Making mold with frosted detail plastic and castaldo very low temperature rubber

Rio Grande has a mold rubber that cures at 160 degrees F. (90 minutes) I see frosted detail and ultra detail can take heat up 176 degrees F.

http://www.riogrande.com/Product/Castaldo-VLT- (Very-Low-Temperature)-38-Mold-Rubber-Strips,-5-lbs/701005?P os=1

VLT® Silicone Molding Rubber Instructions for Use: http://www.castaldo.com/english/use/u_vlt/u_vlt.html

It appears that this can actually make a production mold. The pour molds don't seem to have the detail and also can't be used for production.

Anyone with experience with this or this sort of thing?

Are you wanting to make molds for wax injection?

Yes, I do want to make molds for jewelry.

I ordered some items in Frosted Extreme Detail plastic.

Supposedly this rubber can vulcanize at 160 F in 90 minutes, gets fine detail, almost no shrinkage, and can be used as a production mold. It comes in pre-cut sheet form.

From the cost point of view the frosted detail would be cheaper. I may try that later and see how it comes out.

Do you have any knowledge that would help in this area?

Thanks

No, I've never tried it. However, I don't think it will work because it has a heat distortion temperature of 114.8 F at 66 psi, so it's probably not going to work because the model will deform before your mold vulcanizes. This data is coming from the material data sheet found here.

I would think that the silicon resin molds would be able to obtain the same level of detail provided one used vacuum degassing and pressurization during the curing. These types of molds can be used for making wax masters, but for how long they last I'm not sure. A good place to go for resin is Smooth-On. They even have a product called Sorta Clear that is specifically designed for this type of mold making.

I have a wax injector, but haven't used it yet because I've been doing 3D printing for masters compatible with burnout and also a new one I'm going to be working with soon that dissolves in water, so let me know what you find out on this because I'll be interested in pretty much doing exactly what you're doing eventually.

Yes, I think you're right. It looks like the material I ordered won't work. However, it looks like I can try the Strong & Flexible Plastic Material. It has much higher temperature tolerance. It doesn't start softening until 325 degrees F. I would have liked the finer detail stuff.

https://www.shapeways.com/rrstatic/material_docs/mds-strongf lex.pdf

I've been retired for quite a while but I was in the jewelry business for 25 years so I'm generally familiar with the process. 3D printing and making molds from plastic is new to me. The poured molds are good for short runs however they still don't hold the detail that pressurized rubber does.

The company's data sheet fro the low temp rubber says that there isn't any meaningful shrinkage which is nice if you have parts going together or stones..

I'm more or less haft serious and not in much of a hurry. I find it fun learning Blender and this is my first experience with having something 3D printed.

And it would be too bad if I made a little money from the efforts.

Thanks,

James

By the way, James, thanks for pointing that out.

James

I wonder if electroforming a shell of copper or nickel would give the acrylic enough strength to stand up to the heat and pressure. Some detail would be lost but it might work.

As for the polyamide, yes this would work great and I heard that it can even be burned out effectively if one wanted to go down that route. The print lines though, ugg. I guess if one wanted to use it as a master for making a mold it would be ok because one could spend time removing the print lines and carving on it to accentuate the details.

Hmmmm... That just gave me an idea. Lets say one had complex detail that they needed on a piece like a text engraving for example, well one could print the text engraving portion in frosted extreme detail and make it as an inlay to fit exactly into a polyamide base. The acrylic text engraving inlay in this case may be able to hold shape long enough to complete the vulcanizing.

Or how about this. Lets say one used the extreme detail plastic to make a mold and then filled the mold with something that would be far more robust like polyurethane.

Or how about a multi piece mold made from extreme detail that could be used with a wax injector. Given the precision of 3D printing a very nice multipart mold could be made without too much trouble for some types of geometry.

Right now for the fine detail I suspect that the pour material and then making production molds from the master is the most labor efficient route. However I see that they only take .1 mm off when they polish strong and flexible. So that might do with a little engraving before molding.

It appears that more stuff is coming in 3D printing. Shapeways I think will check everything out and if there is something better they will do it.

Check this out: where they are going to have a printer for metal clay. I don't think it will have very good resolution though.

http://davidhartkop.com/cms/?q=mmm

Workflow to save money and time in every aspect of this is of great interest to me.

Onward!

James

Funny you should mention that because that's one of the big things I've been working on for years, an efficient way of printing noble metals and their alloys. I want to make a design and just print it with having to get all of the traditional methods involved ie investment casting and the ancillary processes. The Mini Metal Maker is not even close to what I'm working on nor is SLM or DMLS, but it's in the subject area. I don't think they will be successful with their attempt to get a patent on this because there is nothing new they are doing here. On the other hand, their patent application could have aspects about it that have not been made public yet.

I suppose any ideas I have about the subject of printing directly into metals you've thought over a 1000 times since you've been thinking about it for so long. But it sure is an interesting problem.

The first thing that struck me was remembering granulation and with the tiny balls the surface melted first. I believe that may be because of the oxygen available at the surface causing it to heat sooner and also sometimes treating of ball's surfaces causing the surface to melt at a lower temperature. I would gather a laser would have to be used and a lot of problems likely would arise.

Anyway, good luck with that.

Thanks I'll keep that in mind, it's good to have a reminder of this and how the melting temperature of alloys change based on the alloyed metals and their proportions. Yes very interesting, because it is very difficult to do it without supports that need to later be removed, but my intuition tells me there's a good way to do it, floating around somewhere out there in the universe. The other interesting thing to think about is printing metals immediately adjacent to plastics, I'd like to find a way to do this too if possible.