Casting big objects in resin

[tommynator1024]

Hey folks,

for an upcoming soccer tournament, I promised to cast a trophy. I was thinking about doing something close to the FIFA World Cup trophy below, since it's one of the most beautiful trophies ever IMO. Anyway. Here's the question: if I do this solid, to what maximum thickness can I cast resin in one sitting? ebay offers for resin mostly state 5cm (2") thickness tops. I was wondering, can't I cast it fully in one go? Won't it cure?

The size I have in mind is like a big double fist

Thx for any info.

 

[XRobots]

You probably need to hollow-cast it by rotating resin around in the mould as it sets in thin coats so it leaves the middle hollow. If it's that big and you fill it with resin then it'll end up extremely heavy, also the heat produced by the curing process for that much resin will probably cause the whole thing to warp.

The other option is to fibreglass it so you are again left with a hollow shell.

 

[tommynator1024]

I would not mind it getting heavy at all! The original is solid gold.. ;-)

How you mean, the heat would warp it? I realize the chemical process produces heat, but can it destroy the cast? I might have to let it cure outside anyway for a while (currently it's around 0-5°C here) because of the fumes.

 

[MasterAnubis]

If your mold it right, it won't matter if you do it solid or hollow. The resin you use will be a chemically cured mix, so it will cure anaerobically. Check your specific resin company to make sure.

How you mean, the heat would warp it? I realize the chemical process produces heat, but can it destroy the cast? I might have to let it cure outside anyway for a while (currently it's around 0-5°C here) because of the fumes.

There are a couple major catagories for rubber used in molding. You need to make sure that you select the best compatable one for what you want to do. Some will allow anything to cure, other will not. The heat of the resin on some rubbers will break down the material and you will have a mold with a short life span. There are a couple of very good comanies out there that have how-to vids and such using there compounds.

check out:
http://www.smooth-on.com/
http://www.polytek.com/

 

[SUICIDALRAIDER]

I have to agree with MA. if your mold is good and solid you can cast it as thick as you would like.Aeromarine on ebay sells some good quality resin at a good price.

 

[hez1]

If you've made your mold and mother mold properly then I don't see how it would warp. I've cast some pretty darn chunky items with smooth on resins without any issues. It will get pretty hot though, which might shorten mold life as Master Anubis mentioned, depending on the rubber used.

You would probably need to ask someone from either polytek or smooth on about curing it outside, but at those sorts of temperatures I think it might have an adverse effect on the curing. Most people wouldn't cast something that size solid simply because of cost. Smooth ons tech guys are pretty helpful if you email them with details of what it is you're doing...they'll be able to recommend a resin that will do what you want. I'm sure Polytek is the same.

 

[Roydraven]

no offense but shouldn't this be posted in Huntorials & Help http://www.thehunterslair.com/index.php?showforum=6 not the Non-Predator Costume Construction
section

 

[Nintendude]

I love using resin only because I have dealt with it for a long time, the cure time depends on the heat, amount of catalyzer and the amount of resin that you use to make the casting with. I would recommend for something big like that slushcasting it in the mold which you should'nt need more than about 2 cups worth of resin to the hardener. Thats the cheap method to go with, your alternate methods are to use Smooth-on which can run you up around $80 or higher to do something that size. If you "slush-cast" the trophy make sure that you pour out the excess material after you have slushed it around in the mold for a while otherise if some sits in the bottom you can end up with it still liquid under a hard shell between the hardened fiberglass and the mold or a really big air bubble. The heat that the fiberglass produces should'nt damage the mold but you will want to use a mold release agent before pouring.