Wax casting, vintage looking finishes, CAD and some new business questions

[josef1]

That does seem a bit expensive but I suppose its down to how much you value your time. The main problem you have with making moulds for production is taking into account shrinkage, not so important in the models you have shown but when you need to make rings of a specified size which will have openings for stones of a specific size the master model may need to be remade several times to get the dimensions right there is no hard and fast rule to account for shrinkage which can be upto 15% across the process in the case of larger items . The models you have shown would also be time consuming to model in CAD and get it looking right but can be done. I would maybe cad it without the texture then add the texture by hand to save time or even carve it by hand and scan it. The main cost for me is in the CAD and prototyping its not really a case of just knocking up a quick model it has to work properly. Same with a mould you have to be able to cut it so it doesn't show part lines in areas that are difficult to clean up and also that the model is easy to extract from the mould. For casting I try to charge by the flask so the more you can get in it the cheaper it becomes for you. The cost is similar to cast 1 or 100 rings if its in the same flask just a bit more time injecting moulds and treeing up. Obviously not the metal costs! If its just a case of casting your carved model, finishing it to a master standard, moulding it and recasting say 10 copies for you to finish. I would recon £250 ish would be a fair price less metal costs for a simple ring sized item. printing your own cad file would probs add £50 to that provided its a good model as they will not always work. Also what metal is used can effect cost silver is usually a bit more expensive to have done because you don,t make as much on the metal.

[Shamsham]

OK, here's one way to view it:

If I am asked to produce a piece to a design (of variable detail) then I will produce that piece as a one-off. The files and everything else that I've created are mine and in that scenario nobody else has any rights to them. It's taken on trust that it won't subsequently be used as a master in a run. If you have significant design input on it, then it's also taken on trust that I won't make them & sell them either.
If I'm asked to produce a model for a run of n pieces, and I'm to sign over the rights to all the modelling work and files, then the price will usually be much higher than the cost of an individual piece (but not 1000 times higher because you want to manufacture 1000). The cost to you for the CAD work is then much lower per piece. It's not a direct cost of the mould, but that is part of the process.

If you want a least-cost option then I'd look at carving the pieces directly in wax, then having your own master cast & moulds made from that. The organic nature of what you've shown would lend itself well to that, possibly better than it would CAD.

Regarding loss of detail on your resin piece, you can have a mould cold-cast (RTV rubber rather than higher temperature vulcanising rubber) using the resin as a master; the detail pickup is good, the major downside to RTV is it has a much shorter life than "proper" rubber moulds. You'd lose a bit, but not all that much.

There remains the issue that just because you can draw something on a computer doesn't mean it will work in real life... Design for manufacture isn't as straightforward as it might be with CAD to casting.

This is extremely helpful, thank you very much.

I am looking to get myself onto a wax carving course so I have some basic understanding of how to carve my own pieces in wax which I think will help me massively as I've assumed the starting point will always be a CAD drawing.

Also have a better appreciation of where cost for production comes from although I still believe he may be on the high side of things as I think he is fairly well regarded and has done a lot of work for a lot of designers.

Appreciate your help, thank you!

[Shamsham]

That does seem a bit expensive but I suppose its down to how much you value your time. The main problem you have with making moulds for production is taking into account shrinkage, not so important in the models you have shown but when you need to make rings of a specified size which will have openings for stones of a specific size the master model may need to be remade several times to get the dimensions right there is no hard and fast rule to account for shrinkage which can be upto 15% across the process in the case of larger items . The models you have shown would also be time consuming to model in CAD and get it looking right but can be done. I would maybe cad it without the texture then add the texture by hand to save time or even carve it by hand and scan it. The main cost for me is in the CAD and prototyping its not really a case of just knocking up a quick model it has to work properly. Same with a mould you have to be able to cut it so it doesn't show part lines in areas that are difficult to clean up and also that the model is easy to extract from the mould. For casting I try to charge by the flask so the more you can get in it the cheaper it becomes for you. The cost is similar to cast 1 or 100 rings if its in the same flask just a bit more time injecting moulds and treeing up. Obviously not the metal costs! If its just a case of casting your carved model, finishing it to a master standard, moulding it and recasting say 10 copies for you to finish. I would recon £250 ish would be a fair price less metal costs for a simple ring sized item. printing your own cad file would probs add £50 to that provided its a good model as they will not always work. Also what metal is used can effect cost silver is usually a bit more expensive to have done because you don,t make as much on the metal.

I agree, there's a lot of expertise required in knowing what the dimensions need to be for things to materialise the way you want them, it's why I wanted the first piece to be done all by the jeweler who could run the production from start to finish as he knew exactly what needed to be done to create the end result. I appreciate I may have paid a premium for this level of expertise.

Thanks for your response