Epoxy
costs money, and you would be surprised how much is actually left inside
a jug of epoxy or hardener when it appears to be empty. Here's how I get
ALL of
my epoxy for my money.
WASTE-NOT, WANT-NOT!
Epoxy
costs money, and you would be surprised how much is actually left inside
a jug of epoxy or hardener when it appears to be empty. Here's how I get
ALL of
my epoxy for my money.
When there is not enough left in the jug to do anything with I pour
it into the next jug. That's easy but there is a lot left clinging to the
sides and the bottom of the jug and to stand there and hold it for the
length of time it
would all take to run into the new jug would be very tiresome indeed.
Viscosity you know!
Here's the solution!
After you have used a few jugs, you should keep the caps. Usually the hardener caps are a different colour from the resin caps and you need two of each. Get a spade bit from the drill-bit collection that's just a tad smaller than the inside diameter of the cap. Carefully drill out the cap so that all that is left basically is the wall of the cap, (perhaps with a little ridge for strengthening). Do this with all four caps.
Get some electrical tape and tape the two sets of caps together as seen
in the photo and the drawing here.
When it's time to drain a near-empty jug you can see from the photo
how this is accomplished. Screw the two jugs together, put the full one
on the bottom and the near-empty one on top and go away for a day. When
you come back there will be near NOTHING left in the near-empty jug!
Remember, epoxy costs money! Don't waste it!
EASY MIXIN
For a long time I used measuring cups from 5-gallon tubs of washing detergent for measuring out epoxy and resin. I would measure out the particular components and then mix them together in empty dog-food cans. One thing to be sure of naturally, is that you have two measuring cups and that you keep them separate. I mark one with a piece of black electrical tape and use this one for hardener only.
The
only problem with this technique is that the measuring cups soon get pretty
grungy! The hardener and the resin residues get really sticky and nasty.
I still liked the quick measuring technique but not the mess.
Here's my new solution!
I bought a whole mess 'o plastic cups at my local food price-club! I took a clean and new measuring cup from a new five-gallon tub of detergent and carefully measured out the following into one of my new plastic cups:
1/4 cup
1/2 cup
1 cup
At each point I placed a piece of black electrical tape. As it turned out, the bottom of the first piece of tape was for 1/4 cup and the top exactly fit the 1/2" cup. A separate piece made the 1 cup. These tape markings can be seen in the photo together with the detergent measuring cup used to calibrate them. I use RAKA epoxies, and these are all 2:1 mix ratio. Thus, I can mix up batches in various quantities. 1/4 cup to 1/2 cup. 1/2 cup to 1 cup, etc. And here's how it keeps all clean and nice!
I put the cup into which the mixture is going to be made INSIDE the marked cup. When I add the resin and hardener it is easy to see when it reaches the calibrated marks. The calibrating cup never receives any of the material and so stays completely clean. The resin is added directly to the hardener, the inside (mixing) cup is removed, the measuring (outside) cup set aside and then the epoxy mixed and used. Following this of course that plastic cup is thrown away.
KEEPING POWER TOOLS FREE OF EPOXY
I completely encased two good variable speed drills with epoxy before
I thought of the simple alternative described below.
Epoxy is wonderful stuff; dependable, strong, highly water-resistant,
etc. It is also messy, sticky and pernicious. By now
we all know enough to use vinegar to clean off uncured epoxy from our
tools and ourselves, but even with thorough
cleaning and good discipline, epoxy does get on the tools once in a
while. A prime candidate is the drill/driver. I gave up
my corded power drivers in place of a really nice 9.6 volt Makita and
I really did not want to get this expensive tool all
covered with epoxy. (The two drill/drivers which I previously damaged
were $20.00 Black and Decker's so it wasn't a
terrible loss, but the Makita is too good and too expensive to gum
up).
The solution was dead simple.
Each time I use the Makita now I simply grab a gallon-size Zip-Loc™
bag and shove the drill, bit holder and all into the
bag. I stick the bit and holder through one corner and then fold the
bag down over the tool. This way, the rubber gloves
which I wear and which get real slimy with the epoxy, DO NOT transfer
all the mess to the tool. The cordless tools don't
require too much ventilation and so being enclosed in the bag doesn't
seem to bother them. Anyway, they are not run
continuously so they get plenty of time to cool off. Also, the bag
is open at the bottom so there is some air transfer through
that and out through the hole in the corner. The bag is flexible enough
so that it doesn't interfere with the operation of the
trigger or the general handling of the tool. Works terrific!
If you try this, be sure to push the bag back around the chuck so that
is close to the body of the tool. Otherwise, you will
wind the whole bag up in the chuck teeth.
EPOXY SOLDERING
I have all copper piping on board Toad Hall. I have outlined its' vertues in another tip on this page and I won't repeat them here. The problem with soldering copper in very confined (and wooden) spaces is the heat from the torch flame. I know, there are shields that you can buy to protect the surroundings, or even better, make one up from a bit of flashing, but sometimes, it is just darned difficult to solder in the very confined spaces on board a boat.
I decided to try epoxy.
I epoxied a copper end cap to a piece of 1/2" copper tubing and let
it cure. I did not thicken the epoxy; just used it right out of the mix.
When I painted it on to the end of the tubing and applied the cap I rotated
the cap a quarter turn to make sure that the epoxy was well spread. (This
is also good soldering practice).
The next day (I used a fast setting epoxy) I hose-clamped the piece of tubing and epoxied-on cap into a garden hose, attached the hose to a hose bib and turned it on. House pressure in Philadelphia is about 55 psi. The epoxied cap held perfectly with NO LEAKS!
I subsequently used this technique in a couple of places on Toad. Since my water pressures are mostly gravity feed I don't think there will be any problem.
Most water pressures on a boat are not anywhere near house pressure so I think this is a good technique for use when you can't risk a flame.
A CUP OF THIS AND A PINCH OF THAT
I distrust those pumps that they sell to measure out your resin and hardener. I just cannot bring myself to believe that the accuracy is all that great. A little air, a little too weak or too exuberant pumping!; I'm sorry, I just don't trust them.
I like to be able to see the ratios and measure them that way. Some people measure by weight but the epoxy that I use is a 2:1 volume type. I use those little polyethylene cups that come packaged with laundry detergent. They are marked in "cup" and "fractions of a cup" measures. Using these little cups I can see exactly what I am measuring out and get it right every time.
If you do this, put a piece of black friction tape, or some other kind of marker, on one or the other of the two cups so that you do not inadvertently mix resin and hardener in the same cup. They can be used for a long time; especially if you keep them clean between uses.
VINEGAR
By now, I am sure that everyone knows that the best solvent for cleaning up uncured epoxy is plain, old, white vinegar. The cheaper the better! It is non-toxic and readily available. But, you can also use vinegar to extend the life of your epoxy brushes. I can get several uses out of a brush if I store it standing in a tin of vinegar.
If you have ever tried storing a used brush in a can of acetone you know it just won't work. The brush still hardens up. The acetone doesn't inhibit the reaction just slows it down a lot.
After I use a brush to apply epoxy, I wash it out in the dog-food can of vinegar and then leave it standing in there until next time. Before the next use, I clean it as best I can, squeezing out the excess with a paper towl and getting it as dry as I can. Someone asked me once if I wasn't afraid of contamination of the epoxy with the vinegar, but I can get the brush dry enough that I don't think there's much danger; at least it has never given me any trouble.
If you do this, you will need to change the vinegar after every couple of uses as it seems to lose its strength.
WAX PAPER, OH NO!
Don't use wax paper beneath any material to which you are applying
epoxy. While in cool temperatures you may encounter no difficulty, on hot
days the wax can soften and attach itself to the work, making removal difficult,
and epoxy re-coating even more chancy if the removal is not diligently
accomplished.
Use polyethylene sheet or Zip-Lock Bags (gallon size) cut open and flattened to form a protective cover between the work and the bench.
COVER FOR THE WORK TABLE
Cut a piece of polyethylene sheet with which to cover your epoxy table.
This will prevent any spilled activated resin from welding itself in inconvenient
lumps to the surface and make it possible to easily remove any work, the
epoxy for which has bled onto the surface.
A CONVENIENT LITTLE SPREADER
The foam brushes which are useful (especially for varnishing) are often
attached to a wooden handle. Once the foam tip has come to the end
of its usefulness, toss it but hold on to that handle. Attached to the
end of the handle is a thin plastic shape which makes a very handy spreader
for thickened epoxy. This little spreader can get into tight places and
is especially useful when spreading thickened epoxy onto strips when strip
planking. It is also easily cut to make a specific shape (such as fitting
into a curved fillet). Thanks to Gary Clements of G.F.C. Boats, builders
of the beautiful updated Sam Rable "Titmouse".
REALLY TACKY
There are many opinions on the best way to actually apply the fiberglass
to the material when sheathing, but I believe there is only one best way,
and that is as follows.
Apply a coat of FAST curing resin to the material. Once this has tacked up (the resin I use gets quite tacky in just one hour) carefully apply the fabric to the surface, smoothing it out thoroughly. Then, you can put on the first fill coat and any additional coats at your leisure. No air bubbles this way!
UPENDING THE CAN
When you are sheathing flat surfaces, upend the container of epoxy
on the work surface while you are spreading out the remainder of the material.
This is especially desirable if you are sheathing and coating a number
of small parts. You will be amazed at just how much material remains in
the can, clinging to the sides and to the bottom, and just how much deposits
itself on the work surface if you upend the can. Epoxy costs too much to
waste it!
POT LIFE
If you are working with a fast acting resin/catalyst combination, don't
brush the material onto the work surface from the can but pour it out in
whorls onto the surface of the work. If you keep it in the can, fast-acting
resin will soon go off from the volume effect. If you pour it out over
the work, this will extend the pot life of the material.
SCRAP FIBERGLASS
Hang on to those little odd-shaped scraps which result when you trim
fiberglass to fit a specific shape. If you keep these in one place you
will without question come upon a time when you need one, several or even
all of them at one time. This conserves the glass and you will undoubtedly
find that some of those little scraps are the exact size and shape for
stand-by projects.
STANDBY PROJECTS
When you have a lot of fiberglassing work to do (such as building a
boat) always keep a bunch of small jobs lined up in the shop. Don't attempt
to do them by themselves, or even as a group, but keep them for the time
when you finish one job and have resin left over. This will happen a lot!
When it does, you can pick up just the right little job and use up the
resin expeditiously. Save money!
STRETCHING EXERCISES
One great value of the tack coat is that when it comes time to apply
the cloth (and the tack coat should be distinctly sticky and tacky) you
can actually stretch the cloth over the surface by smoothing it down with
your hands in the x and y directions. The stickiness of the resin holds
the glass in this position very effectively and this flattens the material
and eliminates the chance of air bubbles. With the tack-coat method, air
bubbles are almost completely eliminated and you get a very smooth and
close-fitting coat of fiberglass over the work. This works even better
when applying fiberglass overhead or on the vertical. This is where the
air bubbles are especially troubling, but the tack coat eliminates these
almost entirely.
THE UBIQUITOUS BUCKET
In laying out a large number of pieces to be coated, sheathed and recoated,
the space in the workshop becomes prime. It is not always possible to lay
everything out on the bench or on the epoxy table since space is simply
not available. A useful substitute are the ubiquitous 5 gallon plastic
buckets in which everything from joint compound to laundry detergent can
now be purchased. These are plentiful and can be had for the asking from
users or found in dumps and along the road. They make excellent supports.
The material can be positioned on their lips (discard the lid) with no
danger of the epoxied material adhering to the bucket (they are polyethylene)
and they can be positioned around the floor, on tables, or wherever it
is convenient to work.
THE BED OF NAILS
When you have to support a piece of work which is epoxy coated on one
side and the edges, drive some nails or dry-wall screws through a piece
of wood and lay the piece on the points. This will keep it suspended from
any surface to which it might adhere itself and prevent any unwanted bonding!
Don't try coating two sides at a time however. I have done this to save
time but what you end up with is one side with a lot of little round stalagmites
hanging down. These can be sanded off and if this is not a problem then
go ahead. If the bottom side is expected to end up finished however, then
do one side at a time.
LEAVE AN EDGE
When sheathing and glassing a flat piece (like a tank top) which will
subsequently be glued in to another structure (like the boat) don't apply
any epoxy to the edge which is to be glued. By leaving this bare, the thickened
epoxy glue will be able to achieve the molecular bond which epoxy likes
and not just the mechanical bond which is the result if the wood is already
coated with the epoxy.
PRESSURE-TREATED WOOD
There is some thought that epoxy will not adhere to pressure-treated
wood-- you know, that green stuff! My own experience and that of many others
with whom I have discussed the issue is that it will. I feel however that
it is a good idea to run a belt sander over the surface with a course 80-grit
belt in order to clean off a little of the cuprous-oxide or whatever else
was used to treat the wood and which leaches to the surface. By running
over with the belt sander it seems to expose a little less treated surface.
It is a good idea to sand across the grain in this case so as to also create
as much of a tooth as possible to aid the epoxy and fiberglass to adhere.
DON'T FORGET TO WEAR A MASK WHEN YOU DO THE SANDING! The material is toxic!
NAKED SHEATHING
DO NOT coat fir plywood with epoxy only and expect the treatment to
last, especially if the plywood is exposed to the elements. It will soon
check. If you want to coat plywood and expose it always put on a layer
of fiberglass. This provides a much stronger bond to counteract the propensity
of fir plywood to check the moment your back is turned--epoxied or not!
HULL FAIRING
For fairing the hull when using fillers or putties use a wallpaper
applicator. This long thin panel is very flexible and is also made of plastic
and the epoxy will not firmly adhere. Its flexibility makes it both easy
to fair the surface and to crack off the cured epoxy.