Vacformedhero
Sr Member
@DaveG just to say thanks for your clear instructions and guidance , I have cast my first parts which means I can continue my studio scale journey
first mistakes I made so others can avoid
I didn't leave enough room around the edge to allow the glue gun in to seal the edges to the wall, so I glued underneath , this meant the mould box was slightly unlevel , meaning when the silicon dried and you go to pour in resin in flows away from what your filling,
SO LEAVE SPACE AROUND YOUR PARTS, AND POUR YOUR SILICONE ONLY WHEN YOUR PARTS ARE ON A LEVEL SURFACE
Believe the curing time on your resin contains , it is ACCURATE .
When I poured my first batch of resin , I didn't believe I had mixed it correctly as I couldn't feel too much heat initially
first two moulds were going fine , third moulds disaster ......as I'm pouring its turning white as it's hitting the mould , and I watch in fascinating horror as it hardens as I pour all the way to the jug (see exhibit A) great fun but a missed parts opportunity, but a learning experience for not only me , but my family as I ran downstairs with a lump of red hot plastic to demonstrate exothermic reaction (yes there was quizzical looks )
other miss is was not putting a flat surface with weights on top of the resin, this let to a waste of resin , and rounded rear of parts that need sanding
one step I personally would remove is using rice to measure the volume , do it with maths as the clean up of rice from the mould was a pain
you will see in the images the moulds are different colours , I think the second batch is more red , not sure but I think I added too much hardener , I may order Smooth-on with 50/50 mix for convenience. This was Polycraft general Purpose RTV
First Moulds
View attachment 683420
first castings
View attachment 683419
EXHIBIT A
View attachment 683418
Another schoolboy error, in my first castings I ran an old brush around the mould when I put the first resin in then continued the pour , this helped disturb bubbles.
On the second pour I forgot to do this and as a result there are more bubbles ,
for or the second pour I added a pigment to my resin .
this really adds something to the pieces once cast, there is a nice sheen off them, making them look like injected moulded pieces.
My favourite pieces compared to originals , even with some missing pieces they look great
Cockpit dashboard came out perfect as bubbles had room to escape via shield
other parts like Messerschmidt landing gear I couldn't cast correctly and even with air channels had errors so I have to revisit them
final advice , I think going forward I will mould my parts by the height of the piece this way I won't feel like I am wasting silicone.
mixing heights means your mould is dictated by the tallest piece , by placing all flat items together you will save a good bit of rubber .
first mistakes I made so others can avoid
I didn't leave enough room around the edge to allow the glue gun in to seal the edges to the wall, so I glued underneath , this meant the mould box was slightly unlevel , meaning when the silicon dried and you go to pour in resin in flows away from what your filling,
SO LEAVE SPACE AROUND YOUR PARTS, AND POUR YOUR SILICONE ONLY WHEN YOUR PARTS ARE ON A LEVEL SURFACE
Believe the curing time on your resin contains , it is ACCURATE .
When I poured my first batch of resin , I didn't believe I had mixed it correctly as I couldn't feel too much heat initially
first two moulds were going fine , third moulds disaster ......as I'm pouring its turning white as it's hitting the mould , and I watch in fascinating horror as it hardens as I pour all the way to the jug (see exhibit A) great fun but a missed parts opportunity, but a learning experience for not only me , but my family as I ran downstairs with a lump of red hot plastic to demonstrate exothermic reaction (yes there was quizzical looks )
other miss is was not putting a flat surface with weights on top of the resin, this let to a waste of resin , and rounded rear of parts that need sanding
one step I personally would remove is using rice to measure the volume , do it with maths as the clean up of rice from the mould was a pain
you will see in the images the moulds are different colours , I think the second batch is more red , not sure but I think I added too much hardener , I may order Smooth-on with 50/50 mix for convenience. This was Polycraft general Purpose RTV
First Moulds
View attachment 683420
first castings
View attachment 683419
EXHIBIT A
View attachment 683418
Another schoolboy error, in my first castings I ran an old brush around the mould when I put the first resin in then continued the pour , this helped disturb bubbles.
On the second pour I forgot to do this and as a result there are more bubbles ,
for or the second pour I added a pigment to my resin .
this really adds something to the pieces once cast, there is a nice sheen off them, making them look like injected moulded pieces.
My favourite pieces compared to originals , even with some missing pieces they look great
Cockpit dashboard came out perfect as bubbles had room to escape via shield
other parts like Messerschmidt landing gear I couldn't cast correctly and even with air channels had errors so I have to revisit them
final advice , I think going forward I will mould my parts by the height of the piece this way I won't feel like I am wasting silicone.
mixing heights means your mould is dictated by the tallest piece , by placing all flat items together you will save a good bit of rubber .
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