Quote:
Originally Posted by Terra Nova
Some people are very sensitive to epoxy, and so must wear protection. Most of us are not sensitive to it.
I am a marine professional and have used barrels of WEST epoxy, mostly for glue-ups, tabbing and coating. I fortunately am not sensitive to it, and typically work with no protection other than a dust mask, while sanding--not even gloves, unless doing a large layup, where I must handle large pieces of wetted out biaxial. The trick is to not get it on you and, once you have, to immediately remove the contamination; for this I use paper towels, often moistened with acetone.
I have seen and/or repaired delaminated polyester/wood bulkhead tabbing on numerous boats. And so would NEVER use polyester resin for this critical application.
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At last, someone with some experience.
I too have repaired polyester tabbing failures, that have occurred due to poor design, application, vessel use, or just simple wear and tear.
I have also repaired epoxy tabbing failures, for all the same reasons.
There are all kinds of claims all over the
internet regarding epoxy vs polyester. Many that proclaim significant advantages of epoxy over polyester, are affiliated with epoxy manufacturers.
In my experience, properly applied polyester resin in a secondary mechanical bond, is as strong, or stronger than the materials bonded whether
wood or polyester FRP.
I suspect some of the difficulties some DIYers experience with poor adhesion is from using box store polyester resin products that contain wax to facilitate curing in air.
Similarly if one adds wax to epoxy, poor adhesion results will occur.
As I have stated before, I tend to make
repairs with polyester where I can, for a variety of reasons. When I require its max
adhesive properties, I use unwaxed resin and then a proper method to facilitate curing in air if required (peel ply,
gelcoat, wax paper, wax curing agent in final resin rich coat, etc.)
If the naval architect and engineers specified polyester, that is what I use.
If they specified epoxy (very rare) that is what I use.
I will warn that one can use epoxy with no ill effects for years, and then one day, out of the blue, flair up, and from that day forward, can't go near it. I've seen 3 different people who have had this happen.
For some, this can happen first use, for others, no sign whatsoever, until one day...
Epoxy is made with known carcinogens. One should always use an organic mask when working with uncured and cured materials.
During curing, various toxic gases are emitted. People are lured into believing they are safe, because the smell is not offensive to them. Incorrect!
Even for cured material, the cutting and
sanding process causes the material to heat up, releasing carcinogenic vapours that can permeate the highest quality dust mask, which are typically rated to only filter 95% of hazardous particulate. Toxic vapours permeate without any real restriction.
The best
rule of thumb when working with epoxy and other hazardous materials; if you can smell it, your mask is not working, and harmful vapours are entering your lungs.
Be safe, this is a recreational sport and not worth risking
health over.
For me, this is part of my livelihood (I perform all manner of yacht repair,
maintenance, and improvement, fibreglass being about 25%), and I am careful not to needlessly risk my health over it.
It is very wise to read the MSDS for any material worked with, and follow the
safety precautions specified. If in doubt, err on the side of caution.
I had one prospect complain about my hazardous material rate for a
teak deck acid wash. "I've used that stuff wearing nothing but shorts and a T-shirt", he claimed. As he told me this he was being treated for Stage 3 cancer.
Stay safe.