DIY POURABLE SILICONE for mold making. Thin silicone w/Naphtha, fast cure w/cornstarch. 

Whenever I use a ziplock freezer bag for something like this, or for my Amish friendship bread starter in the freezer, I lay the 'empty' bag on a small breadboard, with the cut opening hanging just off the edge, and use something like a credit card to squeegee every drop in the entire bag up to the opening, without getting the card dirty at all. I keep an old empty gift card on the inside of one of my kitchen cupboard cabinet doors.

I would like to thank NightHawkLight for recommending my video. Beyond validation of my content, I really love his videos as well. Cheers everyone, and enjoy.

Acetoxy silicone is the preferred type of silicone to use with naphtha, it's the regular one that normally smells of vinegar as it cures. It should be stated on the label which type it is and it's very cheap compared to RTV 2 part cures. One tip is to use a tubular bag for mixing so that you can more easily squeeze it out. You can also buy reusable caulking guns and place the bag with the corner cut inside it towards the nozzle end. Obviously if you go that way you need to ensure the other end is securely tied with cord or have the end draped over the side while allowing the plunger to freely squeeze down unhindered. Good luck and thanks for the demo. Professional mould maker from the UK . Yes that's how we spell it :)

Just wanted to say thanks , I've used silicone /cornstarch to make molds but always had a mess until I saw your bag method , luv it , Thanks again and can't wait to try a thinned mix on my next project

I’ve submerged fully cured silicone molds in mineral spirits for a day or 2 and they become substantially larger. It’s really cool. I’ve never tried this and can’t wait to. Thanks!

Try rolling the silicone in the bag to the bottom with a rolling pin and clamping off the empty part of the bag before you pipe it out.

Thank you so much. I just made a mold for a pice of tiled furnace we're rebuilding and it was missing a corner piece. I had to thin it quite a bit with naphta to make it almost the consistency of paint to make it pourable. I just hope it cures.

I also have just found your channel within the last hour, I have subscribed, very interesting, many thanks.

U wont belive but ur video gave me idea.i belive i can fix silicone for mould as u did in tnat ziplovk and thrn i can put that silicone on my object i want to mould.thank u so much.u have no idea how long im breaking my head and how much material i trown away.ty

WHAT!! Most solvent can be absorbed through the skin. Whish I'd known this much earlier. Thanks.

Great video I think if you live in Australia you need to buy shelllite. I believe it the same as Naphtha. Cheers Graham

I so needed this tutorial...THANKS

...loving the bag mixing idea! tyfs this with us honey!

Nice! I've tried this without any solvent (and using a tiny dab of acrylic or oil paint to colour the silicone) and it works well, giving a thick paste that cures in anything from half an hour to an hour, depening on the amount of cornflour. I've also tried it using white spirit (here in the UK, I'm not sure we can actually buy naphtha - if anyone knows differently, please let me know!) and cornflour, and apart from the smell - which takes a while to dissipate - it seems to work fine, except the molds are prone to considerable shrinkage as it evaporates. Does the same thing happen with naphtha?

I’m here because NightHawkInLight sent me. I have no regrets.

Is it rigid or flexible. I need flex to easily demold wax. I'm going to add mineral oil and see if that works.

Does adding cornstarch or naphta result in weaker (or otherwise different end result) silicone? Thanks.

I'm glad I'm not the only person who gets pi$$ed at that stupidly short auto-off "feature" of these scales lol

I am learning how to make molds for soaps. So if I make this pourable, pour over say an acrylic mermaid, should I use a release agent? Also, do I just play around with the thinning and cornstarch to make a mold that is flexible, but hard enough to pour soap into. (It’s just melt and pour soap) I love that you are sharing with the world how to do this. I imagine the $40 2 part I buy has some agent that slows it down as I have an hr to use it. The rtv kit makes it easy to pour from the side to eliminate bubbles. I’m hoping if I’m making them for myself I can make many to use instead of paying $25+ for a mold. I want to pour my molds over like a 3-4” tall and maybe wide object. Is it possible to make this pourable amount over a 3” x 4” object and wait and then demold? Will it dry ok that big? I have watched the videos. Would love to see you make a mold that big for us to see the pliable results. Guess I’ll just go buy the stuff at Home Depot and try. Guess I was hoping you would do a video for us millions of soap makers who buy bigger molds;) I’m spreading your videos around the fb groups! Thanks a million!

Question...can the mixture be applied with a brush to make a mold in layers? Thank you...

Chemistry 101.

I've used the mixed "white spirit" stuff to thin out as a trial and tried a few thinnesses. I found that when it's thin enough it seems to set as quite matte. I'm still playing around and I think your mixing method looks like a brilliant technique. I do have a question though (if ya see comments on this video, especially since it's from a few years ago now): When thinning with naphtha, does the silicone lose the gloss effect if it's too thin?

Your dad was right. Bad things happen when I try to hurry.

Hello, What is the naphtha stuff in uk called, I can't find it. 🤔

10:52 looks like turdle :)

Can you make this as thin as maple syrup? I need to make about 4 to 5 cups worth of this for a mold and im not sure how to do it for a large amount? Thanks

Question 🙋‍♂️ if I use clear silicone will the cornstarch cause the silicone to lose transparency?

What’s another alternative for naptha? I live in California and they don’t sell that here. Can I use acetone instead?

Can this method be used on 3d printed PLA filament parts without messing up the original?

Turtle ?? Am I the only one that saw a pile of Fake Dog Shit with proper coloring ?? 💩🤣

Put the lid back on that can

THANKS Very imformative. Lets all try to chill out in this crazy time, or as your Dad said - The hurrieder I am, the behinder I get. ha ha. Lets go slowerer. There was a woman who gave a lecture in the 1920s - 30s, about spiritual matters and she maintaint that the world was supported on the back of a Turtle (perhaps a bit like Atlas) and a man in the audience said - but what is supporting the Turtle ? She said you are very clever young man, but don't you know its turtles all the way down. Your friend Anka might agree about Turtles - they are so beautiful - one of my favourite sea creatures. Anyway, meanwhile back at the ranch Thanks for video

Does the silicone shrink overtime?

So i mixed the naptha with the silicone ( was unaware of the adding cornstarch) and it has sat overnight and is still not cured. So will it take longer or is it just a flop and i need to start over?

5 parts yellow Polyurethane Gorilla Glue mixed with 1 part Type 1 Yellow Wood glue makes a nice low pressure expanding foam that sets up in about 15 minutes and gets very hard overnight. Parts by volume and weight seem similar. Changing the ratio too much yields poor results. Type II Yellow Wood glue works but not as well, less foam, longer cure time.

I'm here because NightHawkInLight s newest video today 1/31/2022 3:19pm est. (I have a reason for date and time reference) As some one who likes to play with silicone, and casting, machining and chemistry, within seconds of eating this video I have subscribed and decided to comment in appreciation. Thank you kind new channel

Your recipe worked out perfectly for me, making a mold for plastic lures. The cost savings is dramatic compared to buying products made just for this. I did vary the recipe slightly. One tube of clear silicone, One cup of Naptha, and 35 grams of corn starch. I mixed the silicone and naptha first. Then added the cornstarch. Once in the mold I gently punched down the silicone to assure total contact to lures (finger dipped in water and Dawn). No bubbles. On my first experiment I mixed everything in a bowl and unfortunately made many bubbles. The bag worked perfectly. Thank you very much for this video!

I'm also here because of NightHawkInLight's video. Can't wait to try some of these with my kids. Thank you for your time and inspiration.

Dude! This is exactly what I was looking for! You earned a sub! I'm using mineral spirits but as you have said, it all works the same.

Thank you so much for your time and easy understandable, informative and proven findings. You sir are a Gem. I appreciate your Credo as well..Well done :) .

Not a fail. You just found out how to make silicone never harden. Now we just need to find a use for it

Why wouldn't you add the naptha first and the cornstarch last? Would give you more working time... no?

K. Findley is spot on. I tried the mineral spirits method of mixing. Disaster! Over a week and still not hardened. Going with naptha now. Thanks!

Yes nighthawkinlight suggested a very good channel. I have subscribed. great content 👁️👍

This is a part solution: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-XF3lmJ7OVE8.html I have a 3D printer and CAD skills. I am going to make an injector which mixes a cornflour+white spirit slurry directly into acetal silicone via a spiral mixing nozzle.

It's great to see someone take a well thought out practical approach to solving problems. As an extensive user of all types of silicone myself, I would be lost without naphta. Whereas cornstarch has the edge in many applications, I mainly use fine talc that ensures exceptionally smooth consistency.

You are a genius, unique practical wisdom. Thank you for sharing

Does the form shrink as it cures? (I would think it does, as the added naphta evaporates)

The mold shrinks when it cures. I noticed after a few days, the size of my mold had shrunk. I don't know if there is already a comment somewhere on this, but definitely an important note if the actual size is needed. But other than that, I used camping gas, and a little of corn starch with my 100% silicone and it worked just fine. I appreciate your helpfulness. I hope my comment was also helpful. Thanks.

Just a note from other videos: The label should state 'Silicone 1'... 'Silicone 2' will not fully cure.

Can you tell me if that mixture sets hard and inflexible or soft and pliable? I'm hoping to make silicone molds for soap making and don't want to have to buy the 2 part mix that they use if I can help it.

I've tried doing this before and it was an awful mess but am inspired to try again with your method. That said, I'd like to see you do a practical demonstration and then perhaps something cast from your mold. Appreciate your sharing your knowledge.

Thank you for this tutorial! I am an artist and was looking for a way to make pourable silicone, for mold making, rather than buying those expensive 2 part kits. So this has been a great video for me! But I do have a question, does the 10:1 ratio for the silicone and corn starch work in smaller quantities as well? Like say if I wanted to make a mold the size of a quarter, and an inch thick, but I don’t want to make a large batch of pourable silicone, can I still use the 10:1 ratio for that small of a batch? Or would my measurements need to be tweaked? And for the naphtha/mineral spirits etc, is it not measured? But instead based on how thick you want the mold to be? Because I’d like to make a consistency somewhat like pancake batter, would that much naphtha effect the drying time? I guess I have some experimenting to do! Haha

Could you imagine using this method to get a liquid pour? Could you imagine this working with a vacuum chamber to degas without the solvent eating at any plastic parts? I know solvents are tricky to handle, but casting silicone makes some larger projects prohibitively expensive. I am interested in using the resulting product to pour molds in silicone. I will likely try this and report back, unless you have the answers already. Thanks again for your amazing work!

Thanks . Very informative. Very practical.

This is actually really great!!! Thanks💪🏼💪🏼💪🏼

I am so glad to have come across your video. I was wondering what to replace the naphtha because in France we can not find it . Thanks for your answer You are a good teacher like Gyro Gearloose

Thanks for the informational video! I found you through NightHawkInLight. I want to use this to make a silicone mat to go around/under the burners on my stove to facilitate easier cleanup. I'm a messy cook.

The Bob Ross of silicone! So, what exactly was this made for? Is it just for custom molds? It seems like a lot of work for any large project.

I started of looking for cold porcelain recipes, ended coming across your channel, and I've actually learned so much already, absolutely amazing thank you 😊 👌🏼💕🇬🇧

Hello thanks but what is naphtha? Sorry to ask but I'm not sure where to find this in South Africa

I followed this video and tried the process, unfortunately some of the silicon did not set, it stayed all mushy. Any ideas why this happened and solutions to prevent it. I used 100% silicon and mineral spirits ( naptha is more expensive around here), thanks

when i google naphtha, it comes up with petroleum for like on the bbq, lighting fluid basicly. is that right? also 1/2 cup is 125ml correct? thanks in advance

Thank you for posting this. Would this work with a plasticine object, or will the naphtha melt it?

good work .. but how can i obtain liquid silicon that i can pour into a mold and let it harden overnight .. using the same silicon like in this video ..and which is better transparent or white silicon ?? ... thanks

How stiff is the silicon in the end? Don’t suppose you are familiar with durometer?

Thano you fornthe recipie! Used it for molds for jewelry. I appreciate content that is responsible and trustworthuy.

and if you want to add color to this mixture what measurements should you put in?

Thanks very much, what could you use to prevent the mold from.sticking to a porous surface, i.e. I was making a mold of a paver? Cooking oil? Thanks in advance

Why don't You measure the fluids in ml? The rest of the developed World do...

If mineral spirits is used to remove silicone from objects... won't it deteriorate the silicone when used in making it pourable?

Hi bit of an emergency I need to make silicone molds for a class project but I can't find mineral turpintine anywhere Will normal turpintine do the same job?

I really appreciate your video. This appears to be a quick cheap silicone mold solution. However, Naptha is basically lighter fluid, so it shouldn't really be done inside the house as the gases are dangerous and quite flammable. I wonder just how long the molds will out gas fumes?

I wonder if you used high temp silicone if you could use it pour aluminum into for a mold.

FYI, Anka said "TURDdle". Also, good video!

I have used naphtha before and using enough of it to make it pourable also caused the mold to shrink. I will try your recipe and add a little more naphtha I want it just fluid enough to be a good mold, but not enough to cause it to shrink. Perhaps just buying the pricey 2 part silicone is the way to go.

Can i use one comp aciatic based sealant silicon for Casting after adding with solvent like Mineral spirit?

If you substitute mineral spirits for Naphtha, is the amount the same?

NightHawk referred me, thanks for the useful info.

Do you have an email address I can send a question to? Too wordy of a question for this platform. Regarding making a silicone mold for a vehicle interior plastic console.

liked the video up untill that end speech felt a bit hash but its your channel

In a previous video, you said that as soon we add cornstarch the quality for fine detail diminishes so maybe one should add only very little cornstarch?

Ive made this in the past. I guestimate amounts, mix it in plastic chinese container with wooden popsical. Much quicker than your messy bag. Yours isnt a pour its too thick

Did anyone notice that he's using a dry measure to measure liquid naphtha? Liquid and dry measures give different results.

How much does this shrink from the mould after curing

would acetone work instead of naphtha?

Thanks.

Hey! Excellent video, just one question... if i wanted to make it of any color, what type of paint should i use? Acrylic, oil based, another one?

Is it type 1 or type 2 silicone that you're using

I wish there were more RU-vid'ers like you, who cared about the accuracy and integrity of their channel's content, (including comments). New Sub here. Sent by NightHawk

i agree lol 2:40

Really useful shortcut. Never considered a solvent , silicone and binder combi.

I appreciate you giving us measured recipes. Drives me crazy to see someone pour "about that much..." All of the two part expensive silicones I've used shrank about 10 percent. If I thinned your version enough to paint on would your naptha/silicone still shrink? I'm trying to paint onto petroglyphs, make a plaster support layer and pour an epoxy positive. If the silicone were to shrink 10 percent over time it would not be helpful since any measurements would not be accurate. Is there a way to make it dimensionally stable? Mix in a fiber glass filler agent like is used in fiber filled plastics? Thanks!

You didn't make a mold of anything! How do we know it works without any fissures when a mold is turned out?

Is this the thinner material?

Very interesting. Do you know if another solvent would work? Where I live you can't easily get bottles of naphthalene. Would acetone work, do you think?

thanks for sharing this

I’m gonna try to mold a stupidly expensive intake manifold for a v8 with this. No reason a lower intake is $1000. If it works I can use the negative molds to make positive molds and use them to make sand cores to cast aluminum with. Thanks.

I'm here via NightHawkinLight too. I loved his video on waterproofing bed-sheets and had to see where he got his inspiration from. Didn't hurt that I'm interested in starting to make some of my own silicon molds. Great video. Thank you for sharing!

Excellent video! Thank you for sharing this with all of us. I also found this video because of NightHawkInLight.