Couldn’t find any previous general topics on this so I thought I’d start a new one. Feel free to post your own questions below.
Say you don’t have access to a 3D-printer or other common rapid prototyping tools, but wanted to make a model in your kitchen or garage using traditional techniques and simple tools instead. Reasons could be cost savings or whatnot, it doesn’t really matter, but personally I’ve always enjoyed working with my hands. Also, despite the advent of rapid technologies, I firmly believe that mastering these traditional methods are very valuable to any designer.
In my case, I’m currently working on a project that will probably require many iterations before reaching production status. Many minor adjustments and detail tweaks will have to be made to get it right and there simply aren’t enough resources right now to outsource these processes which is why it has been decided to try and do the majority “in-house”.
I would like your opinion on making a master model of a similar(ish) part as in the image.
My intention is to make a master, from which a mold and then possibly vacuum cast the prototype(s).
I have access to a woodshop, I know where to get most common materials, I just need your advice on materials and techniques to making the master.
I would however, appreciate your thoughts on the viability of rapid prototyping methods regarding the project. So if you think rapid is really the only viable way to go, please elaborate.
If a structural part is needed, I would suggest a one sided mold and laying up fiberglass and resin. Possibly RTM molding if you need multiples and the shape allows. This way you have a lot of flexibility and can modify quickly.
I’d also go for fiberglass and resin, a bit tricky at the beginning if you have never used it, but you learn fast and can modify the result by sanding, cutting and re-applying. Surf shapers have this resin that only reacts to UV light, so it’s quite helpful for beginners. It’s also a bit more expensive, I think.
Got me thinking, is there possibly a laminating resin available that is more flexible and less brittle than standard polyester laminating resins? I’ve heard epoxy is an alternative, but it costs bonkers money. Also I’ve read about polyester additives but have no experience with them.
is there possibly a laminating resin available that is > more flexible and less brittle > than standard polyester laminating resins? I’ve heard epoxy is an alternative, but it costs bonkers money.
West Systems G-Flex epoxyfits that spec. An 32oz. kit (resin & hardener) is around $60 depending on where you find it; that’s about twice the cost of polyester. G-flex is thicker than “regular” epoxy; the trick being to heat the mixed cup in a warm water bath to raise it’s viscosity. Of course doing that also shortens it’s “cup life (working time)” somewhat.
I’ve been down this exact route of designing prototypes for production.
I can understand why you want to develop the prototypes by hand yourself - it gives you more control and the part does need to advanced modelling skills.
In my case I worked with a local model maker who drew up CAD from my drawings then vacuum cast the parts. It cost several thousand dollars and when we took it the factory they had to start over and make their own prototype.
So, I would say it is best to work with a factory who will be able to develop it on CAD for you and save lots of time and money.