New to the site and jumping in feet-first...

[Ghostsoldier]

Hello folks,
FNG here from sunny Florida! I've been lurking around here a while, like what I saw, and decided to join last week. You guys have a really nice forum here!

As a father-sons project (a 16 year old and a 13 year old), my boys and I have decided to do a little SW costuming, and as you can guess, Fett is the subject that came up! So, here I am, finding myself building not 1, but 3 helmets simultaneously! Anyway, I've downloaded Alan's superb templates, and studied Honus, SD68, and slew of others' tutorials on the forum, and as of last night we cut out all the template pieces. We also made a trip to Walmart/Home Depot/Lowes last Saturday, and secured batting helmets and trash cans (for armor!). For the helmet material, we found some clear, sheet acrylic plastic that's about 3/16" thick (thicker than the sintra "For Sale" signs I found-I wanted something a bit heavier)) and bought that. Which leads me to the reason of this post...I'm a pretty handy guy, but plastic is not my forte, hence these few questions:

1) What can I cut this stuff with? I've got a Dremel with cut-off wheels and a variable-speed jig saw with 24 TPI blades...will these work?
2) Can I heat this acrylic using the boiling water method, or should I get a heat gun?
3) What would be the best adhesive for this stuff? I bought 8 tubes of Super-Glue to start with...should I get something better? If so, what?
4) I'll be finishing these off with Bondo, but I wanna be sure to get the construction down-pat first....any tips for us noobs?

Thanks for reading, and sparing a little time to answer the silly questions of this ol' 43 year old Mandolian!
Rob

 

[eighteendelta]

Acrylic seems more inviting at first but I would recommend sticking to the sintra for a couple reasons. The first is that the acrylic will become very brittle and prone to cracking if you heat form it. Secondly it is very UV sensitive and degrades much quicker than the PVC of sintra. I know you might be thinking that a layer of paint over it will protect it, but that's just not the case. I don't want to discourage you from experimenting with new materials or techniques, but if you can help it, try one at a time with a new material/technique at a time and limit potential frustrations and loss of materials. The TiO2 in PVC help protect it by forming a protective layer that reflects and prevents deeper damage. The clear acrylic allows it to pass though leaving damage to the crosslinked polymers and breaking it down all the way through. In any case good luck with your project, I am doing the multiple sets at once thing for myself a friend and my two little ones. I think you will have fun as long as you don't overwhelm yourself all at once.

-x

 

[Laan]

Sweet! Science class. I have no idea if that is true or not but man that sounds goood. Good info

Acrylic seems more inviting at first but I would recommend sticking to the sintra for a couple reasons. The first is that the acrylic will become very brittle and prone to cracking if you heat form it. Secondly it is very UV sensitive and degrades much quicker than the PVC of sintra. I know you might be thinking that a layer of paint over it will protect it, but that's just not the case. The TiO2 in PVC help protect it by forming a protective layer that reflects and prevents deeper damage. The clear acrylic allows it to pass though leaving damage to the crosslinked polymers and breaking it down all the way through.
-x

 

[stormtrooperguy]

i don't know all of the technical stuff, but i can vouch for the brittle part of that

i've shattered many pieces of acrylic.

3/16" sounds really thick too... i can't imagine that would be easy to bend!

 

[Ghostsoldier]

Wow...never thought of that...but your right....I've got several items made of acrylic that have seen their better days because of the ultraviolet breakdown (hazing, cracking, etc)...guess it's back to the ol' Home Depot to pick up those sintra "House for Sale" signs!
One other question, tho...if I use the sintra, will the finished helmet be study enough on it's own, or is there an established way to reenforce it? They (the sintra signs) just seem awful thin and flimsy to me (although I did find a "Handicapped Parking" sign made by the same company that was a wee bit thicker than the other sign versions....)
Thanks for the replies!
Rob

 

[stormtrooperguy]

i usually use those parking signs for stuff.

 

[eighteendelta]

I would say if you are worried about trooping in the sintra helmet afterwards, use a glass reinforced polyester on the inside. I would lean towards the glass mat, not the fabric since it's easier to make conform to the curved surfaces. SD68 has a very nicely done helmet in sintra, maybe he can answer to the sturdiness and say if he chose to reinforce?

I'm actually a materials engineering consultant, I deal with all these things on a daily basis, though it bores the living daylights out of me usually.

-x

 

[mbhdesign]

Another ultra-raw newbie about to take the plunge with you, Ghostsoldier!

I'm new to the forum, but not to scratch prop building. From what I've seen on this site, these guys are THE resource to ask these questions. Hands down.

I've worked with 3mm (1/8") PVC sintra before, which holds up fairly well for me as long as there aren't too many complex joints and stress curves involved. But I've usually used it in layers, compression glued together and then sanded into a solid shape. So I'm curious about the reinforcement question, too.

By the way, I've been ordering my sintra from these guys... if you need pre-cut thicker stuff:
http://store.foamboardsource.com/sintra-pvc-foam--sintra-pvc-board--sintra-pvc-3mm.html

I think we came to the right place, Ghostsoldier!

mbh

 

[drokkul]

I've also found that clear acrylic does not cut easy witha Dremel or jigsaw. The friction heat that builds up usually melts the plastic back closed behind your cutting wheel or blade.

Go to a True Value or ACE Hardware. They carry a Tow Away Zone Sign that is a very nice thickness. This is much thicker than the "For Sale" or "Garage Sale" signs that I've seen at Home of De'pot or Lowes.

The signs look like this:

 

[Ghostsoldier]

I think we came to the right place, Ghostsoldier!
mbh

Roger that, mbh! Thanks for the sintra link, and I look forward to seeing your progress! I'll post mine in a later thread, when I get that far along!

 

[mbhdesign]

Ghostsoldier,
Cool! Same here.

drokkul,
Thanks for the tip on the Tow Away signs. That's good to know. Helps to have a local supply available.