I spoke to Tomas Keenan, head technician and proprietor of Exquisite
Mobile Electronics, a full-service auto customization and electronics
garage in Franklin Sq., NY. This is what he said to me:
"He's using the right gun and the right head. The effect that he is
getting is called 'fisheye.' There are pretty much two options to help
him out. There is a product available from auto paint/finish suppliers
called 'fisheye killer', which will probably work, but the problem is
that it can change the color of the paint. If he were to use that, he
would have to make sure to use the smallest effective amount of
fisheye killer to solve the problem.
"However, the actual cause of the problem is impurities in the air or
the paint. The second option to solve the problem would be to procure
an air-line filter, which will remove all moisture, oil, and other
assorted grime from the airstream by passing the air through several
successive filters. These units are rather expensive (up to $3000) so
it may not make sense financially if this is a one-time operation.
Also, to minimize the amount of impurities in the paint, he should
make sure to pass his paint through a filter before mixing--this will
remove any impurities that may have been present in the paint can at
the time it was filled."
Mr. Keenan has seven years of experience in the automobile
customization industry. If you wish to confirm Mr. Keenan's level of
expertise on these matters, his business's webpage,
www.exquisitemobile.com, contains contact information.
You may be able to find fisheye killer and an air-stream filter (or
any other auto body supply) at Albert Kemperle Auto Body Supplies, a
nationwide retailer. If you call 516-872-3200 (the store local to Mr.
Keenan), they may be able to provide you with a catalog or the
location/phone number of the Albert Kemperle nearest you. In addition,
Albert Kemperle may be able to address some of the issues you're
having more directly, and confirm the advice that I have quoted above.
If for any reason you find this answer unsatisfactory, or if you find
that you are still having trouble, please request a clarification and
I will do my best to help resolve your problem.
Some sources for fisheye killer:
Also, fisheye killer in various formulations should be available at
your local automotive paint supplier.
Google search terms: "fisheye killer automotive" "fish eye eliminator
Some sources for air filtration systems:
(The type of filter Mr. Keenan describes is along the lines of
SHA-6760 on this page under "filters")
Once again, your local automotive paint supplier may be able to help
Search terms: "paint gun air filter"
For more information on preventing fisheye, check out:
Search terms "fisheye automotive paint causes"
Request for Answer Clarification by
09 Nov 2002 13:30 PST
THE EQUIPMENT BEING USED TO SPRAY THE UV. FORMULA IS THE BEST THAT
MONEY CAN BUY. I DON'T THINK IT IS THE BEST POSSIBLE CHOICE OF SPRAY
TYPE FOR UV. COATINGS BECAUSE IT TENDS TO BE SHEARING THE COATING. ALL
MY OTHER CUSTOMERS USE AN AEROBEL, WHICH IS A ROTARY SPRAY HEAD IE. NO
AIR INTRODUCTION INTO THE COATING. BUT I HAVE TO MAKE MY CUSTOMERS
HVLP EQUIPMENT WORK IN THIS APPLICATION. I SAW A COMPETITORS UV.
COATING BEING SPRAYED THROUGH THIS SYSTEM AND IT CAME OUT LOOKING AS
BAD AS MINE, BUT ALL THE BUBBLES SNAPPED OUT WITHIN 90 SECONDS. SO I
KNOW THERE IS AN ADDITIVE COMBINATION THAT WILL WORK OUT THERE
SOMEWHERE! ALSO THE SUBSTRATE IS COMPLETELY CURED AND NOT OUT GASSING.
Clarification of Answer by
10 Nov 2002 09:22 PST
Hello again, handsome1,
Thanks for the added information. Give me some time to get in touch
with my contacts and I will see if I can give you any other
suggestions. Depending on their accesibility over the holiday weekend,
I may not be able to contact them until Tuesday.
In the meantime, double-check to make sure you have absolutely
eliminated every possible source of contamination in the airline, the
paint line, and on the surface as well. Is the paint gun you are using
being used only for the clearcoat? Residue from different formulations
in the same gun can cause contamination. Are you using the correct
thinners and cleaners? Have you cleaned the surface to be painted?
Have you tested your competitors' formulation side-by-side with your
own, on the same surface, in the same painting booth, and using
identical equipment? Is your mixing room absolutely free of exhaust,
dust, and other contaminants?
Basically there are only a few possibilities:
1: Your formulation is correct and along the lines of your
competitors', but the equipment being used for your formulation is
2: Your formulation is correct, but the paint is being contaminated
somehow in the mixing room.
3: Your formulation is correct, but your surface is dirty.
4: Your formulation is not correct.
By testing your formulation alongside your competitors', on identical
equipment (with the same usage history) and identically prepared
surfaces, then you can rule out contamination in the equipment or air
line or on the surface. If your formulation continues to have the
artifacts described and your competitors' doesnn't, then equipment and
surface contamination can be ruled out. This means that either your
formula is incorrect or that your mixing room is dirty or contaminated
somehow. If the possibility of a dirty mixing room can also be ruled
out (don't forget basics like wearing a clean-suit while mxing), then
it is your formula that is to blame.
I would be interested to know whether adding fisheye killer to your
mix has any effect on your results.
Here is another idea to isolate the problem. Assuming your formulation
and your comonents' are compatible chemically, start adding individual
components from your formulation to your opponents' and see if any
particular component causes the same problems in your competitors'
formulation as you are seeing in yours. If you can isolate a single
element or combination of elements in your mixture that is causing the
problem, then you are on your way to solving it. It may be a simple
matter of swapping out one of the components you are using for a
similarly functioning but chemically different one.
Once again, I will post further clarification as soon as I can get in
touch with my contacts. Any further information or results would be
valuable to hear in diagnosing your problem more accurately.
Clarification of Answer by
10 Nov 2002 13:07 PST
Hello again handsome1,
A quick update: One of my contacts recommends this specific product to
remedy your bubble problem. It is a fisheye killer, but even if the
cause of your bubble problems is not contamination it may be the
additive you are looking for.
The product recommended was "Marson Fisheye Killer" in particular. It
acts by slowing down the curing time of the paint, giving the bubbles
more time to snap out. The longer drying time increases the chances of
dust and other undesirables landing on the paint, but in a properly
maintained painting booth this should not be an issue.
I do not know if this particular fisheye killer is compatible with
your application, but certainly a retailer would be able to tell you.
In any case it's my feeling that some sort of fisheye killer may solve
your problem, even if the possibility of contamination has been
Marson Fisheye Killer is available here
which happens to be one of the sites listed above.
I am still planning on getting in touch with my other contacts after
the holiday, to see if any other opinions may be offered.
Good luck once again,
Clarification of Answer by
10 Nov 2002 14:56 PST
Hello once again, handsome1,
Sorry about the repeated clarifications, but I wanted to address
endo's excellent comment without delay. I am still planning on
following up with my contacts, as mentioned.
Endo's father clearly knows his stuff, so I thought I might make a
suggestion for how to remedy your problem, based on the combined
information from my contacts and from Endo's comment below.
I would try the following suggestions in this order:
1: Make sure there is no chance of contamination, as mentioned.
2: Make sure your surface is clean and properly prepped. As endo
suggests, a smooth surface such as glass would be ideal for testing.
3: Start by thinning out your mixture with an appropriate thinner or
solvent. Begin by adding a small proportion of thinner and increase
the proportion until the bubbles are able to snap out on their own. If
the viscosity is low enough that the wetting agent can be eliminated,
then that will prevent the "second wave" of bubbles from appearing
4: Increase the time before curing and slow the curing process through
the various means described in Endo's comment -- lower intensity UV,
keep surface further from the lamps, etc. Avoid exposure to heat to
prevent boiling in the film.
5: If the wetting agent is still necessary, or if the bubbles are
still not snapping out, try the fisheye killer.
6: Try swapping the resin for another one, or changing up other
elements of your mixture or procedure (such as the wetting agent,
which seems to be a major cause of bubbles).
Last but not least, as Endo mentions, the manufacturers of the
components of your mixture will be able to furnish to you information
on compatibility among the ingredients.
More after the weekend.
Clarification of Answer by
13 Nov 2002 11:47 PST
I have not forgotten you; I am still working on providing you with
more potential solutions to your problem. In the meantime, have you
tried any of the suggestions that have been offered so far? Have you
had any success or changes? Any further information could help towards
When I saw this question, I immediately knew that's something that my
dad knows, he's been in the paint business for the last 25 years. So I
copy/pasted your question to him and I'm going to copy paste his
answer, if you have any other questions don't hesitate:
HVLP spray guns are the wrong application spray method as lots of air
foaming (i.e. bubbles) is introduced into the film. The bubbles can be
from the spray equipment or/and due to the film itself.
Foaming or entrapped air can be reduced by reducing the application
film thickness, i.e. to allow the entrapped air to escape easier,
another way is to reduce the viscosity of the coating that will also
allow the air to escape.
From the question it seems that the wetting properties of the paint
are poor that's why he is adding the wetting agent. So it points back
that the viscosity needs to be adjusted. Probably the bubbles that
appear after adding the wetting agent are caused by the wetting agent
or from entrapped air in the substrate.
The applied film needs time to allow the bubbles to escape before UV
curing. It might be that he is not allowing enough time for flash off
before UV curing.
Practically all spray applied UV coatings that we market, after the UV
coating is spray applied a minimum of one minute flash off is allowed
for the solvents and the bubbles to escape then the coating is cured
by UV lamps. Practically all spray coatings need some sort of
"Solvent" or a monomer to act as solvent to adjust viscosity, wetting
agents are not enough.
Another possibility can be UV curing the film too fast. A solution can
be that initially the film is exposed to a lower intensity UV
radiation then gradually to higher UV radiation.
Another possible problem can be the substrate, if the surface is not
smooth, then air is being entrapped and not allowed to escape. Also if
the substrate is not cured well it might be cause of the bubbles.
Also its possible that the substrate surface temperature is too high.
To eliminate all possibilities, you apply on a cured smooth surface
such as glass, do not cure the coating for five minutes and observe if
the bubbles disappear, reduce the viscosity to allow the bubbles to
escape measure the time needed to allow the bubbles to escape that the
time of the flash off.
The lower gram mage of film application the faster the bubbles escape.
Simply reduce viscosity, reduce quantity to apply, allow to flash off
before curing, reduce conveyor speed, cure slower by reducing the
power of the first lamp (this can be compensated by reducing the
conveyor speed as the panel will be exposed for lower radiation to a
Also it's possible that the UV lamps are too near to the coated
surface and this is heating the coating and letting bubbles to appear,
increase the distance between the lamps and the applied surface and
Heating as you mention might not be the correct way as it might
increase the problem, it might reduce viscosity but allow material in
the film o boil and cause bubbles.
In addition try to use another resin for the formulation, are they
using UCB resin? They can refer to the initial resin manufacturer for
suggestions to the problem, as they will suggest what is the best
I am curious to know if it's a student is asking the question and also
if they are applying on composites then I presume its for decorative
purpose and next he will need to do a pigmented finish?
I hope this helps,