New Project: Custom Cast Signs

These signs look fantastic!  Great job!

They turned out great! Couple questions, how long does it take to prep the mold and can the sand be used over? I would think any type of mass production would be bothersome unless using a bigger mold with multiple gates to patterns?

Great signs! JohnA

I used a product called Delft Clay to create the molds.  I am not 100% sure of what it is made of, but I believe it is some mix of sand, oil, and probably a few other things.  Creating the molds isn't too lengthy a process.  After a few where I packed the sand too loosely, I started using the round end of a ball peen hammer to more tightly pack the sand into the mold pieces.

Once the bottom half is packed full, I leveled off the top with straight edge.  Before pressing the mold into the sand, I dusted the surface of both the bottom mold and model with baby powder and then brushed off the excess.  I read a few places the powder helps to keep the sand from sticking to the model and the top half of the mold.  After the model is pressed into the bottom half, I placed a few dowel pieces adjacent to it to provide branches in the mold to pour into.

After all that is in place, I placed the top half of the model onto the lower half and again packed it full and leveled it off.  Once everything is packed, I carefully separated the halves and removed the model and dowels.  This was usually the place I could tell whether the mold was going to work or not.  Sometimes the details in the sand would stick to the model and ruin it.  When that happens, you have to dump the sand and start over.  If the mold looked good, I drilled two holes in the top half to line up with the branches. 

After the holes are clear, I reassembled the molds and poured the Pewter.  I usually kept pouring until I see the Pewter rising up the second branch hole.  On a few occasions it came out the sides if I didn't have the mold tight enough together. 

Overall, it probably took about 20 minutes or so to prep each side of the mold.  The earlier attempts took longer.  The Delft Clay casting worked well I think for one off molds, but because they need to be broken up to get the casting out, they are good for one use only.  The sand can be reused though.  In fact, I found it useful to put an old baking sheet under the molds when I was packing them to catch any sand that fell off.  As for making multiples in one mold, I didn't venture that far into the process.  I would think it would work ok though, the key would likely to be laying them out in a manner where the Pewter can easily flow between the models.

Thanks,

Tom

These are terrific. Love these. A lot of work, but you must get a great deal of satisfaction from making them.

Thanks for the details Tom! Agree with Will, its gotta be satisfying work. Maybe to the point where making a bunch of them begins to take the fun out it.

They are amazing!  Nice work.

nice. another way is to use Castable Resin in the 3D printer, Then like making jewelry put the 3D castable resin model in an fine investment 

the 3D  model is then burned away leaving a detailed mold that can be poured with hot metal. Again just like making a ring,

AlanHN, Thank You for the suggestion.  I was unaware anything like that even existed.  I had seen some examples of people carving the green 'flower arranging' foam blocks to make models which then burn up when pouring.  Using a 'disposal' resin model may allow some more details to be added since the mold would be less likely to crumble with something holding everything place. 

Thanks,
Tom

They look great, I've always loved cast metal things like that instead of the plastic things you usually see.

Another option for casting pewter is to use Smooth-on Mold Max 60 a silicone molding material that can be used with low (relatively) melt temp metals such as pewter that would allow you to reuse the molds. There are a lot of maker videos on YouTube showing the various mold making techniques using it but I like Punished Props, they do a lot of work with Adam Savage formerly of MythBusters.

How did you paint them, particularly the raised areas of the casting? I think most of us could manage the casting part but the real killer  at least for me would be the painting.

@Will posted:

These are terrific. Love these. A lot of work, but you must get a great deal of satisfaction from making them.

Will, I'm thinking 48 Club sign here, what say ye?

Jerry

Tom

this castable resin is available from FormLabs.

Like I said its use is usually by either jewelry makers or dentists.

@baltimoretrainworks posted:

Will, I'm thinking 48 Club sign here, what say ye?

Jerry

I say "Amen Brother."