Casting a Dredd 3D helmet

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ljsm

Member
Great videos! While I was there I checked out a few of your others. Really useful to see some of the stuff I've read about put into motion!

Thanks!
 

fullbob

New Member
Nice, very instructive, the rotating slushing machine is very ingenious. Might steal your idea if i have to make copies of my (soon to make) helmet ;)
 

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stormtrooperguy

Sr Member
Nice, very instructive, the rotating slushing machine is very ingenious. Might steal your idea if i have to make copies of my (soon to make) helmet ;)

I can't claim credit for the concept... another local prop guy did something similar that inspired me.

I'm hoping to find the time to take some detailed pics / draw up some specs for how I built it. I made it up as I went along so I'm not even sure how big it is, other than 24" square in the middle.
 

fullbob

New Member
Im about finished with my helmet and ready to make a mold with it, maybe you can help me out with a few answers to questions i have before ordering the stuff:

It seems from the color you used rebound 25 for making the helmet, have you ever used mold max stroke? it seems to do the same job but at half the price...but then again im no specialist.

How many helmets can you make with a gallon of smooth cast 65d?

When making the mold, do you need to spray some release agent on the original or is that only necessary for the one you cast in them after?

Finally, can you make a mold over wet clay and reuse the clay afterward or does it need to be cured(the clay) before?

Thanks for your time and sorry with all my newbish questions ;)
 

stormtrooperguy

Sr Member
It seems from the color you used rebound 25 for making the helmet, have you ever used mold max stroke? it seems to do the same job but at half the price...but then again im no specialist.

I've never used that one. Check out this link about tin cure vs. platinum cure silicones:
The How and Why of Silicone. (Part 1) | naomidlynch

The general rule of thumb I follow is that tin cure molds will fail much faster than platinum, so I always use platinum.

How many helmets can you make with a gallon of smooth cast 65d?

That depends on how thick you make the helmets. I use 24 oz. combined of resin per helmet, bulked up with 9 oz. of filler.

I don't really know exactly how much is in a "gallon" kit from smooth-on, and I don't usually use a gallon all on one thing, so I don't have any specific number of helmets.

I used 2 gallon kits to make the helmets in that video, but I had 4-5 bad castings while getting the machine working.

When making the mold, do you need to spray some release agent on the original or is that only necessary for the one you cast in them after?

I don't use a release anywhere, on the original or castings. Using a release on the mold when casting will help prolong the mold life, but results in castings that need to be cleaned before use. I prefer to just re-make the mold when it starts to wear out.

I've done 30+ helmets out of a mold with no significant degradation, which seems fair to me.

Finally, can you make a mold over wet clay and reuse the clay afterward or does it need to be cured(the clay) before?

I don't know... I don't use clay. My originals are all built out of a combination of Smooth-On FreeForm Air, Bondo and Apoxie Sculpt. That way I know the original will survive the molding process and be available for making additional molds down the line.
 

Uridium

Well-Known Member
the slushing machine is amazing, and great looking helmets!

Thanks for posting the vid, I pick up a new tip every time someone here posts a video or pics of their work
 

stormtrooperguy

Sr Member
Thanks! The slushing machine produces better quality castings than I made on my own, and I don't wake up with aching arms after a night of helmet making!
 

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Propsjonnyb

Well-Known Member
An imperial Gallon gets you 128 fl oz so , if you assume a standard bikers helmet size at say a 1/4" thickness, you should be able to make two helmets or one very good one out of a gallon at 64floz per helmet .

Release agent - get into the habit of always using release agent because ultimately it preserves the life of your mold , as every cast you pull , the mold breaks down , buy the best casting compound you can afford as you want to replicate as much detail as possible , and the same should hold true for casting resin, clean and periodically rest your mold - Don't try to pull 50 helmets in a day , you'll end up with bad casts and no mold !! Take care of your mold and you should get 30 to 40 casts , make a fibreglass mother mold to extend your silicon mold's life. I'd do 5 or 6 as a maximum , remember most resin hardens by thermotropic action , that means heat - a lot of it ! Heat exposure over time will breakdown silicon even high temperature hot metal casting silicon. So rest your molds
and let them cool down between castings.

It is possible to cast over wet clay , but it's not recommended , too many things can go wrong and once you've poured your silicon you are committed !! use modelling clay or any other modelling compound eg super sculpy - plasticine etc these consistently give good results and you shouldn't go wrong , if you want a reuseable product Plasticine is your best bet .
 

fullbob

New Member
Thanks everyone for the great info, guess i will have to make some tests to see what's better for me.

sucks cause im tight on cash atm :\
 

Ray48

Well-Known Member
RPF PREMIUM MEMBER
Thanks gents, I am currently contemplating molding my helmet in a one off scenario. In other words, not planning a run....just want a lighter helmet....after buying silicone and resin, I'm kind of committed to casting it...reason is, after all the Body filler I used it is as heavy as a tank! I need it light. In retrospect I should have just bought one in the junkyard but it is hard to tell what it will look like on my noggin. Anyway, I need info on sealing up the helmet face (oh yeah, it's a Dredd) for casting. What do you use...how do you fasten it to cast the silicone? Planning on painting on a print coat, then a thickened couple of coats of silicone. Never used this stuff so I don't know how long it takes to set up or anything. Grateful for any advice so I don't blow it and further dig myself into a financial hole that my wife will assault my senses over.:wacko
 

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stormtrooperguy

Sr Member
I filled in the opening in the face with a sheet of thin styrene hot glued to the inside of the helmet, then sealed up all the edges with FreeForm Air, a putty from Smooth-On that I always have on hand.

I usually try to do the silicone process over a Saturday or Sunday when I'm not at work. I leave about 1-2 hours between coats, depending on temperature (goes faster when it is really warm), and usually do 5-6 coats. It really is the better part of the day spent on it.

The mold shell is also FreeForm Air, which takes around 4 hours to cure. It's done in 2 parts, so that's another 8 hours.

I typically do 2 coats without any thickener, then alternate thickened / regular until I'm happy with the thickness.

Ultimately (as you've already discovered) you don't really save any money doing it yourself vs. buying a kit. But, it's much more fun to do it this way ;)
 

Ray48

Well-Known Member
RPF PREMIUM MEMBER
If you say so.....I was kind of thinking it would be more fun painting a finished helmet. Thank you for the tips.. Maybe it will save me making a complete fool of myself and making a total mess of it, which would require me buying one anyway. I guess it is a good thing to learn in case I get ambitious and decide to sell a future item. I think that is unlikely though since it looks like you don't make much profit for all the work involved. I've had two people wanting me to sell them my Judge boot pieces, heels, toe caps, and shin guards...I had to decline both offers as they are quite firmly attached to my boots now.:cry
 

Ray48

Well-Known Member
RPF PREMIUM MEMBER
Sorry, forgot to ask about the "Free form Air". It is the first I've heard of this for a mother mold. How different is it from a fiberglass mold and what advantage does it have over that or plaster/burlap? What about cost?:unsure
 
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stormtrooperguy

Sr Member
The air is an epoxy putty that is super super light weight. It has no hazardous fumes and smooths with water. Much nicer to work with than other materials.

Cost is way way way higher than plaster/burlap. You'll pay about $90 for a gallon kit (which is what you'll need)
 

Ray48

Well-Known Member
RPF PREMIUM MEMBER
Thanks for the warning...probably will avoid that stuff like the plague. Plaster should be good enough for a one off.:)
 

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