# Bowl Casting 101



## Bellsy (Sep 2, 2011)

A few months ago at a wood turning guild meeting (TVWG) there was a partially turned bowl placed on the draw table. The bowl was marked as being Silver Maple. It was a burl piece that had missing pieces around the bowls rim that had apparently come off during turning. My best guess is that the person who brought it to the meeting did not want to proceed further with the turning. Much to my surprise I was lucky enough to get through several draws before one of my tickets came up. I immediately picked up the bowl with full intentions of casting the bowl to replace the missing rim pieces. Here is the method that I followed to make a mold which lead to a new casting experience.

The first step was deciding how to fill the internal bowl section and figuring out just how much of the bowl needed casting. I decided to make a pine core to fill the inside completely. While I was making up the internal core I was faced with two additional problems. The first was how do I hold the bowl after casting to turn it again? The second problem was how do I pour the casting medium and fill the inside and outside at the same time? The bowl needed to be cast upside down in order to get the medium to the rim of the bowl. The bowl needed to be held at the rim end of the mold. The mold design was taking on the form of at least 3 pieces to encapsulate the entire mold.

The first piece of the mold was the internal core, which was followed by a transition piece that attached to the core and to the third piece which I will call the outer mold body. The core was turned to suit the internal bowl form and allow for a 1/8” gap for the casting medium. The transition piece needed to allow for a face plate to pass through it. The outer body was then turned to allow a 1/8” gap for the medium to flow through to the bowls rim.

After the core was turned a new problem developed and I was faced with the problem of turning the outer body of the mold. I decided to use the transition piece as a faceplate to hold the outer body and secured it by means of wood screws. The outer body was laminated together to build up a partial thickness of the bowls height. The inside of the outer body was cut on the scroll saw removing a large portion of the waste material. Once the cutting was completed, the remainder of the outer body was formed on the lathe and trial fitted to the bowls outer shape. The last piece of the outer body was added and hollowed out to fit the outer portion of the bowls base.

After the pieces were turned and shaped the entire bowl mold and the bowl were fitted together for one last inspection. When everything fitted properly the thought of air being trapped inside the bowl during casting came to mind. To solve this problem I drilled a vent hole through the core of the mold in the center. The mold and bowl were assembled and to help the casting medium flow better to the inside of the bowl, I added spacers (toothpicks) between the bowl and the mold at the rim. The bowl was then glued (CA) onto the mold core/transition piece with the aid of the tailstock to ensure the bowl was centered for turning after casting. With the bowl secured into the mold I added the outer body of the mold with wood screws and wood glue and clamps. After the glue was cured, the bowl was ready to be cast.
After the bowl was cast, I began to turn away the outer mold until I found the bowls form.

Stay tuned for more photos as the bowl reaches completion.

Dave


----------



## bench1holio (Sep 2, 2011)

think ill drag the esky up near the computer and put my feet up, cause im really keen to see the outcome of this!


----------



## bluwolf (Sep 2, 2011)

Likewise...


----------



## workinforwood (Sep 2, 2011)

Looks pretty interesting. What did resin did you cast it with and what how did you dye your resin?


----------



## PaulDoug (Sep 2, 2011)

Can't wait to see "the rest of the story".


----------



## grz5 (Sep 2, 2011)

Cant wait to see how this turns out.


----------



## glennw (Sep 2, 2011)

Looks like Mother Earth


----------



## paps (Sep 2, 2011)

Very interesting!


----------



## Bellsy (Sep 2, 2011)

Thanks for the comments so far folks.



glennw said:


> Looks like Mother Earth



That was my very first thought as I turned of the outer part off of the mold.



workinforwood said:


> Looks pretty interesting. What did resin did you cast it with and what how did you dye your resin?



Jeff, the resin is Alumilite, the dye is Alumilite Blue and the pigment is a Silver PearlEx. I mentioned in your previous thread that I was going to start  a new thread about a bowl cast in Alumilite and this is it. I know you mentioned the "cost" being so high for the Alumilite and this was on my mind when I first saw the bowl. I do not know what you were faced with in regards to shape/form for your bowls, but this bowl was not so easy as far as making the mold. I kept the resin amount down to @ 14 ounces for the bowl and the 3 wine stoppers took the remaining 7 ounces.

Dave


----------



## workinforwood (Sep 2, 2011)

Yes, that's what I was thinking. The blue alumilite dye is what has stained the bowl. Maybe it still looks ok, hard to tell by the pics, but if you don't like the staining effect in the wood itself, do not use that liquid dye. Just use some oil base paint instead, that won't stain the wood at all. I can't stand the random staining effect from the dye penetrating the wood, I prefer the wood stays wood, and the resin is resin, giving more contrast to the piece.  The bowl looks great though otherwise. The mold work and way you are turning it is very cool!


----------



## Bellsy (Sep 3, 2011)

workinforwood said:


> Yes, that's what I was thinking. The blue alumilite dye is what has stained the bowl. Maybe it still looks ok, hard to tell by the pics, but if you don't like the staining effect in the wood itself, do not use that liquid dye. Just use some oil base paint instead, that won't stain the wood at all. I can't stand the random staining effect from the dye penetrating the wood, I prefer the wood stays wood, and the resin is resin, giving more contrast to the piece.  The bowl looks great though otherwise. The mold work and way you are turning it is very cool!



Thanks for the advice Jeff. I actually like the affect of the dye on the wood grain, but I am sure that the wood if stabilized will not allow the dye to penetrate the wood grain. So this wil give me 2 options for casting in the future. I have often wondered if paint would actually mix and cure if combined with the Alumilite. Now that I know this, it just opened up a whole new colouring scheme for me. Thanks

Dave


----------



## Drstrangefart (Sep 3, 2011)

That's an incredibly good looking bowl. I REALLY like it. Can't wait to see it finished.


----------



## Bellsy (Oct 4, 2011)

Well the wait is over folks....I finally had time in my schedule to get this bowl finished.

All questions welcomed.

Dave


----------



## broitblat (Oct 4, 2011)

Spectacular -- well worth the time and effort.

  -Barry


----------



## hewunch (Oct 4, 2011)

Amazing! I am sure it will be prized!


----------



## seamus7227 (Oct 4, 2011)

<<SPEECHLESS>>


----------



## Pete275 (Oct 4, 2011)

Dave, the bowl is incredible a real treasure, and the best part I bet is you had fun doing it.

Wayne


----------



## sumterdad (Oct 5, 2011)

I bet if that guy that gave up on it saw this he would be wanting that bowl back.  That is really supper nice!


----------



## Buzzzz4 (Oct 5, 2011)

Very cool. Nicely done!


----------



## el_d (Oct 5, 2011)

Awesome work Dave.


----------



## markgum (Oct 5, 2011)

WOW!!!!


----------



## greggas (Oct 5, 2011)

Dave
Thanks for 
Paring your process...have contemplated doing something similar and seeing your steps was very helpful

Interesting how the dye make sthe wood look a little like buckeye Burl

Nice job


----------



## elody21 (Oct 5, 2011)

I can't wait to see then next pictures!!!!
Alice


----------



## MarkD (Oct 5, 2011)

What an ingenious save! Outstanding!


----------



## Bellsy (Oct 5, 2011)

greggas said:
			
		

> Dave
> Thanks for
> Paring your process...have contemplated doing something similar and seeing your steps was very helpful
> 
> ...



Your welcome Greg. 

Thanks to a tip from Jeff Powell, I can also use oil based paint to avoid the staining from the dye. That bowl will be posted in the near future.

Dave

Sent from my-phone.


----------



## jbswearingen (Oct 5, 2011)

Yup.  That's pretty awesome.


----------



## bassinhuntin (Oct 5, 2011)

Freaking Awesome!!!!


----------



## bitshird (Oct 5, 2011)

Dave, I like the random staining from the dye, around here we get a lot of mineral stained woods, (I think where we live was the Lords hazardous waste dump!!) but the casting and particularly the mold process was just flat out awesome. And the finished bowl is just a out and out  beautiful piece. You done it proud!!


----------

