Need advise with molds please
- Thread starter kevin926
- Start date
Don't use oils. Smooth on sells a lot of releases and can help you with any questions. I wouldn't trust baby powder if I'm pouring a multi part mold, silicone loves to stick to silicone. Also, silicone sticks to glass really really well, so don't use glass for molds.
OlivierC
Well-Known Member
Baby powder is not really used as mold released but more as a "grip", to ensure the resin flows everywhere in your mold
I only use mold release where making 2-part molds, when pouring silicon on silicon like swgeek explained.
In the case of a two parts mold, you can use the expensive stuff, or petroleum jelly (vaseline). Once the first half has cured, I microwave the jelly an apply it with a brush, but only on the silicon, not on the part I'm molding, Then when I pour the other half, it does not stick to the silicon
I only use mold release where making 2-part molds, when pouring silicon on silicon like swgeek explained.
In the case of a two parts mold, you can use the expensive stuff, or petroleum jelly (vaseline). Once the first half has cured, I microwave the jelly an apply it with a brush, but only on the silicon, not on the part I'm molding, Then when I pour the other half, it does not stick to the silicon
I made my mold block from corrugated plastic and hot glue. Didn't really like the look of it. Hot glue is messy. I made a second one out of styrene and liked it much better. I still used some hot glue around the outside edges just to ensure no leaking. I plan on using double sided tape to hold parts in place.
I only want to do this once and get it right on this attempt.
Incase you are wondering why I have a section inserted, I am making 2 molds.
1 mold will hold 4 of each piece
The 2nd will hold 1 of each piece.
I figured it would be easier to make one mold block sectioned into 2 parts.
Also , my order came in.
I only want to do this once and get it right on this attempt.
Incase you are wondering why I have a section inserted, I am making 2 molds.
1 mold will hold 4 of each piece
The 2nd will hold 1 of each piece.
I figured it would be easier to make one mold block sectioned into 2 parts.
Also , my order came in.
Ready for round 2..
I packed clay in the parts where resin would leak through per advise on this post..Thank you.
I also used 2 sided tape.
And poured.
Curious to know why they tell you to pour on one corner to fill the mold.
Is this to avoid pockets.?
I packed clay in the parts where resin would leak through per advise on this post..Thank you.
I also used 2 sided tape.
And poured.
Curious to know why they tell you to pour on one corner to fill the mold.
Is this to avoid pockets.?
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Looking good. Yes, the pour in one corner method is to reduce the number of bubbles and make sure everything gets covered evenly. My only criticism would be, try to cover the whole bottom of the mold box with one piece of double stick tape, or multiple pieces that are flat and butt up against each other. You want the bottom of the mold box to be as flat and smooth as possible since it is going to be the face/top of your mold. It will make your life a lot easier when you cast parts and need to sand them flush. If the mold is smooth and even you can sand the parts in the mold and get a consistent smooth finish.
As far as molding a wheel you would use a similar method to what you've already done with the tank cupola. Stick the wheel face down, fill it with clay, put some registration keys on the bottom of the mold box, pour in the rubber. Then after the rubber sets up, carefully peal away the mold box from the rubber, making sure the wheel doesn't come out of the first half of the mold, pull the clay out, then spray the first half with release, build a new mold box around the first half, then pour your second half of the mold. After everything has cured pull it all apart, pull the wheel out and cut in some vents and a pour tube.
As far as molding a wheel you would use a similar method to what you've already done with the tank cupola. Stick the wheel face down, fill it with clay, put some registration keys on the bottom of the mold box, pour in the rubber. Then after the rubber sets up, carefully peal away the mold box from the rubber, making sure the wheel doesn't come out of the first half of the mold, pull the clay out, then spray the first half with release, build a new mold box around the first half, then pour your second half of the mold. After everything has cured pull it all apart, pull the wheel out and cut in some vents and a pour tube.
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Before you pour in your casting plastic, baby powder your molds then blow them out with compressed air, this will keep you from getting the tiny bubbles on the surface and in the cracks from surface tension.
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