Rebound 25 mould making questions

Just thinking about this bird.... I would never block mold something like that. I believe I would divide him up in no more than 3 sections.... Most of the back and the top half of his head in one go, followed by the bottom half of his head including the chest and top/front of his feet. The third section would be under his ass and backs of his feet. Plasticine clay would be used to created the dividing lines between the sections and rebound 25 up to the parting lines. Mold ease is what I have and helps the silicone just fall off the wax and plasticine. As much as I hate plasticine, I would use soft trash to create the "dam" so you can keep the rebound under control especially the first layer as it is runny as hell. (again, see the video of the dogs here) The soft plasticine will be super easy to scrape off all those feathers along your parting line as you move on to your next section. Any of this make sense? I'm still learning and see we don't have mantrid to lean on, I'm always interested in seeing how stuff like this comes together... Below is obviously not a complete list, but how it plays out in my mind. The good thing is, you made your bird out of wax and not shitty clay. So he's nice and stiff and if you F up this molding process, you won't screw up all your hard work and can try again.

1. Plasticine along the parting lines building a 1inch tall dam, registration ball bearings in the clay at this time.
2. Release agent then Runny coat of rebound, followed by 3 coats of thickened r25
3. Remove ball bearings and plasticine and move onto remaining sections... Mold release next section and the new wall of silicone.
4. Repeat until entire chicken is covered in silicone
5. Plasti-paste mothermold up to each parting line using playing cards as dividers
6. Drill the flanges of the hardened MM.
7. Take him apart. Cleanup and reassemble. Pour wax through feet because he is standing now and that will leaving your opening.
8. Cut chest, sprue, shell blah blah blah....

 

The eagle is made in wax not clay

I finished the left wing today. Now I just need to do the neck feathers, carve the feet, add some long tail feathers and go over it to remove burs and blemishes, also add a few details to the head. Oh and of course pick a stick for it to perch on.

Here's what I've got so far:

 

He's looking awesome! What did you think about my last post?

 

Looks amazing Zap.

 

I read your reply last night but was too tired to reply properly then (12 hr days + studying afterwards is bad for the brain - all work and no play makes jack a dull boy).

Yes I think you are right about not block molding him. I think what I'm going to do is cut his feet off and mold the feet and the branch he will sit on separately. I think the main body and head of the bird can be done in 1 sock-like silicone mold with an upside down T slit that allows me to open the mold up to get the bird out. The T will start at the top of the bird's head, run down the belly and then divide into the 2 arms of the T towards the tail feathers. I think this method will allow me to use the two feet stumps as a pouring spout and safely extract the delicate long tail feathers. It will also put the parting line on the belly which will be easier to clean up because the feathers are flame polished there rather than the sharply cut back & wing feathers.

Yeah, I've got some sulfur free oil based clay I can use to make the dams. It is pretty hard to work with when cold but it will probably get the job done? Maybe I need Plasticine clay instead, because the oil based stuff I have is a bit of a b1tch to work with.

Yes I agree. Less chance of screwing up, but working with wax as a sculpting medium also has its downfalls, namely it takes forever to get anything done, and the wax is sometimes a bit sticky and hard to coax into the right texture.

Hmmm... I like the ball bearings idea. I'll definitely be using that, or marbles since mine seem to be constantly falling out of my head lately.

I made a very nice wax tool today. Probably one of the most useful tools I have next to my paring knife and pin tool, I will definitely be using it on almost all my future projects. It is basically an aluminum rod that I ground down into a blunted point (similar to a 0.7 mm pencil tip that has been written with a little bit then polished with 2000 grit sand paper). It essentially lets me draw patterns into the wax without that irritating mounding up effect that you get just next to the cut with really sharp objects like the pin tool & knife. It also seems to work well for removing surface marks in wax and cleaning up edges & corners.

I really need to make a tool video at some point and share some of my wax working tips that I've figured out over time. There really isn't a good tutorial online for working wax and it would have been nice to know what I know now a few years ago. Might not be as snazzy as one of your vids though Jason .

Anyway, I managed to turn one of the toes into a proper finished looking claw. Keep in mind I made most of the finer scales and dimples on the pads of the toe with the new tool. Now I just need to replicate the toe 7 more times... Ugh.

I'll fixthe toes to the branch in the right position... whenever I am able to find a nice looking branch, or make one.

Eagle claw in wax by Zapins, on Flickr

 

Damn that toe is realistic as can be! Nice job. Yes a video showing your tools would be helpful to many of us. I have a couple of ball tools and a booger hooker and thats about it. Visit your local craft store and pick up some plasticine. It's cheap and easy to use and just throw it away when you're done.

Whats the game plan for securing the interior shell in place? You planning on doing the standard chaplet thing? You guys have seen everything I've poured to date and I have yet to do a hollow casting like this so I'm interested in seeing shell INSIDE something as well as on the outside. When you're done, I wonder how hard it will be to remove most of that shell inside this bird...?
Learning all the time with this bronze thing is cool, keeps my attention that's for sure. I'll be taking my first stab at this hollow thing with the roofs for my lanterns... (I think)

 

There are several considerations I have about making one-piece rubber molds. I have done it several times and have always been sorry. It's tempting because it's easy.

One problem I see with your bird is the damage you will do to the wax as you pull a one-piece mold off of it. You just may need that wax at some point.

The second problem is the mating of the edges when you are pouring the casting wax. Unless I have keyed edges, I never get a good mating of the edges. One edge always rides higher than the other and I get an offset in my wax. One way around this is to have some sort of through-tabs to fasten the rubber mold to the mother-mold so it can't flop, but if you are going to that trouble, why not just make a multi-part mold with edge keys?

If you don't care about damage to the wax original, you still have to get the rubber mold off of the casting wax without breaking that. With a figure as complex as your bird, that takes some planning. Some three dimensional thinking.

If you cut your original model into pieces and cast the waxes separately, it is fairly easy to weld them together.

I am going to post the Mantrid Horse and Owl mold making posts in a few minutes. These are the last word in mold making tutorials. The own is made just for you.

Richard

 

Okay, here are the links to get Mantrid's mold making tutorials, complete with all of his photographs. This is not rocket science. Go to these links on my Spideroak server. Click on "Download All Files" It will download as a .zip file. Extract the files into any folder on your computer. Make sure the .htm file and the associated "files" folder (which contains the photographs) are together. Open the .htm file and you will have Mantrid's entire series of posts in your browser.

https://spideroak.com/browse/share/Fantaciworks/forums/forums/alloy avenue/Mantrid/Mantrid_horse/

https://spideroak.com/browse/share/Fantaciworks/forums/forums/alloy avenue/Mantrid/Mantrid_owl/

 

Damn that guy was good. WHERE THE HELL IS HE???

Thanks richard for posting those. I have the photos, but not the explanations to go with it.

 

Rarely have I seen a person disappear so completely, unless he was killed unexpectedly.

Richard

 

If we had his name, I'd search the obits..

 

Thanks Rasper, I'll pull those up when I go to mold everything

As for single part with flap in it vs multi part molds.

I once tried making a multipart mold without keying it and the result was terrible. I am a little hesitant to do multiple parts because of this. But I suppose keying it properly is the important part.

Also, Jason, I'm not sure how to fix the inner silicone rubber to the fiber glass outer shell. Maybe it doesn't need to be rigidly fixed inside it ?

 

You can place some solid silicone tabs on the rubber mold after the final coat of rubber. Those will fit into the holes they leave in the mother-mold. I would think through tabs on the flaps would be better. Make a two part plaster mold using a 3/8 inch wooden dowel as a pattern. Cast a silicone dowel. Cut that in one inch lengths and attach them to the rubber mold of the bird. When you make the mother-mold, these "rods" will extend through the mother-mold. You can then pinch them with clothespin clamps to hold the flaps.

I think it's better to build a properly keyed multi-part mold.

Another thing is to make the silicone mold extra thick at the seams. That helps prevent sagging. If you make the mold too thin, you will get sagging even with a properly keyed mold.

Richard

 

Richard said it well. just like dimples between the sections.. You can imbed Lego blocks in the silicone that will help it lock in place to the mother mold.

 

This is an amazing work of art!
I can't wait to see this eagle fly out of the mold!
R

 

For the last time,
IT’s a Chicken!

Gender confused chicken that thinks it’s an Eagle.