Making a silicone mold for casting Slingshots

[@TheJohnny3d]

Sorry to mention, very good tutorials and no a fence on the music

[@Flederratte]

No problem! I appreciate you writing a comment to my video ;) Have a nice day

[@mayamachine]

Nice mold work, but where's the fill spout? What about bleed spurs? Do you need a vacuum chamber to remove bubbles?

[@Flederratte]

Thanks. I cut the fill spout with a knife after the silicone has hardened. In the video description you can find a link to the second part and the casting process. Bleed spurs (do you mean vents?) are not necessary when casting resin and having the spout attached to the highest point of the mold. A vacuum chamber is beneficial to remove bubbles from the mixed resin before casting. However bubbles can also be avoided by mixing the resin quite slowly and using a slow setting resin. I had some trouble with airbubbles being attached to the silicone walls and getting trapped as the resin was rising. I recommend having a very smooth mold surface or maybe wetting the inside of the mold by applying a thin layer of resin with a brush before filling it up. This project was an experiment and the mold making and pouring certainly work and I learned my lessons but I never did a follow up on how to improve. However it was a failure for making slingshots. Resin slingshots made this way are just not practical. If you want to know my opinions on that also feel free to ask.

[@pazuzu314]

great vidio !!! I have a question.What's the contraction rate of the silicon mold?

[@Flederratte]

Thank you. The silicone transforms from a liquid substance to a rubber-like solid shape. I do not think it contracts around the wooden object at all. Did this answer your question?

[@pazuzu314]

@@Flederratte thank you for answering that. Thank you so much

[@Flederratte]

@@pazuzu314 No problem. If you have a question ask me. I am happy to help.

[@jujucattys156]

hanks for a great video. What material do you use for the mould and can i use any epoxy resin

[@Flederratte]

The material is silicone rubber. There is a link in the description. However every castable silicone rubber will work. Yes you could use any casting resin. However you have to be very careful with slingshots cast out of resin. They are very brittle and if the fork breaks ist comes towards the face of the shooter. Always wear eye protection and inspect the slingshot before you shoot.

[@adhamelsharkawy4601]

Could I put hdpe in the mold

[@Flederratte]

No. You can not cast HDPE like this. It needs high pressure to be liquid. It is too viscous under normal pressure. However you can use resins and fabric or fiber glass.

[@daniellandberg3264]

Where did you purchase the silicone? Do you think it would hold up to molten aluminum?

[@Flederratte]

I got it from trollfactory.de the link is in the video description. It is definitively not possible to cast molten aluminium (660 °C) directly into a silicon mold! However you could use the silicone to help you with modelling some parts and cast them in resin. You could then use the resin together with green sand to make your mold for aluminium.

[@Mangeis6390]

what ingredients to make slingshots?

[@Flederratte]

To make a basic slingshot you do not need much. Two equal bands of good rubber connected by a piece of leather or strong cloth (tied with constrictor knot) are all you need for some simple Slingshot bands. Then you only need a "Y"-shaped branch or any other suited frame to tie the bands on and use it as a Slingshot.

[@funnyvedios6056]

Hi nice video Can i use this 950c

[@Flederratte]

Thank you. What exactly do you mean? Is your question if you can use the silicone to make a mold which can withstand 950°C of temperature? The silicone holds up to temperatures of about 400°C, it is possible to use it with molten tin and molten lead. Molten zink might also work, however I did not get good results. For casting silver at around 950°C you could use the lost-wax-process with an mold made from investment. Also some types of plaster, sand or ceramic molds will work.

[@deddided3109]

Hallo Flederratte. Ich hab mal eine Frage. Gibt es eine Alternative zur Vaseline als Trennmittel? Auf jeden Fall eine gute Idee, ich möchte mir die Uniphoxx Enzo duplizieren 👍

[@Flederratte]

Bestimmt gibt es zu Vaseline alternativen. Für mich hat sich Vaseline allerdings am besten bewährt. Ich habe keine Erfahrung mit anderen Trennmitteln. Was du damit vor hast bleibt auch dir überlassen.

[@sportingchancesafaris5596]

Thanks for a great video. What material do you use for the actual slingshot / material you pour into the mould ?

[@Flederratte]

Thank you for watching :) I could use many materials to pour into the mold made from this silicone. For example gypsum plaster, wax, other silicone, or even molten metals like lead or tin (the silicone can withstand a temperature of 450°C for a short time). However resins are the only material which make a useful Slinghot when they are poured into the mold. That is why I already cast a Slingshot from clear epoxy resin. The video of casting and demolding will be published on saturday evening. Maybe I will also make a wax casting which I can then use to make a mold for casting aluminium or brass. As I do not have much time at the moment this will be a project for the future.

[@nixland]

By the way from where does you pour the casting resin?

[@Flederratte]

Do you mean where you can find the video how I make the actual resin casting? It is here: kzbin.info/www/bejne/apOZoYSXd9GeorM

[@adsertheblade]

how did you stop the slingshot from sticking to the bottom for the first half of the mould? if weighted, i would assume it does not float in the silicone? thanks

[@Flederratte]

Hey thanks for watching and commenting the video. The silicone does not like to stick to anything other except already hardenend silicone. This makes it very easy. My Slingshot is actually coated in boat varnish It has a smooth surface, there are no cavitys for the silicone to fill and it also does not stick to the surfacematerial. It actually does not even stick to wood or concrete. I was worried, that the Slingshot might float in the bottom layer. That is why I put the lead weights on top of it. Maybe it was unneccessary and only made pouring more complicated, but in the end it still worked. However I probably should have poured the silicone into the moldbox first and then press the Slingshot into the liquid and put the weights on top after that. This way it would have been better because there would not be trapped airbubbles between the Slingshot and the bottom part of the mold.

[@adsertheblade]

thanks for the reply. I was asking about the first pour, when the slingshot is put at the bottom of the box. if weighted, i would think that it lies flat on the bottom of the box, and the silicone cannot get underneath it. And if ti is left to float, then it does not leave an imprint in the silicone. did you weigh it so it half floats?

[@Flederratte]

Ah now I understand what you mean :D This is not the bottom of the moldbox this is actually a layer (ca. 5mm to 7mm thick) of already cured silicone which I put in a few hours before. Look at the colour. the moldbox is from grey cardboard but in the bottom there is the red silicone. I used the fact, that liquid silicone really likes to stick to already cured silicone as long as it is clean. By doing it this way I did not have to put my model into clay half the way (which would be another method for making two-part molds) I want to do better videos in the future. I do not have much time at the moment and this video really is a very lazy one without explanation and without great filming and editing.

[@adsertheblade]

Ah, of course, I did notice the extra colour, but due to the cut footage, I couldn't work it out. That's very clever and eliminates a problem that was stomping me, and forcing me to try all sorts of other things that were never as perfect as I wanted them. I suppose that if the very bottom layer of silicone is very slightly tacky, it might help ensure a bond with the next layer, although you seem to have found it sticks anyway... Thanks for sharing

[@Flederratte]

Yes that is true. I did not want to wait for the perfect moment when the bottom layer had the perfect hardness. I should have poured the liquid second layer on top and then press my model and the test tubes into the liquid second layer. Next time I might do that.

[@cintaremaja9962]

perbandingan silicon rubber dan katalisnya berapa

[@Flederratte]

I am sorry, I can not understand your language. Using an online translator I assume you want to know the ratio of silicone to the ratio of catalyst. I used a silicone which is very easy to use. It has two parts and is mixed in a ratio of 1:1 by weight. If you got a different silicone use it as is advised by the manufacturer.

[@bangiwanchannel2234]

👍

[@daniellandberg3264]

I build motorized bicycles and would like to cast some plastic parts in aluminum.

[@Flederratte]

Your best option would be a mold from green sand. This is what I would recommend you. Make wood or resin models. You could also try lost foam or lost wax for more complicated parts. I once tried to use plaster as mold, it does not work very well. In combination with sand it can be used for crude castings but not for good quality.

[@macamanix]

Never have that music again .. the video is great, but the audio is driving me crazy

[@Flederratte]

Ok. I am sorry for that. I created that video back in 2017 when I did not know much about music. Thanks for your comment and for the feedback. I might try to change it some time if it is still possible once uploaded on KZbin.

[@leecoomber3877]

Didn't show you making a slingshot though .🤔 .

[@Flederratte]

Yes I know. I never had time to finish the project. Some time I will probably finish it and upload a video.

[@virtualrealityjeffy1921]

Sorry it is mold

[@Flederratte]

thank you :) I did not know that, thanks for telling me

[@virtualrealityjeffy1921]

Flederratte sorry I just said you spelled mold wrong

[@virtualrealityjeffy1921]

Flederratte good you changed it

[@Flederratte]

yes thanks for that. I corrected it ;)

[@virtualrealityjeffy1921]

Np

[@TheJohnny3d]

Terrible loud music

[@Flederratte]

I am sorry for that! I cannot satisfy everyone who is watching. For you I would recomment to disable the audio of the video and instead listen to some music you like. Anyways thanks for the feedback.