I apologize right at the beginning if there was such a topic before. I tried to search in detail in the current forum posts but could not find what I was looking for.
I am mainly interested in the opinions of experienced shell casters. I would make a shell with polyurethane resin using a silicone mold. I would use a known technique of brush application, but I have no idea what product I could use for it.
I’m thinking of a product called Smooth-On Shell Shock, which is made specifically for brush application. However, I’m not sure this is the best choice.
Do any of you have experience with Smooth-On Shell Shock? Maybe another suggestion? I would not choose fiberglass reinforced solutions now.
What’s wrong with using fiberglass? That’s going to be the cheapest, strongest, and most accurate construction method; as for an actual gelcoat, I’ve always had great success with Smooth-On EpoxAcoat for the detail layer inside the mold, followed by fiberglass cloth/mesh reinforcement.
Resin by itself is going to be too fragile. Unless you want it to weigh 100lbs anyhow. That’s why people use fibreglass. You have a “gel coat” layer of just a good, strong, resin and then layup the glass & epoxy behind that after it has dried.
Shell Shock is less useful for normal pack type things - though it would work - but even Smooth On would only suggest it as a gel coat (you’d back it up with one of their rigid foams, so could be great for a stunt pack I suppose)
Actually I have some experiences with pu resin but never tried fiberglass yet. After searching within forum topics I learned that pu resin is more durable and flexible and lighter compared to fiberglass depending how thick is it. Fiberglass is more rigid an accurate. Found some pros and cros.
I’ve heard that Benofkent uses pu resin for the shell and his’s the one of the best. After checking some pictures it looks very accurate too. Obviously he has lot of experiences with pack casting to create this quality …
I’m open for fiberglass but first i’d like to try pu resin.
Do you have any suggestion which product and in which combination (if necessary) can I use for brushable application to make the shell?
Yes, this is clear. But the whole casting technique of the shell isn’t. I’m relative new in casting and molding, I’ve got experience with parts casting yet but never made shell casting. I’d like to avoid loss of time and money therefore i’m counting on any suggestion.
Gelcoat is a pu resin but this is used only in a thin outer layer to get nice surface and details, right. And if I like to use resin entirely in the shell how to do it? I can’t use Smooth-On Smooth-Cast or Sika Biresin because they are too fluid. I need some brushable solution like at fiberglass technique.
The gel coat is to give surface detail and such. Fiberglass is textured & won’t conform to details. So the thickness depends more on the mold. You can get away with 1/8 of an inch on most larger things, less if it’s not detailed.
