Resin fumes are toxic.
What I didn't know when I began my journey with resin is that when you mix resin and hardener, what happens next is an exothermic chemical reaction. One that gives off toxic fumes. They are invisible, but I assure you they are there! Depending on the brand and quality of your resin, you might notice a faint chemical odor or be sent running for the door by the gaseous smell. That being said, it would be wise to invest in a respirator mask before beginning your resin journey! Your health is precious, and if you plan on spending a lot of time hunched over your projects to get those details just right like I tend to do, you'll want to protect those lungs, baby.
You can find the proper mask at hardware stores like Home Depot or Lowe's. You'll need a half-face respirator with an N95 equivalent rating and organic vapor filters like this one.
Sometimes, if I am pouring only one or two layers on something quick quick, and I know I won't be spending time hovering over a piece, I'll simply throw on a N95 mask like this one. It's not as protective as the half or full-face respirator, and a risk I knowingly choose to take for the sake of convenience. You gotta do whatever you're comfortable with.
Whatever you do, just don't be like me and find out that resin fumes are toxic after pouring in your bedroom, and leaving the pieces to cure overnight by your bedside like a pet dog.
2.) Heating resin before mixing makes for the best pours.
Ever wonder why some resin pieces look crystal clear and others are cloudy and full of tiny bubbles? I guarantee you one of those artists heated up their resin properly before mixing and the other did not. Warming your bottles of resin and hardener for at least 20 minutes before you mix them is the absolute best step you can take to ensure a crystal clear, bubble-free pour. When the resin and hardener are both warm, they mix together more readily and smoothly. Meaning less strenuous mixing you have to do, which is what results in bubbles.
To warm my resin and hardener, I simply fill up the bathroom sink with hot water and put my bottles in there 20-30 minutes before I plan on pouring. Sometimes even longer if I have the time. I then use that time to prep my space and get everything ready on my worktable that I want to add into the piece I'm creating. Pro-tip: wipe down your bottles with acetone beforehand to ensure you don't get resin drips on the side of your sink. Another pro-tip: make sure your bottles are tightly closed before placing them in water. Resin and water do not mix, and if you get water in your bottle, that would ruin your resin and be a huge bummer. Conversely, if any resin goes down your drain that could mess with your pipes and also be a huge bummer.
3.) Flowers and leaves must be dried before putting them in resin.
If you plan on adding flowers or leaves to your resin piece, they must be dried beforehand. I learned this the hard way the first time I ever poured resin, when I put live yellow roses into a mold. They were still bright yellow when I first pulled them out, but over time they began to die inside the piece. Again, what's happening when the resin hardens is a chemical reaction. It sucks the life out of your flowers. Nothing more depressing than watching your vibrant flowers slowly rot and turn brown over time.
Drying your flowers properly will preserve their beautiful color and shape. There are three methods I know of and use to dry my flowers: pressing, hanging, and immersion in silica gel. Check out my other post on drying flowers to learn about each method and how they produce different results.
4.) Silicone molds do not last forever.
Silicone molds are not immortal. Another thing I found out the hard way. Months into my resin journey, I began pulling pieces that were matte and dull out of the same molds that once gave me shiny and glossy creations. What changed? I wasn't prepping my mold properly before pouring the resin into it. Turns out that resin is really hard on silicone, and will wear it down over time.
There's a super simple and cheap solution to this though - a mold release spray! A mold release spray creates a barrier between your resin and your mold that eases the effects of the chemical reaction taking place, and also makes it easier to release your cured piece from the silicone. They are inexpensive and easy to find on Amazon. I use this one:
Treat your molds right! Make them last a long time, and make the money you spent on them work for you.
5.) Resin can overheat
Ahhh yes - the beauty of a chemical reaction. When it goes wrong. So like I said before, what I didn't know before working with resin is that it cures by means of a chemical reaction. I found this out the first time I poured too much resin into a mold at once and it overheated. The entire mixture started to bubble up, bubbles started to leak out of the flower that was already encased in the mold, and the mold became extremely hot to the touch. When I placed my hand above the mold, I could feel heat emanating from it.
My piece was essentially ruined, and what's worse is I was preserving flowers from a funeral with the deceased's army dog tags inside. Luckily, it was for a dear friend and she understood but DON'T LET THIS HAPPEN TO YOU.
Only pour your resin in layers approximately 1/2 inch thick at a time. Any more than that will cause too much exothermic energy to release from the resin in a surface area that is too small. This is where the overheating and sometimes, even smoking or fire can occur. My friends told me they once forgot about a cup full of mixed resin only to find it smoking and about to catch fire. They had to take it outside and spray the hose on it!
I know it can be tempting to pour more at once in an effort to speed along the process - I have done it more than once and always deeply regretted it when I see my beautiful piece bubbling.
Take your time, be patient and know that
Another thing to note with this is that resin begins to cure when it's fully mixed and usually gives you a 45-minute window. Every brand is different - check the instructions - but try not to pour more than you can use in that time. Or else it will harden before you get to it and be a waste. Resin is way too expensive to throw around. I once mixed a half gallon together to pour on a table top, went to go work on rearranging some flowers and - to my horror - returned to find a big cup of gelatinous resin.