Premiered: 09/04/2026 START ROTO #10

Start Roto #10 | First part in hand — what to test before moving forward — LIVE

Inspect finishing, fit, thickness and critical function before releasing a batch. Field test, document and reduce costs safely in rotomolding.

1:21:40 OF TALK 16 CHAPTERS YOUTUBE

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What you gain by watching

  • You learn how to inspect the first part before releasing a batch: finish, fit, thickness and critical function.
  • You walk away with a roadmap to document tests, listen to users and not accept supplier excuses or risk the customer.
  • You see how to reduce cost safely, from recycled material with a report to process adjustments, without sacrificing performance.

About the episode

You've just taken the first part out of the mold. It looks good, shining, and the urge is to speed up to production. But that's exactly where many people burn money, time and reputation. In Start Roto #10, we opened the second stage of ideation to answer how to validate the part with the customer before putting it on the market, going through the four phases of Start Roto: ideation, validation, structuring and scale.

We've already seen people look for a generic framework, come back discouraged and realize that in rotomolding the playbook doesn't cover the particularities of the process. As we said in the episode, 'in theory it's one thing, in practice it's another.' Before buying a machine, defining layout or choosing a niche, all planning revolves around one decision: what is your product. And that's why validation starts long before the equipment.

The first part is not a trophy, it's a test

When the part comes out of the mold, the impulse is to approve it by appearance. We showed that the way is to stop and inspect: visual aspect, finish, sharp corners, holes, seams, fit, lid and alignment. And put yourself in the buyer's shoes, with the question that's worth more than any checklist: 'Would I buy this part with this finish?'

The test that reveals what's hidden is cutting the part. Not only measuring thickness, but seeing if it cooked inside, how the wall behaves and how the internal finish is. Because if the critical function fails, no cosmetic detail saves it. We told of two tupperwares of the same model and manufacturer that didn't close with each other just because of the color, and of the truck driver who tied a thousand-liter box with rope and drove three thousand kilometers in the sun until the elastic deformation became plastic. There was also the part that broke constantly because the truck driver climbed on it to tie the rope. 'Only in real conditions can you catch these nuances.'

The factory floor has the final word

We always hammer this point: bench test, open, close, load, and take it to the field with those who will really use it. Never throw at the customer something that compromises safety or main function without warning. Before producing a batch, make one part. That's how it was with an out-of-standard pallet: instead of risking three hundred parts, we ran one on the forklift with equivalent weight and waited for the verdict. The practical test validated the design and avoided huge losses.

Closing a deal is just the beginning. We've already taken on a commitment and discovered during forming that we needed 50% more material, with the entire loss on our side. The lesson was clear: first close the part technically, then optimize weight, cost and raw material. And asking 'why do you use virgin?' almost always reveals that the reason is color, not technical requirement. With an additive report and traceability, switching to recycled material can reduce at least 40% of direct cost already in the first analysis. Documenting every test, recording on video and listening to those who put their hand on the handle is what separates technical decision from guesswork.

Come watch the full episode and apply these tests to your first part before moving forward.

Summary generated with AI from the episode; some information may not be 100% accurate relative to the original content.

Episode chapters

  1. 1

    Start Roto: the danger of validating your product without knowing rotomolding

    In episode 10 of Start Roto, we open the second stage of ideation to answer a question that holds back many people who want to enter the sector: how do you validate the part with the client before placing it on the market? The path goes through a guide with all the points of attention and through the four phases of Start Roto — ideation, validation, structuring and scale. And we also talk about the warning we heard from those who sought support in a generic framework and came back discouraged, because in rotomolding theory is one thing and the factory floor is another: "many times, everything in the playbook does not apply to rotomolding, because of the particularities of the process".

    In practice rotomolding is a bit outside the curve there of theory. In theory it's one thing, in practice it's another
    Watch at approximately 1:44
  2. 2

    Before buying the machine, understand what your product is

    What to do when the desire to start a business in rotomolding runs into the first hard question from any mentor: what market validation have you already done? We show how Start Roto adapts what is most current in industry 4.0 to our reality and recommend adding SEBRAE to this path, because inside it you find the right mentor for each difficulty in your business. And we tell the case of someone who almost bought a machine that was too big until they realized that the entire planning — layout, equipment, niche — revolves around a single decision: what is your product.

    All the planning you need to do for your company goes through the stage of what product you will, uh, what your product is, right?
    Watch at approximately 7:01
  3. 3

    Before approving the first part: what to look at beyond beauty

    When the first part comes out of the mold and looks beautiful, the impulse is to rush into production — but that is exactly where the flaw hides. In the episode, we show why the path is to stop and inspect the right points: start with the visual appearance, check finishing, sharp corners, holes and seams, and put ourselves in the client's place — "would I buy a part with this finishing?" — before making any decision. The lesson is that the part is approved with the eye of the buyer, not the supplier, because what goes unnoticed by the maker is usually exactly the detail that the product owner sees.

    Would I buy this part with this finishing? You know? So I think these are points that you really have to hit and look at, feel you as a client, not as a supplier.
    Watch at approximately 12:04
  4. 4

    When the Part is a Nightmare in Testing and the Client Approves: The Counterpoint that Saves

    The question that won't go away is: who really evaluates whether the part is within the acceptance criteria? The answer is the client who runs it. In the middle of this, the critical point of use goes unnoticed, and that's where we show how minimal tests – cutting the part, measuring thicknesses, checking if it cooked properly – reveal what the supplier may be letting slip. We also talk about the risk of outsourcing the evaluation and leaving the partner as the only technical voice; the counterpoint of someone who knows the process is what guarantees the best outcome, like the case of the client whose mold only ran on the simplest machine, proving that the problem wasn't the machine, but the process.

    So the problem isn't the machine, the problem is the process. It's who is in front of the machine there, coordinating the whole part of, of, of machine parameters.
    Watch at approximately 17:07
  5. 5

    The pretty part on the outside that didn't cook on the inside: why cutting is the test that reveals everything

    We told the case of the client who operated with a digital thermometer and turned the gas on and off at the right moment — his parts were perfect, none rejected, even with a bad machine, because he had the technical knowledge to compensate. This led us to the central question: and when the part comes out pretty on the outside but didn't cook properly on the inside, what to do? The answer we showed is to cut the part, not only to measure thickness, but to see the internal behavior, the wall and the finish — because if the critical function fails, no cosmetic detail saves it, and the slide that sinks or the fish box that leaks become a bench or an ornament.

    If the critical function doesn't work, no cosmetic detail saves it.
    Watch at approximately 22:09
  6. 6

    When only the different color already prevents the lid from closing

    There are details that seem silly until the part reaches the client's hands: two tupperwares of the same model and manufacturer, one purple and one white, and the lid of one simply doesn't close properly on the other — because the pigment changes the coefficient of expansion and the fit goes away. That's why we look first at lid, closing and alignment, knowing that a different color can become a headache: and it's the same logic that made us swap the galvanized sheet metal of the doghouse for two parts of separate colors, because the fit only forgives when there's clearance — in a stackable box, a loose lid is a risk of load on the floor.

    It's the same model, same manufacturer, but only the color that's different.
    Watch at approximately 27:11
  7. 7

    The truck driver's rope that deformed a thousand liters of plastic in the sun

    Have you ever thought that the biggest threat to your part might be outside the factory, in the hands of whoever transports it? We tell the case of the thousand-liter box that the truck driver tied with rope and drove three thousand kilometers in the sun — the elastic deformation became plastic, the rope sank to floor level and there was nothing more to do with the parts. The lesson we took is that analyzing transport and packaging is part of the project, so much so that we reduced the volume of boxes on the produce return from three to one and then from seven to one, and we understood that bench testing serves geometry, but it's in real use, and at its extreme, that defects show up.

    Watch at approximately 32:13
  8. 8

    The part that became a truck driver's ladder: why the project doesn't see real use

    We designed, tested and approved a part that broke all the time — until we discovered that the truck driver climbed on top of it to tie the rope to the truck, a use that never showed up in market research. The conversation is about this: only the field reveals the nuance that the drawing doesn't show, and what separates evidence from guesswork is documenting everything, from the datasheet to the signed napkin — because the supervisor who showed up saying 'this has already been done and didn't work' cost two days of machining, welding and bending that nobody had recorded.

    Only in real conditions can you pick up these nuances
    Watch at approximately 37:18
  9. 9

    Documenting tests: what separates you from accepting any excuse from the supplier

    When the outsourced supplier swears the part is good, how do you prove it isn't? We talk about the importance of separating tests by stage so as not to contaminate the feedback, and of recording each test on video — because in the moment there's noise, anxiety and too many details to absorb, and only by reviewing calmly can you extract the maximum information. The turning point is that this documentation isn't just for validating: it's what allows you to seek a second technical opinion and refute or confirm what the partner claims, when we get to 90% certainty of the problem just from the description.

    Record it, watch it later calmly. So always, every time you watch this feedback, you'll be able to gather the maximum possible information, even details of the part's behavior during the test
    Watch at approximately 42:28
  10. 10

    When 50% loss seems normal, technical knowledge is missing in the diagnosis

    We often hear industry owners accepting half of production going to waste as if it were a rule of the game — because those advising them nearby don't always have the technical basis to say otherwise. That's where the cost becomes invisible to the eyes of decision-makers, and the solution we show is to call in someone who truly understands rotomolding to validate the process. And there's also the other invisible side of the business, which is the tax overpayment: we brought in Ivan Grisolino, from CX Contábil, to tell how a tax adjustment left hundreds of thousands of reais in the cash of a company that turned over 2.5 million in the quarter — money that goes back into investment, jobs, and growth.

    Watch at approximately 47:39
  11. 11

    Before Producing a Batch, Test One Part: The Mistake That Can Save Your Client

    We always hammer on this point: you only know if the part holds up when it faces the reality of the factory floor, and there's no use designing with all the care in the world if the handle doesn't work in the hands of whoever uses it. That's how it was with an out-of-spec pallet a client requested — instead of risking three hundred parts at once, we made just one, ran it on the forklift with equivalent weight, and waited for the verdict. The practical test validated the design and avoided a huge loss, because even technical simulations can let variables slip through; in the end, nothing replaces putting the part to run for real.

    There's nothing better than… the practical test for you to test the business.
    Watch at approximately 52:40
  12. 12

    Testing at the client's site without warning is a recipe for catastrophic failure

    We've seen parts that worked perfectly on the computer and failed in practice, and the risk appears when someone cuts cost at the limit between ideal and catastrophic failure without testing first. That's why the rule is clear: test on the bench, open, close, load, and take it to the field with whoever will actually use the product — when the pilot client agrees to be a development partner, we adjust the handle, review the ergonomics, and move on, but we never throw at the client something that compromises safety or core function without warning.

    Watch at approximately 57:43
  13. 13

    Minimum weight, maximum safety: the engineering miracle behind the rotomolded box

    The client would come with a hard rule — so many kilos of part per box, not one gram more — and we had to work miracles, sizing structure and reinforcement to reduce weight without compromising the people who operate it. The answer that stuck was simple: document everything, test with those who use the box on the factory floor, listen to the operator before signing anything, because the proof from the person who puts their hand on the handle is worth more than any spreadsheet — and it also opens room to cut cost without delivering an inferior product.

    Watch at approximately 1:02:47
  14. 14

    Closing the order is only the beginning: when the part weighs 50% more and the loss is all yours

    We know what it's like to take on a commitment with the client and discover, when forming the part, that 50% more material was needed — and that the loss was all on our side, because a closed order is a delivered order. But it was that school that taught us that first you close the part technically and only then optimize weight, cost, and even raw material, without forgetting to negotiate alternatives with the buyer — because increasing margin by passing on cost hurts competitiveness, and the only sustainable way out is to reduce your own cost by also working on process and product.

    The important thing is to always look for alternatives, not to stand still in time
    Watch at approximately 1:07:50
  15. 15

    Replacing virgin raw material with recycled can cut 40% of the cost on the very first visit

    Many people still run virgin material for fear of color or strength — but when we ask 'why do you use virgin?', almost always the answer is tone, not technical requirement. That's how it was with a toy client: they tested the recycled material on the slide's little ladder and the color difference was so small it only showed side by side — and with partners that issue an additive and traceability report, the switch reduces at least 40% of direct cost right on the first analysis.

    Nothing sporadic, but it can, if you want a specific color, then you'll work with virgin material, but we also have conditions to develop for you, yes, within the color you need.
    Watch at approximately 1:13:56
  16. 16

    An audience that crosses time zones and generations

    We always remember that there are real people on the other side: a client who joined in the eighth episode and was surprised by how much rotomolding opens doors in different niches, a listener in Portugal who asks at three in the morning if the episode is coming out, the wife who gives a heads-up about the audio and the image, the granddaughter Luísa whom the grandpa misses. It is this bond that drives us, and it is for it that we keep going strong on Friday at noon, with behind-the-scenes on Instagram and the goal of 250 subscribers knocking at the door — aware that we are still a project under construction, but with a community that grows with every conversation.

    He was impressed by how much rotomolding can be, yes, placed on the market in different niches
    Watch at approximately 1:19:06

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