brush to work ou tany trpped air bubbles, and soak up exess resin. Let cure.

TIP: As the resin cures, it gets solid. Before it gets rigid hard, it passes through a gell state. The resin + glass will be solid, but not ridged. You can trim the excess glass from the edges with a utility knife. Let finish curing, and remove from form.