A Cautionary Tale of Chemical Reactions

Sometimes we're just going about our day, when suddenly a curve ball comes at you out of nowhere that you just weren't expecting.

This isn't one of those stories.

Wayne gave permission to use this discourse. He wanted his name included and that takes guts. I don't want anybody calling him names, especially since he's willing to allow this decision to be used as a warning. Many of us have been in the middle of a project and not wanted to change gears or spend extra money. We've all made unwise decisions like cutting towards ourselves or accidentally grabbing the bottle of super glue instead of remover.

To summarize what's going on

Wayne is using Castin' Craft Clear Polyester Casting Resin to create a clear river. (Normally it's used to preserve objects in a hard plastic shell.) In theory this is a great idea. Compared to other water effects, it's not only cheaper, but faster because you can pour the layers thicker.

The way this resin works is that you mix two parts together and they solidify.
HOWEVER, the process that hardens the resin involves a lot of chemically generated heat.

Styrofoam melts easily, not just to heat, but also to glue and other chemicals. We recommended using something to insulate the styrofoam like plaster or spackle.

What's the worst that could happen?

When the resin heated up, it melted through the styrofoam, leaked through the peg-board below it and soaked in to the carpet, before turning solid.

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Responsible Hobbying

Last week I got into a discussion regarding the use of chemicals to strip paint. It was strongly (vehemently) suggested that as adults we're all able to read instructions and make the right decisions. But that's not true. (If it were, there wouldn't be lawsuits over hot coffee and fatty burgers.)

My position was that if there are other (healthy / safe) options available, it's improper to suggest the use of chemicals to the average hobbyist. (Keeping in mind plenty of kids and teens are a part of our hobby.)

This is especially true if there's no warning to accompany the suggestions. People assume if others are doing it, it's safe.

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The choice was made to save time and money, despite warnings.

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Safety First

Be thankful that at worst, a carpet was ruined.

The reason safety instructions exist: that eye, hand and respiratory (nose/mouth) protection is recommended, that you work outside, that we store things out of reach of children is because JUST IN CASE things go wrong, no lasting harm is done to anyone.

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Be Aware

Hobby supplies are often safe. Art supplies have an occasional surprise. Hardware shops sell stuff that's usually lower price and higher quality, but are less safe. When you see things like warning symbols, be aware you're dealing with something that needs extra precautions.

The instructions for this product warned of high heat. While it's not going to come out and say "Warning, this will melt styrofoam," that's where asking questions and a little sound judgement come in to play. If a few other steps are suggested, maybe it's a good idea to pause your project until you decide how you want to handle it.

Test

If you just can't find the answer, do a test on a smaller scale.

In this case, an option would have been to take a small block of styrofoam, make a hole and mix a small amount of the resin to create a little pool.

To Summarize (TL;DR)

Everyone makes mistakes. Responsible hobbying means doing what we can to reduce the frequency and severity of these mistakes.

• Consider using non-chemical products before resorting to those that can cause harm.
• Just because Internet recommends something, doesn't mean it's the best option or even safe.
• Read instructions before and while working with a new product.
• Ask questions and test when you're unsure of something.
• Heed the warnings of fellow hobbyists and warning signs on the products you use.
• Always use appropriate safety equipment to protect your eyes, skin and lungs.

Material Safety Data Sheets (MSDS)

A final note to make, when we say to work outside, in a well ventilated area and use a mask, there's a reason.

Castin' Craft Casting Resin - Material Safety Data Sheet (MSDS)

I've talked about MSDS sheets before, but as a reminder, virtually all liquids, chemicals, cleaners, etc must have Material Safety Data Sheets available. You can find them on the manufacturer's website or by googling "[Product] MSDS". If they're not listed, the manufacturer must produce them upon request. Many regulations require workplaces to keep a binder of MSDS' wherever chemicals and even cleaning products are stored. (I've emailed for them before while on health and safety committees, having to throw out unmarked / generic containers or where an MSDS couldn't be found for.)

These sheets explain everything you need to know about handling, reactions to other chemicals, flash (fire) points, exposure, cleaning, disposal and safety concerns. Before worrying that the sky is falling, nasty stuff like nerve damage, central nervous system depression and carcinogenicity are usually caused by long term exposure. However, eye contact and drinking chemicals tend to be the most urgent emergency situations and your first reaction should be "hospital" or calling 911 while having the container handy so medical professionals know exactly what they're dealing with.

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In this specific case, a solid surface under the foam would have reduced the problems. It should also have been done outside or in a garage for venting of the fumes.

Now, something to his credit, turning a spot on the carpet in to archival quality resin aside, it turned out well. I wouldn't normally suggest it, because temperatures can be unreliable, but in this case, the heat and chemicals melted the styrofoam, through the paint, just enough to give it a rocky riverbed look and paint can be applied from the bottom to touch it up.

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(Conversation and images used with permission)