Comparison: Milliput and Sylmasta Magic Sculpt

[Hobbes]

I've been using quite a lot of putty recently, building my HP.111. This is the first build I'm using Sylmasta Magic Sculpt for; on previous builds I went through an entire package of Milliput Superfine White.

Both are two-part putties; I tend to use these only when I need a large amount of putty, so more structural than filling a seam. On my scratchbuilds, I tend to build a rough form using lengths of sprue lying side by side, then apply a layer of putty over those.

The formulations are quite different. Milliput seems more clay-like: when it dries it almost feels like plaster. This is noticeable when you cut panel lines into it, or when you use a saw on it. When the layer of putty gets very thin, Milliput can crumble under pressure.
Magic Sculpt is more plastic-like: even a thin layer will stay together well. It can be cut with a sharp knife, and there's a tiny bit of flexibility to it.

Milliput's packaging (two cylindrical sticks wrapped in plastic) is more convenient: it allows you to get equal amounts just by cutting off the same length from both sticks. Magic Sculpt is also wrapped in plastic, but this goes into a jar. You have to scoop out a divot and then figure out equal amounts (I do that by rolling both components into sticks, so I can use the equal length trick again).

On both, one component develops a nasty-looking brown film. In Milliput, this film has to be thoroughly mixed in, or it will create spots that don't harden. In the Magic Sculpt, this brown film migrates through both layers of the packaging, so after 2 years the outside of the jar is coated in brown sticky goo.
Magic Sculpt is easier to mix than Milliput (I've had several cases where the Milliput didn't harden everywhere, none of that with Magic Sculp).

Both are fairly hard when mixed, so deforming it can take a bit of pressure. Both respond well to a bit of water (they won't stick to your tools when the tool is wet). Milliput takes about 3 hours to set, Magic Sculpt is a bit faster I think, it gets noticeable more difficult to work with within an hour of mixing. 

Overall, I prefer the Magic Sculpt because it's tougher when it cures.

[The Wooksta!]

I'd give both the heave ho and go for car body filler.  Those in the UK know it as P38 and usually buy it from Halfords.  Mix as per the others and it'll go off quicker if you add more catalyst, usually within minutes.  Get the timing right whilst it's curing and it'll cut like cheese.  Sands easily and will polish to a glass like finish.  Hard, durable and takes scribing.

[NARSES2]

Thanks for the comparisons Harro 

I got some DeLuxe Eze Epoxy Putty at SMW 2019 and it's one advantage is that it comes as a sausage roll of filler where the inner roll is the catalyst, so it's very easy to cut of the correct amounts of both. It works well both freshly mixed and when hardened, which it does relatively quickly. I'm not sure about its shelf life though given the way it's packaged, although if resealed properly the packaging should keep it fresh.

Anyway here's a link to it and yes I will be getting another lot for medium sized filling jobs.

https://deluxematerials.co.uk/products/eze-epoxy-putty-bd68