Are you using fiberglass resin for pepakura props?

DonaldDarth

New Member
Hi everyone,I'm the new joiner from Hong Kong.I would like to make my props.I just read "The PEPAKURA question thread"
However I haven't too much knowledge and some links isn't work in "The PEPAKURA question thread"
Would you mind help me?
What is the difference between fiberglass and fiberglass resin?
Are you using fiberglass resin for pepakura props? or other material?
or Should I use Bondo?
and one more question,how can I fix some pit on the finish pepakura item?

from Surreal Studios pics,you can see his helmet very smooth

 

MattMunson

Master Member
RPF PREMIUM MEMBER
I think it's a terminology issue at stake here. When I say the word "fiberglass", what I'm referring to is a layup that uses both resin and fiber (either the woven matt or the straw like fibers). Some people say "fiberglass resin" when referring to JUST the resin, the liquid part. Some people say "fiberglass matting" when referring to the stuff that is NOT the liquid.

I guess it's just what you're used to.

But, to simplify things, think of it this way: the liquid is "resin", the fabric stuff is "matting".

In general, the common practice for pepakura models is to brush on a layer of resin (ie, fiberglass resin) and once it cures, you go into the INSIDE of the shape and lay in some resin and matting.

I guess the confusion comes in because "resin" is a term that is also applied to other products that have nothing to do with a fiberglass process. Smoothcast is actually not designed to be used with a fiber matting. it CAN be, but it's not designed to be. It's resin, but not resin that is intended for fiberglassing ,if that makes any sense.


SOOO, the punchline is that the resin you want to use when fiberglassing is called "Fiberglassing resin".

oy.

I hope I didn't just make things worse ;)
 
A

Armageddon

Guest
There I have a question: I read in the FAQ that you MUST NOT put the fiberglass on the outside of Peparuka...why?....and if you put it in the inside, how do you achieve that smooth-looking curves?...because the Peparuka model is made of joined flat and angled surfaces, so how can you smooth it if you don't put a lot of fiberglass and sand it to a round curve???
 

PepMaster

Sr Member
I quit using fiberglass resin months ago, now all I use is urathane resin. I brush a coat outside, and slush a coat or two inside. Does'nt smell as bad as fiberglass resin does and it's just as strong.
 

EyeofSauron

Master Member
simple: fibreglass has a texture. and you want a smooth surface

fibreglass is put inside, to strengthen the paper.
on the outside, you usually put a layer of resin, and then use some kind of body filler, and then it needs to be sanded, then filled again, sanding and filling, allways just filling the spots where the surface is not flat and so on
its important not to use too much bondo, as it gets heavier and loses detail. and with fibreglass on the outside, you would have to get the texture of it out, and therefor use more bondo, sanding, and also lose detail

i hope you understood what im saying
 
A

Armageddon

Guest
Sure, got it!....but doesn't all the layers of stuff you put outside add too much volume to the original thing....and mess up with the shape?
 

PepMaster

Sr Member
The heat caused from the fiberglass resin can sometimes warp the piece. Also fiberglass resin does'nt work very well in cold tempatures.
 

EyeofSauron

Master Member
Sure, got it!....but doesn't all the layers of stuff you put outside add too much volume to the original thing....and mess up with the shape?
its not like you put layer upon layer of filler on it

you put one layer of filler on it, and sand it.
then you see, where you have holes and stuff, and put filler on there :) until you have a perfect surface
 

StickyFingers

New Member
I quit using fiberglass resin months ago, now all I use is urathane resin. I brush a coat outside, and slush a coat or two inside. Does'nt smell as bad as fiberglass resin does and it's just as strong.
What brand are you using and where are you getting it? Home improvement, auto, or boat store?
 

PepMaster

Sr Member
Model-Pro Resin from SpecialityResins on eBay, $60 for a 1 Gallon Kit, or $100 for a 2 Gallon Kit is what I pay I think.
 

simul8r

Member
Thought I’d add my 2 cents in order to help DonaldDarth. I had experience building a plywood boat and laminated it in fiberglass.
Resin is a two part chemical mix: 1 part is called resin (for some odd reason) and the 2nd part is the catalyst or hardener. Note polyester resin is the most popular used worldwide due to its simplicity and performance. Go to this link to see the different types of resin that are out there.
Fibermax Composites - Types of resin systems
Fiberglass is usually a short term used to call the type of fabric that are manufactured. The material is of fiberglass stands, how they are weaved have different names to them and are unique in strength from each other. For example fiberglass cloth is weaved finely compared to fiberglass woven rolling but in fiberglass boat building - woven rolling is used primarily for strength building while cloth is used for smoothening out the bumps. Fiberglass mat is used to lay-up or thicken the fiberglass process by sandwiching mat and woven rolling over and over. But combining all three just adds tremendous amount of strength overall. In our application, however, for hardening pepakura models – fiberglass cloth is all that is needed to strengthen with the inclusion of resin of course. See link below.
Fiberglass Cloth Fiberglass Mat Fiberglass Roving Fiberglass Tap - Clark Craft
Using resin without fiberglass fabric becomes brittle under pressure once it cures. The addition of the fiberglass fabric provides the tinsel strength neccessary for us to man-handle the pepakura model while adding bondo (body filler) and sanding.
By the way, bondo is hard once cured but lacks the tinsel strength. Apply to much pressure to bondo and it will eventually crack much like resin without fiberglass. Bondo is applied over fiberglass/resin because it’s easier to fill in pits and dents and is quite easier to sand in comparison.
Hope this helped.
 
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Cal

Well-Known Member
The heat caused from the fiberglass resin can sometimes warp the piece. Also fiberglass resin does'nt work very well in cold tempatures.
Or to Hot. This summer when it was 100 degrees outside I used the exact mixture of hardener to resin that set up perfectly, only this time it never set up and was permanently sticky.

I mixed a new batch from the same supplies a few days later when it was 70 and it dried perfectly again.
 

DonaldDarth

New Member
Thank you simul8r,thanks everyone.
I'm making Dc-17 hand blaster(Rex's gun) now,I've one question.
If fiberglass is basic level inside the paper,but how can I do that for this little gun
Everyone give me more information,but I don't know how to implement now.Thanks.
 

PepMaster

Sr Member
For a pepakura gun that can become intresting, I've done one of three things usually for it. Pour a lot of fiberglass resin into the gun if it has a open end let it get a good coat inside and any leftover resin that's inside I move into the grip area and let it cure. 2. I've used expanding foam, but that can be tricky you don't want to blow up the prop. and 3 the other thing I've done is cut a prop in half, add fiberglass cloth and resin , then close it up.
 

DonaldDarth

New Member
Thanks PepMaster
but i still misunderstand how can I do that .maybe i'm misunderstand your text,would you send me some pics or video?
 

EyeofSauron

Master Member
Not too hard. If your gun has an open end, like the part where the bullet is supposed to come out, just mix a batch of resin, and pour it in. Then turn it around a while, until you think the entire inside is covered. You can then either pour the excess resin out, or let it go into the handle, so that the handle is solid.
 

aron42486

Well-Known Member
Like PepMaster said for option #3: Do a coat of resin on the outside of the pep. Once cured cut the gun down the middle into 2 mirrored halves. Do your 2-3 layers of fiberglass on the inside. Cure and trim the excess glass off at the edges and put your 2 halves back together. Smooth and seal the seam with a filler
 
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