Epoxy Resin - Non Traditional Uses
Bob La Londe
Have any of you guys poured epoxy solids?
Encased things in epoxy?
My daughter said one of her friends said she wanted some paperweights for
Christmas with fish in them or fish shaped paperweights or something like
that. (Yes my daughter's friend is weird.) I thought I might buy some toy
fish at the local toy store or whereever I can find something suitable and
then pour them into some epoxy solids. I figured a cube, a tetrahedron, and
maybe a dome. Making a mold for a sphere is not out of the question either,
but I was thinking maybe just a hemisphere for number three.
I can make molds out of wood or aluminum for the cube and tetrahedron. For
a sphere or hemisphere I would probably have to go with wood.
I was thinking if I go with aluminum I would polish the interior surfaces,
put a tiny bit of clear RTV adhesive silicon in the seams and spray the
inside with non flavored cooking spray to prevent sticking. Basically screw
the pieces together. When the resin is hard remove the screws and knock the
sides off. Then cut the bottom square and epoxy on a layer of felt. Any of
you guys see any problems with that approach?
For wood I was thinking I could make it similar to the aluminum, but coat
the wood pieces with epoxy first. Would take longer because I would have to
make sure the resin coating the wood was fully cured, and thick enough to
machine smooth for drilling and assembling the mold. The advantage to wood
is I could more easily make a sphere or hemisphere shape, and it would be a
lot cheaper than a piece of aluminum thick enough to make a reasonable size
sphere.
You have any tips?
Any Alternatives?
Reasons why my idea is totally stupid?
I have several gallons of two part epoxy left over from a previous project.
I also considered milling some fish shapes out of wood and using them in the
"paperweights", but I am concerned that escaping air might cause bubbles in
the end solid. I suppose I could paint the shape with epoxy before encasing
it.
cavelamb
A better choice is acrylic casting resin for jobs like this.
It is generally crystal clear, but can be tinted or pigmented,
or filled with a filler (sand, marbles, keys...)
Any thickness (depth) of epoxy will likely go thermal on you and boil.
Bob La Londe
news:jeCdnV00dcgHYorW...@earthlink.com...
That's what I was afraid of. One of the reasons I was considering aluminum
as it transfers heat very efficiently, and I have some. I also have epoxy
on hand which is why I was considering it. How about small batches, partial
cure and then next pour?
Bob La Londe
What about regular polyester resin? I might have enough on hand to do one
item?
Trying to do this with stuff on hand. She isn't "my" friend. LOL.
IanM
done that, kicked the burning pot out of the workshop.
Also the shrinkage will *kill* you as without reinforcement it will
crack round any object you include.
If you *want* a nasty yellow lump, go for it ;-)
If I *had* to do this, I'd use slow cure epoxy at a carefully controlled
low temperature in a PVA mold release treated polished round flat
bottomed metal mold or a PVA treated polyproplyne mold and pour not more
than 1 cm deep at a time. The objective is a flat, puck shaped
paperweight with a relatively THIN object inside. Its probably best to
work upside-down for simple stuff. Pour 1/2 cm top, cure slightly past
gel. Position epoxy dipped object, with something holing it down. Pour
another 1/2 cm and cure again. Pour enough more to cover and this
time cure to a firm green cure. Remove from mold, clean up the
meniscus, sand the back smooth, rough it up a touch and build up tape
dams round the edge. then cast on a layer of opaque black epoxy
(graphite or carbon black in large quantities - its black for the rest
of the process) then what ever weight you want like lead shot, or iron
filings in epoxy. Finish with a thin layer to smooth the base. Post
cure for about a week as near to 100 deg C as you can comveniently
manage, chill , and sand and polish out any defects and glue black felt
on the base.
You may need a bell jar and vacuum pump to get the bubbles out of each
layer before letting it cure. As has been said, best done in Acrylic
casting resin, but if you choose an object that would benefit from a
honey coloured resin, it could look good.
--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & >32K emails --> NUL:
brian whatcott
>...
> Have any of you guys poured epoxy solids?
>
> Encased things in epoxy?
>
> a layer of felt. Any of you guys see any problems with that approach?
The problem I can see is the runaway heating you might get for the
two-part you have on hand which (I assume) is intended for binding glass
etc. That would lead to cracking. People do use water-clear epoxy for
deep glassy layers on table-tops or encapsulating. I am supposing that
is formulated with an eye to avoiding thermal runaway. Perhaps you could
pour two egg cups full, and put one in the fridge to slow the set.
Contrast & compare??
Brian W
Bruce In Bangkok
wrote:
Normal boat building resins are not the best materials for casting
solid objects. For one thing you will have to be careful how you mix
them to avoid heat buildup and for a second it is hard to "get the
bubbles out". For some reason mixing, particularly epoxy, seems to
generate a multitude of tiny bubbles which do not disappear when you
pour the mixed epoxy into a mold.
But having said that I have successfully cast epoxy in wedge shaped
blocks to level depth sounder transponders which are mounted inside
the hull.
Cheers,
Bruce
(bruceinbangkokatgmaildotcom)
Bruce In Bangkok
wrote:
>"cavelamb" <cave...@earthlink.net> wrote in message
If you mix epoxy rich enough that it gets really hot the aluminum
molds will probably not absorb heat fast enough. The reason is that
the heat build-up actually causes the mix to react faster so it is
somewhat of a circle. More heat faster reaction causing more heat...
With epoxy you can mix batches with a bit less hardener to harden
slower and likely get away form too much heat. Polyester is harder to
use as the percent of catalyst is only 1 - 2% which means that just a
drop, or so, extra is too much.
But try it, keeping the thought in the back of your mind, "it may get
hot". I've had polyester get hot enough to char a paper cup.
Cheers,
Bruce
(bruceinbangkokatgmaildotcom)
Bob La Londe
news:hf972j$2ve4$1...@energise.enta.net...
> You may need a bell jar and vacuum pump to get the bubbles out of each
> layer before letting it cure. As has been said, best done in Acrylic
> casting resin, but if you choose an object that would benefit from a honey
> coloured resin, it could look good.
Just for the heck of it I looked up acrylic casting resin. I ran across
some polymer resins that claim to have low thermal curing properties and
near glass clear finish, but are only about as hard as stamp rubber when
cured. I may buy some of that to make some stamps. LOL. Not my choice for
a paper weight though. Then the Acrylic casting resins I found seem to need
to be cured in an oven or something like that. So what exactly kind of
resin was the stuff I used way back in high school in general science class?
It was super hard when cured, it didn't get stupid hot while curing, it was
clear with no bubbles, it seemed to wet out the stuff we put in it just
fine, and we just cured it by leaving it sit on a lab bench over night.
Bob La Londe
www.YumaBassMan.com
cavelamb
If I may add something here, Bruce?
The heat buildup works from the inside - out.
So absorbing heat at the outside isn't going to stop it from boiling in the middle.
>
Brian
"Bob La Londe" <nos...@nospam.no> wrote in message
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Try this link
http://www.smooth-on.com/gallery.php?galleryid=327&cPath=1271
Bruce In Bangkok
wrote:
True. I should have said that.
Cheers,
Bruce
(bruceinbangkokatgmaildotcom)
mmc
"Bob La Londe" <nos...@nospam.no> wrote in message
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http://shop.ebay.com/?_from=R40&_trksid=p3907.m38.l1313&_nkw=fish+paperweight&_sacat=See-All-Categories
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