epoxies and the dreaded bysphenol-A

[Boston]

hi folks
Ive been out of the boat building scene for way to long
any one know if there is a decent alternative to Bysphelol-A based epoxies out there ( serious endocrine disruptor )
hopefully one that wont cost an arm or a leg or both
oh
and not the formaldehyde based glue ( recipricol I think )
Ive been building houses for eons and if Im going to live aboard I want it both smelling and looking sweat
( turns out formaldehyde is a little hard on the old nose )
doing feasibility study on the ted Brewster design Thursdays child
thanks folks
B

[BWD]

epoxy = bisphenol A + hardener, no way around that that I know of
but how do you feel about vinylester?

[Boston]

Ill have to take a look at its chemical make up
but as a rule the softer the plastic the more plasticize r's are in it
and its those additives that tend to be the biggest offenders
all plastics degrade and release there binders and plasticize r's
so how bad one is compared to another is generally based on what the original content of those agents were
pvc is the worst
and polycarbonate is being banned from food contact in a new country every time I sneeze

polyester is fairly neutral if I remember
vinyl is definitely not
if the product is a combination of the polyester fiber in a vinyl matrix
then Ild say its toxicity is kinda questionable
but would be significantly less than epoxy that is some huge percent BPA
at least to work with

tell me what you know about this vinylester stuff
and Ill see what I can find out
B

[Boston]

vinylester
I did a short search of vinylester and found the following

it is a structurally inferior ester using a blend of epoxy resin with an unsaturated monocarboxylic acid. ( straight out of Wikapedia )

I dont know jack about carbolic acids
but the use of liquid styrene would be it for me

and uses styrene as a reactive solvent
styrene is some nasty stuff
samples from workers exposed to styrene found contamination in 100% of tissues taken
( that means its extremely permeable to human skin )
also
in 100% of breast milk samples taken
( that means its stored in the fatty tissues )
and is a known carcinogen and tarterogen
and causes nervous system damage
( were it hangs out and melts you one little tiny piece at a time )

I was kinda hoping to LIVE on this boat
not die on it
or building it

there must be a reasonable friendly glue out there
frankly if I cant find one
Ill just go with epoxy and encapsulate it

"Study Finds CFC Alternatives More Damaging Than Believed," The Washington Post, December 10, 1989.
"Styrene: Health Affects of Low-Level Exposure," FASE Reports, Foundation for Advancements in Science and Education, Los Angeles, CA, Winter 1988, p. 1.
"Reproductive Effects of Environmental Chemical Exposure," FASE Reports, Foundation for Advancements in Science and Education, Los Angeles, CA, Spring 1992.
"Re:sources," Environmental Action Magazine, Environmental Action, Takoma Park, MD July/August 1988, p. 19.
"Styrene: Health Effects of Low-Level Exposure," op. cit.
"Re:sources," op. cit.
"Plastics Industry Grasps for Straws," Everyone's Backyard, January/February 1990, Citizen's Clearinghouse for Hazardous Waste, p. 6.

[BWD]

frankly if I cant find one
Ill just go with epoxy and encapsulate it

Seems to be the common conventional/rational choice for most. Of course, if you are up for it, you can avoid all that sticking to the old ways...
I use epoxy myself, try to be neat and clean, and hope I never end up regretting it.
Good luck.

[Boston]

ya I was just hoping maybe an alternative had reared its ugly head
in all the eons Ild been gone

thanks for the input
B

[Boston]

found this floating around


ABSTRACT
One-part polyurethane wood adhesives comprise a new class of general purpose consumer products. Manufacturers' claims of waterproof bonds brought many inquiries to the Forest Products Laboratory (FPL) from users constructing aircraft, boats, lawn furniture, and other laminated materials for outdoor use.

Although FPL has technical information on several types of polyurethane and isocyanate-based adhesives for wood, no information was available on this new class of adhesives. Four commercial polyure-thane adhesives, along with a resorcinol-formaldehyde adhesive to represent a standard of performance, were subjected to a series of industry-accepted tests that assess varying levels of bond strength and durability.

In bonds to yellow birch and Douglas-fir, the polyurethanes did not differ significantly from each other in their performance; as a group, though, their dry shear strengths showed that they were significantly stronger than the resorcinol. Dry wood failures by the polyurethanes were high and did not differ significantly from the resorcinol.

After three water-saturating procedures, wet shear strengths of polyurethanes and the resorcinol were statistically comparable. Wet wood failures, however, were very low among polyurethanes, which is a sharp contrast to the high wood failure by the resorcinol.

A moderately severe delamination test indicated varying levels of water resistance among the polyurethanes, but the resorcinol was completely resistant to delamination. A very severe cyclic delamination test caused severe delamination of polyurethane bonds. However, a recently discovered hy-droxymethylated resorcinol (HMR) coupling agent dramatically increased delamination resistance of polyurethane adhesives. In a test of resistance to deformation under static loads, polyurethane bonds withstood extreme exposures of temperature and relative humidity for 60 days without deformation.

http://www.fpl.fs.fed.us/documnts/pdf1998/vick98b.pdf

[Boston]

Resorcinol Phenol Formaldehyde Adhesive
Resorcinol alone was used for some years as the phenolic substance. Later it was realized that the important properties of a resorcinol formaldehyde adhesive could be retained, and the cost reduced, by replacing part of the resorcinol with ordinary phenol. Cresol is less suitable but limited amounts of vegetable tannins may be used. All the earlier remarks relating to "pure" resorcinol, apply broadly to resorcinol/phenol adhesives, at least in the amounts in which phenol is normally used to replace resorcinol. The usual replacement is up to one half the molecular proportion of total phenolic constituents, but as much as 80% has been suggested. Without sacrificing too many desirable properties it is certainly possible to replace considerably more than one half, but the process of room temperature hardening after gelation becomes progressively slower as the proportion of phenol is increased. Another disadvantage of using too much phenol is that the characteristic phenolic smell (completely absent with resorcinol) may be pronounced, even in the fully hardened glued joint.

There are two principal methods of preparing resorcinol/phenol resins; formaldehyde may be reacted with a mixture of resorcinol and phenol, or the resorcinol and phenol may be reacted with formaldehyde in separate stage. Both methods can lead to similar products; properties of the product depend much more on the molecular ratio and pH of the reaction than on anything else.

[Boston]

Recorsinol
materials data safety sheet for weldwood recorsinol powder catalyst part A

http://www.dap.com/docs/msds/3022022.pdf
7 pgs

not sure I should be posting what Im learning about glue here but
if Im going to glue fifty thousand in wood together Ild like to know what Im sticking it together with
and who knows
maybe some one will find it interesting
B

[Boston]

I was looking at the issue of epoxy failures when used on white oak
as Im planning white oak frames for my own project
and found this next enlightening

http://www.fpl.fs.fed.us/documnts/pd...frihart003.pdf

[Boston]

apparently some one made a epoxy specifically for oily or water repellent woods like white oak and teak
http://www.smithandcompany.org/OT/UsingOT.html