need help finding resin for pepakura model

[Halojay123]

i am constructing a Bobo Fett helmet using 210gsm card (so it isnt as weak as regular paper), this helmet is a display piece and wont be knocked around or worn, just sitting there looking cool. so what type of resin would a need to use for this sort of purpose, it doesnt need to be ridiculously strong and durable, it just needs to be able to keep its shape and be able to be spay painted over ( and if i sprayed over the exposed card like it is at the minute, the moistness would cause it to cave in, this is why i want to harden it abit).

based on the fact that it wont be worn or "used" in anyway, would i need to apply the resin to the inside as well as the outside , and how many coats would it need. ive heard that fibreglass resin can "morph" the shape as it dries, so can someone who knows what they are talking about recommend me a good and reliable resin or other type of hardener.

i have read up about this but all i have been able to find is about people who are making helmets that they intend to wear, and are there for using many different types of resins, bondo, rondo and other stuff. and since i am only making a display item would i need to mess around with all of this stuff, if anyone could find a way for me to just use one substance for me to use that will do the job i want it to and not burn a hole in my wallet that would be great!

all comments would be greatly appreciated!

 

[Teddz]

If you don't plan on doing any shaping to the pep and are fine with the angled look, just use CA (Cyanoacrylate) glue to harden it. I use CA glue to reinforce all the seams on any peps I do to keep the resin from reacting with the glue and undoing the joint. I found it also stiffens the paper quite a bit. Do this outside and wear a respirator. CA fumes are nasty.

The "morphing" is from the heat created from the hardening of the resin. Heat will soften resin, in this cast the first outside layer, and peps without proper reinforcements will warp. Nature of the beast. Sometimes it's fixable, other times you learn a valuable lesson about proper reinforcements and supports and get to do it all over again.

 

[Halojay123]

If you don't plan on doing any shaping to the pep and are fine with the angled look, just use CA (Cyanoacrylate) glue to harden it. I use CA glue to reinforce all the seams on any peps I do to keep the resin from reacting with the glue and undoing the joint. I found it also stiffens the paper quite a bit. Do this outside and wear a respirator. CA fumes are nasty.

The "morphing" is from the heat created from the hardening of the resin. Heat will soften resin, in this cast the first outside layer, and peps without proper reinforcements will warp. Nature of the beast. Sometimes it's fixable, other times you learn a valuable lesson about proper reinforcements and supports and get to do it all over again.

so let's say I'm ok with the angled look, if I just poured this CA glue into a container and used some sort of brush to cover the entire model, would it harden the whole thing enough to stand spray paint without getting all soggy and caving in like plain paper does? How much of this glue would be needed and how many coats? Would I still need to use some sort of resin over the top of the CA glue? Thank you for the reply I will go check out this CA glue!! Thanks

 

[Teddz]

I forgot to mention that CA glue is also known as "crazy glue" in the states. If you know anything about crazy glue (CA) you'll know there is no brushing this on as it'll harden the brush pretty quick and you may end up with a Picasso Fett with a brush attachment.

What I did with my Stormtrooper helmet is just squirt it onto the seams and let it fall where it may. The glue is pretty thin (also available in thicker consistencies) so it'll travel. The thin glue also gets soaked up by the paper so that's where some of the rigidity comes from. I used 2 1oz. bottles of thin CA for the helmet which was just enough for all the joints. You may need a couple more bottles. The blue labeled CA is the thin stuff I used.

Once the glue is dry, the paper will be much stiffer than it would have been normally and will stand up to quite a bit of abuse. It's still paper and you can still destroy it, but it's not as soft as before. For a test, make yourself a paper cube and leave one side off. Douse the whole thing in CA glue and let it dry. This will give you a better idea how rigid it'll be after it's all set because a cube with a side missing can flex very easily around that area. You should also test your painting on it since you don't want to test on the actual pep.

You won't need more than one coat outside and one inside, but feel free to add more coats to get the whole thing covered. You'll know when it's all covered because the paper will take on a "wet" look. You should also reinforce and support areas to keep them in place while you're adding the CA.

You may need a primer/sealer before paint just to make sure there's no reaction between the CA and the paint, but it'll be fine standing up to the paint. Just don't glob on the paint or it'll run and look horrible.

You may also need to figure out a way to support the pep when you're displaying it because over time, the pressure of the pep exerted on the support point (assuming you're going with the typical rod with a ball at the top) may distort the piece. I don't know since my peps don't stay with the CA very long and get resin & fiberglass soon after it's set.

I'm sure there are others who have a different technique, but this is what's worked for me.

Best of luck.

 

[Halojay123]

I forgot to mention that CA glue is also known as "crazy glue" in the states. If you know anything about crazy glue (CA) you'll know there is no brushing this on as it'll harden the brush pretty quick and you may end up with a Picasso Fett with a brush attachment.

What I did with my Stormtrooper helmet is just squirt it onto the seams and let it fall where it may. The glue is pretty thin (also available in thicker consistencies) so it'll travel. The thin glue also gets soaked up by the paper so that's where some of the rigidity comes from. I used 2 1oz. bottles of thin CA for the helmet which was just enough for all the joints. You may need a couple more bottles. The blue labeled CA is the thin stuff I used.
http://www.modelcrafttoolsusa.com/26-large_default/102-insta-cure-superthin-ca-glue-1-oz.jpg

Once the glue is dry, the paper will be much stiffer than it would have been normally and will stand up to quite a bit of abuse. It's still paper and you can still destroy it, but it's not as soft as before. For a test, make yourself a paper cube and leave one side off. Douse the whole thing in CA glue and let it dry. This will give you a better idea how rigid it'll be after it's all set because a cube with a side missing can flex very easily around that area. You should also test your painting on it since you don't want to test on the actual pep.

You won't need more than one coat outside and one inside, but feel free to add more coats to get the whole thing covered. You'll know when it's all covered because the paper will take on a "wet" look. You should also reinforce and support areas to keep them in place while you're adding the CA.

You may need a primer/sealer before paint just to make sure there's no reaction between the CA and the paint, but it'll be fine standing up to the paint. Just don't glob on the paint or it'll run and look horrible.

You may also need to figure out a way to support the pep when you're displaying it because over time, the pressure of the pep exerted on the support point (assuming you're going with the typical rod with a ball at the top) may distort the piece. I don't know since my peps don't stay with the CA very long and get resin & fiberglass soon after it's set.

I'm sure there are others who have a different technique, but this is what's worked for me.

Best of luck.

what would happen if I just went straight to epoxy resin? Or would wood glue do a decent job?
thank you for all your help, as you an tell this is my first big piece, I made a master chief helmet when I was 13 but that soon broke, so now I know about these methods of strengthening I want to make sure im using the most effective one that will defend my piece well.

 

[Teddz]

Here's the thing with going straight to epoxy or polyester resin, there's a slight chance that it'll react with the glue you used to put the pep together and start to undo the joints. Some glues have no issue and you can go from pepping to resin without the CA, but some glues react. I did the CA step because I didn't know if the resin would react or not with the glue I used and I wasn't about to wait and see if the thing fell apart while I watched.

I've never used wood glue on a pep so I wouldn't know, but do know they use it to coat foam peps with.

also check out this guy's youtube channel... he's got a lot of info that should help you as well.
https://www.youtube.com/channel/UC2kInwJRdwJxJvvOGqwggAw

 

[Halojay123]

Here's the thing with going straight to epoxy or polyester resin, there's a slight chance that it'll react with the glue you used to put the pep together and start to undo the joints. Some glues have no issue and you can go from pepping to resin without the CA, but some glues react. I did the CA step because I didn't know if the resin would react or not with the glue I used and I wasn't about to wait and see if the thing fell apart while I watched.

I've never used wood glue on a pep so I wouldn't know, but do know they use it to coat foam peps with.

also check out this guy's youtube channel... he's got a lot of info that should help you as well.
https://www.youtube.com/channel/UC2kInwJRdwJxJvvOGqwggAw

thank you for your help, could you possibly show me an example of your work? You seem to know everything about making peps so I imagine your models are to a very high standard

 

[Teddz]

here's my stormtrooper WIP... http://www.therpf.com/showthread.php?t=246479

the first couple of pics in that thread show the helmet after pepping was done and I had applied the CA glue. It's noticeable in a couple of spots, just look for "wet" looking streaks. One is on the nose plate.

 

[Halojay123]

wow, just from listening to your advise i gathered that you knew what you were doing and that you had some experience with this sort of stuff but that model is so cool, it could easily be used in the next star wars movie if you ask me! how long did it take you altogether??

 

[DizzyStrmtroopr]

in response to the original question ive always used bondo brand polyester resin. there isn't too much deformation when the resin cures but with a fett helmet you need the internal supports since its literally like a bucket and easily loses shape. resin can always be reheated and shaped by itself with a hair dryer/heat gun, but when you have fiberglassed it not so much. when I do my peps I coat one section at a time with resin, coating both sides of the paper in that section. for example you can do one cheek at a time, or just the dome, etc. when it cures ill take a heatgun top any deformed areas and hold them for a minute to cool and set again. then I shoot spray adhesive inside and lay one layer of fiberglass, then coat with resin again, lay another layer of glass and coat again. 2 layers of glass is suffiecient but if im making a plug for molding and need stronger support for bondo or something ill do 3.

 

[Leigh]

I'm no expert

I did mine with Polyester resin. I used the stuff designed for car repairs because it sets quickly, 5 to10 minutes! Even though mine was my first Pep attempt I do have experience with the materials. I brushed a coat on the outside first supporting the Pep from the inside with my left hand. I predicted a little deformation here & there & chose this way to do it so that I could use my supporting hand to apply pressure to any deforming area's while it set & to make sure the top didn't flatten. Luckily it didn't deform while it cured

I then brushed another coat on the outside & let it set. Polyester can remain a little sticky to touch even after setting so I dusted mine with a little talc, it just makes it a bit easier to handle

I then sloshed a coat around the inside & let that set before fiberglassing the inside.

The quick setting stuff I used comes with a hardener that's a red paste in a little foil pouch the same as the stuff supplied with body filler. The more you add, the quicker it will set.

The advantages of Polyester IMO are its cheap, its easy to buy in most car accessory shops/ DIY shops, its strong & its fit for purpose.

The disadvantages.... IT STINKS!! use it in a well ventilated room or outside


Edit:

Just to add... I used Evo-Stik weatherproof wood adhesive to stick my Pep together. Its PVA glue & it grabs the card quite quickly allowing you to move on to the next part quickly. It had no reaction with the Polyester

 

[Halojay123]

If I was to do 1 layer of epoxy resin on the outside and then the inside, would that be enough to keep it in shape? As it will only be a model and just sit still forever I don't know if it's worth going through so many layers of different materials.

 

[Leigh]

In my limited experience I would suggest a layer or two of fibreglass.
Brushing the resin on is no different to brushing paint! its no more complicated
I would think that just a single coat of resin inside & out would leave your Pep fragile. I imagine if you drop it or knock it on something while your working on it, its likely to dent! this will leave a crease around the dent & even if you successfully push the dent out it will still show & then you'll have more work to correct it.

If you decide after all that you would like to sand it & make it smooth prior to painting it, you'll need a sturdy understructure with some thickness to it otherwise you may end up sanding through & then creating even more unnecessary work for yourself.

Don't be daunted by the prospect of using materials your not familiar with! make yourself familiar & get stuck in!

Try knocking up something small & insignificant out of the paper you'll be using on your Pep & practice with the resin. Take a single sheet of the card you'll be using, A5 size. Lay it on a sheet of foil & paint one side of it with your resin (Epoxy or Polyester which ever you choose) Let it dry, flip it over, paint the other side & let it dry. Then fold it, break it, bend it, get a feel for it & then you'll know whether to reinforce it with fiberglass or not

I hope that doesn't seem condescending

HTH

 

[Halojay123]

In my limited experience I would suggest a layer or two of fibreglass.
Brushing the resin on is no different to brushing paint! its no more complicated
I would think that just a single coat of resin inside & out would leave your Pep fragile. I imagine if you drop it or knock it on something while your working on it, its likely to dent! this will leave a crease around the dent & even if you successfully push the dent out it will still show & then you'll have more work to correct it.

If you decide after all that you would like to sand it & make it smooth prior to painting it, you'll need a sturdy understructure with some thickness to it otherwise you may end up sanding through & then creating even more unnecessary work for yourself.

Don't be daunted by the prospect of using materials your not familiar with! make yourself familiar & get stuck in!

Try knocking up something small & insignificant out of the paper you'll be using on your Pep & practice with the resin. Take a single sheet of the card you'll be using, A5 size. Lay it on a sheet of foil & paint one side of it with your resin (Epoxy or Polyester which ever you choose) Let it dry, flip it over, paint the other side & let it dry. Then fold it, break it, bend it, get a feel for it & then you'll know whether to reinforce it with fiberglass or not

I hope that doesn't seem condescending

HTH

Thanks for the reply and the help with deciding on what to do. I think that I will use epoxy resin since it does not shrink when drying as much as polyester/ fibreglass resin does. But just one more query, let's say that I feel the same way as you do and I think that the one layer on the inside and out is not strong enough, could I just put more layers of resin on rather than putting on fibreglass? And do you mean strips of actual fibreglass or do you mean put fibreglass/polyester resin on over the first layer? Thanks for all the support I'm getting on this, it's my first big make, I made something smaller when I was 13 , and now I'm 15 so the idea of resins and fibreglass and things like that is a bit daunting as I do not want to waste my money and time if I end up ruining all my hard work! Good job this site was made.

 

[Leigh]

That's one of the best things about this community, we will help where we can if the person asking has shown that they're willing to do their own homework rather than expecting to be spoon fed You've clearly shown you've looked up the materials & put some effort in :thumbsup


I personally haven't used Epoxy but I'm assuming you could put another layer on over a cured layer without prep? If I'm wrong someone correct me!
Lets assume you can If you were fiberglassing the inside you would be best to cut your glass into strips say about 1 inch by 4-6 inches. I would knock up another batch of resin, brush it on & then lay my glass strip into it & work it in with a stiff brush until its thoroughly soaked in resin & then continue round overlapping each strip of glass until the whole of the inside of the helmet is covered. I would allow the glass to overhang the edges & trim off the excess after curing.

I think you should try my suggestion of running a test piece of card & your resin to see how it responds to being reinforced with resin, it may well be strong enough for your needs without fiberglass.

Even if you do make mistakes it wont be a waste of money because you'll have learned something

 

[Halojay123]

I think I'll giver the epoxy a go, I'll put 2 or 3 layers on a test piece and if it's not strong enough I'll fibreglass the test piece and see how it holds up. does the thickness of the fibreglass strips matter or is it best to keep it thin and layer it up? And I know that people often fibreglass the inside to make it stronger but no one ever mentions anything about the outside, is this because it's a bad idea to fibreglass the outside or is the inside just easier.

 

[Leigh]

Fiberglass is purely for structural support, its not pretty & by its construction it doesn't sand back as nicely as filler. When you mix fiberglass with resin the combination of the two forms a very strong & light material, on their own they don't!

Do a google search for GRP (Glass Reinforced Plastic) it should tell you all you'll need to know about the reasons for using fiberglass in combination with resin
But as I say you may feel you don't need it for your build after running a test.
Don't forget to start a new build thread when you get stuck in with it

 

[Halojay123]

What do you mean start a new thread? Sorry if i seem a bit simple im very new around these parts