My take on the Alien as a toddler! UPDATED 6/1
- Thread starter Beeb89
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Re: My take on the Alien as a toddler! UPDATED 5/13
Thats kind of where I'm leaning right now... Thanks for your input, buddy!!
Thats kind of where I'm leaning right now... Thanks for your input, buddy!!
Re: My take on the Alien as a toddler! UPDATED 5/13
Love this!
Love this!
Re: My take on the Alien as a toddler! UPDATED 5/13
I think I'm going to try the technique you suggested with slump method... The way I understood it was having a negative mold of the dome with a jig cut to the outline of the dome edge. Am I understanding that right? I do feel like that's a great idea!
-B89!
I think I'm going to try the technique you suggested with slump method... The way I understood it was having a negative mold of the dome with a jig cut to the outline of the dome edge. Am I understanding that right? I do feel like that's a great idea!
-B89!
cavx
Master Member
Re: My take on the Alien as a toddler! UPDATED 5/13
So you need to make a jig which is a board with an oval cut out. The cut out needs to be the exact size of the final part. You need to take plastic thickness into consideration given you are placing the dome over the head.
Slump forming is just that - Mount the plastic to the board and heat the plastic to soft state and let gravity take over. Remove the heat when the desired height (slump) has been achieved.
Vacuum assisted means you build a box around the jig and use suction to help pull the dome.
Your jig will look something like this.
So you need to make a jig which is a board with an oval cut out. The cut out needs to be the exact size of the final part. You need to take plastic thickness into consideration given you are placing the dome over the head.
Slump forming is just that - Mount the plastic to the board and heat the plastic to soft state and let gravity take over. Remove the heat when the desired height (slump) has been achieved.
Vacuum assisted means you build a box around the jig and use suction to help pull the dome.
Your jig will look something like this.
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cavx
Master Member
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Re: My take on the Alien as a toddler! UPDATED 5/13
Thanks for posting that, my friend! However, after watching the video I'm not sure it's going to work for this particular project. If it needed to be just a smooth rounded form, this would be perfect, but the dome has a specific shape and form that is needs to be so I'm back at either trying to get a vacuuform pull or casting it in clear resin. Either way, we'll find out how it's going to work very soon!
-B89!
Thanks for posting that, my friend! However, after watching the video I'm not sure it's going to work for this particular project. If it needed to be just a smooth rounded form, this would be perfect, but the dome has a specific shape and form that is needs to be so I'm back at either trying to get a vacuuform pull or casting it in clear resin. Either way, we'll find out how it's going to work very soon!
-B89!
cavx
Master Member
Re: My take on the Alien as a toddler! UPDATED 5/13
The video does mention about heating one end more to change the shape. But I guess that could be a bit hit and miss just relying on heat and gravity and not having a stop point.
Because I am working on a female tooled vacuum rig right now, I am always thinking of how to make the female tools. One product that got my attention is expanding foam, (and not the stuff in a can) because it will form perfectly over a positive shape or buck to produce a negative or female tool of that part. The foam I am looking at also skins, so the finished part is smooth on its inside surface. Apparently, this is hard enough to make positive bucks out of as well but I do have to wonder how many pulls you would get. In a female tooled vacuumed systems, the hot plastic doesn't touch the tool until right at the end, so heat should not be an issue either. In my system, the chamber will provide the mechanical strength needed. The softer foam simply acts as the stopping points. The vacuum will pull down into the tool but there is not enough force to crush the tool because the plastic is soft.
The best way to make female tools is of course to make male shapes first from a soft medium like clay or Plasticine. This way you can dig the soft medium out of the foam part without damaging it.
The reason I am loving this process over tradional vacuum forming is that it is easy to correct a pull that does not work out 100% the first time.
Thanks for posting that, my friend! However, after watching the video I'm not sure it's going to work for this particular project. If it needed to be just a smooth rounded form, this would be perfect, but the dome has a specific shape and form that is needs to be so I'm back at either trying to get a vacuuform pull or casting it in clear resin. Either way, we'll find out how it's going to work very soon!
-B89!
The video does mention about heating one end more to change the shape. But I guess that could be a bit hit and miss just relying on heat and gravity and not having a stop point.
Because I am working on a female tooled vacuum rig right now, I am always thinking of how to make the female tools. One product that got my attention is expanding foam, (and not the stuff in a can) because it will form perfectly over a positive shape or buck to produce a negative or female tool of that part. The foam I am looking at also skins, so the finished part is smooth on its inside surface. Apparently, this is hard enough to make positive bucks out of as well but I do have to wonder how many pulls you would get. In a female tooled vacuumed systems, the hot plastic doesn't touch the tool until right at the end, so heat should not be an issue either. In my system, the chamber will provide the mechanical strength needed. The softer foam simply acts as the stopping points. The vacuum will pull down into the tool but there is not enough force to crush the tool because the plastic is soft.
The best way to make female tools is of course to make male shapes first from a soft medium like clay or Plasticine. This way you can dig the soft medium out of the foam part without damaging it.
The reason I am loving this process over tradional vacuum forming is that it is easy to correct a pull that does not work out 100% the first time.
Re: My take on the Alien as a toddler! UPDATED 5/13
Those are good techniques for sure, but I had another member contact me with another possible option that I think might be a little better suited for this. I'll be posting the process as I get to it... I'm learning as I go with this so it should be fun!
Here's where I am currently... Starting the "sand, prime, fill cracks, sand and repeat" stage of the dome... Though it seems monotonous, it's worth it in the end! Sculpey, while I LOVE sculpting with it, can crack during the backing process. I tend to do the "low and slow" method where I bake it at a low temp for longer times and most times that takes care of the cracking issues but it might have been a little dried out having been set aside for a bit before I was able to get it finished... Either way, fixing the cracks is no biggie, all part of the fun!
-B89!
Those are good techniques for sure, but I had another member contact me with another possible option that I think might be a little better suited for this. I'll be posting the process as I get to it... I'm learning as I go with this so it should be fun!
Here's where I am currently... Starting the "sand, prime, fill cracks, sand and repeat" stage of the dome... Though it seems monotonous, it's worth it in the end! Sculpey, while I LOVE sculpting with it, can crack during the backing process. I tend to do the "low and slow" method where I bake it at a low temp for longer times and most times that takes care of the cracking issues but it might have been a little dried out having been set aside for a bit before I was able to get it finished... Either way, fixing the cracks is no biggie, all part of the fun!
-B89!
cavx
Master Member
Re: My take on the Alien as a toddler! UPDATED 5/25
I have some "sculpty" here but never used it. I did wonder if cracked when it baked. The main reason I didn't use it was I was sure if it would react to my silicone. I know the products I do use are safe. Nothing worse than demolding a part to find a goo pool inside.
I have some "sculpty" here but never used it. I did wonder if cracked when it baked. The main reason I didn't use it was I was sure if it would react to my silicone. I know the products I do use are safe. Nothing worse than demolding a part to find a goo pool inside.
daredevil665
Sr Member
Re: My take on the Alien as a toddler! UPDATED 5/25
Hello, have you tried to print a dome?
Perhaps it is necessary to create a larger volume in the outside shape of the mold, to improve the extraction. But perhaps this will also depend on thickness of the plastic you're going to print.
Hello, have you tried to print a dome?
Perhaps it is necessary to create a larger volume in the outside shape of the mold, to improve the extraction. But perhaps this will also depend on thickness of the plastic you're going to print.
cavx
Master Member
Re: My take on the Alien as a toddler! UPDATED 5/25
@Beeb89 be careful not to make too much of an undercut.
As this stands now, you may have to cut the plastic away from the buck. As the plastic cools, it shrinks onto the buck. This also why I am massive of female tooled vacuum forming. As it cools, it shrinks as well, but now pulls away from the tool.
Looking at your image, you might want to build up and out the side parts so that the line around the base of the dome is a line and not a hard undercut. Building up the sides will still give you your distinct edge, but allow the plastic to lift off.
It is looking really good, so keep going.
@Beeb89 be careful not to make too much of an undercut.
As this stands now, you may have to cut the plastic away from the buck. As the plastic cools, it shrinks onto the buck. This also why I am massive of female tooled vacuum forming. As it cools, it shrinks as well, but now pulls away from the tool.
Looking at your image, you might want to build up and out the side parts so that the line around the base of the dome is a line and not a hard undercut. Building up the sides will still give you your distinct edge, but allow the plastic to lift off.
It is looking really good, so keep going.
Re: My take on the Alien as a toddler! UPDATED 5/25
With sculpy, from what I understand, to help reduce cracking, when you bake it, it's best to turn off the oven, but leave your sculpt in the oven and allow it to cool down slowly with the oven. If you take your piece out, especially if it's built over an armature like waded up tin foil, the sculpy cools too fast and causes the cracks.
With sculpy, from what I understand, to help reduce cracking, when you bake it, it's best to turn off the oven, but leave your sculpt in the oven and allow it to cool down slowly with the oven. If you take your piece out, especially if it's built over an armature like waded up tin foil, the sculpy cools too fast and causes the cracks.
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