Thread: Making a vertical silicon mold

Ian in doing the calcs for volume with subtracting for the dowels gives about 4lts which is 4kg.

Without the dowels your container is 150x150x200=450000 volume of the dowels 130x35x5 + 25x130x4 work out approx .5

BUT the material your using to make the mold weighs different due to its mass/density.

Look at a 4kg ice-cream container (this is how we did the maths for resin/fibreglass we always allowed 5-10%) its always best to have to much than not enough.

You can always make a smaller mold for left overs and not waste anything of the mix.

Wongo master of Maths may like to varify.

Something is not right here.

Volume of the dowel should be r*r*pi*h (r = radius, h=height, pi = pie)

You want the interior volume of the container - blocks - cylinders

It is too much for me to read. Can you tell me the thickness of the plywood , exterior dimensions of the container and length of the dowels?

Scott thanks for the in put. correct measurements may have helped.

As I said I can't make it to easy It's easy I just filled it with water and measured it and as I thought it's around 2.5kg

Cheers Ian

Originally Posted by salty72

Neil which soft silicon are you referring to... bananSkin or ultraSil

With ultraSil I have no problems with wall thickness around 8mm even on the 30mm long funnel I made - As you can see from the TECH data below BananaSkin is very soft and will stretch ALOT whilst the UltraSil is harder and less flexable/stretchy

TECH details for BananaSkin

Hardness, Shore A 12Tensile Strength [mPa] 3Elongation at Break [%] 600Tear Strength [KN/m] 18

Linear Shrinkage [%] 0.1

TECH details for UltraSil

Hardness, Shore A Approx 25
Tensile Strength [mPa] UNK
Elongation at Break [%] 300-400
Tear Strength [KN/m] UNK
Linear Shrinkage [%] 0.1

Sorry Salty, didn't see this. I don't use either, too expensive. I use a soft silicon I get off Ebay that is a lot cheaper, the same as the molds from USA are made from, a cream primary product with a blue dyed catalyst. I find if you use less than 15mm thick it tears too easily.

Originally Posted by wheelinround

Ian in doing the calcs for volume with subtracting for the dowels gives about 4lts which is 4kg.

Without the dowels your container is 150x150 145x200 164 (130+19+15)=4500003,567,000 volume of the dowels 130x35 30x5 + 25x130x4 work out approx .5 714,000 less volume of squares (40x40x5+35x35x4)x19=245,100 less filler 35x19x(130+19)=99,085

so all up 2,508,815 ie ~2.5 litres (~2.8kgs)

See corrections above, so Ian's water test is Ok (as expected and always best way IMHO)

Hey Neil I am going to take your suggestions on board and although I have the actual mold made but not yet silicone casted. I am going to reduce the number of 30mm tubes to 3 instead of the current 5 and increase the 25mm tubes to 6 so I will now have 3x30mm tubes and
6 x 25mm thinking this may be a better idea.


Cheers Ian

Ian just understand it will increase the volume of material (silicon) required.

Yes Ray I do realize that but ll will be good.

Cheers Ian

Originally Posted by Dorno

Yes Ray I do realize that but ll will be good.

Cheers Ian

Budget man its gonna cost you more it was your biggest concern...............oh you got $$$$$ last night

3 things Ray it won't use much more silicone (please don't do the maths and remind me )
best I make so i can get the best bennifit out of it and not spend ALL this money and not use it and finally no i didn't get any money last night OR today

Cheers Ian

Sorry Ian I see the way I typed that came out rude.

Neil, the stuff you get off EvilBay (have to disguise the name as Juanita wont let me play there any more -but that's another story)
Do you have a SPEC sheet for it 'cause if it's OK don't see any reason to fight the white... (excuse the pun)

Originally Posted by salty72

Neil, the stuff you get off EvilBay (have to disguise the name as Juanita wont let me play there any more -but that's another story)
Do you have a SPEC sheet for it 'cause if it's OK don't see any reason to fight the white... (excuse the pun)

Sorry, no data sheets on Ebay, nor on container