I got the following note a few months back off a website. It made a lot of
sence to me so I kept it. His soda bottle solution makes the most sense to
me because it is cheap, allows the amount of epoxy to be matched easily with
the weight of cloth and seems fast. It would also be possible to store the
bottles partially 'squeezed' to avoid any volume of air over the epoxy in the
bottles.
I hope this makes sense and is helpful.
Dave Leonard
Deigo Garcia
Still trying to settle on a design....
>>>>Hello ......................, To answer your question about an epoxy pump
warm
box: I bought an expensive, variable ratio resin / hardener pump and put it
in
a warm box.
My box is a cube about 2ft X 2ft x 2ft (I'm too lazy to run down to the shop
and measure it). Dimensions are not critical anyway as long as it is big
enough to hold the pump. I built it out of the "free" 3/8 inch thick plywood
crating material that my kit came in, using 2 inch by 2 inch square lumber to
provide a frame work. Screwed it together with drywall screws. For
insulation I lined the inside of the top, back, front, and sides with some
drop
in ceiling tile pieces that were lying around. For access, the top and front
lift off as a unit--no hinges, real simple. Only hardware is an old drawer
handle on the top. Mounted it on an old rolling Sears tool box that the
neighbor put out for trash.
For heat I installed a porcelain light bulb socket and a line thermostat from
Home Depot. The line thermostat handles the 110 volts directly. I use a 100
watt bulb. A coiled nichrome wire heater element screwed into the socket
proved too hot and tended to scorch the plywood. I have a small piece of
aluminum sheet shielding the plywood closest to the bulb. I keep a
thermometer
inside the box and try to maintain 70 - 80 degrees F inside. I'm using Aero
Poxy, but I'm not sure what the recommended storage temperature is, or if Aero
Poxy has ever published one.
Now that I've given you all that good info let me ask you a question: Why
bother with an epoxy pump? Here is my thinking. To start with you have to
have a pretty good scale, I would think, even if you bought a fixed ratio
pump.
I know that I would check the ratio out with some independent means, and with
a variable ratio pump the scale is mandatory to adjust the ratio properly.
That will take some fiddling and should be checked every so often. So you
start out with that $80 postal scale from Aircraft Spruce or Wicks..
Then why not buy or find a couple of those after market, screw on drinking
tops
for plastic soft drink bottles that allow you to open or close them with a
push
or pull? Then get a couple small plastic funnels from the Dollar store (used
to be the 5 & 10 cent store). Use a magic marker to mark one R for resin and
one H for hardener. Then wash, rinse, and dry out two plastic soft drink
bottles of a convenient size and different color and mark them Resin and
Hardener also. Then pour your resin and hardener from the factory containers
into the two bottles--don't be sloppy--and screw on the drinking tops.
Now, either with a pocket calculator, or better yet, a computer spread sheet,
work out the numbers (using grams, ounces are too crude) for various
quantities of the required mixture by weight. The formula looks something
like: X resin grams +
Y hardener grams = (X+Y) mixture grams. ( In my case it is 100 rg + 27 hg =
127
mg because the specified ration is 100:27 for my stuff). Dividing by 127
yeilds: .787rg + .212hg = 1mixture gram. Decide what you consider to be
appropriate quantities of mixtures to have, and multiply the above equation
accordingly. ( I'd pick 10, 20, 30, 40, 50, ........and so forth. (My pump
puts
out 16 grams of mixture per stroke and I very seldom use less than one
stroke).
Now with your calculated table or spread sheet handy, decide how much epoxy
mixture you want either from weighing your glass fabric or other appropriate
technique. Turn on the scale, put on an empty mixing container, zero the
scale,
and squirt in the proper amount of resin--you should have pretty precise
control--then squirt in the proper amount of hardener until the scale reads
the
proper total amount. Proceed to stir and use the mixture. This may not be as
quick as just stroking the pump a few times (with the pump you still have to
calculate how many strokes to take if you are looking for a specific amount of
mixture), but it sure ain't going to slow you up that much.
Some miscellaneous thoughts. You can keep all your resin and hardener
supplies
in temperature controlled living quarters because all containers are sealed
airtight at all times (store the soft drink bottles upside down if you want to
be absolutely sure that no air flows in or out). If you are concerned that
maybe some of the resin or hardener may be coagulating and separating a bit if
it sits a long time (I am), you can slosh your factory containers around a bit
before you pour into the soft drink bottles and you can slosh the bottles
around a bit before you pour for mixing. You can't do that with the pump
containers. You won't have a constant faint (you hope) smell of hardener in
your shop (the pump containers are not airtight). And you won't have a crusty
build up around the top inside of the pump hardener container. Or suspicions
of clogging at the end of the pump outlet tubes. Or worry about the pump
going
out of adjustment. Or air gaps in your pump outlet tubes that can give you a
wrong mixture if you are mixing a small batch. And if you have any
suspicions
that either the hardener or resin may be sensitive to light, you can store the
soft drink containers in a dark place. And the damn pump and stand won't be
eating up valuable floor space in your shop. Spend the money you save on the
pump to keep your significant other happy. It will pay off in the long run.
I welcome comments and questions from others on this subject.
Good luck with whatever you decide and please keep us posted--we care.
'OC' Baker, Builder of KIS TR-1 #116 4/14/97 - ?/?/?<<<<
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