Wooden master and stunt casts

[thd9791]

this is a really big concept for me, never having done it, so I'm constantly learning. True, if it was pegged, and glued back together it wouldn't need filler... lol pardon my lateness to that.

Does anyone know what were seeing on the wood piece - there seem to be lengthwise lines, as opposed to cross lines youd see from lathing

 

[Edraven99]

Ok, I need some clarity here. Are some of you insinuating that the wooden buck is actually two halves that have been glued back together?

That makes no sense to me... I did aluminum sand casting in metal shop in high school eons ago - I cast a Jaguar hood ornament while some of the other kids in class made casts of a toy handgun... ah simpler times - and the master was always a solid piece.

Just Google "aluminum sand casting".

 

[SethS]

I don't if this helps or not, I'm confused about most of what's being said in this thread!

 

[Edraven99]

This is more of what I was talking about:

 

[Gerard2567]

I can think of a few possibilities.

If it is cut in half:

They added a spacer to make up for the missing thickness before molding two halves and combining or:

They cut off centre to have one half with an exact radius all the way theough which they molded twice.

If it wasnt cut in half:

They probably did lost wax investment casting or:

The sand casting of a solid mold such as the process in this video: 1:45 mark- It's a solid piece

The reason people use two halves is that it's easier to retrieve the parts; It's more professional.

 

[LOM]

I don't know if this was from the original owner or from the "archives" but it's often referred to as the "eBay" photo.

I'm also fairly certain that the "bootster" was machined (if lightly) for the V3 as well. Most definitely the clamp/body section if it were to fit a clamp. This is most definitely the one pictured here, only fit back together and the seam filled.

Ah, that image! I always figured it was from the auction. I agree with thd, I'm seeing the other side around the emitter, but it could just be an illusion as said.

Spent nearly 1 1/2hrs looking on ytube for someone casting using a one piece pattern. Closest I could find are what are termed pattern boards. These either have a pattern on each side for drag & cope (bottom & top mould halves) or have separate boards for the drag & cope. Also learned that the 'green' in greensand refers to it being damp & nothing to do with it's colour.

I also don't get how a one piece pattern could get out of register.

I don't have to much experience casting, but after the buck was removed, I'd assume when moving the mold to wherever the pour would occur they probably bumped into something or dropped the mold a bit, causing it to get a little out of register on some castings.

I found some videos I watched awhile ago where someone does cast with a one piece pattern: (around 2:20)

and here: (around 3:10)

Pretty much the method is fill the box with sand then press in the thing you're going to cast, then add the second half of sand on top of it. And it seems to work alright well here.

 

[E Williams]

We have that old Archives photo showing it laying flat and as a half-piece.

Does anyone have this photo to post?

 

[PoopaPapaPalps]

Pretty much the method is fill the box with sand then press in the thing you're going to cast, then add the second half of sand on top of it. And it seems to work alright well here.

That's essentially how it would have to be done. That's what I did when I was toying with Starkiller's V2 when I was practicing my mold making. The problem that I always ran into was one side sinking in further once I put the other half. I know it's from not packing the sand densely but packing it too densely would mean I'd never get the impressions to sink in far enough to fill the undercuts, and risk breaking the master.

Removing the top half of the mold isn't so bad, but removing the solid single master when it's sunk further in, it breaks and distorts the negative impression as it's being removed. If you could imagine balling your hand into a fist, and then cupping your fist with the other hand, and pulling your fist upward, your fingers straighten as you pull your fist up. I'm not saying it's not doable, again, but this was a common problem for me and it often lead to very poor and problematic casts.

If it was an entire single piece the whole time, I wonder if this brown splotch on the master was a mount hole where they could put a screw in to remove it from the sand. There's a circular discolored area in it that makes me think this was filled.

 

[PoopaPapaPalps]

There was likely another wooden buck. I don’t know how else the wood grain would be visible in the picture below, because that would be the inside of the handwheel on the wood buck we have pictures of.

View attachment 1284499

Now, see, this stump is what interests me most as this feature was most definitely for mounting the cast in a chuck of a lathe. You can see the underside of it in these photos and its surface texture/finish shows that it was cast as it is, and not machined down from the full pommel. However, the stump shows markings to that of it being filed or sanded down. A machine finish wouldn't have such chaotic markings.

I don't think that's wood grain in the area you've marked. I don't know how to explain it so it makes sense, but the surface of these cast aren't entirely smooth, it's almost like medium fine to fine sandpaper. If you take down the surface, they'll leave blemishes like this, especially on rougher parts; on the bottom of the nub, you can see something similar.

My current theory on this is that they filled the negative of pommel area of the buck to make this stump, either with another pattern or simply carved it out, and was cast it thusly. It being for two purposes: one for future machining, and also as a vent for pouring. I've got to wait on a new master for me to test this, though.

 

[teecrooz]

I’ll agree to disagree. The grain clearly lines up with the rest of the hilt.

 

[PoopaPapaPalps]

Then is seems more and more likely that another wood pattern was used to make the stump. The grenade rings match up so this cast does come from this master. This stump would've been an added detail.

 

[teecrooz]

Maybe Thomas can share images of his blank before he finished it. vadermania , would you be willing to share any images?

 

[Mouse Vader]

Phew lot to reply to here.

Does anyone have this photo to post?

This is in the next post #28 (& post#14). Personally I'm with thd & LOM & don't think this is 1/2 of a 2 part pattern but a whole wooden saber.

Seth : your video is for casting a resin saber in a silicone mould & is exactly what I was trying to explain earlier for resin casting. A silicone mould will not withstand the temperatures of molten ally.

Edraven99 & LOM 1st video : both these solid patterns have a flat side & I mentioned this in my earlier posts as exceptions to 2 part patterns. I have cast myself from such patterns.

LOM: 2nd video is getting there, but his pattern is a sword & he's only got to press it in little way & he has to stand on it to do so. PoopaPapaPalps says he's tried this method with the V2-3 pattern & had real problems. This clearly works with some patterns but it looks like our pattern is too thick for this to work & produce what we see in the actual casting.

Gerard2567 : Now your video is new method to me & interesting. What he does is mould one 1/2 into an additional shallow box such that when actual mould box is lifted it gives a raised part of 'excess' sand which is then cut back level with the mould box & pattern before the other side is filled. This, or a variation of this, looks like a viable method to me for using a solid pattern. Though I'm still puzzled by those out of register areas on the ally casting.

thd : length ways lines are the grain of the wood, This is a soft wood such as pine.

The Stump : I always assumed that stump was for mounting the pommel on. I agree it would also be useful for mounting in a chuck. Is it also possible that the pommel we see on the wooden pattern is a separate piece fixed to the stump on the rest of the pattern? A bit it like the emitter being a separate piece.

Good work everyone. This is looking like a useful thread.

 

[steven giunta]

One thing we gotta think about is the guys doing this we’re more then likely very,very good at it. They were professionals making props for movies with years of experience. I’m sure they casted 100s if not 1000s of props in aluminum. So although it may be difficult for most people,it may have been an easy mold for them to make. Look at the difference between your average cosplayer areand Adam savage.his costumes and props are amazingly good.
As for this piece being cut and glued back together I’m saying no way. I work with wood all the time and one of tge first things I was taught was account for the blade width while cutting. Even though it’s only 1/8 inch thick or less it can make a big difference. I think you would see the seam line if it were there.maybe you could hide it with filler and sanding but sanding the seam line would have made the saber very smooth by the line. Since we can clearly see tiny lines or wood grain up and down the saber.

 

[Edraven99]

Edraven99 & LOM 1st video : both these solid patterns have a flat side & I mentioned this in my earlier posts as exceptions to 2 part patterns. I have cast myself from such patterns.

I think you missed the part in my post where I mentioned that I made a cast of the Jaguar hood ornament in my shop class; definitely did NOT have a flat side to that unless you count the base stand.

 

[chazzychaz]

My first metals shop class lesson was casting handles for a tool box, using the sand mold technique. a wood buck was made of the handle and one half of the mold was filled with that nasty smelling black sand. the patter was imbedded the surface along with pour spout and vent smoothed out then coated with a nasty smelling spray. waited for that to dry then attached the second half of the mold, filled it with sand tamped then readied for molten aluminum. once it comes out of the mold the pattern has a seem line. its actually an interesting lesson. the same techniques were used to make the bronze oring bushing for the seawolf submarine. I mixed and poured the bronze into the molds. don't miss that job at all, brutal temperatures. I assume the props guys either called upon a local foundry or did it themselves.

 

[steven giunta]

Now that we know the top part of the neck on the v2 actually slides down Into the bottom part could that be the reason there is a seam there?if they casted it a few times,cut the emitter and top of neck off then recasted just the emitter and neck.sanding down the bottom piece got slide into the piece on top of the windvane. .

 

[thd9791]

The split for both the V2 and V3 is at the groove in the upper neck, not where the windvane meets it. Id say coincidence and it just broke like the emitter flange

 

[vadermania]

Maybe Thomas can share images of his blank before he finished it. vadermania , would you be willing to share any images?

It seems that I didn‘t take any pics of my blank before I converted it into the replica V3. That was back in 1998.

There is almost no seam line on my saber. Of all the blanks I know of plus the original in the archives, it looks like my blank is the cleanest one.

I, too, think that the wooden master was not cut in half for molding. I had a few items from my collection cast in aluminum at a local foundry in the past, they always got solid pieces from me, which I got back from them after molding in one piece.

 

[Mouse Vader]

One thing we gotta think about is the guys doing this we’re more then likely very,very good at it.

Have agree with your post whole heartedly & it's looking very likely I've made an ass of myself (see I'm not intractable). I too can't see any join in that wooden pattern. I'm still not 100% convinced that the push it into the sand method works for something with this diam. The examples given of the Jaguar mascot & tool handle don't have the same thickness / displacement (I do believe you both). I'll keep looking for confirmation on how something if this diameter is done.
Just to remind everyone, my experience is with brass which is a much higher temp melt & may need a more robust mould (leave me a shred of dignity please).