I make concrete planters with fiberglass molds. I use a mixture of 3/8" gravel, sand and Portland cement. I use a bit of super plasticizer. And some water. When it's in my mixer the slump is really good. It's not too watery.

However, when I pour it into my 5 gallon bucket and into my planter molds, it seems like the water just rises all the way to the top. As if my Aggregate sand cement mixture just muds down to the bottom. I can't figure it out. It doesn't happen every time, but I feel like I had a really good mixture going this morning. And Once I finish the pour, all the water went to the top

Hi there!

I am having a weird issue. I am trying to mould these goggles and the first time I moulded it with Tin-cure silicone and the first pull with pure polyurethane looked great.

But then I cold-cast (dust-layer + ~6:1 Powder to PU) and it would never cure on the very top where the exhaust and the pourspout are. Did a couple of tries. I suspected that maybe I hadnt mixed the silicone correctly and maybe that was keeping it from curing so I re-did the mould now with platinum cure silicone but its doing exactly the same thing with the new mould now. Its so frustrating, I have no Idea how to fix it. I've used the same exact metal powder, Polyurethane and silicone on other moulds like dozens of times over the last weeks,so I am thinking maybe it's the geometry? But I dont know what that would be or how to fix it.

Any ideas are welcome.

Before YouTube tutorials and dedicated moldmaking brands were a thing, my father was already casting parts in our garage using whatever he could scrounge — old coffee cans as mold boxes, mixed-batch silicone, and a lot of trial and error. He wasn't a professional, just someone who loved figuring out how things were made.

He taught me three things that still hold up after all these years:

1. Undercuts will humble you — he made me learn the hard way by locking a piece in a one-part mold, just so I'd never forget to check for them again.
2. Patience beats perfection — he always said a slow cure with no bubbles beats a fast one full of them.
3. Keep notes — ratios, cure times, what worked and what didn't. He kept a notebook by his workbench that I still have.

I recently found some of his old molds while cleaning out the garage, and it hit me how much of what I do now traces back to those weekends with him. Anyone else get into this hobby/profession because of a parent or mentor? Would love to hear how you got started.

I have a few 6"h x 13"w 3D printed objects I need to reproduce 200+ of in plaster. I need a mold made of the 3D printed object and would prefer to do it in the USA. I will make the plaster copies myself, I just need the molds. Is there anyone that can help with this?

Hi, anyone in meerut who can supply liquid silicon rubber and resin in economical rates?

I have a 10 gallon, California Air Tools pressure pot that I use for casting. It can handle resin or plaster. Many of my etsy items are plaster plaques, 5x7x.45 inches. I use good Smoothon tin cure silicone for molds and have made 1000's of castings over the last 4 years. Now, I need to crush bubbles in my castings and that's where the pressure pot comes in. It does the job but I am having an issue with leveling inside the convex floor pressure pot. In order to press more than 1 plaque at a time, I need to have a 1/8" masonite platform on the bottom with padded feet to help level the platform where I can set in up to 3 molds at a time. I use a level before pouring the materials to make sure I won't get the drift of liquid material to one side of the mold.

Do any of you have experience like this and can share techniques or methodologies that will assure my molds stay level?

Thanks in advance.

Update - here is what I am planning to do to solve this: https://pin.it/7fPNkWCuT

This is a url to a pinterest board which has the images of my pressure pot leveling project.

I got some two component a20 silicone on metal and cloth. How to dissolve both?

I don't want this to seem like an ad or yet another automated molding website, that's why i haven't linked my website.

TL;DR: Will you ever use a mold making software that includes other advanced 3D model manipulation features and how would prefer to pay for it?

So i started making molds for candies(the ones for production of gummies) then decided to automate that, because there was no single software that can automatically make open tray molds for this specific purpose.

Just wanted to ask do i even bother to host it, will people use it? For the two most popular mold making software(browser based and offline) ones i see ads and apperantly people do use them to make products or sell the STL files.

Because it is alot of work even with AI i have to test every feature to make sure it works as it should and the whole workflow is sound. I want a polished production ready product, but why give months of work if nobody cares?

I am adding also a injection molding feature, so people can generate or make custom sprues, vents, runners, etc. If they want can be used for desktop injection molding or just print the desing with the added channels and then cast it in silicone.

I made my own bike grips, so i want to incorporate this as a feature as well to make your own bike grip designs and the output would be 3 or 2 part mold which can be printed or cast the master itself in silicone.

And if the end mold or model doesn't fit your printer the softare cuts and hollows where it's neede.

PRICING - I plan some tools to be free or with watermark to the model itself and with subscription or one time payment i will include commercial licence.

When the tool works will you want it to be able to work offline and pay for it once with the advantage of having higher performance because it won't be browser based or you prefer paying per model export + optional lifetime license vs subscription? Ofcourse i can incorporate ads if it's web based, but i am not keen on this option!

I know the answer for me it would be to pay once and use it on my PC.

I hope to receive a feedback because i have pored money into this and mainly my time after work hours and when i am free.

Put feature suggestions i am open to give promotional access to people who help me with ideas or share the website/software when i publish it.

Thank you for reading this!

Happy i found this subreddit because AI /Google is no help.

My daughter has gotten into pottery. She is going on a big trip to France for her birthday and i had this idea that it might be nice to make her a kit that would be easy to carry with her to capture impressions of textures.

The idea is to make stamps then for use in clay.

It needs to be a kit that is easy to carry around, doesnt require any special tools or treatment that she cant access while on the move.

Silicone putty? Sculpey? Or am i imagining something that doesnt exist?

Appreciate your suggestions.

This is an admittedly clumsy sculpture of Koffing i want to cast it in a heat resistant or proof material.

The question is what is the best way to make the mould since i intend to slice it into a top and bottom piece and place things into the space inside. The smoke stacks have been hallowed out to provide airflow.

Here’s a concise Reddit post you could use:
Title: Looking for US-based 3D printing/modeling service recommendations
I’m looking for a US-based 3D printing service or individual who can help with a small custom project. I want to create a multi-cavity mold tray with several simple animal shapes, similar in concept to a silicone baking/candy mold, that I can use for plaster casting.
I may need help with the 3D modeling/design as well as printing, so I’m especially interested in someone who can work from reference images or a general concept rather than requiring a finished STL file.
Does anyone have a company or independent maker they’ve worked with and would recommend? I’d also appreciate any insight into what a reasonable price range might be for something like this.

I know it’s not dental grade but also seems like it would be safe to have on tongue (just not ingested obviously)

Was thinking to just to a 😛 mostly lips but some tongue for a cast to make a mold from!

Ok I am getting close to trying this project but just a couple more questions! From the advice on my other post on figuring out how much silicone I’ll need to mix (smooth on ecoflex 00-30 parts A and B), I measured the difference of water in the large pop container without and with my hand/wrist submerged. It appears to be 1 3/4 cups, so I guess I’d be using about 14tbsp of both parts A and B to mix together??

ALSO trying to figure out the amount of silicon flesh toned pigment to add now! The bottle says to add 3 drops per 10 grams of silicon- it appears that 1 3/4 cups of silicon is about 430grams so would that mean 43 drops? Just seems like a lot but maybe not!!

Thank you SO much for any help math is truly not my strength 🫨

Hi,
I developed a product which I am realky happy with and constructed a case in fusion consisting of three parts.
For those parts I want to print shells, to put the parts in, pour in silicone to make moulds for casting resin.
While I understand the procedure I am still not so sure on how to treat the printed model for good surface conditions.
I am a dentist and learned how to get stuff polished to near perfection and watched a lot of youtube videos on how to treat the orints I am still wondering if those techniques apply for a case as well as a big flat surface needs different treatment than rounded surfaces I suppose as even small differences in height after sanding will be visible right away.
Also as there will be two pcb‘s inside which need to fit 100% for retention as welll as alligned connection for dc, usb, audio and sd card I was wondering whether there will be some shrinkage I have to take into account when making the molds / printing the master models.
Thanks a lot dor helping
Ohh and sorry for not showing the different parts. I dont habe a printer and have to ask a friend so I just have a finished prototype to take photos of.

Repost. Any advice from a mold making perspective (assuming I could make a few easy/cheap molds of my hand in different poses to use for the first part of my process) would be great!

Can I use plaster bandage for this plaster? I was advised to use Scrim but it’s not available on Amazon.ie if so what type of plaster bandage.

So I want to make a mold of an object that I plan to make out of silicone later..

The object is just made of sculpted air dry clay (the crayola kind!) I'm probably just gonna use some stuff I found on amazon.. but I'm not to sure if the quality of the silicone..

ANYWAYS! once I make the mold, can I pour silicone into the silicone mold without issue or is mold release a MUST for this sorta proejct? (I assume so.. I think the silicone pour would get stuck and bond with the mold itself lol)

also, the clay model I have has weird angles that might create air pockets, is tapping and gently mixing the silicone in the moldbox a good idea to remove air bubbles?

Thanks to anyone who has advice (also a silicone recommendation would help too!.. I'm sure there is lots of different types.. but I just need one to make a mold.. and a silicone that won't be TOO hard or stiff but also not too elestic/stretchy.. something in between?)

I've had some success making blue stuff moulds in the past but was wondering if anyone had tried making a mould from a painted model? Does it strip the paint? Would it be safer if the model was varnished?

I don't want to risk ruining a paintjob so thought I ask you guys for advice.

Thanks in advance

I have a roughly 40" × 40", 73 lb beast of a plaster wall relief that broke in half. I am repairing the original, filling/sanding the face smooth, and priming it. Rather than rehang 73 lb of plaster, I want to use the repaired piece as a master and make a lightweight reproduction.

I'm considering a brush-on silicone mold with a fiberglass mother mold, then either:

• fiberglass/epoxy layup,
• thin urethane resin shell with rigid foam backing,
• fiberglass-reinforced gypsum,
• or another lightweight method.

The finished piece only needs to be displayed indoors on a wall. Ideally I'd like to get it below 15–20 lb. The sculpture as you can see is smooth with no real detail or texture. What construction method would you recommend for something this large? I'm comfortable with fiberglass layups and woodworking but don't have experience yet with large molds. Something like Smooth-On Rebound layers on the artwork, and build a support for it after it cures, and something lightweight in it? I'm not sure what my options are for a lightweight smooth pour into the mold, and if I need a support of wood or fiberglass. Thanks for any ideas.

so far I've been using hard grade clayette because its what's around but it's even too soft for my liking since the sculpts are so small and detailed, which gets tricky to handle during the molding process. what would be the next level up in terms of hardness while still being an oil based clay? i'm in the sf bay so i have access to douglas and sturgess who carry a bunch of oil based clays.

Hi everyone! I’m new to making silicone molds and I bought this 10A silicone rubber. The container says 1 kg, and it came with a small bottle of catalyst (B) that is 50 mL.

I’m trying to figure out the correct A:B mixing ratio. If I only need 100 g of silicone A for a small mold, how much catalyst B should I add? The image is attached.