How to use Kreem
from an post to the Yamaha 650 email list by Bill Denton 8/30/99
I have used Kreem w/ v good success, but as with most things in life, the preparation is the most important part. Four important fine points to consider:
#1 - Tank preparation:
The inside of the tank should be completely free and clear of all
loose particulate (i.e rust, dirt and sludge). Even more
importantly, it must be totally devoid of any and all hydrophobic
(oily) substances, including any and all traces of gasoline, oil
and grease. To achieve this, I drop two 8" lengths of
medium size linked chain into the tank, then pour a small bottle
of liquid degreaser full strength in and slosh vigorously with
all the openings capped off. Do this good and long, and
don't forget to invert the tank and get all of the surfaces
degreased up around the filler neck, as well as the very top of
the inside of the tank.
Next, add about 1/2 gallon of the hottest water you can get, and
add this to the degreaser and the chains still in the tank (don't
pour out the degreaser yet... leave it in there) and slosh it
around again. The degreaser will emulsify (turn milky
white) and hold all of the oils in suspension... this is a good
thing. After you are quite certain that you've degreased
all surfaces... give it one more slosh just for good luck.
Then, pour out the entire mixture and fish out the two
chains. After that, pour about a TBSP of hand dishwasher
detergent and about a gallon of very hot water into the tank and
slosh thoroughly (note: you can use automatic dishwasher
detergent here, but as it is formulated to be very low sudsing,
it is more difficult to determine when all of the residue has
been removed via rinsing.) If you degreased properly in the
last step, this wash should produce mongo volumes of suds... also
a good thing, as suds are an indication (in this case) that the
oily residues (read gasoline) have been successfully
removed. Follow by as many cold water rinses as necessary
to remove all traces of detergent.
Only now are you ready to phosphate etch the metal in the tank with Kreem kit bottle #1 (Phosphoric acid). Although the directions call for a specific quantity of hot water to be added to the quantity of acid provided, IMO it is better to have a FULL tank of etching solution than to have the exact proportion of acid to water. In the case of an XS650 tank, this amounts to adding perhaps 3.75 gallons of HOT water (3.25 for early tanks) to the acid, as opposed to 2.5 gallons, which (I believe) is the quantity specified in the directions. Again, as in the degreasing step, it is vitally important to have the etching/phosphating solution come in intimate contact with ALL inside surfaces of the tank, including up and around the filler neck. Seal all the tank openings and slosh that bad boy around, but after you're through sloshing, don't forget to slightly crack open the stopper on the filler neck, or the hydrogen gas evolved from the chemical process will blow it out of the hole and across the room, probably splattering phosphoric acid solution on your nice new paint job (don't ask).
#2 - Dewatering:
The small bottle of solvent (Kreem kit bottle #2) is MEK (a close
cousin to acetone) and is a very good water remover. After
you have thoroughly rinsed the phosphate solution out of the
tank, it is time to get things dried up and ready for the polymer
coating step. Actually, "Dry" may be a bad word
to use here, because the intention is NOT to get the inside of
the tank dry from all liquid residue, but rather only to get all
WATER residue out. The inside of the tank will still be wet
when you are done with this step, but it will be wet with MEK,
which is perfectly fine, because that is the same solvent which
is used in the polymer to keep it dissolved. Caution: do
not dawdle after using the dewatering solvent. IMMEDIATELY go on
to the polymer coating step. If you wait too long before
you go to the next step, you may "flash rust" the
inside of the tank, which will require starting over. If
the inside surface of the tank begins to physically dry out,
you're taking too long and are in danger of forming flash
rust. Get you ass movin' boy!
#3 - Coating:
Conservatively speaking, there is enough polymer in bottle #3 to
do AT LEAST two (probably three) XS650 tanks. What this
means is that, unless you have two or three tanks prepped all at
once, you are going to not use all of the polymer provided in the
kit. You must remove the excess polymer from the tank that
you are working on. Follow the instruction very carefully
here, rolling the tank around for a few minutes, then letting it
set on one side, followed by rolling around again and letting it
set on another side, repeating until you are secure in the fact
that all interior surfaces have been thoroughly coated.
After that, you MUST pour out any remaining polymer, or you will
have a puddling problem. Even after you pour out the
excess, you must continue the process of rolling the tank and
then letting it set on alternating sides, while the remainder of
the polymer still in the tank forms a non-moving film.
#4 - Drying/curing time:
Probably the one most crucial mistake leading to premature
failure of Kreem coatings (after improper degreasing) is
insufficient drying or curing time before putting the tank back
into service. After you are satisfied that the majority of
the polymer in the tank has skinned over, follow this procedure:
Remove all stoppers from all openings, both top and bottom
(filler & petcock holes).
Turn the tank upside down (preferably on a hot surface like your
black asphalt driveway at noon in July (January if you're in Oz)
and block it in place so the filler neck is facing vertically
straight down. Then, rig up a small air pump and hose and
stick the hose into the tank from the underside through the
filler opening, being careful not to allow the hose to touch the
inside surfaces. An air pump from a fish tank fits this
bill perfectly. Turn on the pump and let the forced air
dispel the vapours from inside the tank, which will aide drying
and curing. After a few hours, you will no longer be able
to smell vapours coming from the tank. It is then safe to
move the tank, but DO NOT use the tank yet. Move the whole
rig up into your hot, oven-like attic and allow the air pump to
run for another two days minimum, with the hose still in the
tank. One day is probably enough, which is why I always do
it for about a week just to be sure. It pays to watch the
weather and plan to Kreem the tank on a day that is going to be
sunny, hot and dry, if at all possible.
If you add the above tips to the (already pretty good) instructions included with the three part Kreem kit, you will end up with a well sealed, carefree fuel tank for many years to come. Good luck!
Bill in Yardley, PA