Suggestions please: Alternate equivalents to Varathane "Colors In Plastic" (polyurethane) paint?
Ken Moiarty
moldings, and other miscellaneous household surfaces by brushing on white
Varathane 'Colours In Plastic' (oil based polyurethane) paint. However, I'm
finally throwing in the towel as far as using a brush with this stuff is
concerned: Can't seem to avoid the creation of little pin-head sized bubbles
everywhere. Most of these bubbles eventually pop on their own, but always
too late in the setting process not to leave tiny pimple-like craters
scattered everywhere, simply making for an unacceptable finish. I'm going
to have to switch to applying Varathane paint by spray from here on. (I've
discovered there's no problem with bubbles when applying the Varathane by
spray.)
But spray painting means having to move or remove whatever I want to
paint with this stuff into an area suitable for spray painting and this just
isn't practical for every surface I would like to touch up. Therefore, I'm
looking for suggestions as to other products and/or other types of paint I
might turn to that are like Varathane insofar as they produce a smooth, hard
and durable enamel-like coating, but without the problem of countless
micro-bubbles forming when being applied by brush.
TIA,
Ken
Stephen Hull
"Ken Moiarty" <kmoia...@shaw.ca> wrote:
> I've been trying to do some sprucing up some assorted fixtures,
>moldings, and other miscellaneous household surfaces by brushing on white
>Varathane 'Colours In Plastic' (oil based polyurethane) paint.
[snip]
>TIA,
>
>Ken
>
Ken,
Presuming the prepared surface has no contamination of any kind as you
probably know grease, oil etc can create pinholes or craters.
The pinholing which usually leads to tiny craters can be caused in many
different ways, the most common is when paint material is applied too
quickly or too thick, even excessive brushing can cause air to become
trapped, this is more apparent when using polyurethane finishes.
It is possible that solvents may have become trapped in the substrate as
the surface starts to skin dry, blocking solvent release forcing tiny
air bubbles to pop into craters.
Scraping a charged brush on the edge of a paint tin instead of using an
alternative paint tin will in some cases also produce air bubbles.
Air bubbles can be introduced in a paint material by over agitation
during the initial stirring just prior to use.
Air bubbles can sometimes be avoided by not over brushing and should be
eliminated completely by adding a little raw linseed oil to ease off
the faster drying properties associated with polyurathane finishing.
Steve.
--
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Goedjn
wrote:
Are you using something to either thin the paint or accelerate the
drying? Are you trying to apply the paint it too thick a coat at once?
>
Ken Moiarty
"Goedjn" <pr...@mail.uri.edu> wrote
[...]
>
> Are you using something to either thin the paint or accelerate the
> drying? Are you trying to apply the paint it too thick a coat at once?
>
No, no, and no. I have tried thinning the paint with mineral spirits. No
benefit. And I have tried applying the paint thicker... this among numerous
other ad hoc variations in 'random trial-and-error style' to see what, if
anything, might work different or better (all to no avail, needless to say).
Since posting this message I've poured over the internet reading about other
people's experiences in brushing Varathane paint, and I'm now pretty much
now convinced that the "tiny bubbles" problem when applying Varathane with a
brush is unavoidable. I've developed the hunch that other people who seem
to not experience this problem are maybe just not as fussy as I am with
their work, and/or their lighting is such that these tiny blemishes are not
so plainly visible and/or bothersome to them. (So as to see what I'm doing,
in addition to normal overhead lighting I illuminate my painting surface
with two 500 watt flood lamps, positioned at oblique angles to the major
plane being painted...)
Ken
Ken Moiarty
"Stephen Hull" <St...@127.0.0.1> wrote
> [...]
> Air bubbles can sometimes be avoided by not over brushing and should be
> eliminated completely by adding a little raw linseed oil to ease off
> the faster drying properties associated with polyurathane finishing.
>
> Steve.
>
Hmmm... Raw linseed oil to delay drying, eh... I'll be giving this a try.
I didn't know I could delay the drying time of Varathane, being that,
ostensibly, unlike ordinary oil-based paints polyurethane solidifies not by
solvent evaporation but by the chemical reaction of isocyanate reacting with
the moisture in the air (which, as an interesting aside, is known to release
CO2). Yet, there's obviously already some oil in this "oil-based"
polyurethane product and this may, for all I know, perform discrete
functions beyond the obvious. So who knows? It seems to me that this
Varathane sets up so quickly, losing its ability to flow freely so soon,
that the holes left by the bubbles don't have a chance to fill themselves
back in. So maybe this will be the key. Thanks.
Ken
Stephen Hull
"Ken Moiarty" <kmoia...@shaw.ca> wrote:
>"Stephen Hull" <St...@127.0.0.1> wrote
>> [...]
>> Air bubbles can sometimes be avoided by not over brushing and should be
>> eliminated completely by adding a little raw linseed oil to ease off
>> the faster drying properties associated with polyurathane finishing.
>>
>> Steve.
>>
>
>Hmmm... Raw linseed oil to delay drying, eh... I'll be giving this a
>try. I didn't know I could delay the drying time of Varathane,
[snip]
Most people would automatically add turpentine or white spirit into
paint in an attempt to retard the drying process when experiencing
drying problems but these are also classed as driers and although
they'll ease application it doesn't always decrease drying times.
There's a product called Owatrol that will also retard the drying
process.
Unfortunately Polyurethane is proven to set-up too quickly and sometimes
needs a hand to slow it down.
An alternative method would be to use a recognised slower synthetic
thinner perhaps 10% and if possible paint on a cooler day.
Steve.
--
http://www.stephen.hull.btinternet.co.uk
Coach painting tips and techniques + Land Rover colour codes
Ken Moiarty
early and try painting again. I was impatient to try the "linseed oil"
idea. But I don't have any linseed oil in the house and nothing's open here
at 3 AM. So on a whim I used some food-grade MTC
(medium-chain-triglyceride) oil I happened to have lying around (from my
days if experimenting with fad body-building food supplements). MTC oil is
a very light oil. But one advantage the MTC oil happens to offer as paint
additive is that it is completely colourless. OTOH linseed oil being yellow,
whilst my paint being white... well you can see where I'm going. Anyway, I
just finished putting up a coat of Varathane, after thinning it with this
MTC oil. And man, what a difference! Although a little on the runny side
for my liking, the problem with the bubbles has now been completely
resolved! By delaying the Varathane setup, and thereby increasing my time
to work with it, I am now able to painstakingly tease out all the bubbles
with my brush before leaving the project to dry. (Also, as a bonus, brush
marks now less prominent. I'll see later if they don't have enough time to
disappear completely on their own before the paint does finally begin to
set.)
Thanks again,
Ken
"Stephen Hull" <St...@127.0.0.1> wrote in message
news:cfa356d1...@btinternet.com...
Stephen Hull
"Ken Moiarty" <kmoia...@shaw.ca> wrote:
>Woke up and couldn't fall back to sleep this morning so I decided to
>get up early and try painting again. I was impatient to try the
>"linseed oil" idea. But I don't have any linseed oil in the house
>and nothing's open here at 3 AM. So on a whim I used some food-grade
>MTC (medium-chain-triglyceride) oil I happened to have lying around
>(from my days if experimenting with fad body-building food
>supplements). MTC oil is a very light oil. But one advantage the MTC
>oil happens to offer as paint additive is that it is completely
>colourless. OTOH linseed oil being yellow, whilst my paint being
>white... well you can see where I'm going. Anyway, I just finished
>putting up a coat of Varathane, after thinning it with this MTC oil.
>And man, what a difference! Although a little on the runny side for
>my liking, the problem with the bubbles has now been completely
>resolved! By delaying the Varathane setup, and thereby increasing my
>time to work with it, I am now able to painstakingly tease out all
>the bubbles with my brush before leaving the project to dry. (Also,
>as a bonus, brush marks now less prominent. I'll see later if they
>don't have enough time to disappear completely on their own before
>the paint does finally begin to set.)
>
>Thanks again,
>Ken
In the coach painting industry it has usually been the norm to speed up
the drying process particularly on finishing coats as this type of paint
can stay workable for hours, mainly because it contains more oil than
pigment and less drying agents are added.
Modern paints unfortunately tend to dry from the opposite end of the
scale, too quick, probably for faster reapplication and quicker turn
around.
I've heard paraffin can be used to slow down the drying process but
wouldn't recommend it, it's not pure enough to use in paint.
However your MTC oil method seems quite a plausible solution.
The colour of Linseed oil is on the yellow side but it would hardly make
any difference when added to white especially in such small quantities.
Anyway I'm glad you've managed to get it sorted.
Ken Moiarty
wet as when I applied it, which was well over eight hours ago. Obviously I
used too much oil in my 'test sample'. Fortunately this was only a test
paint job, and not the real thing. I'll have to attempt this again, only
with much less oil. The upshot of course is that I have not yet in fact
solved my "Varathane bubbles" problem afterall; as I had so
enthusiastically -but prematurely- concluded in my previous post. But I am
still quite certain that you have put me on the right track towards getting
there in pursuing this approach.
Ken
"Stephen Hull" <St...@127.0.0.1> wrote in message
news:539a7ed1...@btinternet.com...
jtno...@yahoo.com
is probably "overengineered" for your use anyway. The commercial
"boiled linseed oil" has chemical drying agents in it that will allow
it to set up in a reasonable period of time, not so with raw linseed or
apparently your MTC oil. Best wishes on your projects.-Jitney
Norminn
> But spray painting means having to move or remove whatever I want to
> paint with this stuff into an area suitable for spray painting and this just
> isn't practical for every surface I would like to touch up. Therefore, I'm
> looking for suggestions as to other products and/or other types of paint I
> might turn to that are like Varathane insofar as they produce a smooth, hard
> and durable enamel-like coating, but without the problem of countless
> micro-bubbles forming when being applied by brush.
>
> TIA,
>
> Ken
>
>
brush? Brushing too much? Clean surface?
Norminn
> Woke up and couldn't fall back to sleep this morning so I decided to get up
> early and try painting again. I was impatient to try the "linseed oil"
> idea. But I don't have any linseed oil in the house and nothing's open here
> at 3 AM. So on a whim I used some food-grade MTC
> (medium-chain-triglyceride) oil I happened to have lying around (from my
> days if experimenting with fad body-building food supplements). MTC oil is
Are you serious? :o) You can try butter - that way you can just wipe it
off when you get tired of it, because it will not be dry :o)
Stir the stuff gently, do not shake. Use good quality natural bristle
brush. Thin per the label instructions. Do not use linseed oil. You
may be putting it on too thickly, or brushing out too much.
Ken Moiarty
"Norminn" <nor...@earthlink.net> wrote in message
> Have you shaken the can prior to appl?
Not a good idea... (Perhaps I should clarify: my description of the problem
would be different if I hadn't already been successful in preventing bubbles
from forming in the paint prior to its application.)
> Using good quality bristle brush?
Two $30+ Purdy's. One synthetic, the other natural bristle. The best they
have in my local HD store. HD is not the ideal place to shop for quality, I
realize, but could a better brush than these really make a difference in a
problem of this description?
> Brushing too much? Yes, I've brushed too much, too little, and everything
> in between... I've spent too much time trying everything hoping to strike
> it lucky and find that "just right" brushing technique, or the knack
> thereof, presumptively required to avoid the problem.
>Clean surface?
Initially.. clean but not obsessively so. But as I've kept doubling and
re-doubling my efforts to assiduously control for 'this variable and that
variable', so as to get at least a handle on the problem... well let's just
say I don't know how much cleaner it could get beyond what I have since been
getting it.
Ken
Ken Moiarty
Just curious... Have you yourself done a paint project applying Varathane
paint (i.e. Colors in Plastic) with a brush? And if so, had you not
experienced this problem with "tiny bubbles" forming upon application, such
as what I have described (and which I have become frustrated enough by to
try everything 'including the kitchen sink' to overcome)?
Ken
"Norminn" <nor...@earthlink.net> wrote in message
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Ken Moiarty
Ken
"Ken Moiarty" <kmoia...@shaw.ca> wrote in message
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Grolsch
effect on final cure and film properties. Adding a little boiled linseed oil
would work though. A trick we used to use when painting gloss enamels in
cold weather was to add a touch of boiled oil AND a touch of Japan Driers.
This improved flow-out while still able to cure a reasonable rate.
--
"Ken Moiarty" <kmoia...@shaw.ca> wrote in message
news:fKOif.648108$tl2.646851@pd7tw3no...
Grolsch
Urethane modified alkyd. Some causes of "pinholing" are:
Poreous surface/substrate - material gets into the poreous substrate, the
surface of the applied paint "surface cures" (skins), then the trapped
solvents break through this "skin" after the material is past optimal flow
point. Adding more and more volatile solvents may compound the problem.
DuPont makes a product for the automotive finishing industry called Fish-Eye
Eliminator (flow modifier), It works quite well. Also most makers of
Urethane have "flow modifier" solvents.
Applying too thickly. Again, trapped solvents must breakthrough the surface
skin.
Excessive volume of hot or warm air will increase surface drying and
compound the problem.
Try thinning as per label, don't use heat or fans if possible or use them
indirectly (don't blow heated air across the surface). Also try putting on a
very thin coat (20% thinned) to fill surface porosity (?).
Also try foam brush or mohair applicating "pads". I have had good success
with them for small jobs.
Larger items are probably best sprayed.
FYI, I am a Journeyman Painter (28years), NACE Certified Coating Inspector.
I know of what I speak!
--
"Ken Moiarty" <kmoia...@shaw.ca> wrote in message
news:tcwif.632086$oW2.346600@pd7tw1no...
Stephen Hull
"Grolsch" <a3a4...@telus.net> wrote:
>Raw Linseed Oil! I don't think I'd add a non-drying oil because of the
>effect on final cure and film properties. Adding a little boiled
>linseed oil would work though. A trick we used to use when painting
>gloss enamels in cold weather was to add a touch of boiled oil AND a
>touch of Japan Driers. This improved flow-out while still able to cure a
>reasonable rate.
>
Indeed,
However during certain coachpainting processes Raw linseed oil was added
because it is a (less cooked) slow drying oil that did slow down the
faster drying oil paints and varnishes, which already contained a high
proportion of driers, thus gave an overall better drying balance.
It was not uncommon with certain pigments when applying paint by brush
to paint a complete panel, then go for lunch and return an hour later
and the panel could still be layed off. This was only necessary on
troublesome pigments where the naturally slow flowing out properties had
been undermined by faster acting driers which the painter had no real
control over being already pre-manufactured paint etc.
Steve.
--
http://www.stephen.hull.btinternet.co.uk
Coach painting tips and techniques + Land Rover colour codes
Grolsch
advanced to the point where final film properties are key rather than "can
the material be applied at all". I mean we don't use colours in lead and
painstakingly mix material on the job.
--
"Stephen Hull" <St...@127.0.0.1> wrote in message
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