IMO you should wear a respirator.  You need to be sure that the filter cartridge you are wearing is rated for VOCs or it won't do any good.

I didn't wear one at first and I developed a sore throat after a long session of glassing the inside of the hull.  Since then I have worn a respirator.

-- jaydilloyo

Applying you should be OK assuming well ventilated shop.  I wear mine when working in confined area (aka in the inside of the boat) and while mixing cab-o-sil, that powder is really bad for you.  Once it is mixed and no longer power, I ususally ditch the mask, unless it is a little cooler out and I cannot have the cross ventilation open.

Sanding you definitely want a respirator.  You mentioned only one mask, is it a canister one or a paper dust mask?  Invest in a canister one, your lungs will thank you.  properly cared for, they last forever and what a difference!

http://www.leevalley.com/en/wood/page.aspx?p=62067&cat=1,42207,42220

The reason why CLC doesn't mention it is that you don't really need one when using the MAS epoxies.  They are very low-VOC and don't have a horrendous odor.  That being said, I use one when working with large quantities, just for the fact that I'm exposing myself for longer periods of time.  The cartridges that Jay is referring to are organic cartridges... they'll filter out 99% of VOC's. I would also wear one when varnishing...

~Chris 

Wow- thanks for the quick and thorough replies.  Three helpful responses in less than 30 minutes!  Keep up the good work.

Jeremy

I built my boat in my basement and found that without the respirator I got nasty headaches...this cannot be be good. So thereafter I always wore mine. Especially when applying a large amount over a broad area, ie, the hull or deck. Ditto varnish.

You should wear the respirator when working with fiberglass even without the epoxy.  Even just smoothing it out can cause tiny filaments to become airborne.  Without a mask these tiny, sharp, pieces of glass will get into your throat and lungs.  A dust mask would probably do, but when you add epoxy into the mix (no pun intended) you won't have to switch out. 

be sure to keep the canisters in a seal bag when not in use and to change the cartriges as they will absorbe slovent and no longer be of any use

Lots of advice here, but I think one thing is missing.  A small percentage of the population is susceptible to becoming hypersensitive to epoxy (some to the resin, but I think more to the so-called "hardener".)

If you are one of those people, then managing your exposure level with a canister type mask may prevent hypersensitivity, or at least postpone it and give you more years of enjoyment of the hobby without going to extreme measures required once you become hypersensitive (like Tyvek suit, double-gloving, etc.).

Note: I've never seen any scientific evidence that fibreglas or fused silica powder are bad for you, but like the other post-ers I tried to avoid inhaling either one just on general principles, and the canister mask does a better job of this than a paper filter mask--it seals better.

I think that most people on this forum believe that inhaling fused silica or fibreglas is a proven cause of serious lung disease.  Believing that is probably a GOOD thing, because it makes us more cautious.  But I think they are confusing silica and fibreglas with airborne asbestos, which actually IS a proven cause of serious lung diseases (mesothelioma and cancer), because of the shape of its particles.  Cabosil and glass particles do NOT share this shape, fortunately, which is why they are apparently quite harmless.

Camper,

There's always silicosis, which is caused by inhaling large quantities of silica dust, especially crystalline forms. Fortunately, cab-o-sil is the amorphous form and home builders usually only use a little of it for a short periods of the build, so the risk is pretty low, even without a respirator.

That said, every kind of dust (including sawdust) in large enough quantities over a long enough time is bad for your lungs, so dust masks and vacuum systems to control dust are a good idea.

FWIW, I'm in the same boat as Dan. Exposure to hardener fumes gives me a sinus headache. I take that as a signe that I'm one of the folks who could get allergic, so it's a VOC respirator for me (and dust masks when it gets dusty).

Laszlo

You're in the same boat?... but I only built a single... ;-)

This is a great post and has me wondering if I have been careless up to this point. I am using the MAS epoxies and I was surprised at the low oder which to me was less offensive than say a urethane which does not bother me either.I have glassed and epoxied the inside and outside of my bottom hull with no respirator and no noticable side effects. I do break out a good respirator when sanding --not good ?...........CZ

I'm in the same boat as CZ, build in the basement and really didn't mind the smell of MAS, kinda sweet. BUT when it came to sanding that stuff ( in the garage) I wore a North mask for particulates, The fine powder is nasty, and gets everywhere.

I was wondering how, in the video, John spends a long afternoon, outdoors sanding, and comes up spotless, I look like frosty the snowman and leave a trrail of dust like pigpen from charlie brown.

Yes I have a sander with in pad holes for dust, with a hose attached to the vacume, but it is still nasty.

Ted B

I use a vacuum attached to my sander also have a Jet dust collector running in my shop when sanding. I still use a respirator. When may ROS died I purchased a Festool sander. The dust collection is amazing.

Festool does make some top notch tools but unfortunatly for me gets a top notch price. Congradulations on a fine power tool-it will last you a lifetime--if you factor the cost and divide it by your anticipated life time it all looks better --CZ

I have to agree. After I left the store, I had second thoughts. But after using it for the last three months, I am lad that I spent the extra money.I enjoy wood working and dont plan on stopping any time soon. Heck with all the kayak designs that I want to build, I have the next ten years already planned. So many cool boats to build with so little time.

W-5

I was in our local Wood Craft store today and I found that Festool does make some top notch abarasive as well. They make a 5" disc which will fit my Dewalt-R.O. and I plan to give them a try. Happy sanding--CZ