Start Roto #15 | Can I make my own mold? — Key points — LIVE

What you gain by watching

• Discover why manufacturing your own mold can be the riskiest decision for your factory — and what to evaluate before internalizing this process.
• Learn to identify and eliminate the silent villains that generate losses of up to R$ 44 thousand per year, such as sharp corners, clogged vents, and poorly designed parting lines.
• Understand how to master the four pillars (machine, mold, material, and labor) to stop losing money due to a lack of technical knowledge.

Episode chapters

1. 1

   Making your own mold at home: why this decision can define the success or failure of your rotomolding factory

   The fifteenth episode of Start Roto opens with a question every rotomolding entrepreneur has asked: is it possible to manufacture your own mold at home? We present the starting point of this journey — the project structuring stage and the essential precautions before internalizing this process, one of the most critical in the entire factory. And, as always, we reinforce that no one needs to repeat the mistakes we've made on the factory floor: the right information and support from partners are what separate a sustainable project from a stillborn one.

   We don't know everything, we don't own the truth

   ▶ Watch at approximately 5:21
2. 2

   The leap from level 2 to 12 in rotomolding: the partnership that reveals the size of our gap

   In today's chapter, we return to the question that unsettles those who are starting out: is it time to make your own mold or hire specialists? We revisited the trajectory of our friend and researcher Nilton Nicolette, who dedicated 45 years of research to the Portal and showed us an impressive thermometer: while top Brazilian companies operate at level 2, he researches level 12, and the most advanced in the world reach level 10. From this partnership, we discussed the need to master the four pillars — machine, mold, labor, and material — and told how, in practice, we developed local suppliers to escape long lead times, making it clear that making a mold requires more than welding: it requires transferred knowledge.

   So we are very proud to say that he is Brazilian, Nilton Nicolette.

   ▶ Watch at approximately 10:23
3. 3

   3D vase mold: when the beautiful part requires aluminum casting

   On the factory floor, the question that always comes up is: 'can this part be made using rotomolding?' And the answer is never an automatic 'yes' — as we recounted in the episode, a client brought a vase modeled on a 3D printer and discovered that, due to the internal cavities, the mold wouldn't work with carbon steel: it had to be cast in aluminum, with the opening thought out right in the design. It was then that the conversation turned to the central warning: those who are starting out should not make their first mold at home, because the part that seems simple can hide execution pitfalls — and we recommend outsourcing to someone with experience, validating the product in the market, and only then structuring your own production.

   One little screw-up you make on your watch, if you do it wrong, you've already killed the mold

   ▶ Watch at approximately 15:43
4. 4

   The invisible cost that erodes profit: why the mold isn't just about copying the part

   On the factory floor, the conversation exposed a problem that haunts those who manufacture their own mold: every forgotten detail in the design — the vent that wasn't placed, the shrinkage calculated incorrectly by 0.5% for a technical part, or the lid that comes out sealed and needs to be cut off — becomes an invisible cost that drains profit every production cycle. We showed the case of the partner who made impressive molds without formal structure, and the client who loses up to a kilogram of material per part at twenty-two reais per kilo, to reveal the central insight: saving on mold manufacturing can make the process unviable, and what seems like savings turns into rework that would pay for three or four specialized molds.

   It's only one layer, it's not hollow. … Just the shell of it, right? It's very weak.

   ▶ Watch at approximately 20:48
5. 5

   Eight molds leaking 600 grams: the calculation that reveals R$ 44 thousand lost per year

   On the factory floor, a third-party client had eight molds losing about 600 grams of material each cycle — and, to make matters worse, that resin didn't even return to their process; it simply went away as waste. We did the math live: four kilos per batch, 52 kilos per day, R$ 3.7 thousand per month, and R$ 44 thousand per year thrown away. We showed how our loss calculator, available on the website, exposes this hidden value and points to potential savings of 45% — material that could be diluted and reused in the same cycle.

   It's a terrible waste… he could reuse that material there and recycle it back into the process, even if he didn't use it 100%, but it would be diluted along with the virgin material he already uses.

   ▶ Watch at approximately 26:19
6. 6

   Unveiling the Calculator and the Essential Rotomolding Course

   On the factory floor, a warped or crumbling part can seem like an unsolvable mystery, and the lack of communication between IT and operations only deepens the problem. In this excerpt, we show how a simple cost calculator reveals the difference a good resin partner makes — with a 45% reduction in the cost per kilo — and we present the Essential Rotomolding Course, from Science to the Factory Floor, which takes participants from absolute zero to an advanced level of knowledge, enabling them to solve 80% of production problems. With classes already scheduled in Guarulhos and expansion plans for the Northeast, South, and Minas Gerais, it's clear that the path to efficiency begins with practical education and the right partnerships.

   We don't know, we don't own the truth

   ▶ Watch at approximately 31:36
7. 7

   Lack of knowledge costs dearly: rotomolding that stops for not knowing shrinkage

   We talked about how the lack of qualified labor causes entire companies to halt production, and how the right knowledge becomes gold: those who get certified get ahead, earn better salaries, and are sought after from north to south — without even having to wait thirty minutes with the phone ringing. And we went further: we showed that it's no use copying a part if the mold isn't born for rotomolding, because forgetting the material's shrinkage can turn demolding into a nightmare — with a stuck part, the machine lifting a thousand kilos, and hours lost in a process that should have been simple.

   Stop losing money due to a lack of knowledge

   ▶ Watch at approximately 36:55
8. 8

   Sharp corners and close walls: the silent villains of rotomolding

   In this episode, we delved deep into the problems that cause the most headaches on the factory floor: sharp corners and walls that are too close together. We showed, with practical examples, how a poorly designed radius can concentrate material at one point and leave the part weak enough to tear, while a well-designed radius distributes the thickness evenly. We recounted the real case of a client who almost condemned a three-meter mold, valued at 150 thousand reais, until we discovered the error was in the design — and that a simple break in the sharp corner could have saved it. We closed with the golden rule: abhor sharp corners, respect the minimum distances between walls, and remember that even threads can be designed to avoid failure points.

   A sharp corner is something we generally abhor, right

   ▶ Watch at approximately 41:56
9. 9

   A close wall isn't always a problem: the forced bridge technique that turns a defect into structural reinforcement

   In the middle of an important warning about the risks of folding in rotomolded parts, we returned to the question that lingers on the factory floor: after all, is a wall that's too close always bad? We showed that it isn't — and revealed the forced bridge technique, which uses the contact between walls to create real structural reinforcement, with the practical rule of at least two and a half times the material thickness for the minimum spacing. Between one example and another, we celebrated the channel's 250 subscribers with the audience and reinforced the commitment of those who live this niche market: each subscriber is a multiplier of knowledge for those who are starting out or facing difficulties.

   The segment Ícaro is talking about is important for us to reach, because we see followers out there in the… millions. No, we have few, but they are quality people

   ▶ Watch at approximately 47:08
10. 10

    Forced bridge in the mold: the difference between a flimsy flap and structural reinforcement

    When we talk about walls that are too close together in the mold, the risk of unwanted bridges appearing is real — and we cited the case of trash bins, where the flap came out flimsy and even acceptable for street use, but became a problem when the destination was a condominium. It was then that we showed how the manufacturer solved it by respecting the minimum spacing of 25 millimeters and creating a fold that generates the so-called forced bridge — the one that looks like a cheese cracker full of holes, but in practice is structural reinforcement that leaves the part almost solid and firm. We also talked about how this connects to the material's flow, the need for reversal on the machine, and the importance of knowing these variables to consciously decide whether you want to avoid or intentionally provoke this effect in your product.

    It's like you, people make trusses for structure, right? They put a beam on top, another below, then they make that crossing. That's the purpose, right, exactly that purpose.

    ▶ Watch at approximately 52:19
11. 11

    Accounting that gives money back: when tax becomes an investment

    We started with a provocation that stirs any manager: is accounting just a cost or can it be the company's best investment? We showed a real case of tax savings, where a transport company that billed R$ 2.54 million in one quarter avoided paying R$ 480 thousand in taxes with proper planning. And next, we also explained how plastic shrinkage can be your ally or your villain when removing a part from the mold, with a practical design example.

    Do you still think accounting is a cost for your company or is it an investment? I'm going to prove to you that it's a huge investment.

    ▶ Watch at approximately 57:45
12. 12

    Why doesn't your part come out of the mold? Draft angle and shrinkage in rotomolding

    When the question is about the shrinkage rate to consider in the design, we answer with the average of three percent in all dimensions — and we show in practice how to apply this in mold development, especially in parts with critical measurements like one thousand millimeters. But the conversation reveals that the real challenge lies in the geometry: if the draft angle is negative or neutral, the part gets stuck and won't come out, even with the calculated shrinkage. We recounted the real case of a part with a flap that, due to having a neutral angle, created a region that trapped the mold — and how these details define who is capable of producing technical parts in Brazil, at a level of precision that few master.

    So it's closed here at this degree, so the part doesn't come out. That's a draft angle. It's either straight or positive for the part. […] If it's negative, the part doesn't come out.

    ▶ Watch at approximately 1:03:02
13. 13

    When a clogged vent deforms all parts in rotomolding

    On the factory floor, a part that was produced in fiberglass was migrated to rotomolding and soon revealed a critical challenge: the geometry trapped the part in the mold during cooling, requiring special techniques, such as air injection, which aren't always viable on the rotation because they leave marks. But it was during a visit to a company that we found the most revealing case: all the parts came out deformed and no one knew why. We discovered the molds had no vent — a fundamental technical detail for gas exchange and pressure control. After installing a simple Teflon tube, the problem completely disappeared, and we highlighted how something so small can be the difference between a perfect part and an entire unusable batch.

    When you don't have a vent, the mold will seek air, it will start to generate pressure inside, and it will catch exactly at the mold's parting line. Then it will start to leak, and you'll have a series of problems.

    ▶ Watch at approximately 1:08:03
14. 14

    Parting line: the critical point that can deform your mold and leak material

    On the factory floor, the mold's parting line is a silent trap: if the closure isn't perfect, the heat expands the plates, the material leaks, and the part is born with bubbles or warped. We talked about a real case where a 2.75 mm carbon steel plate folded the flap and didn't close, and the solution came with a 3/8" bar underneath, creating a flange — but without overdoing the thickness to avoid becoming a thermal insulator. We also showed the labyrinth trick, an external guide that forces the material to make a curve to seal without being straight, and the importance of cleaning, removing built-up mold release, and choosing well where to place the vent — because that's where a hole is that can become a weak point, and even the floats get rubber plugs afterward. We closed with the question everyone asks: can you make a mold at home? Yes, you can, but with all these precautions — and if the doubt is economic, we guide you first so you don't spend twice on the same mold.

    The moment you looked at the mold, the part was like this, see. So that means it couldn't close properly there, because no matter how close you put those quick-release clamps, there will be a distance of at least thirty centimeters. Here it doesn't expand, but here it starts to expand during heating and starts to leak material and deforms the mold more and more.

    ▶ Watch at approximately 1:13:21
15. 15

    Badly made mold: the error that starts with you and becomes the client's headache

    In this episode of Portal Rotomoldagem, we talked about the importance of mastering the production process before venturing into mold manufacturing, highlighting the four pillars — machine, mold, material, and labor. We showed that improvising without technical knowledge is a risk that starts in your operation and can turn into serious losses, like the case of a float that sinks or a slide that causes an accident — and we revealed that recording every alteration made to the mold is essential to avoid repeating mistakes, in addition to announcing that we will soon bring experts in machined molds to delve deeper into the topic.

    If you master the process, if you understand the process, you can master the so-called 4M, which is what we talk about, which are the machine, mold, material, and labor.

    ▶ Watch at approximately 1:18:28
16. 16

    Tools that summarize hours into minutes: the value of accumulated knowledge

    Closing another stage of our journey, we showed that true efficiency on the factory floor comes from accumulated knowledge — like that presentation that used to take hours and now we do in five minutes with the tools we developed ourselves. We recounted the classic case of the ship engineer, who charged R$ 10 thousand for a single hammer blow after six years of study to know exactly where to hit, and revealed that the next step in this structuring will be the factory layout, with the importance of just in time, in addition to announcing that a special Rotocast on burners is coming with a closed partnership.

    No, I studied for six years, I went to college, I did a specialization, six years to get there and solve your problem in ten minutes, you know? To know where I was going to hit the hammer to make it work.

    ▶ Watch at approximately 1:24:07
17. 17

    A closing on schedule and the behind-the-scenes that almost got left out

    We closed the episode with that farewell vibe of someone already thinking about the next commitment — and we even joked about our own organization, scheduling the next conversation for Friday at noon. Before the final hug, we also remembered the behind-the-scenes that almost escaped, directing everyone to our Instagram, because behind-the-scenes are also part of the story we tell here.

    And don't forget our… Rotocast. No, what? You're going to do the little promo now, in a bit there at, put it on- Oh, in the behind-the-scenes! In the behind-the-scenes! Forgot the name. Our behind-the-scenes there on Instagram.

    ▶ Watch at approximately 1:29:28