Thermoformed helmets

OK tech-heads! Here is your theoretical question for the day:



I like Sweet Helmets.

Flatpick reccomended them for fit & finish & function.

I have a “mellon head”.

The largest Sweet helmet fits too tightly at the sides.

I believe the Sweet’s shells are “thermoformed”, that is, hot resin is injected into a mold containing the reinforcing material, and then allowed to cool.

Does anyone with thermoforming experience believe that the Sweet shell could be gently warmed (hairdrier, or a commercial heat gun on low) and the sides gently pried apart for more clearance and allowed to cool?



Jim

Don’t mess around with it

– Last Updated: Jul-14-05 4:41 PM EST –

just go to the emergency room












sorry, couldn't resist ;)

Now that’s a hoot Clarion.
You’ve sent my Joel and Ethan Coen influenced movie-making mindset into its synapse-simulated Twister game featuring Charlie Chaplin and Harold Lloyd verses the team of Stan Laurel and Oliver Hardy, and the misfiring neurons keep projectin’the same image to me:



Slowly pan back from a tight-in closeup of John Goodman’s (herein playing the part of a character suffering the same dilemna as you ascribe to Jsaults)grimacing and snarling face, with ocassional muttered curse-words escaping the pursed lips.



As the camera withdraws and slowly widens its angle, we first see a shiny black helmet squeezing in upon a brow-hidden head of Mr. Goodman. His cheeks appear as if they’re being slowly crushed, when not puffing out in a highly reddened state under glaring and menacing eyes, by the wedge-like grip of the helmet’s side panels. With the camera’s further withdrawal we spy in bold white script upon the helmet the word, “SWEET.”



With further withdrawal of the camera we see several emergency fire personnel wrestling with a jaws-of-life device that has somehow malfunctioned (perhaps another bit part is in order for Steve Buscemi here), and as it, too, puts the squeeze on big John’s cranium, a boom and hoist are slowly observed attaching and then raising, still panning back, John’s hulk from the hull of a QCC kayak which has somehow flown free from the roofrack of some itinerant New Hampshire kitchen-counter installers (how this entire ensemble came together will need to be established in an earlier scene) and came to rest protruding through the plate-glass window of a street front beauty salon.



As John emerges via hoist from the cockpit to dangle beneath the jaws-of-life making all sorts of strange pneumatic sounds, and one Sweet helmet, we observe his legs kicking and flailing about inside a leather kilt, and standing somewhat beneath him to his side, Jeff Bridges in sweatpants and loose Hawaiian shirt, with bowed, shaking head, and mildly dissappointed face holding a industrial-grade hairdryer in one hand and a flame-sputtering Zippo in the other is overheard,



“Geez! Man! Walter, man, I’m sorry. I’m sorry, man.”



As the camera continues its rearward and skyward retreat, a crane-hoist pan reveals the gathering crowd and various emergency vehicles and auto-wrecks strewn about this chaotic scene, as the soundtrack comes in with Slim Whitman singing Jimmy Cracked Corn.



Not sure if that’ll help ya pop your top, Jim, but it might get you a few appearances on the late-night talkshow circuit. Well, at least the local public access late-late night circuit.



Tom

Dunno…
“thermoformed” or whatever… I think once the resin is mixed in with the composite material and set, it’s pretty much the shape it’s in. I think trying to heat it and reshape it will only destroy or weaken the integrity of the helmet.



BTW, I once tried to remove a fiberglass ferrule from an lil dipper werner with a heat gun. All I managed to do was to singed the surface. In terms of the bond of the ferrule to the shaft, it was beyond my strength to do anything with it. I just tired myself out to no avail.



sing



sing

Jim, check out Greatful Heads
Kevlar reinforced and fit by using mincell liners of different thickness. Many styles and custom graphics. http://www.gratefulheads.com/helmets.htm

But
they Grateful Heads aren’t as PRETTY as the Sweets!



Jim

Seda FG Helmet…
I admit it, I not wearing my pink helmet this summer. I don’t need the extra room to squeeze it 5 mm hood. Instead, I picked up a Seda fiberglass helmet because it offers ear protection, is light and has some flex which fits around my L/XL head with a baseball cap on nicely. Also, it’s less than 50% of the Sweet Strutter.



Here’s a lousy pic of the Seda helmet. Comes in white, yellow and blue (I took the latter):



http://www.theboatpeople.com/images/atr/sedahlmt.jpg



My Seda has some “sand rash” already from getting dragged across shallow beach breaks.



sing

Ahhh Memories.
I used a Seda back in the '70s as my WW helmet. Fit my mellon perfectly, and saved me from some pretty nasty bumps. Alas, Seda no longer makes helmets. That was actually my first choice.



Jim

Speaking of memories
I still have a Bell Toptex in my junk bin. Anyone remember those? I used mine for climbing, caving, and paddling. Truely a multisport device!



Jim

Are You Sure…?
I picked mine up just last month at New England Small Craft/MA. They had at least 6 of 'em.



I really do like the comfort, fit, and light weight of this helmet. I put on some home made reflecting tape decals. Way cool.



sing

Hmmmmm
They are no longer listed on the Seda website. I will contact them directly. Maybe it is a dealer only thing.



Jim

I had same problem…
http://www.gratefulheads.com/hardhit_lg.htm



The URL above is the exact helmet I bought from Flatpick (when he owned the store). I much preferred the Sweet helms but like you my head was too big.



My wife DID buy a Sweet and it really is a great helmet. One of the best features of the Sweet is they fit inside the day hatch of a kayak.



I’ve been happy with my Grateful Heads helmet though.



Wade



PS: Here’s a photo of me, in my Grateful Head helmet on one of Flatpick’s 4* Training sessions.

http://www.cs.pdx.edu/~walpole/pics/kayak/aoc/16.html


Hmmmm part 2
Sorta looks like a Seda…



Jim

Go for it , keep the temp below
130 for now and slowly put a tiny bit of weight or pressure on it… it will change shape without the thermoform matrix debonding from reinforcing material. Typically, the thermoformed stuff is built way above these temps and can withstand much higher temps without any negative structural metamorphisis.


  • Typical classic thermoformed stuff is renown for it’s high temp toughness, resiliancy(sp?) and toughness. Picture material commonly assumed as ‘plastic’ for the bonding matrix instead of typical ester or epoxy resins. Faster cycle times, cheaper cost, lower performance ( not so for helmets… only heavier) and better profits for manufacturers. Similar to injection molded stuff`.