Hey everyone, it’s Jake from the thiourea supply team—you know, the guy who gets a million DMs a week asking “Wait, how do I actually make a solid thiourea solution without messing it up?” Look, I get it. When you’re working with thiourea—whether you’re using it for metal plating, photography, or even those weird little organic synthesis projects your lab’s been tinkering with—sometimes buying pre-mixed solution isn’t ideal. Maybe you need a specific concentration, or you’re in a pinch and can’t wait for shipping. That’s why I’m breaking this down like we’re chatting in a warehouse break room, not a college chem lecture hall. No stuffy jargon, no confusing steps—just real, tested tips from someone who’s shipped this stuff out to hundreds of small manufacturers and hobbyists over the last 7 years. Thiourea
First off, let’s get one basic rule out of the way right now: thiourea dissolves in water, but it’s not like dumping table salt. If you toss a big pile of solid thiourea into a bucket and walk away, you’ll end up with a lumpy, concentrated mess at the bottom that never fully mixes. I see that mistake all the time—newbies think “it’s soluble, right?” so they skip the stirring part, and then they’re calling us panicking because their plating line’s clogged with undissolved crystals. Don’t be that person.
Let’s start with what you actually need to make this solution. I’m not gonna list lab-grade glassware unless that’s what you’re using—most folks I work with use 5-gallon food-grade buckets, magnetic stirrers (or even a big old stir stick if you’re on a budget), and a digital scale (way better than guessing with cups, trust me). Also, make sure your water is room temp or slightly warm—hot water will speed up dissolving, but boiling water can actually make thiourea break down a little, so skip the kettle. And obviously, you need solid thiourea crystals (let’s call it TU for short, ‘cause we all do) — I only sell high-purity prills, no dusty old granules that have caked up in a dusty warehouse.
Now, the concentration part. This is where people get confused. The most common solutions people ask for are 10%, 20%, and 50% by weight. Let’s do an example so it makes sense. If you want a 10% thiourea solution, that means 10 grams of TU for every 90 grams of water, right? Wait no—wait, 10% of the total solution is TU, so yeah, 10g TU + 90g H2O = 100g of 10% solution. Easy. Let’s say you need 5 gallons of that. A gallon of water weighs roughly 8.34 lbs, so 5 gallons is ~41.7 lbs, which is ~18927 grams. So 10% of 18927g is ~1893g of TU, and the rest is water. Got it? If you need a different concentration, just do the math: (desired % / 100) x total weight of solution = grams of TU needed. No need to overcomplicate it.
Now the actual mixing step, the part that everyone messes up. Step 1: Pour most of your water into your bucket first—leave like 10% of the water in the jug for rinsing out the TU bag later, waste not want not. Step 2: Start stirring that water slow—don’t crank the stirrer up to full speed right away, you’ll get a foamy mess all over the garage. Step 3: Add the TU slowly, a little at a time. Like, don’t dump half the bag in. Toss in a cup of prills, let them stir for 2 minutes until they’re fully dissolved, then add another cup. This is key because if you add too much at once, the water can’t hold all the TU, and you get that sludge at the bottom. I learned this the hard way when a client tried making a 40% solution in 30 seconds and ruined their entire 55-gallon drum. Oops.
Wait, what about dissolving in different temperatures? I mentioned earlier—room temp (68-77°F, or 20-25°C) works fine, but if you need it to mix faster, you can warm the water up to 100°F (38°C) max. Any hotter, and thiourea starts to decompose, giving off a weird ammonia smell, which is not something you want near your work area. And never use metal containers? Wait, no—actually, thiourea reacts with some metals, like copper or iron. If you’re storing the solution for more than a week, use plastic or glass containers, not metal buckets. That’s another mistake I see—someone uses a galvanized metal bucket to mix, and the solution turns cloudy in 2 days. Fix that, keep it in plastic.
Now, safety stuff, ‘cause I don’t wanna get anyone hurt. Thiourea isn’t super toxic, but it’s not candy. Wear gloves when you’re handling the solid prills, ‘cause if you get a bunch on your hands and don’t wash it off, it can irritate your skin. And don’t inhale the dust—when you’re pouring solid TU into the bucket, use a funnel if you can, or wear a dust mask. Inhaling that stuff all day isn’t great for your lungs. If you get it in your eyes, flush with water for 15 minutes, easy enough. No need for a hazmat suit, just common sense.
Wait, what if you need a solution that’s more concentrated than 50%? I get that question sometimes. Thiuera’s solubility in water is about 108g per 100mL of water at 77°F, so max you can make is around 52% by weight at room temp. If you need stronger, you have to warm the water up—at 140°F, it’s like 140g per 100mL, so you can get up to a 58% solution. But then when it cools down, some TU will precipitate out, right? So if you need a super concentrated solution that stays liquid, you gotta keep it warm, or add a little bit of another solvent like ethanol. But most of my customers don’t need that—they’re sticking to 10-30% for plating or cleaning, so that’s what I stock.
Let’s do a quick quick example for the folks who don’t wanna do math. Say you need a 20% solution, 1 gallon total. 1 gallon is ~3785 grams. 20% of that is 757 grams of TU, so add 757g TU to 3028g water, stir slow, add TU gradually. Done. That’s it. No fancy lab equipment needed.
Now, what about storage? Once you make your solution, how long does it last? If you keep it sealed in a dark, cool place, it’ll stay good for 3-4 weeks. If it’s warm and exposed to sunlight, it’ll start to go bad in a week—turn cloudy, get that ammonia smell. So don’t leave it sitting on a workbench in the sun. And if you see crystals forming at the bottom when it’s cold, that’s just precipitated TU—warm it up a little, stir, and it’ll go back to normal, no problem.
Look, I’ve been doing this for long enough that I know half the people reading this are gonna skip a step and mess it up, and that’s fine. That’s why we have pre-made solutions ready to ship same-day, in whatever concentration you need, no mixing, no guesswork. But if you do wanna make your own, just remember: add TU slow, stir steady, don’t use hot water, and keep it in plastic.
If you’re tired of wasting solid TU on bad mixes, or you need a consistent solution for your next project, hit us up. We can hook you up with high-purity solid thiourea, or pre-mixed solutions in any concentration, for whatever use you’ve got—plating, photography, water treatment, whatever. No weird minimum orders, no hidden fees, just good product and honest advice.
Now, before I go, a quick pro tip: if you’re making a solution for metal plating, add a tiny bit of citric acid (like 0.5% by weight) to it. It keeps the solution from getting contaminated with metal ions, which makes the plating finish way smoother. I learned that from a regular customer who’s been in the plating business for 20 years—works like a charm.
Happy mixing, and if you got questions, just reach out. We’re here to help.
Sodium Percarbonate References:
- CRC Handbook of Chemistry and Physics, 97th Edition, Thiourea Solubility Data
- Occupational Safety and Health Administration (OSHA), Chemical Safety Guidelines for Thiourea Handling
- plating Resources Association, Guide to Plating Chemical Solution Preparation
Tianjin JOY Co., Ltd.
Tianjin JOY Co., Ltd. is one of the most professional thiourea manufacturers and suppliers in China, specialized in providing high quality sodium sulphide and sodium hydrosulfide. We warmly welcome you to buy thiourea made in China here from our factory.
Address: Room 406, Chuangzhi Building 482, DongmanZhong Road, Eco-City, Tianjin, China
E-mail: postmaster@rstchem.com
WebSite: https://www.ruisterchem.com/
