brass + rubber = oxidized brass + rotten rubber???
ampquot
hi all. i am an artist and i am experimenting with materials.
recently i soaked in rubber (liquid latex) some of my drawings (ink on
paper, with brass leaf) and then polished them with a car polish.
brass goes darker (oxidize?) and gets green in zones with a
larger amount of rubber. thats nice, but i wanted to know what
happens.
but the bad news is that i notice now that while the one i got
on tne wall is still looking nice (a bit smelly though), one another i
wrapped in paper and put away for a while has gone rot in a smelly and
totally sticky substance in the areas upon brass leaf
i am quite ignorant in chemistry, so i ask you what do you
think is happening, if you can give some hints to preserve my work or
even suggest some more resistant but yet versatile material
and a last question.. i work soaking my hands liberally in
latex. is it toxic? should i use some glove (but gloves are latex, i
am afraid they will stick together)
thank you in advance
amp quot
Uncle Al
Liquid latex is an emulsion of natural rubber stabilized with
ammonia. Ammonia attacks copper and its alloys. Natural rubber
is highly unsaturated and not crosslinked. It will air-oxidize
into a horrible mess unless a preservative package is added.
Copper and its alloys are also labilized by unsaturation (soft
Lewis base vs Cu(I)).
You would do better with a solvent-borne saturated Kraton rubber
or a solvent-borne or water emulsion of polyurethane elastomer
(e.g., Spandex).
--
Uncle Al
http://www.mazepath.com/uncleal/
http://www.ultra.net.au/~wisby/uncleal/
(Toxic URLs! Unsafe for children and most mammals)
"Quis custodiet ipsos custodes?" The Net!
ampquot
first of all many thanks for your attention :)
On Sat, 23 Jun 2001 09:05:20 -0700, Uncle Al <Uncl...@hate.spam.net>
wrote:
>Liquid latex is an emulsion of natural rubber stabilized with
>ammonia. Ammonia attacks copper and its alloys. Natural rubber
>is highly unsaturated and not crosslinked. It will air-oxidize
>into a horrible mess unless a preservative package is added.
i bought my liquid latex in a common paint shop. can
you please suggest me a preservative to add or a more specific
product to look for?
>You would do better with a solvent-borne saturated Kraton rubber
>or a solvent-borne or water emulsion of polyurethane elastomer
>(e.g., Spandex).
could you kindly provide me some commercial name for
those materials? is spandex or others available as liquid in stores?
and also, an online reference to learn just a bit of chemistry
not to ruin all my works or intoxicate myself using unconventional art
materials? ;))
thank you again
amp quot
Mark Thorson
> i am quite ignorant in chemistry, so i ask you what do you
> think is happening, if you can give some hints to preserve my work or
> even suggest some more resistant but yet versatile material
Wax would be very inert and wouldn't attack brass.
Rosin would also be corrosion-free, but it's brittle.
Rosin and wax can be mixed to form a material
with intermediate properties. Pure rosin is hard,
shiny, and transparent at room temperature,
ranging in color from light yellow to dark brown.
It's used as a soldering flux and as an important
ingredient in printer's ink. Rosin ultimately comes
from trees, either from collected sap (gum rosin)
or as a by-product of papermaking (tall oil
resinates).
Shellac is also transparent and light yellow to dark
brown, but it's much more flexible and tough. I doubt
it would be corrosive. It can also be mixed with wax.
(Raw shellac naturally contains wax, which is removed
from the commercial product.) Shellac is used for
the shiny surface on some candies (malted milk balls)
and pharmaceuticals. Shellac ultimately comes from
secretions of the lac insect, which is cultured for this
purpose, mainly in India. There's a good site for
shellac, http://www.shellac.net, which has both raw
shellac in various forms for sale and plenty of advice
and information. (I have no connection with these
people -- I found their site on a Google search for
a special grade of shellac.)
Bill Walker
Pearl Paint / Pearl Art Supply.
"Artist Beware" or something like that is about health hazards of many
artist's materials.
Ask the salesperson to earn their minimum wage by helping you.
There are a wide variety of spray-on coatings specifically designed for
what you want made by people who actually know what they are doing.
Why not pick up some spray at the art store (heinously expensive) or get
a gallon at Home Depot and use a paint sprayer?
There must also be a few art newsgroups that you can post to...
Bill