[bigwig]

Hello,
How do you get a good crackle type paint finish?. You know the sort
found on old scientific instruments etc. I want to get the sort with a
raised effect much like an old RCA projector I once repaired,
georgeous and also fairly hard wearing. I would like to use this on my
aluminium chassis so an etch primer will be needed.
Cheers Matt

[dre7]

Auto Parts Store. Look for Krylon or VHT black wrinkle paint. Tell the
clerk you want the stuff for valve covers.

Andrew


bigwig wrote in message
...
Hello,
How do you get a good crackle type paint finish?. You know the sort
found on old scientific instruments etc. I want to get the sort with a
raised effect much like an old RCA projector I once repaired,
georgeous and also fairly hard wearing. I would like to use this on my
aluminium chassis so an etch primer will be needed.
Cheers Matt

[bigwig]

On 6 May, 23:59, "dre7" wrote:
Auto Parts Store. *Look for Krylon or VHT black wrinkle paint. *Tell the
clerk you want the stuff for valve covers.

Andrew

bigwig wrote in message

...



Hello,
* *How do you get a good crackle type paint finish?. You know the sort
found on old scientific instruments etc. I want to get the sort with a
raised effect much like an old RCA projector I once repaired,
georgeous and also fairly hard wearing. I would like to use this on my
aluminium chassis so an etch primer will be needed.
* * Cheers * Matt- Hide quoted text -

- Show quoted text -

Krylon, Cheers Matt

[bigwig]

On 6 May, 23:59, "dre7" wrote:
Auto Parts Store. *Look for Krylon or VHT black wrinkle paint. *Tell the
clerk you want the stuff for valve covers.

Andrew

bigwig wrote in message

...



Hello,
* *How do you get a good crackle type paint finish?. You know the sort
found on old scientific instruments etc. I want to get the sort with a
raised effect much like an old RCA projector I once repaired,
georgeous and also fairly hard wearing. I would like to use this on my
aluminium chassis so an etch primer will be needed.
* * Cheers * Matt- Hide quoted text -

- Show quoted text -

Just remembered, they made the dyes I had most success with when I was
messing about with anodising. It was normal clothes type dyes, very
nice colour but faded in sunlight a bit.
Cheers Matt

[[email protected]]

On May 6, 6:47*pm, bigwig wrote:
Hello,
* *How do you get a good crackle type paint finish?. You know the sort
found on old scientific instruments etc. I want to get the sort with a
raised effect much like an old RCA projector I once repaired,
georgeous and also fairly hard wearing. I would like to use this on my
aluminium chassis so an etch primer will be needed.
* * Cheers * Matt

Be sure and read the directions on the can, it's not like regular
spray paint, it has to go on really thick. The paint I had was
supposed to be applied in a single coat, as thick as possible without
running. If it's not thick enough it won't crackle up, and I found it
very difficult to do it right in a single coat. I found that building
the paint up in layers worked fine, as long as it was not allowed to
dry past the "tack" stage between coats. It's a good idea to practice
on some scraps. Crackle finish doesn't lend itself to spot repair and
if you screw up you have to start over from scratch. I've had good
results on aluminum without using a primer, but I did etch and
degrease by soaking in dilute lye solution until it was fizzing good,
followed by a thorough rinse. I effected the heat cure by setting the
piece close to my wood stove, but an oven would work just as well.

Have fun, and good luck.

fank

[Dr. Barry L. Ornitz]

"bigwig" wrote in message
...

How do you get a good crackle type paint finish?. You know the sort
found on old scientific instruments etc. I want to get the sort with a
raised effect much like an old RCA projector I once repaired,
georgeous and also fairly hard wearing. I would like to use this on my
aluminium chassis so an etch primer will be needed.

Be careful with your nomenclature here. Crackle finish is quite different
from wrinkle finish. In fact, there were many different finishes used in
the 1930's and 1940's. One of my former employers (Eastman Chemical
Company, formerly Eastman Kodak) had an large research library in which I
found an excellent reference book on paint and varnish technology. The
book had a lithograph with about 20 differing surface finishes along with
their trade names. Unfortunately, this page would not reproduce properly
with any of the digital scanners available to me at the time. It would
have been a useful reference to place on a website for restorers of
antique radios and test equipment like myself.

The crackle effect is obtained when the paint shrinks as it polymerizes.
A good crackle paint will produce a finish made up of thousands of small
islands formed when the surface film shrinks and tears leaving shallow
cracks. Alligator hide looks like the magnified finish. Wrinkle finish
paint works by an opposite mechanism; it expands as it cures causing the
surface film to wrinkle up and produce a larger surface area. Originally
both finishes were considered painting defects until they could be
reproduced in a controlled fashion. Then someone had the bright idea
that a textured paint required far less surface preparation than did a
glossy finish paint. Most military electronic equipment produced during
WWII was painted in wrinkle finishes.

There is another finish seen in metallic paints containing aluminum
powder. This is called a splatter finish. Essentially the object is
first painted and before it has a chance to cure, solvent is lightly
sprayed onto the surface in small drops.

Most of the old technology that produced these paint finishes is now
lost. Manufacturers kept most of their information proprietary and many
even kept their secrets from ever being recorded. It is known, however,
that most wrinkle finishes were produced by what is known as "gas
checking." The drying ovens were usually natural gas fired, and by
adjusting the mixture to be rich, carbon monoxide was produced. This
reacted with alkyd enamels to produce wrinkling.

Today, the best textured finishes are obtained by powder coating. Here a
powder is sprayed electrostatically onto a surface, and then the object
is heated in an oven. This melts the powder and simultaneously cures the
resin in the powder.

Today commercial wrinkle finish paint is found in spray cans - but in a
limited range of colors.
If you need a specific color that is not produced, you can overspray an
existing wrinkle finish with a thin lacquer. Just be sure that the
wrinkle finish has cured properly. It is best to have patience and wait
a week or more before overspraying.

Dr. Barry L. Ornitz BLOrnitz48@charter/net

[Mark Harriss]

bigwig wrote:
Hello,
How do you get a good crackle type paint finish?. You know the sort
found on old scientific instruments etc. I want to get the sort with a
raised effect much like an old RCA projector I once repaired,
georgeous and also fairly hard wearing. I would like to use this on my
aluminium chassis so an etch primer will be needed.
Cheers Matt

Paint with standard quick-dry enamel paint, allow it to dry for a day
or so and sand with coarse sandpaper to scuff the paintwork, try and
sand in two directions at 90 degrees to each other. Then paint with a
second coat of the same quick-dry but with some general purpose thinners
added.

The GP thinnners will soften up the original coat which will then
permanently wrinkle in alignment with the sanding marks. This gives a
crocodile skin wrinkle finish.

Old time painters used to mix enamel paint with an incompatible paint
like acrylic or nitrocellulose to get common garden quality wrinkle.
I've never tried this recipe, just told about it by an old WW2 sheet
metal worker.

[PeterD]

On Thu, 07 May 2009 19:26:50 +1000, Mark Harriss
wrote:

bigwig wrote:
Hello,
How do you get a good crackle type paint finish?. You know the sort
found on old scientific instruments etc. I want to get the sort with a
raised effect much like an old RCA projector I once repaired,
georgeous and also fairly hard wearing. I would like to use this on my
aluminium chassis so an etch primer will be needed.
Cheers Matt

Paint with standard quick-dry enamel paint, allow it to dry for a day
or so and sand with coarse sandpaper to scuff the paintwork, try and
sand in two directions at 90 degrees to each other. Then paint with a
second coat of the same quick-dry but with some general purpose thinners
added.

The GP thinnners will soften up the original coat which will then
permanently wrinkle in alignment with the sanding marks. This gives a
crocodile skin wrinkle finish.

Old time painters used to mix enamel paint with an incompatible paint
like acrylic or nitrocellulose to get common garden quality wrinkle.
I've never tried this recipe, just told about it by an old WW2 sheet
metal worker.

I've sprayed a very active thinner over a slow (enamel) paint and
gotten that effect. The thinner softens and expands the very top of
the enamel causing it to wrinkle, the active thinner then evaporates
without leaving time for the enamel to shrink back to original size
and there you a wrinkle finish.

(A real PITA when painting cars!)

[Sofa Slug]

dre7 wrote:
Auto Parts Store. Look for Krylon or VHT black wrinkle paint. Tell the
clerk you want the stuff for valve covers.

Andrew


bigwig wrote in message...
Hello,
How do you get a good crackle type paint finish?. You know the sort
found on old scientific instruments etc. I want to get the sort with a
raised effect much like an old RCA projector I once repaired,
georgeous and also fairly hard wearing. I would like to use this on my
aluminium chassis so an etch primer will be needed.
Cheers Matt


Be sure and heat up the metal's surface with a heat lamp or gun before
painting - otherwise you may not get a very pronounced "wrinkle" effect.
See: http://www.fancollectors.org/info/wrinkle.htm

[bigwig]

On 7 May, 17:14, Sofa Slug wrote:
dre7 wrote:
Auto Parts Store. *Look for Krylon or VHT black wrinkle paint. *Tell the
clerk you want the stuff for valve covers.

Andrew

bigwig wrote in message...
Hello,
* *How do you get a good crackle type paint finish?. You know the sort
found on old scientific instruments etc. I want to get the sort with a
raised effect much like an old RCA projector I once repaired,
georgeous and also fairly hard wearing. I would like to use this on my
aluminium chassis so an etch primer will be needed.
* * Cheers * Matt

Be sure and heat up the metal's surface with a heat lamp or gun before
painting - otherwise you may not get a very pronounced "wrinkle" effect.
See:http://www.fancollectors.org/info/wrinkle.htm- Hide quoted text -

- Show quoted text -

Wow,
Thanks for all your answers, I have really not bothered looking into
paint finishes. Just prepped it well, degreased and spray/paint away.
The effect I was looking for is wrinkle finish, I think I will need to
read a bit and play about.
Cheers Matt

[bigwig]

On 7 May, 17:14, Sofa Slug wrote:
dre7 wrote:
Auto Parts Store. *Look for Krylon or VHT black wrinkle paint. *Tell the
clerk you want the stuff for valve covers.

Andrew

bigwig wrote in message...
Hello,
* *How do you get a good crackle type paint finish?. You know the sort
found on old scientific instruments etc. I want to get the sort with a
raised effect much like an old RCA projector I once repaired,
georgeous and also fairly hard wearing. I would like to use this on my
aluminium chassis so an etch primer will be needed.
* * Cheers * Matt

Be sure and heat up the metal's surface with a heat lamp or gun before
painting - otherwise you may not get a very pronounced "wrinkle" effect.
See:http://www.fancollectors.org/info/wrinkle.htm- Hide quoted text -

- Show quoted text -

Outstanding, sorry I have finally found some time to read through
everyones stuff. Thank you to the Doctor (how should I address you?)
for the vey interesting and also thought provoking knowledge on the
process. So many good books go missing. We used to have four book
shops in my town, one of them sort of specialised in non-fiction stuff
ie. real books. I have a very intersting one about the brazing and
welding of copper and its alloys dated 1936. All the shops have now
gone, replaced by a large one that you go in and ask for books by the
ISBN, hmmm great, that is really helping further human knowledge.
I had a wrinkle effect once when I used trike (111) near some half
cured parts, I dont know what the paint was but I was not popular.
The finish acheived in the link is absolutely perfect. I see the
reason for heat, to bake off the (possibly slightly incompatible)
thinners. I will have to get some Plasti-Kote and try. Preperation is
the key I guess, as with anything. I have access to a bead blaster and
decent de-greasing. I may have trouble with the actual painting but
starting again is no hardship with a blaster, just costly in paint and
time consuming. The heating is a different matter. I have some West
PID temperature controllers and some big SSRs so I could build a
smallish oven. Trouble is it would be a lot of effort, how was the
heating/turning done?.
Cheers Matt

[bigwig]

On 7 May, 03:41, "Dr. Barry L. Ornitz" wrote:
"bigwig" wrote in message

...

* How do you get a good crackle type paint finish?. You know the sort
found on old scientific instruments etc. I want to get the sort with a
raised effect much like an old RCA projector I once repaired,
georgeous and also fairly hard wearing. I would like to use this on my
aluminium chassis so an etch primer will be needed.

Be careful with your nomenclature here. Crackle finish is quite different
from wrinkle finish. *In fact, there were many different finishes used in
the 1930's and 1940's. *One of my former employers (Eastman Chemical
Company, formerly Eastman Kodak) had an large research library in which I
found an excellent reference book on paint and varnish technology. *The
book had a lithograph with about 20 differing surface finishes along with
their trade names. *Unfortunately, this page would not reproduce properly
with any of the digital scanners available to me at the time. *It would
have been a useful reference to place on a website for restorers of
antique radios and test equipment like myself.

The crackle effect is obtained when the paint shrinks as it polymerizes.
A good crackle paint will produce a finish made up of thousands of small
islands formed when the surface film shrinks and tears leaving shallow
cracks. *Alligator hide looks like the magnified finish. *Wrinkle finish
paint works by an opposite mechanism; it expands as it cures causing the
surface film to wrinkle up and produce a larger surface area. *Originally
both finishes were considered painting defects until they could be
reproduced in a controlled fashion. *Then someone had the bright idea
that a textured paint required far less surface preparation than did a
glossy finish paint. *Most military electronic equipment produced during
WWII was painted in wrinkle finishes.

There is another finish seen in metallic paints containing aluminum
powder. *This is called a splatter finish. *Essentially the object is
first painted and before it has a chance to cure, solvent is lightly
sprayed onto the surface in small drops.

Most of the old technology that produced these paint finishes is now
lost. *Manufacturers kept most of their information proprietary and many
even kept their secrets from ever being recorded. *It is known, however,
that most wrinkle finishes were produced by what is known as "gas
checking." *The drying ovens were usually natural gas fired, and by
adjusting the mixture to be rich, carbon monoxide was produced. *This
reacted with alkyd enamels to produce wrinkling.

Today, the best textured finishes are obtained by powder coating. *Here a
powder is sprayed electrostatically onto a surface, and then the object
is heated in an oven. *This melts the powder and simultaneously cures the
resin in the powder.

Today commercial wrinkle finish paint is found in spray cans - but in a
limited range of colors.
If you need a specific color that is not produced, you can overspray an
existing wrinkle finish with a thin lacquer. *Just be sure that the
wrinkle finish has cured properly. *It is best to have patience and wait
a week or more before overspraying.

* * * * Dr. Barry L. Ornitz * * BLOrnitz48@charter/net

On the subject of test equipment, I only just noticed that I lost the
bidding (if you can call it that) on a TEK 555, flea bay. I dont think
the guy knew what he had. It went down to 30 odd seconds then the
snipers came in. Shame really, it had the power supply but looked
tatty, guess it will be gutted and raped for its innards. It would
have been a two hour drive to get it but I was ready to go :-( Item
no. 330325703625 .

[Dr. Barry L. Ornitz]

"bigwig" wrote in message
...

On the subject of test equipment, I only just noticed that I lost the
bidding (if you can call it that) on a TEK 555, flea bay. I dont think
the guy knew what he had. It went down to 30 odd seconds then the
snipers came in. Shame really, it had the power supply but looked
tatty, guess it will be gutted and raped for its innards. It would
have been a two hour drive to get it but I was ready to go :-( Item
no. 330325703625 .


I don't know if you read my earlier comments on the Tektronix lab scopes,
but I hope this one was not bought for parts. Everything in these
venerable old scopes is readily available. Even the CRT and power
transformer can usually be found. If I remember correctly the 555 was a
dual beam scope with two electron guns in the same tube. These tubes
might be somewhat harder to find. With two vertical plug-ins and two
timebases, it is like having two oscilloscopes in one.

You can still get the CRT for the 585, however, and it has over ten pairs
of deflection plates (driven by a distributed amplifier for extreme
bandwidth). So keep looking.

Also buy a copy of Stan Griffiths' book: "Oscilloscopes: Selecting and
Restoring a Classic"
http://www.reprise.com/ash/clients2/book.asp. It is well worth the
money, and Stan is a great guy who is happy to answer questions and help
you find parts.

I rode back from Charlotte, NC, to Kingsport, TN, with a friend who was
driving an ancient Toyota with my Tek 585 filling every available cubic
inch in the trunk. We had to drive over the mountains that night and I
worried about every icy mountain curve. It took two of us to carry the
monster into my house. But it is still my favorite scope, even after 24
years.

Good luck on finding a real "keeper."

--
73, Dr. Barry L. Ornitz WA4VZQ

[bigwig]

On 8 May, 06:46, "Dr. Barry L. Ornitz" wrote:
"bigwig" wrote in message

...

On the subject of test equipment, I only just noticed that I lost the
bidding (if you can call it that) on a TEK 555, flea bay. I dont think
the guy knew what he had. It went down to 30 odd seconds then the
snipers came in. Shame really, it had the power supply but looked
tatty, guess it will be gutted and raped for its innards. It would
have been a two hour drive to get it but I was ready to go :-( * Item
no. *330325703625 *.

I don't know if you read my earlier comments on the Tektronix lab scopes,
but I hope this one was not bought for parts. *Everything in these
venerable old scopes is readily available. *Even the CRT and power
transformer can usually be found. *If I remember correctly the 555 was a
dual beam scope with two electron guns in the same tube. *These tubes
might be somewhat harder to find. *With two vertical plug-ins and two
timebases, it is like having two oscilloscopes in one.

You can still get the CRT for the 585, however, and it has over ten pairs
of deflection plates (driven by a distributed amplifier for extreme
bandwidth). *So keep looking.

Also buy a copy of Stan Griffiths' book: "Oscilloscopes: Selecting and
Restoring a Classic"http://www.reprise.com/ash/clients2/book.asp. *It is well worth the
money, and Stan is a great guy who is happy to answer questions and help
you find parts.

I rode back from Charlotte, NC, to Kingsport, TN, with a friend who was
driving an ancient Toyota with my Tek 585 filling every available cubic
inch in the trunk. *We had to drive over the mountains that night and I
worried about every icy mountain curve. *It took two of us to carry the
monster into my house. *But it is still my favorite scope, even after 24
years.

Good luck on finding a real "keeper."

--
73, Dr. Barry L. Ornitz *WA4VZQ


The idea of dual beams is what atracts me, plus the amount of plug ins
available. I recently moved house and now have a nice workshop with a
well lit "clean area" for electronics and other cleanish stuff and
another room just off it for "dirty stuff" all mechanical things,
milling, drilling, turning, welding and general fabrication. It does
get fairly cold at night so a big old Tek would warm the place
nicely:-).
That 555 did look a bit lugged about but I am sure I would have had
no trouble repairing it. I have quite a few 6080s and have read these
work quite hard in the PS so at least that would not be problem. I am
a member of the Tek scopes group so advice on any weird thing like
tunnel diodes would be no probs. I will continue my search and will
probably end up with more than I need, I have a bit of penchant for
test gear, much to the dismay of my better half. At least I can hide
away now without worrying about condensation in the old shed or using
the dining room table:-0.
As for picking one up, I drive on average 1000 to 1200 miles a week
as part of my job. We are supposed to be a carbon neutral company, but
I guess thats what happens if you do a good job, they send me to all
the difficult jobs that no one else could be bothered with. Yesterday
a pigeon flew out and hit my windscreen, it scared the sh%^ out of me.
Not much left of the pigeon but the windscreen survived although my
wing mirror came off and went under the back wheel. Must be something
to do with Welsh pigeons.
Cheers Matt
Cheers Matt