Questions about fiberglass resin, Plaster and bondo

[Weapioneer]

Greetings everyone!
I have a couple of questions regarding modeling and a few materials for modeling, and i hope this is the right place to ask about them. I recently got my hands on a fiber glassing kit and bondo, but i am having a few issues with them.
First off, the fiberglass kit(David's fastglass). I have a lot of trouble getting the mixture right, because the proportions are weird and the hardener is, as usual, lacking in quantity and it is like a flat tube of toothpaste. I need to get its proportions in relation with the thick resin correct or it won't set, so does anyone have any tips on getting the right mix without just going overboard on the hardener? Also, i recently made a replica of Corvo's sword from Dishonored, in PVC sheeting, and gave it a paint job. As a finisher, i wanted to use resin in order to achieve a scratch proof surface, but in my foolhardy haste i did not add enough hardener and as a result, after 72 hrs it is still slightly soft and tacky to the touch. Is there any way to make it dry without having to manually scrape off the resin?
Also, i found some water activated fiberglass strips(for bone casts) a while ago, and i was wondering if they are a suitable material for modeling. It is not strong in a single layer(obviously meant for multiple layers), but may be easier and cheaper to use than regular fiberglass kits. Will it last long or only for a short time? has anyone prior experience using these things?
also, does anyone have tips for getting bondo mixed and used properly? i don't want a repeat of the resin incident with the sword. Can anyone with prior experience tell me the strengths and weaknesses of bondo? will it crack if dropped?
I am a vegetarian by choice and i don't like using leather, but many cosplays require leather work for belts, bracers, straps, etc. Is there any alternative i can use for leather which is thick, tough and strong like leather but not an animal product?
I am also making a bust of my head in plaster of paris to satisfy my huge ego(just kidding to make helmets on and for display, but i do not have access to people who can help me nor silicon/alginate molding materials. Any method for the lone cosplayer?

TLR
New here, need help with materials, questions below-
1. Tips for getting resin/hardener mix correct in fiberglass resin and bondo?
2. Resin coating on a sword but not enough hardener in the mix, anyway to easily remedy?
3. How strong and lasting are water activated fiberglass strips for things like armour?
4. how strong/crack resistant/heavy/etc. is bondo?
5. Any material with the exact properties of leather but NOT from animals?
6. How to make head cast without silicon/alginate molding?
7. How effective is krylon clear coat at protecting painted props from scratches? impact and drop resistant?
8. Further questions if i remember them

Thank you for reading, and please help!
~W

 

[Weapioneer]

well, 48 hours and no responses. is this because of too many questions, slow-to-respond community or simply because no one knows because this is the wrong group to ask?

 

[BigAdam]

Hey, I know some of these for once.

1. Tips for getting resin/hardener mix correct in fiberglass resin and bondo?

I use isopon body filler, its pretty easy to mix stuff. Add a blob of grey stuff to a blob of pink stuff, mix, apply. It goes off pretty easy just with a little cross contamination. Fibreglass resin is a bit more of a pain. Again, found stuff for cars (again isopon brand, comes in a yellow bottle / box) to be really easy. They use the same hardener. I got some "proper" resin a while back, its mixed by weights. So if you pick up a little kitchen scale it easy enough to do.
If you're buying all the bits at a car place, just read the packet for instructions. Pas that, mix like a beast and make sure you use clean ish kit (disposable cups for resin, a random old CD / DVD case for mixing bondo on).

2. Resin coating on a sword but not enough hardener in the mix, anyway to easily remedy?

Thats almost poop creek with no paddle. Had this with a toolbox I was doing. You got 2 options;

1) Spray some hardener on and hope.
2) Spray some hardener and add a bit of heat with a heat gun.

I dumped a load of extra hardener on mine, they gave it a blast with a heat gun till everything was warm to hot and left it overnight. Next day it had all gone off.

4. how strong/crack resistant/heavy/etc. is bondo?

Not very really. Bondo isn't a building compound. Its to smooth out minor dents in body work, not build things out of. You want it on something strong (fibreglass) then bondo skim to get it smooth. You don't want to sculpt stuff from it. It can be weighty if you pile it on, its also fine with vibration but will crack with force (heard of plenty of people with cars where one day the entire "door" popped off, was all body filler).

5. Any material with the exact properties of leather but NOT from animals?

Leatherette / artificial leather? Depends on if you want looks or use.

Hope that helps, it all comes from a oaf who messes about with cars.

 

[Weapioneer]

Thanks! So i should mostly use resin and fiber glassing for the basework and thin skims of bondo on top of it? Great, i was going to make nearly solid bondo shells for an portal gun i was making, saved me quite the mess. So for the sword you say that putting more hardener on the top might work? problem is, my hardener is not a liquid but this thin paste in a flat tube, so measuring it is completely impossible by weight. I think you have to do it by eyeballing the color but i can't tell colors that well. Ah, well. Next time i will be very generous with hardener. Do you think giving my sword another coat with resin or something like wood varnish or krylon clear coat might work? It is almost completely dry, but still slightly soft if you press it hard.
Thanks,

 

[mattycsi]

Thanks! So i should mostly use resin and fiber glassing for the basework and thin skims of bondo on top of it? Great, i was going to make nearly solid bondo shells for an portal gun i was making, saved me quite the mess. So for the sword you say that putting more hardener on the top might work? problem is, my hardener is not a liquid but this thin paste in a flat tube, so measuring it is completely impossible by weight. I think you have to do it by eyeballing the color but i can't tell colors that well. Ah, well. Next time i will be very generous with hardener. Do you think giving my sword another coat with resin or something like wood varnish or krylon clear coat might work? It is almost completely dry, but still slightly soft if you press it hard.
Thanks,

Don't go in heavy with hardener, the working time is quite short anyway and if you put too much in you'll barely get anything done. Not to mention the waste.

With fibre glass resin, the rule of thumb is about 2cm length of hardener to ever 10ml of resin. Squeeze it out in thin strings on the base of your mixing containing for the amount of resin you're going to use. I recommend about 40 ml at a time, unless you're working really quick you wont get much chance to use much more than this.

For the sword, adding extra hardener to it now, I would squeeze a small amount of it onto a soft cloth and spread it over almost like a polishing compound. But a correctly mixed coat over the top would do the trick and would be easier it think.

 

[Weapioneer]

well, i finally fixed the sword. cleaned it a bit, added another layer of resin, and it is done! the excess resin gave me two big problems, it made the sword reddish and made the sword so thick it did not fit into the saya i made. i nearly used it for throwing practice from my roof, but cooled down in time. I had to hack the inside of the collar of the saya, but thankfully, i was spared having to make another sword. Now i learnt my lesson, and i am trying to find a strong, water based clear clear coat to use to protect my weaponry from now on rather than resin coating.