My first try
- Thread starter caesar
- Start date
benniejordaan
Sealiner
caesar wrote:
However it is best to be as accurate as possible. Use a kitchen scale to weigh the Silicon then add 10% catalyst.
eg. 100 grams of silicone + 10 grams of catalyst.
When you mixing up, get only the required quantity mixed up. If you are short, you can mix up more and pour over even if it has dried already!
One way you can assess what quantity you need is to fill the mould box with beans or something sililar. Then pour the beans into a measuring jug. 100ml = Appr. 100 grams!
Doesn't have to be 100% with MM30. I have made moulds where I don't even measure, I just pour until it looks right and it's been fine.
However it is best to be as accurate as possible. Use a kitchen scale to weigh the Silicon then add 10% catalyst.
eg. 100 grams of silicone + 10 grams of catalyst.
When you mixing up, get only the required quantity mixed up. If you are short, you can mix up more and pour over even if it has dried already!
One way you can assess what quantity you need is to fill the mould box with beans or something sililar. Then pour the beans into a measuring jug. 100ml = Appr. 100 grams!
benniejordaan
Sealiner
Only a pleasure!
LGF is a pro at this stuff and may have a few pointer too, I'm sure!
Keep us posted as you go please - Step by step if possible! It may be helpful as we can assist you and hopefully it will help others.
LGF is a pro at this stuff and may have a few pointer too, I'm sure!
Keep us posted as you go please - Step by step if possible! It may be helpful as we can assist you and hopefully it will help others.
Little Green Fish
Sealiner
Kay one thing I can tell you is that your sprue needs to be the correct size and placed in the absolute correct position, why well air is the most troublesome issue to get rid of when pouring anything into a mold.
Size of the sprue is normally determined by the product you are using, like for instance with the 170 degree plastisol I use, it needs to have an even cylindircal resevoir (sprue) that is big enough to draw some (still molten) plastisol into the cavity as it cools down.
With resins and the likes it's not all that important to have the absolute correct size sprue but having a small resevoir will allow for any trapped air to slowly rise into that ammount of material so as to replace itself with some material in the sprue.
Now location location location. What I've found is that when dealing with molds of any kind and materials of any kind going into that mold, the sprue's location works best,if it is located on the top part of the mold when the material gets injected or poured into it.
Having said that, it doesn't mean that the sprue entrance to the cavity should be on the top of the lure, it can be anywhere on teh lure given that the area will be at the highest point of the lure and that it will be easily accessible when having to clean of the sprue and marks it will leave when removing it.
One more thing I found, is that with some resins, when you've mixed it too roughly and millions of tiny airbubbles get trapped, it helps (worked on some of the resins I used so far , NOT ALL, so check a small ammount first) is you microwave the stuff for a couple of seconds, really just a couple, 5 -10 seconds max, it just thins out the resin enough to make the air travel out faster to the top, thus giving you a clear casted lure, etc etc.
I also found that with plastisol (and it's specialised plastisol paint) it is best to reverse spray the desing and colouring into the mold prior to casting, this however is a little tricky as you need to spray the whole thing in reverse with the top colour first and the base colours last, yaeh is sounds like madness, but time and some serious practise will put the pudding on the table so to speak.
One last thing, I too could never get hold of silicone thinners, and had to do it in another way. takes a whole lot longer but it worked for me, instead of mixing 10% catalyst try mixing 9%, that way the silicone takes longer to cure but that allows for longer time for the air to escape from the silicone.
Oh and make yourself some L shaped sidewalls from say 8-10mm thick perspex, then place them in a box shape (the size of your intended mold) with their ends towards the outside and just clamp them down with some clamps it's gr8 cause they are completely free with respect to sizes that you wanna make, also the silicone doesn't stick to that as much as with other materials. Will see if I can post a pic of the setup I've used.
Size of the sprue is normally determined by the product you are using, like for instance with the 170 degree plastisol I use, it needs to have an even cylindircal resevoir (sprue) that is big enough to draw some (still molten) plastisol into the cavity as it cools down.
With resins and the likes it's not all that important to have the absolute correct size sprue but having a small resevoir will allow for any trapped air to slowly rise into that ammount of material so as to replace itself with some material in the sprue.
Now location location location. What I've found is that when dealing with molds of any kind and materials of any kind going into that mold, the sprue's location works best,if it is located on the top part of the mold when the material gets injected or poured into it.
Having said that, it doesn't mean that the sprue entrance to the cavity should be on the top of the lure, it can be anywhere on teh lure given that the area will be at the highest point of the lure and that it will be easily accessible when having to clean of the sprue and marks it will leave when removing it.
One more thing I found, is that with some resins, when you've mixed it too roughly and millions of tiny airbubbles get trapped, it helps (worked on some of the resins I used so far , NOT ALL, so check a small ammount first) is you microwave the stuff for a couple of seconds, really just a couple, 5 -10 seconds max, it just thins out the resin enough to make the air travel out faster to the top, thus giving you a clear casted lure, etc etc.
I also found that with plastisol (and it's specialised plastisol paint) it is best to reverse spray the desing and colouring into the mold prior to casting, this however is a little tricky as you need to spray the whole thing in reverse with the top colour first and the base colours last, yaeh is sounds like madness, but time and some serious practise will put the pudding on the table so to speak.
One last thing, I too could never get hold of silicone thinners, and had to do it in another way. takes a whole lot longer but it worked for me, instead of mixing 10% catalyst try mixing 9%, that way the silicone takes longer to cure but that allows for longer time for the air to escape from the silicone.
Oh and make yourself some L shaped sidewalls from say 8-10mm thick perspex, then place them in a box shape (the size of your intended mold) with their ends towards the outside and just clamp them down with some clamps it's gr8 cause they are completely free with respect to sizes that you wanna make, also the silicone doesn't stick to that as much as with other materials. Will see if I can post a pic of the setup I've used.
benniejordaan
Sealiner
Good info LGF,
I like the idea of a perspex box! Got to make me one of them!!
I like the idea of a perspex box! Got to make me one of them!!
Little Green Fish
Sealiner
No probs guys, lemme just get free from the wife and then I'll quickly go take them pics, almost forgot about it...
Little Green Fish
Sealiner
Kay so here's the pics as promised
First is the shapes of the perspex and the way I fastened them to get the 90' angles, couple of screws and some PVC adhesive, just drill the holes prior to screwing the screws in otherwise the perspex will crack as there's not enough meat to absorb the expansion of the raw screw being tightened into the perspex
First is the shapes of the perspex and the way I fastened them to get the 90' angles, couple of screws and some PVC adhesive, just drill the holes prior to screwing the screws in otherwise the perspex will crack as there's not enough meat to absorb the expansion of the raw screw being tightened into the perspex
Little Green Fish
Sealiner
kay so all of a sudden I for the life of me cannot get the pics to load, help please? I'll even mail them to somebody if they're albe to get pics to load!
benniejordaan
Sealiner
Little Green Fish wrote:
Select all the pics by holding "ctrl"
Right click and select "send to email"
It will ask if you want to reduce the pics. Select small
It will attach them in an email.
Simply select those pics and drag them onto your desktop
Upload those images.
They are probably too large. Easiest...
Select all the pics by holding "ctrl"
Right click and select "send to email"
It will ask if you want to reduce the pics. Select small
It will attach them in an email.
Simply select those pics and drag them onto your desktop
Upload those images.
benniejordaan
Sealiner
or you can email them to me.
Little Green Fish
Sealiner
will do the latter quickly will, try and paste them in order of appearance, the last two will indicate the freedom of size of the mold and the midd;e one with the one clamp one will be indicative of the way the four peices fit together to make the box.
benniejordaan
Sealiner
While LGF tangles with his PC... hehe
Here is a pic of one of my moulds. A little more complicated than the average. This will hopefully guide you though.
1 - Make sure you have somewhere for air to rise straight up and out. If air can get trapped anywhere, you need to make vents.
2 - Ensure the wall thickness is min 15mm all rounds. I usually make it at least 20mm especially with MM30
3 - Keys. Remember keys, the more the better. Don't make them big, rather lots of them.
4 - I always cut my sprews in with a utility knife after. Upto you though.
Here is a pic of one of my moulds. A little more complicated than the average. This will hopefully guide you though.
1 - Make sure you have somewhere for air to rise straight up and out. If air can get trapped anywhere, you need to make vents.
2 - Ensure the wall thickness is min 15mm all rounds. I usually make it at least 20mm especially with MM30
3 - Keys. Remember keys, the more the better. Don't make them big, rather lots of them.
4 - I always cut my sprews in with a utility knife after. Upto you though.
Attachments
Little Green Fish
Sealiner
Still uploading in te email thing in te background, and thoiought about getting the first halve done, and thought I should've taken a pic of the base where the blank will rest in the play dough and the keys are drilled into that, this os wher I also insert the sprue, but like Bennie mentioned he does it later.
Perhaps Bennie already has pics of the base with the blank resting in it, otherwise I'll take a pic of that too.
Perhaps Bennie already has pics of the base with the blank resting in it, otherwise I'll take a pic of that too.
Little Green Fish
Sealiner
e-mail sent Bennie. Thanx 4 assisting.
Little Green Fish
Sealiner
Little Green Fish wrote:
Oh my, please forgive the "TYPo's" lying in bed with the screen's luminescens (spelling ?) as the only source of light on the keyboard and I'm old and can't find my glasses, whahahahahaha
Oh my, please forgive the "TYPo's" lying in bed with the screen's luminescens (spelling ?) as the only source of light on the keyboard and I'm old and can't find my glasses, whahahahahaha
benniejordaan
Sealiner
As soon as it arrives I'll post it up! No problems!
