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

[@ShawnT-h6j]

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.

[@GEOsustainable]

Excellent idea. Thanks for sharing. I am going to use your trick from now on.

[@GEOsustainable]

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.

[@xarin42]

I'm here from him, and I'm glad he sent me your way :)

[@Mitchell_is_smart._You2bs_dumb]

That's where I came from as well. I've tried so many variations of so many recipes from KZbin, all with various degrees of failure. I have never seen this video or recipe, but I trust NightHawk. I just happened to be stripping the paint off a table today and am wondering about the solvents I'm using. I'll post my results here along with the recipes I use, but I have a feeling that this is the best way to achieve desired results. Thank you GEO sustainable.

[@marty01957]

NightHawkInLight sent me also! Great video, clear and concise, Thanks for this!

[@willsmith1689]

I also came from him and completely agree with everyone else, I'm glad i came to your channel. I loved what you said at the beginning of this video about the information you're trying to put out there. It is indeed, uncommon and therefore, quite valuable. I doubt I'll win a Nobel peace prize with this new information but it is something I didn't know a min ago. I got to learn something new, that just might come in handy one day. So, thank you for that, it was quite interesting to watch. Take care, sir 😊.

[@russellspeer3989]

...here because of him too. Have used corn starch with silicone before to make specialty seals/gaskets/repairs at sea when we didn't have what we needed onboard to do so. I used a safety solvent we had, not VM&P Naptha like you. Although my concoction worked, it looks like yours is better... Thanks for the suggested ratios too, I'll try your formula next time.

[@ps7462]

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!

[@GEOsustainable]

Great to hear. I am so glad the formula worked so well for you. Thank you for taking time to tell us all how you did it.

[@ps7462]

On a second experiment I used 1/2 tube silicone, 1C naptha and 25 grams cornstarch. I glued the lures to glass, built the mold with legos and used thinned vaseline for release. The pour was runny as expected. After an hour, looking through the glass everything looked good and I easily removed the legos. I let it set one day. Once released from the glass the silicone block curled too much. The silicone did not appear to cure well next to the lures.

[@ps7462]

Just a continuing FYI. Made a two piece mold. I put in the first mold, two nuts and a small clay rod for registration. Used vaseline for easy release. Before pouring the second part I brushed on vaseline for easy release. Now I have them clamped together for continued curing and so they don’t curl. I have found that if you let the mold sit without some sort of weight on it it will curl. My molds are about 1 inch thick, each mold.

[@GEOsustainable]

@@ps7462 excellent to hear.

[@reecehudson5913]

P S you had success pouring a runny liquid silicone?

[@jupiterjunk]

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.

[@GEOsustainable]

Awesome! Thank you! I has been my pleasure. And I truly thank NightHawkLight, I love his videos too.

[@lagunafishing]

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 :)

[@GEOsustainable]

First, thank you for clearing that up. I sometimes forget to spell mould properly, bad American habit I am afraid. I really enjoyed reading your comment. Thank you for your professional information. I especially love your tip with the reusable caulking gun and tubular bag. Great tips! I am so glad you like my video.

[@suicidebylifestyle9267]

I've always just heard that referred to as "Pure silicone" or at least every tube I've evre bought smells strongly of white vinegar.

[@jkbughunt]

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

[@GEOsustainable]

Thank you John. I am glad I was able to share my idea with you.

[@tek4]

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

[@tek4]

12:15 thank you so much, you have no idea how important that is. The community of diy ers im in calls this bro science. Because its not scientific or the evidence is completely based off of there bro that told them, rather then any scientific quest or research. I'm very excited to see some of my ideas put to the test and I've tried the cornstarch silicone mold before. It worked but I used the wrong ratio and didn't use a solvent. The ideas I have now, and evidence that you put forth have guided me to trying a new approach and I will update on my channel the findings when I am able to run this experiment. Thank you again.

[@GEOsustainable]

I am glad my ratios helped you. Always glad to hear from fellow KZbinrs.

[@GEOsustainable]

Thank you for your kind words. I am always happy to hear from fellow KZbinrs.

[@Knate1104]

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!

[@GEOsustainable]

Interesting! That is an incredible find. Thanks for sharing. Do they stay enlarged?

[@georgewallace2002]

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!

[@GEOsustainable]

Glad to help. The corn starch is what hardens the silicone, keep in mind. Cheers.

[@Declan-pg8cg]

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.

[@GEOsustainable]

Thanks for sharing your knowledge. I have to try that.

[@jamesdonnelly8888]

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

[@GEOsustainable]

My pleasure! Glad it was helpful. Stay tuned as I am giving another secret away soon. Styrofoam made from milk.

[@cavision]

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 :) .

[@GEOsustainable]

I am happy you found my video helpful. I am inspired when a viewer let's me know I have been helpful. Don't forget to subscribe, as I will be making many on the subject of mold making with silicone, as well as other materials.

[@TheStonehammerFiles]

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.

[@GEOsustainable]

Glad to help. And thanks!

[@DCBpower]

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.

[@GEOsustainable]

That is a very cool trick. Thanks.

[@suicidebylifestyle9267]

I assume this formula is weight based not volume? yes?

[@thehighwayman78]

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.

[@GEOsustainable]

To ensure proper cure, don't forget the cornstarch in the ratio I give. Good luck! Thank you for your comment.

[@whatanitemare]

Could you let us know if this worked out for you? Did it cure? Any problems?

[@thehighwayman78]

@@whatanitemare Its been a while now so lets see if i remember what I did - it failed for me. I think I didnt have the correct corn starch ratio. It also stuck to my tile. so I ended up 3D printing a splittable mold instead.

[@whatanitemare]

@@thehighwayman78 Thanks for taking the time to update! I very much appreciate your sharing.

[@GypsieT17]

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 😊 👌🏼💕🇬🇧

[@GEOsustainable]

It is my pleasure. I am thrilled you like my content. Greetings from Maryland. 🇺🇸👋

[@CovertRadio]

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

[@GEOsustainable]

Thank you.I am so glad you like. I too am a huge fan of NightHawkLight.

[@TheGrungy1]

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

[@GEOsustainable]

@TheGrungy1 Ever seen mud wrestling? :)

[@TheGrungy1]

@@GEOsustainable not in person. Lol but i think that might work

[@michellemwina6051]

how about applying it to a model with hands like putty unlike the brush-on or runny pourable type....will it eliminate bubbles? i guess quite well

[@GEOsustainable]

@@michellemwina6051 I love that idea!

[@SynapticTransmission]

Greetings from Canada! Nighthawk at Night sent me here. Excellent information - Thank You!

[@GEOsustainable]

Awesome! Thank you! I have to thank him. Always glad to hear from fellow KZbinrs.

[@namo6504]

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

[@GEOsustainable]

Welcome aboard! I love his stuff too, and am thrilled to be counted among one of the greats on KZbin. I plan on doing much more.

[@jeffgoldenberg9579]

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.

[@GEOsustainable]

Thanks Jeff. One of my molds or one of my products? Jeff, the mess must have been, you have to use corn starch if you pour more than 1/4 thick bead of caulk, or it cannot get air. Could you perhaps shoot me an email of exactly what you would like to see and even discuss your problem you are having getting results? Thanks again.

[@jeffgoldenberg9579]

I think I just got the proportions of everything wrong. And I wish I had known about mixing it in a plastic bag! I think I just want to see you make a mold of an object and then cast it in plaster or resin. FYI I'm a model maker and artist. Thanks for the response and videos!@@GEOsustainable

[@GEOsustainable]

@@jeffgoldenberg9579You got it Jeff. Next video. I will make a mold and cast a something using plaster. It will take about a week to shoot, so hang in there.

[@alisonmary1443]

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

[@GEOsustainable]

Thanks so much!

[@user-kt2mc1cm5h]

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

[@andreubruguerariera8423]

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

[@GEOsustainable]

Correct, the form shrinks the amount of added solvent. The shrinkage can be calculated.

[@andreubruguerariera8423]

@@GEOsustainable ok! In a form, would the shrinkage come from the top, and the silicone would "settle", or does it shrink into a center point, from every surface (interested for mold making)

[@goatmealcookies7421]

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

[@GEOsustainable]

My pleasure. I am glad you find value in my content. I do hope you share your results with us.

[@davenkristenboughton3870]

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.

[@GEOsustainable]

I had covered that is a previous video, and how to calculate to get an exact size needed in a video on clay. Yes, you will lose an equal volume of material to Naptha, and can be fairly avoided if you take care of how much you thin it. Glad you liked and you are most helpful.

[@772777777777777]

This a major draw back with this method

[@dewexdewex]

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.

[@GEOsustainable]

I love it. Yes. I should pin this for others to read.

[@mazenmazen1065]

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

[@GEOsustainable]

In this video, I use silicone caulk from a tube, it is liquid. I teach you how to thin it out. Clear or White depends on you.

[@jamesdonnelly8888]

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!

[@GEOsustainable]

That would be cool! Look here for a way to thin without using a destructive solvent. kzbin.info/www/bejne/eZqVaYxpj5iVj7c

[@kawaiipetal1644]

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

[@GEOsustainable]

True that, you have some experimenting to do. I can offer you a general guide based on your interests. 10:1 works for all quantities, giving a cure time of about one hour, regardless of how much Naphtha/Mineral Spirits you use. Pancake batter is fine, I have thinned it to the consistency of syrup without issue. If you make a lot of molds, this will save you some money, for sure.

[@kawaiipetal1644]

@@GEOsustainable thank you so much for taking the time to reply to me! I’ll take your tip into consideration when I do my experimenting! Thanks again!

[@Freizeitflugsphaere]

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

[@GEOsustainable]

My pleasure.

[@elisabeth934]

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

[@GEOsustainable]

Glad I can help. I always include my email, should you need answers to questions not precisely covered in my videos.

[@elisabeth934]

@@GEOsustainable Thank you for your quick reply, I just sent you an e-mail.

[@GEOsustainable]

@@elisabeth934 checking now

[@danabery7999]

Hello ,I have same question.We do not have Naphta in Denmark

[@RajendraVermaa]

Thanks . Very informative. Very practical.

[@GEOsustainable]

Very glad you found value in this. Thank you for your kind words, Rajendra

[@omsingharjit]

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

[@GEOsustainable]

I'm pretty sure, yes. 100% acetic acid cure silicone. I am doing a new video on silicone, stay tuned.

[@bobrobert9413]

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

[@GEOsustainable]

No, not a chance. High temperature silicone only rates at about 600F. Aluminum melts at 1200F. I get this question a lot, what you need is green sand for metal casting.

[@MarkMichalowski]

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?

[@GEOsustainable]

Awesome info, thank you for guiding our UK friends. Yes, the same thing happens with Naphtha.

[@MarkMichalowski]

@@GEOsustainable Wow! Thanks for the fast response - especially to a comment on such an old video :) Have a subscription for your efforts, young man! Would storing the molds in an airtight container (assuming you wanted to keep them for reuse) help? I guess it would reduce shrinkage a bit - but it's probably a fussy way of keeping your molds long-term, isn't it?

[@ferretface8782]

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

[@GEOsustainable]

This will be flexible, so you are on the right track. A little mold release won't hurt. A note: If the mold is fairly even in volume and dimension, you can dunk it to release the wax. The mineral oil will work to dissolve the surface a bit, you know that though. Cheers

[@enriqueruizalfonzo636]

gracias caballero estuve unos 2 anos buscando acido acetico para poder hacer esto y usted ya me dio la solucion ....muchas gracias

[@GEOsustainable]

Estoy muy contento de haber ayudado. Buena suerte.

[@ralphdeem6635]

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.

[@GEOsustainable]

Silicone remains soft and pliable for 50 years. Saving you money is why I made these videos on silicone. I urge you to watch them, as I have demonstrated a few different methods.

[@mrsdizi1234]

Can you embed a small object using this method as we do with easy mold silicone putty? Thanks for sharing your knowledge.

[@GEOsustainable]

I did that in a previous video. Check here to see how. kzbin.info/www/bejne/hZOcimqpn65nf6M

[@whatanitemare]

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!

[@GEOsustainable]

Welcome aboard! I love his videos as well. I am thrilled to be mentioned. Enjoy. The cool thing about my channel is that I never know what I am going to do. There are a couple of inventions amongst them.

[@ValhallaIronworks]

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?

[@GEOsustainable]

I'm not sure, so I will be trying this. You are the second to ask this, so it deserves a try. Stay tuned, I will try it in my next video on silicone. However, my gut tells me it will work...my gut has been wrong before.

[@Subsessor]

@@GEOsustainable i hereby also register a request. unless someone can tell me in which kind of store and under which brand name you can buy something like naphta in germany...

[@peglegtoo]

Have you ever tried mixing with sand for much harder mold? I am hoping to build a shape to hammer form a brass boat propeller.

[@GEOsustainable]

I have not. It sounds like you know what you are looking for, try it. I do wonder if the sand will mark the brass.

[@peglegtoo]

@@GEOsustainable How hard or springy is the dried mix of silicone and cornstarch? how would it react to being hit by a hammer? is it more like plastic or more rubbery? I realize these are hard questions to answer as all are subjective. Thanks for the reply and the content. I will check out your other videos as well.

[@pollyoz2193]

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

[@GEOsustainable]

You are correct, the Naptha would probably melt it. You may be able to use silicone oil. I did a quick video awhile back. check this out to see if it will work for you. kzbin.info/www/bejne/eZqVaYxpj5iVj7c

[@dennisshoemaker2789]

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

[@GEOsustainable]

My pleasure.

[@eCitizen1]

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?

[@GEOsustainable]

A few hours to a few days is my experience. I have done my best to explain the risk of Naptha.

[@thecargotsold]

So can i just use lighter fluid instead? Which one is cheaper?

[@theflamingone8729]

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

[@GEOsustainable]

I have just the video for you, I coated plaster. Check it out. It is my favorite go to release agent. kzbin.info/www/bejne/amaVqmx8hpyUZq8 PS, watch the whole thing or it won't work properly for you, there is a finishing technique that is critical.

[@theflamingone8729]

@@GEOsustainable nice one, thanks.

[@mjdj1999]

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.

[@GEOsustainable]

Yes, for custom molds. Getting in tight places. Thanks for the compliment.

[@easyfoodchannelsa]

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

[@GEOsustainable]

South Africa is a new challenge for me. I may need to do some research. However, I have discovered another. Watch here: kzbin.info/www/bejne/jZK4k6Sdgt-AiJI

[@Koen75NL]

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

[@GEOsustainable]

The addition of Naphtha softens it a bit, making it more cushioned at about a 50/50 mix; at 1/4, not much. The small amount of cornstarch for a one hour cure does not seem to have any affect,. Neither affect the flexibility. This is answered better in a newer video here: kzbin.info/www/bejne/qXq0nHmMm9l3kLc

[@keera5274]

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

[@haidafella8651]

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

[@GEOsustainable]

Never heard of it, but I get the gist. Silicone acts like rubber, if you have ever felt rubber. So, not very stiff.

[@MermaidAleshaAmor]

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

[@GEOsustainable]

You got it! Add the naptha first because once you add the cornstarch, it begins to set.

[@MermaidAleshaAmor]

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

[@GEOsustainable]

The mineral spirits does not deteriorate the silicone, it completely evaporates over time, leaving the silicone intact and flexible for 50 years.

[@MermaidAleshaAmor]

@@GEOsustainable thank you for that explanation.

[@everything5066]

I loved this video! Question : what are other names for naphtha

[@GEOsustainable]

I have heard it called Mineral Turps and White Gas, and commonly called lighter fluid. I am glad you liked my video.

[@everything5066]

@@GEOsustainable thank you so much for taking the time to answer me ❤

[@user-Ammar1996]

Is this the thinner material?

[@GEOsustainable]

I do believe yes. Thank you for watching.

[@nonkazimlokulati-seth7593]

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

[@GEOsustainable]

Start with a few drops and go from there. Have fun! Thank you for watching.

[@MsJaydot]

I so needed this tutorial...THANKS

[@GEOsustainable]

I am so glad I helped. Thank you.

[@christastarkey5744]

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!

[@GEOsustainable]

Thank you so much for your comments. I have just the video for you I am in the process of uploading it now, once KZbin wakes up, it will be available. I had soap on my mind when making it, actually :)

[@lenny108]

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?

[@GEOsustainable]

That has been my observation, yes. It feels more grained. I use 10 gr of cornstarch to 100 gr of silicone to give a cure time of about one hour. This seems to retain the high detail I want.

[@firstmkb]

Someone else suggested using talcum powder for a very fine finish.

[@joannaritoni9213]

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

[@GEOsustainable]

The cheap stuff. It doesn't have a number. Look on the label for 'acetic acid is evolved in curing'.

[@tematrixmayhem]

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

[@GEOsustainable]

This is true for any solvent. When in doubt, PPE. Glad I helped.

[@shirleymalar304]

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

[@GEOsustainable]

Yes, about the same.

[@mikeb.3373]

would acetone work instead of naphtha?

[@GEOsustainable]

I just uploaded an answer to that question. Well, sort of. It will be live in a couple of hours.

[@whatanitemare]

I had to come back and ask..... Does this quick cure method make the silicon mold less flexible or more brittle than using straight silicon? Also, does the baking soda stop the mold from shrinking over time like it does if you just used the mineral spirits? Thanks in advance for your time.

[@GEOsustainable]

The flexibility is unaffected. The shrinkage is caused by what ever evaporates out...simple physics, you are losing the full volume of what you added. Plan to account for this should your item need to be precise. I get shrinkage of 10 to 25%, some report 40%. I think I say this in a few of the videos in my silicone series, just not this one. Hope you watch like all of them. Cheers

[@whatanitemare]

@@GEOsustainable Thanks for your taking the time to reply. All of this is great information. I didn't think the soda would impact the evaporation but I needed to know for sure since some of what I want to do actually requires that shrinkage. I love that you're doing experiments and sharing their outcomes. Makes for both informative and entertaining videos that I'm looking forward to viewing the rest of. Thanks again!

[@ALBASSEM60]

Thank you so much

[@GEOsustainable]

You're most welcome.

[@dbrown1576]

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.

[@GEOsustainable]

The amount of Naphtha will affect shrinkage. I may have a solution for this in a newer video. Watch here. kzbin.info/www/bejne/eZqVaYxpj5iVj7c

[@dbrown1576]

GEO sustainable thanks Geo. I’ll try it.

[@772777777777777]

How much does this shrink from the mould after curing

[@GEOsustainable]

An amount exactly equal to the amount of Naphtha or any solvent you add to silicone. 25% total volume added equals 25% shrinkage. With this information, you can calculate so that your article cures to the exact size you need. I hope this helps.

[@AS0144]

Wow that is amazing! Do you think it could be used for life casting? Do you also think this could work with turpentine or white spirits? In Portugal some products are hard to find...

[@GEOsustainable]

For life casting, use another formula I have developed here: kzbin.info/www/bejne/eZqVaYxpj5iVj7c

[@melanie-rosannastevens7861]

Do not ever use that kind of silicone to make life casts. Ever! Bathroom tiling silicone is not body safe and neither is naphtha. For cheap life casting use alginate. For reusable life casts, always use platinum cure body-safe silicone specifically designed for life casting

[@mazenmazen1065]

Isn't naphtha a paint thiner ??

[@GEOsustainable]

Yes, exactly.

[@joemoore3385]

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

[@GEOsustainable]

I never tried it. Give it a go and let us know.

[@centaurus777]

Yes, the clear silicone will turn white.

[@billbucktube]

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!

[@GEOsustainable]

Well, I give measurements when needed, but, I also let folks know when 'a bit of this' is all that is needed. Somethings are affected by heat, moisture, product variances..so, a bit of trial and error is needed. When using a solvent to thin silicone, the volume of solvent will cause the silicone to shrink. So, it depends on how much you use. Best to keep accurate notes and plan for the shrinakge. I do love your idea of using fiberglass, it may just be the trick to prevent shrinkage. Please, let us know if it works, we all have to deal with shrinkage. I like your comments so much, I am pinning you to the top for others to gain from you. Thanks for sharing with the GEO community!

[@billbucktube]

@@GEOsustainable Back at ya. Thanks

[@whatanitemare]

Did you ever figure out how to make a dimensionally stable mold? Would you share what your outcome was with the fibreglass filler agent? I'm sure it would be appreciated by many of us to know, no matter what the outcome.

[@billbucktube]

@@whatanitemare There is a finely chopped (nearly powdered) fiber that is used in ABS plastic to maintain dimensional stability. Unfortunately, I don't know what the name is. It can be seen as shiny thread-like streaks in some black plastic items used outdoors. It was in our aerial terminals used in the phone company. I haven't found any to experiment with...

[@whatanitemare]

@@billbucktube Thank you for that! At least now I know what type of product I should be looking for.

[@sheeshodadial1082]

I am from india.I watch your videos .your videos are very interesting.Actually I trying to make a wood paste.I have tried to make a wood paste by your method.I use silicon+turpentine+corn starch+fine sawdust. actually there are still some problem .Its very rubbery and some cracks after drying .which matrrial and resin can i use.what can i do can you help me .would be a very grateful

[@GEOsustainable]

Thank you for watching. You have a different problem. I am not sure how I can help. Using silicone to fill wood is different, and I am not sure it will stick if the wood gets wet. Keep trying, you will get there. Perhaps substitute the silicone with some of my Casein experiments, it drys hard.

[@sheeshodadial1082]

Thanks alot

[@GEOsustainable]

@@sheeshodadial1082 My pleasure. The Casein can be sanded, so I give it high marks for solving your problem.

[@sheeshodadial1082]

I will try my best to do it and thanks for the advice

[@mariad4183]

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

[@GEOsustainable]

You are most welcome. I am glad you like it.

[@josephlarsen]

now i need to test this out. When you made it the consistency of syrup did you find that the mold had any shrinking? If not, then have you don't any cost analysis on this vs the more expensive stuff?

[@GEOsustainable]

well, it is cheaper and more fun.

[@pablonunez8461]

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?

[@GEOsustainable]

Excellent question. And I have the answer for you. I made a video on how to add color to silicon that I think you will love. kzbin.info/www/bejne/iWammXutnr2FopI

[@pablonunez8461]

@@GEOsustainable oh thanks! Just watched that video, thank you for the advice 🙌🏼

[@jkg2754]

Could this be poured 6” thick 6” wide and 16” long to use to water seal around some pipes inside a wall ?

[@GEOsustainable]

Yes, use the ratio I supplied, pour any thickness, sets in about one hour. Make sure the pipes are not water supply lines, as this formula uses Naphtha.

[@aniqaibu032]

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?

[@GEOsustainable]

yes, normal is mineral. Or use mineral spirits or Naptha.

[@aniqaibu032]

@@GEOsustainable thank you so much ! I really appreciate it!

[@andreastimper9848]

Does it need to be corn starch, or will potato starch also work?

[@GEOsustainable]

I don't know, I never tried. If potato starch holds moisture, it should work. Try it and let us know.

[@andreastimper9848]

@@GEOsustainable Will do. In Europe, potato starch is more readily available, that's why I asked...

[@yuancarlos23]

How about using paint thinner Sir?

[@GEOsustainable]

Look here, I have several video that may help you. kzbin.info/aero/PLmAU7fwOLS3FSvjEzf3OJMHL5a1UO1ayJ

[@2degucitas]

Thanks.

[@WaschyNumber1]

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

[@GEOsustainable]

I have heard charcoal lighter fluid is Naphtha.

[@WaschyNumber1]

@@GEOsustainable ok, thank you. 😊

[@alcestis639]

This is genius!

[@GEOsustainable]

Much appreciated. Glad you enjoyed.

[@LT72884]

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

[@GEOsustainable]

You can and here is how I did it. kzbin.info/www/bejne/qXq0nHmMm9l3kLc

[@soundofthegardenwatc]

hello. i bought the Radians in-ear and messed up the process on one of the molds. it dried too fast. what is the best diy walmart solutions

[@GEOsustainable]

Easy fix. Use 10 gr cornstarch to 100 gr Silicone. This ratio gives you 1 hour cure time.

[@soundofthegardenwatc]

@@GEOsustainable can i start over and use your solution for both ears?

[@soundofthegardenwatc]

@@GEOsustainable with radians I had to leave in ears for tens

[@erikhernandez1948]

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

[@GEOsustainable]

Watch the videos, listen to the words coming out of my mouth. I have literally said it in my videos 10 times. Your answer is in the video. And, one smart fella went to Washington state to get Naphtha.

[@rachaelbrooksgoodlow237]

What's the consistency that you're wanting to achieve? Mine is pudding is too thick? I shall see.

[@GEOsustainable]

It really is a choice. Make as thick or thin as you need for your project.

[@tuphdc8779]

thanks for sharing this

[@GEOsustainable]

So glad you like. My pleasure.

[@zorgfleeter]

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

[@GEOsustainable]

Correct, Naptha is used as lighter fluid. Very close on the conversion, 1/2 is 120 mL, and for this project, close enough.

[@Johnf275]

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

[@GEOsustainable]

No, it cannot. Use silicone oil to thin if using PLA.

[@Johnf275]

@@GEOsustainable Thanks for letting me know.

[@NA-sy2fm]

This tip is a whole other video you could make on the topic of PLA/Molding. Thanks for the info. I was seconds away from a melted master mold.

[@michellemwina6051]

Well, ive thinned silicone before using turpentine.....it stayed sticky for long, and weak too. I didnt like it. I think if i needed a longer cure time i would rather use IPA but question is, why cornstarch? what makes it cure fast and wont cornstarch deteriorate the mold after some years, maybe moulds

[@GEOsustainable]

Great questions. You have a tricky problem. I have a couple of videos for you, that will answer your questions and lead you to the proper thinner. kzbin.info/www/bejne/qXq0nHmMm9l3kLc and kzbin.info/www/bejne/hZOcimqpn65nf6M

[@michellemwina6051]

i get the absorption property of cornstarch....for longer putty like use, we use a small amount of it in the silicone...great! thanks

[@pugzcy6641]

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

[@GEOsustainable]

I can offer you as much help as you need. Let's go through what you may have missed. Firstly, the ratios were correct as for cornstarch? 100gr. Silicone to 10gr. Cornstarch. Mix very well all three...very well. these ratios will give a set time of about one hour. Depending on the speed that you can make your mold, you can increase the amount of cornstarch, slightly. This will shorten the set time significantly, This does take practice, as with any craft, so give it a few tries, changing one variable at a time. Lastly, I have never used Mineral Spirits, as it is the opposite in price for me.

[@randalltaylor1428]

I use naptha mixed with silicone molding rubber to reduce the size of molds. Wont this shrink the mold?

[@GEOsustainable]

Yes.

[@LT72884]

What about acetone?

[@GEOsustainable]

Try it and let us know.

[@chillvibessweetbaked7458]

thank you so much!!!!! I did it!! and it really works!!!!!!!!!! 🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰🥰 God bless..

[@chillvibessweetbaked7458]

I have question? can I use this molder in my FONDANT CAKE??? look forward for your response. thank you 🥰

[@GEOsustainable]

I am thrilled for you!

[@GEOsustainable]

I would not use this method for food contact. Also, the working temperature of this type of silicone is only 350F, not oven safe.

[@chillvibessweetbaked7458]

@@GEOsustainable just for molding method sir. not for oven. is it ok? for cake design details only. ☺️ is it ok to use? just for molding details like letters etc

[@PokeWitty]

does the silicone shrink mich doing this? im wanting to silicone mold a fish bit dont want to spend $500 on smoothon

[@GEOsustainable]

It won't shrink. Lot's of folks use this for fish lures.

[@PokeWitty]

thankyou so so much. i did this today and made it a runny paintable mix. i painted on one side of a large fish that was in a bedding material. when it was about 40min after painting a layer i added another layer and waited a hour.flipped the fish and abit of vaseline as a mold release on the silicone and started process again. 4 hours had me a nice silicone 2 part mold that iv just now started laying up a fibreglass mother mold to hold it all together. total cost of the silicone mold was $25 Australian dollars compared to what would have been $200 if i used smooth on. i guess the real test will be when i take the fish out and make the fibreglass repoduction but all looking good so far

[@ferretface8782]

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

[@GEOsustainable]

I think those are a brand I don't use. But, others will thank you for this, I get a lot of questions on silicone 1 and 2. I may want to do some work with these, as a lot of folks use them.

[@jodahobnob1973]

This is a great channel, but I have a few questions. If you continue to add a thinning agent to the silicone and cornstarch mix, will the solidity of the mold be affected overall or will the just the dry time increase? or possibly both? And is there anything you could add to make these molds more heat resistant? For casting pewter? Thank you for sharing all this valuable information with us viewers.

[@GEOsustainable]

Great questions and thank you. I have never taken it to very thin, you would need to try it. Let us know how it turns out. Silicone will not be useful to cast molten metal of any kind. The maximum temparture of this silicone is 350F (175C). Use casting sand for your project. Stay tuned, much more to follow.

[@jeriborders3839]

I tried doing this a few hours ago and honestly, I didn’t measure. I was trying to cover a large platter so I used two tubes of silicone, nearly half of the bottle of naphtha, and probably not nearly enough cornstarch. Can I more corn starch now or will this have 0 benefit at this point?

[@GEOsustainable]

As long as the silicone is not set, you may be able to add cornstarch. If not, well, you may have to start over.

[@jeriborders3839]

Thank you! It’s rubbery. lol I’m going to add it anyway and pray for the best 😅

[@iqinsanity]

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.

[@GEOsustainable]

That should work just fine. Let me know how it turns out!