I've been restoring an old fiberglass sailing dinghy, and find I'm working with a wide range of highly toxic paints, solvents, and bonding agents. It's interesting that something as natural and non-polluting as sailing requires the use of so many noxious products to keep the boat afloat. And it's not only because I work for a safety company, but because I honestly believe using the best possible respirator for painting is essential when working on projects like this.
When we started, I expected the repairs would take a few weeks of work in the evenings. But as one part of the boat started to improve, the rest seemed to pale by comparison, and soon I was involved in an eight-month odyssey of fiberglass, epoxy, solvent, and paint.
As work began on the damaged fiberglass hull, I used a respirator to block the airborne particles from getting in my lungs. I didn't use gloves because I know from past experience that a little dust on my hands and arms doesn't really bother me much. But I know it affects people differently, and many folks like to cover up entirely, wearing not only gloves, but a disposable Tyvek suit or a long sleeve shirt, pants, and a hat.
Once the wet work began, I was cutting fiberglass mat and working with two-part epoxy every day. For me, that's when it's time to get serious. My 3M 7500 series half-face mask with organic vapor cartridges (3M 6001) keeps the vapors from the epoxy getting through and damaging my nervous system and giving me headaches. On top of the cartridges I added a prefilter. This is what keeps the clouds of fiberglass particles from getting to me. I use a 3M 5P71 prefilter that blocks 95% of airborne particles. The prefilters are held in place by a retainer.
This set-up is sold as a kit under the name 3M Pesticide & Paint Respirator. It comes with a box of ten of the prefilters.
As work progressed, I did need to replace those filters. It's pretty easy to know when to replace both cartridges and filters. If you find it difficult to suck in a breath, you're either woefully out of shape, or your filters are clogged (possibly both).
When the cartridges have absorbed all the organic vapor they can hold in their activated charcoal, the vapors will start making it past them, and you'll smell what you're trying to block even when your mask is fitting just right.
One little note about the cartridges: Don't leave them in the area you are working in. They will wear out more quickly. To preserve the cartridges, simply pull them off and put them in a plastic zip-lock bag. Or if the mask is fairly clean and not covered in smelly paint or solvents, put the whole mask in a bag. This gets the cartridges out of the air and doesn't allow them to absorb more vapor while they are not being used.
Once the fiberglass work and the endless sanding had been completed, we sanded the entire hull. For this type of work, even though I wear prescription glasses, I always make sure to put on wrap-around safety glasses.
For paint we used a regular one-part enamel. Not as toxic as the two-part epoxy paints, but respirators were definitely still necessary. Because she has a small face, I found a Moldex half-face respirator fit best. We used the Moldex 7000 series mask in the small size for her both because of the cost (less than $10 at the time of writing), but also because the fit was very good for her shape of face.
This is really important. Faces are different. You may find one brand does not fit as well as another. If you have to buy two masks, it might be worth while buying two different brands experimenting with the different masks produced by the various manufacturers will you find the one that suits you the best.
Again with her mask, we used an organic vapor cartridge with prefilters. And like the 3M, Moldex has a kit available. The Moldex Multi-Purpose Respirator is actually even better than the 3M in that it has a HEPA P100 prefilter. This blocks 99.97% of all particles down to the ridiculously small .3 microns and is more than a match for any dust or particulate matter this project is going to send our way.
I will say, my personal preference is always for the 3M 7500 series mask because of the soft silicon construction. It's softer, and is far more comfortable over extended periods of time. And believe me, I've been wearing it for extended periods during this project. Close inspection of the picture above will show that I am wearing her respirator, and she mine. What can I say? She liked mine better.