Measuring Epoxy

Measuring Epoxy

Post by bob fortun » Thu, 24 Dec 1998 04:00:00



Merry Christmas One and All,

I was goofing around between wrapping Christmas presents and putting
ornaments on the tree and ended up epoxying something that broke.  I
like to use 4 to 1 epoxies, the stuff I get is from Tap plastics here in
California.  It seems pretty similar in characteristics to the West
Systems stuff.  

Well, since it's 4 to 1 it's a bit of a nuisance to mix properly so I
usually end up making a batch that's about 12.5 cc's because I use those
disposable plastic medicine cups you find at the hobby store.  There is
a 2.5 cc mark and I guess at the 12.5 cc since it's halfway between 10
cc mark and 15 cc mark on the cup.  I have been told that I can weigh it
but my scale is not that accurate so I'm either stuck with a largish
batch or I have to use 1 to 1 which doesn't seem to be as robust but is
easier to mix accurately.  If someone has smaller cheaper accurate cups
or spoons please let me know.  

First I mix it up good then I split the batch in two if it happens to be
too much and freeze half for later.  Then I dump the half I'm using on
the top sheet of a legal pad of paper with wax paper between the sheets.
 That way I can add the goodies I need like cab-o-sil or milled
fiberglass or microballoons and mix it up well.  When the paper is
covered or too goopy after a couple of batches I tear off the top sheet
and move the wax paper down one.  This is getting way longer than I
thought, sorry.

So here I need a ***y bit of epoxy, I have this pad of paper, so I
thought what if I used quad rule paper, the kind with vertical and
horizontal lines, then I would know (sort of) how much area the epoxy
covered and could (sort of) calculate the ratio. I squirted out the A
resin component, counted how many boxes it covered once it had spread
out, divided the number boxes by four and added that much of the B
catalyst to the paper next to the A.  Yes it is not as accurate as
measuring in a cup, spoon, dropper or weighing but it seemed to work in
this particular pinch.

Just thought I'd pass that along.  I was reminded of a story while I was
writing this.  I was working with this Englishman, Tom Leppere, and we
happened to see a huge flock of blackbirds winging overhead.  He says to
me "There are 346 birds in that flock" Of course I said "How in the
world do you know that?" To which he replied, "It's easy, just count
their feet and divide by two!"

Happy New Year To You Too!

Bob Fortune

 
 
 

Measuring Epoxy

Post by Bob Kapl » Fri, 25 Dec 1998 04:00:00


Quote:

> Well, since it's 4 to 1 it's a bit of a nuisance to mix properly so I
> usually end up making a batch that's about 12.5 cc's because I use those
> disposable plastic medicine cups you find at the hobby store.  There is
> a 2.5 cc mark and I guess at the 12.5 cc since it's halfway between 10
> cc mark and 15 cc mark on the cup.  I have been told that I can weigh it
> but my scale is not that accurate so I'm either stuck with a largish
> batch or I have to use 1 to 1 which doesn't seem to be as robust but is
> easier to mix accurately.  If someone has smaller cheaper accurate cups
> or spoons please let me know.  

I use small veternary syringes. They are calibrated in .1cc, so I can mix
very small batches. With 7:3 and 100:11 mix ratios, it's the only way to go.

        Bob Kaplow      NAR # 18L       TRA # "Ctrl-Alt-Del"

Kaplow Klips:   http://members.aol.com/myhprcato/KaplowKlips.html
NIRA:           http://www.nira.chicago.il.us  NAR:    http://www.nar.org


 
 
 

Measuring Epoxy

Post by Bob Chmar » Fri, 25 Dec 1998 04:00:00


Bob:

This is Bob.  Along the same lines as Bob's suggestion:

Quote:
>Well, since it's 4 to 1 it's a bit of a nuisance to mix properly so I
>usually end up making a batch that's about 12.5 cc's because I use those
>disposable plastic medicine cups you find at the hobby store.  There is
>a 2.5 cc mark and I guess at the 12.5 cc since it's halfway between 10
>cc mark and 15 cc mark on the cup.  <in-line snip>  If someone has
>smaller cheaper accurate cups or spoons please let me know.

My local pharmacy carries 3cc syringes that are graduated in .1cc increments
and that have removable needles.  I use the plungers to measure out 2.5cc of
resin and 0.5cc of hardener (I use West Epoxy which calls for a 5:1 ratio)
or any multiple thereof.  One added benefit of using the syringes is that
the needle covers can be forced back onto the end of the plungers.  With the
tips of the covers cut off, they make a great tool for applying the epoxy as
long as the mixture isn't too thick.

<snip>

Quote:
>So here I need a ***y bit of epoxy, I have this pad of paper, so I
>thought what if I used quad rule paper, the kind with vertical and
>horizontal lines, then I would know (sort of) how much area the epoxy
>covered and could (sort of) calculate the ratio. I squirted out the A
>resin component, counted how many boxes it covered once it had spread
>out, divided the number boxes by four and added that much of the B
>catalyst to the paper next to the A.  Yes it is not as accurate as
>measuring in a cup, spoon, dropper or weighing but it seemed to work in
>this particular pinch.

Prior to finding the aforementioned syringes, I e-mailed West to inquire
about their recommendations for mixing small amounts of epoxy.  Along the
lines of your idea, they suggested drawing two circles on a piece of paper,
the larger with five times the area of the smaller and then pouring the
resin and hardener on the paper.  They did mention that the reason this
works is because the surface tension of the West resin and hardener were
similar.  I would imagine that for small batches, you might be able to fit
three or four sets of circles on one 8.5x11 sheet of paper.

<snip>

Quote:
>Happy New Year To You Too!

>Bob Fortune

--
Happy Holidays!
Bob Chmara
NAR TRA HUVARS (additional letters added as acquired)
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