Date   

Re: 1S1 sampling bridge GaAs diodes: What alternatives?

Tom Lee
 

I have not actually fixed one this way, but I would expect an HSMS-28xx Schottky to be a perfect replacement here. These are readily available.

Tom

Sent from my iThing, so please forgive the terseness and typos.

On Dec 9, 2020, at 14:26, "leonard scheepsma" <tubes.leonard@hetnet.nl> wrote:

Dear all, my 1S1 gave up. It looks at least one of my sampling diodes has died. Searching through the related messages I noticed most comments are pretty old, so I hope some new ideas might have been launched on getting alternatives for the original GaAs diodes, just assuming these are completely unobtainable.
Looked at the Agilent/KeySight site, they mention some ultra fast GHz diodes there but these go through a distributor and I suspect ut won't be easy to get 4 of these at reasonable cost (not knowing they would work either)
Any tips, suggestions?

Thanks so much, Leonard





Re: OT - VTVM’s are awesome

Stephen
 

On Wed, Dec 9, 2020 at 10:50 AM, Jim Ford wrote:


Well, tubes (valves, for the Brits in the audience) are for audio and
displays, if you ask me. Maybe in TWTs for moon-bounce. I haven't
found a reason to buy a scope with tubes, other than the CRT, in it yet.
But then, I'm only 55, a mere youngster on this group! ;)

Jim
I’m 54 and I love anything with tubes in it.
If it’s well designed of course, not the cheap Chinese stuff that have tubes glowing just for the looks.

As for VTVM’S or VOM’s for that matter, I use them as much as my DMM’s.
There’s no better or worse. As it has been mentioned, they all have their place.
I personally find needles easier on the eyes. And they can be very accurate if you look closely at the position of the needle, and if your meter has a parallax mirror. Now, if you absolutely need 50000 counts or more of accuracy, that’s not for you...
But honestly, how many times do you really need that level of accuracy or definition. And I mean « need », not « want ». Personally, not many times.

On a side note, like Tektronix scopes of yore, they are just well designed and built to last. The quality is exceptional by nowadays lame standards IMO. These older things are objects of art.


1S1 sampling bridge GaAs diodes: What alternatives?

leonard scheepsma
 

Dear all, my 1S1 gave up. It looks at least one of my sampling diodes has died. Searching through the related messages I noticed most comments are pretty old, so I hope some new ideas might have been launched on getting alternatives for the original GaAs diodes, just assuming these are completely unobtainable.
Looked at the Agilent/KeySight site, they mention some ultra fast GHz diodes there but these go through a distributor and I suspect ut won't be easy to get 4 of these at reasonable cost (not knowing they would work either)
Any tips, suggestions?

Thanks so much, Leonard


Re: OT - VTVM’s are awesome

Jim Ford
 

LOL about sleeping on top of a pile of 7000 mainframes! Don't give my wife any ideas or I'll be living that!

Jim Ford

------ Original Message ------
From: "Tom Lee" <tomlee@ee.stanford.edu>
To: "TekScopes@groups.io" <TekScopes@groups.io>
Sent: 12/9/2020 1:49:04 PM
Subject: Re: [TekScopes] OT - VTVM’s are awesome

Absolutely right! The flame wars are entertainingly silly. I resolve the conundrum personally by not limiting the choices to this or that. Why not both? I get a lot of use out of my $4 cheapo DMM, and I don't shed a tear if I break it or lose it. I've got many other meters for other purposes. Of course, sometimes storage space eventually becomes a factor, but a bunch of 7000-series mainframes lashed together with a mattress on top is a pretty decent bed.

Tom

Sent from my iThing, so please forgive the terseness and typos.

On Dec 9, 2020, at 13:39, "tgerbic" <tgerbic@gmail.com> wrote:

I am also a fan of VTVMs. They have their place.

I have seen a lot of discussions, some turning into flame wars, on the net about analog vs. digital test equipment. I learned long ago that there are no perfect test instruments. You need to determine what works when, how you need things displayed and how much accuracy you really need, or makes sense. Though I have multiple midrange bench/handheld Fluke and HP DMMs on the bench, I restored a Heathkit IM-25 and it sits in the middle of the bench. Not actually a VTVM but a solid state version of one. It is accurate enough for many uses and I have lab calibrated instruments if I need higher accuracy.

What is really important, as pointed out below, is the large analog meter. For many measurements a moving needle meter is much easier to read and easier for my eyes to follow than a digital readout. Some meters have bar graphs but not much resolution compared to a large meter. Where VTVMs really shine is when tuning things where you are looking for a peak or null, or when trying to follow signals that vary all over the place. In many cases you don't even need to stare at the meter to get readings (like on a digital meter) but just keep an eye on it in your peripheral vision as you make some preliminary adjustments. A scope can be used in some cases but might be overkill. I also have an analog frequency meter for tuning and following frequency changes. I have spectrum analyzers ranging down to 5hz but an SA might again be overkill or too much setup.

I still have a bunch of Heathkit, RCA and EICO VTVMs and will use one from time to time, mostly on older tube equipment where I might worry about permanently damaging my Fluke meters.

Bottom line is to determine what you want to measure, how much accuracy is needed and how you want/need to see the display. VTVMs still have a niche to fill.

Regards








Re: 494AP-How does the Front Panel Amp Cal ie, Blue Shift CAL function work? Mine has a problem

 

Bob,
I realize this might not be terribly helpful, but I have encountered a pair of similarities with my plain 494 that I have been waiting to worsen so that I might better trace the problem.
When first turned on, the screen characters, but not the other traces, on my screen exhibit a vertical shake of perhaps 1/16-inch.  This gradually subsides in less than a minute.  But then when reducing the Frequency Span, in switching from 500 kHz to 200 kHz, the screen displays "Phaselock Failure -- 1st LO."
Now by turning the power off and back on again, everything works OK and the analyzer will phaselock properly down to a resolution bandwidth of 30 Hz.
The voltage test points, near the left-front, show no evidence of jitter.  I have not changed the power resistors on the deflection board, as recommended by John Miles, but now have replacements on hand.  It is possible these resistors in the vertical deflection circuit are arcing internally, but eventually heat and heal.
Interestingly, if the Peak/Average control is turned all the way CW so that the horizontal line is off-screen at the top, the screen characters will jitter vertically.  I assume this is an intentional warning feature that is digitally generated, and unrelated to the fault.

Bruce, KG6OJI


Re: OT - VTVM’s are awesome

Jim Ford
 

Well, tubes (valves, for the Brits in the audience) are for audio and displays, if you ask me. Maybe in TWTs for moon-bounce. I haven't found a reason to buy a scope with tubes, other than the CRT, in it yet. But then, I'm only 55, a mere youngster on this group! ;)

Jim

------ Original Message ------
From: "Tom Lee" <tomlee@ee.stanford.edu>
To: "TekScopes@groups.io" <TekScopes@groups.io>
Sent: 12/9/2020 1:31:38 PM
Subject: Re: [TekScopes] OT - VTVM’s are awesome

Hi Jim,

Yes, in this case, "better" was the enemy of "best", where "best" was what solved the problem the soonest and with stuff in my junk box. I wouldn't trust the ohmmeter to hold tight tolerances over a wide temperature range (or ever) with this circuit, but it never got too hot or cold in San Diego. Worked well enough to fix TVs and radios. And the VTVM was thankfully hard to kill, even when probing a horizontal output tube's plate voltage. Love them toobz!

Tom

Sent from my iThing, so please forgive the terseness and typos.

On Dec 9, 2020, at 13:14, "Jim Ford" <james.ford@cox.net> wrote:

No need to overthink it. If it works, go with it. The engineer in me wants to make sure it has some margin, though. Jim Ford Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------From: Tom Lee <tomlee@ee.stanford.edu> Date: 12/9/20 1:05 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] OT - VTVM’s are awesome I didn’t like having a battery in my Heathkit VTVM, either. Having lost countless flashlights and toys to leakage was enough of a lesson. It was in the days before the LM317 (maybe Dobkin was in the process of designing it), so that wasn’t an option. I just put two diodes in series, powered through another rectifier off the filament supply (I think), with a big old ‘lytic across the series diode pair. Not elegant, but as a junior high school student, I was very pleased to have it work. When I revisited the meter after many years in storage, I thought briefly about upgrading it with a more modern implementation. But it still worked well, so I let laziness make the decision.TomSent from my iThing, so please forgive typos and brevity.> On Dec 9, 2020, at 12:47 PM, Jean-Paul <jonpaul@ix.netcom.com> wrote:> > Hi: The Heathkit, Eico, Paco and Knight (Allied) VTVMs all had bannana jacks and probe cables of rubber, that cracked over the years. I recall one meter with the old microphone screw coax perhaps for AC input shield. > > The VT bridge circuit seems to limit meter movement (200 uA?) overload, I never had damage to the movements even with extreme overload. > > IM-28 were the newer series but basically same as the VT-7.> > Hope that someone can please post a link to the Zener or LM317 battery substitue circuit? > > Jon> > > > > > > >







Re: OT - VTVM’s are awesome

Tom Lee
 

Absolutely right! The flame wars are entertainingly silly. I resolve the conundrum personally by not limiting the choices to this or that. Why not both? I get a lot of use out of my $4 cheapo DMM, and I don't shed a tear if I break it or lose it. I've got many other meters for other purposes. Of course, sometimes storage space eventually becomes a factor, but a bunch of 7000-series mainframes lashed together with a mattress on top is a pretty decent bed.

Tom

Sent from my iThing, so please forgive the terseness and typos.

On Dec 9, 2020, at 13:39, "tgerbic" <tgerbic@gmail.com> wrote:

I am also a fan of VTVMs. They have their place.

I have seen a lot of discussions, some turning into flame wars, on the net about analog vs. digital test equipment. I learned long ago that there are no perfect test instruments. You need to determine what works when, how you need things displayed and how much accuracy you really need, or makes sense. Though I have multiple midrange bench/handheld Fluke and HP DMMs on the bench, I restored a Heathkit IM-25 and it sits in the middle of the bench. Not actually a VTVM but a solid state version of one. It is accurate enough for many uses and I have lab calibrated instruments if I need higher accuracy.

What is really important, as pointed out below, is the large analog meter. For many measurements a moving needle meter is much easier to read and easier for my eyes to follow than a digital readout. Some meters have bar graphs but not much resolution compared to a large meter. Where VTVMs really shine is when tuning things where you are looking for a peak or null, or when trying to follow signals that vary all over the place. In many cases you don't even need to stare at the meter to get readings (like on a digital meter) but just keep an eye on it in your peripheral vision as you make some preliminary adjustments. A scope can be used in some cases but might be overkill. I also have an analog frequency meter for tuning and following frequency changes. I have spectrum analyzers ranging down to 5hz but an SA might again be overkill or too much setup.

I still have a bunch of Heathkit, RCA and EICO VTVMs and will use one from time to time, mostly on older tube equipment where I might worry about permanently damaging my Fluke meters.

Bottom line is to determine what you want to measure, how much accuracy is needed and how you want/need to see the display. VTVMs still have a niche to fill.

Regards





Re: OT - VTVM’s are awesome

tgerbic
 

I am also a fan of VTVMs. They have their place.

I have seen a lot of discussions, some turning into flame wars, on the net about analog vs. digital test equipment. I learned long ago that there are no perfect test instruments. You need to determine what works when, how you need things displayed and how much accuracy you really need, or makes sense. Though I have multiple midrange bench/handheld Fluke and HP DMMs on the bench, I restored a Heathkit IM-25 and it sits in the middle of the bench. Not actually a VTVM but a solid state version of one. It is accurate enough for many uses and I have lab calibrated instruments if I need higher accuracy.

What is really important, as pointed out below, is the large analog meter. For many measurements a moving needle meter is much easier to read and easier for my eyes to follow than a digital readout. Some meters have bar graphs but not much resolution compared to a large meter. Where VTVMs really shine is when tuning things where you are looking for a peak or null, or when trying to follow signals that vary all over the place. In many cases you don't even need to stare at the meter to get readings (like on a digital meter) but just keep an eye on it in your peripheral vision as you make some preliminary adjustments. A scope can be used in some cases but might be overkill. I also have an analog frequency meter for tuning and following frequency changes. I have spectrum analyzers ranging down to 5hz but an SA might again be overkill or too much setup.

I still have a bunch of Heathkit, RCA and EICO VTVMs and will use one from time to time, mostly on older tube equipment where I might worry about permanently damaging my Fluke meters.

Bottom line is to determine what you want to measure, how much accuracy is needed and how you want/need to see the display. VTVMs still have a niche to fill.

Regards


Re: Tek blue (and gray) paint

Roy Thistle
 

On Wed, Dec 9, 2020 at 12:06 PM, Mark Wendt wrote:


As Keith wrote earlier, there is no such thing as an oil or water based
lacquer.
Yes... very good. (Although... are you sure you mean "... no such thing as oil or water based lacquer." ... that's eliminating a lot of solvents!)
While I realize calling a horse's tail a leg, doesn't make it a leg... it's Rust-Oleum calling it a "lacquer." ... not me. And, they are not the only manufacturer doing it.
Also, Xylene, Toluene, and other so called “high-flash” solvents are from the petroleum-distillate family are definitely used in automotive lacquer thinners... look on the MSDSs for lacquer thinner products.
If you want to spray over Tek panels, finished with an oil-based paint... it would be good to know whether what you are trying to use is compatible.


Re: OT - VTVM’s are awesome

Tom Lee
 

Hi Jim,

Yes, in this case, "better" was the enemy of "best", where "best" was what solved the problem the soonest and with stuff in my junk box. I wouldn't trust the ohmmeter to hold tight tolerances over a wide temperature range (or ever) with this circuit, but it never got too hot or cold in San Diego. Worked well enough to fix TVs and radios. And the VTVM was thankfully hard to kill, even when probing a horizontal output tube's plate voltage. Love them toobz!

Tom

Sent from my iThing, so please forgive the terseness and typos.

On Dec 9, 2020, at 13:14, "Jim Ford" <james.ford@cox.net> wrote:

No need to overthink it. If it works, go with it. The engineer in me wants to make sure it has some margin, though. Jim Ford Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------From: Tom Lee <tomlee@ee.stanford.edu> Date: 12/9/20 1:05 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] OT - VTVM’s are awesome I didn’t like having a battery in my Heathkit VTVM, either. Having lost countless flashlights and toys to leakage was enough of a lesson. It was in the days before the LM317 (maybe Dobkin was in the process of designing it), so that wasn’t an option. I just put two diodes in series, powered through another rectifier off the filament supply (I think), with a big old ‘lytic across the series diode pair. Not elegant, but as a junior high school student, I was very pleased to have it work. When I revisited the meter after many years in storage, I thought briefly about upgrading it with a more modern implementation. But it still worked well, so I let laziness make the decision.TomSent from my iThing, so please forgive typos and brevity.> On Dec 9, 2020, at 12:47 PM, Jean-Paul <jonpaul@ix.netcom.com> wrote:> > Hi: The Heathkit, Eico, Paco and Knight (Allied) VTVMs all had bannana jacks and probe cables of rubber, that cracked over the years. I recall one meter with the old microphone screw coax perhaps for AC input shield. > > The VT bridge circuit seems to limit meter movement (200 uA?) overload, I never had damage to the movements even with extreme overload. > > IM-28 were the newer series but basically same as the VT-7.> > Hope that someone can please post a link to the Zener or LM317 battery substitue circuit? > > Jon> > > > > > > >




Re: Yet another use for a curve tracer

 

Hi Sean,
Lucky you to own a 577D1!

One clever thing you can do with the 577D1 that no other Tek curve tracer can do is find the perfect bias point for a junction FET. You should bias a FET right at the point where the temp coefficient is zero but how do you find that point except by trial and error? FETs are very temperature sensitive little critters with a very unusual temperature coefficient. It is positive up to a certain point and then it turns negative. For your circuit's best temperature stability you need to bias a FET right at the point where the temp coefficient is zero but how do you find that point except by trial and error?
The 577D1 can find that exact zero temperature coefficient point to bias the FET in less than 30 seconds.

Here is how to do it: Display a set of typical FET curves on the 577D1 with storage turned on. Heat the FET up with your finger, or with anything hot for just a second. As the FET die warms up the gate voltage curves will begin to move up above a certain bias voltage and they will move down below that voltage.

The result on the CRT will be that one gate voltage curve will not move so it will remain sharp. All the other bias voltage curves will smear as they move away from the perfect point to bias the FET.

You can also use something cold like an ice cube touched to the FET. The results will be the same except the smears will go in the opposite direction. But one bias curve right in the middle of the smeared ones will be sharp because it didn't move at all.

Give it a try. It is fascinating to watch and it only takes a minute to do this and it is a perfect example of yet another use for a curve tracer. But in this case it is hard to do without storage so that is another reason why my favorite curve tracer is the 577D1.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of sdturne@q.com
Sent: Tuesday, December 08, 2020 6:38 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Yet another use for a curve tracer

Dennis,

This is most definitely true. I got me a very nice 577D1 on the same trip I picked up my 519 on, and suffice to say, I am discovering something new it can do every day. Now to collect all the handy test fixtures Tek made...

Sean

On Tue, Dec 8, 2020 at 10:53 AM, Dennis Tillman W7pF wrote:


Hi Ed,
Curve tracers are very versatile instruments and the only real
limitation they have is the person at the controls.
Nearly everyone I know who owns a curve tracer thinks they are only
good for checking transistors.

What you did was think outside the box, and as you said in the
subject, you found another use for a curve tracer.
I hadn't thought of using it to test lamp dimmers myself so I learned
something new.
But I have used it to test capacitors, inductors, transformers, pots,
SCRs, TRIACs, DIACs, MOVs, OpAmps, Voltage Regulators ICs, Spectrum
Tubes, light bulbs, etc.
Anything with two or three leads is fair game for a curve tracer.

Anyone who owns a curve tracer is extremely fortunate. You can learn a
great deal about how electronic parts of all kinds respond when you
connect them to a curve tracer.

Thanks for sharing your clever idea.

Dennis Tillman W7pF






--
Dennis Tillman W7pF
TekScopes Moderator


Re: OT - VTVM’s are awesome

toby@...
 

On 2020-12-09 3:47 p.m., Jean-Paul wrote:
Hi: The Heathkit, Eico, Paco and Knight (Allied) VTVMs all had bannana jacks and probe cables of rubber, that cracked over the years. I recall one meter with the old microphone screw coax perhaps for AC input shield.

The VT bridge circuit seems to limit meter movement (200 uA?) overload, I never had damage to the movements even with extreme overload.

IM-28 were the newer series but basically same as the VT-7.

Hope that someone can please post a link to the Zener or LM317 battery substitue circuit?
A datasheet for the adjustable or fixed 3-terminal linear regulators
lays it out pretty well. You need about three capacitors in addition to
the regulator and that's it. (Add a trimmer for an adjustable reg.)

--Toby


Jon








Re: OT - VTVM’s are awesome

Jim Ford
 

No need to overthink it.  If it works, go with it.  The engineer in me wants to make sure it has some margin, though.    Jim Ford Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: Tom Lee <tomlee@ee.stanford.edu> Date: 12/9/20 1:05 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] OT - VTVM’s are awesome I didn’t like having a battery in my Heathkit VTVM, either. Having lost countless flashlights and toys to leakage was enough of a lesson. It was in the days before the LM317 (maybe Dobkin was in the process of designing it), so that wasn’t an option. I just put two diodes in series, powered through another rectifier off the filament supply (I think), with a big old ‘lytic across the series diode pair. Not elegant, but as a junior high school student, I was very pleased to have it work. When I revisited the meter after many years in storage, I thought briefly about upgrading it with a more modern implementation. But it still worked well, so I let laziness make the decision.TomSent from my iThing, so please forgive typos and brevity.> On Dec 9, 2020, at 12:47 PM, Jean-Paul <jonpaul@ix.netcom.com> wrote:> > Hi: The Heathkit, Eico, Paco and Knight (Allied) VTVMs all had bannana jacks and probe cables of rubber, that cracked over the years. I recall one meter with the old microphone screw coax perhaps for AC input shield. > > The VT bridge circuit seems to limit meter movement (200 uA?) overload, I never had damage to the movements even with extreme overload. > > IM-28 were the newer series but basically same as the VT-7.> > Hope that someone can please  post a link to the Zener or LM317 battery substitue circuit? > > Jon> > > > > > > >


Re: Tek 465M saga

Tom Lee
 

Hi Roy,

Were there two different versions of the 465M? That model was created specifically for a military contract (which is why it’s nothing like a 465 internally), so your question surprises me.

—Tom

Sent from my iThing, so please forgive typos and brevity.

On Dec 9, 2020, at 12:40 PM, Roy Thistle <roy.thistle@mail.utoronto.ca> wrote:

On Wed, Dec 9, 2020 at 10:56 AM, Harrison wrote:


Look forward to any comments.
CR552, VR552, VR553.. It's a kind "crowbar" over-voltage protection... suppose to blow the fuse, if the HV regulator fails... and the HV goes to high. But, I'm sure you know that.
Did you check the zeners?
Are you using the service manual posted on KO4BB? (That's for the military version of the 465M)





Re: OT - VTVM’s are awesome

Tom Lee
 

I didn’t like having a battery in my Heathkit VTVM, either. Having lost countless flashlights and toys to leakage was enough of a lesson. It was in the days before the LM317 (maybe Dobkin was in the process of designing it), so that wasn’t an option. I just put two diodes in series, powered through another rectifier off the filament supply (I think), with a big old ‘lytic across the series diode pair. Not elegant, but as a junior high school student, I was very pleased to have it work. When I revisited the meter after many years in storage, I thought briefly about upgrading it with a more modern implementation. But it still worked well, so I let laziness make the decision.

Tom

Sent from my iThing, so please forgive typos and brevity.

On Dec 9, 2020, at 12:47 PM, Jean-Paul <jonpaul@ix.netcom.com> wrote:

Hi: The Heathkit, Eico, Paco and Knight (Allied) VTVMs all had bannana jacks and probe cables of rubber, that cracked over the years. I recall one meter with the old microphone screw coax perhaps for AC input shield.

The VT bridge circuit seems to limit meter movement (200 uA?) overload, I never had damage to the movements even with extreme overload.

IM-28 were the newer series but basically same as the VT-7.

Hope that someone can please post a link to the Zener or LM317 battery substitue circuit?

Jon








Re: OT - VTVM’s are awesome

Stephen
 

On Wed, Dec 9, 2020 at 09:47 AM, Jean-Paul wrote:


Hi: The Heathkit, Eico, Paco and Knight (Allied) VTVMs all had bannana jacks
and probe cables of rubber, that cracked over the years. I recall one meter
with the old microphone screw coax perhaps for AC input shield.

The VT bridge circuit seems to limit meter movement (200 uA?) overload, I
never had damage to the movements even with extreme overload.

IM-28 were the newer series but basically same as the VT-7.

Hope that someone can please post a link to the Zener or LM317 battery
substitue circuit?

Jon
Out of my 6 VTVM’s only 1 uses batteries for resistance reading.
But here’s a link I found. Hope this helps.
https://youtu.be/IlaGhx2rqK8


Re: OT - VTVM’s are awesome

Jean-Paul
 

Hi: The Heathkit, Eico, Paco and Knight (Allied) VTVMs all had bannana jacks and probe cables of rubber, that cracked over the years. I recall one meter with the old microphone screw coax perhaps for AC input shield.

The VT bridge circuit seems to limit meter movement (200 uA?) overload, I never had damage to the movements even with extreme overload.

IM-28 were the newer series but basically same as the VT-7.

Hope that someone can please post a link to the Zener or LM317 battery substitue circuit?

Jon


Re: Tek 465M saga

Roy Thistle
 

On Wed, Dec 9, 2020 at 10:56 AM, Harrison wrote:


Look forward to any comments.
CR552, VR552, VR553.. It's a kind "crowbar" over-voltage protection... suppose to blow the fuse, if the HV regulator fails... and the HV goes to high. But, I'm sure you know that.
Did you check the zeners?
Are you using the service manual posted on KO4BB? (That's for the military version of the 465M)


Re: Tek blue (and gray) paint

Mark Wendt
 

On Wed, Dec 9, 2020, 14:50 Roy Thistle <roy.thistle@mail.utoronto.ca> wrote:

On Wed, Dec 9, 2020 at 05:38 AM, Keith wrote:


there is no such thing as “oil based lacquer”. That’s enamel. No oil in
lacquer, or you will be really really sorry when you spray it. I assume
(from the clean-up solvents used) it is some kind of acrylic.
Rust-Oleum Corporation sells a spray can product they call "lacquer" that
is oil-based. (30 min dry time, gloss finish, clean-up with xylene or
mineral spirits.)
You can get it in CONUS, at the home despot.
What does an automotive painter mean by "oil based?" (None of the
"trades-people at the despot, here in the colonies, appear to know.)

As Keith wrote earlier, there is no such thing as an oil or water based
lacquer. If it has oil in it it's an enamel, a urethane or a polyurethane
based finish. If you clean, thin or reduce the finish with xylene or
mineral spirits, it's definitely not a lacquer finish.

If you depend on the paint experts at Home Depot it's easy to see why you
think lacquer can be oil or water based.

Mark


Re: Tek blue (and gray) paint

Roy Thistle
 

On Tue, Dec 8, 2020 at 08:35 AM, Jean-Paul wrote:


Of course, it must be an oil based lacquer
Maybe not, if you're thinking of water-based, over oil-based... if the problem is caused by not fully cured oil-based paint. (It's supposed to be some sort of solvent off-gassing?)
On some of the Tek 500s, some of the oil-based paint must be over 50 years old.
Has anyone recently tried a water-based product, on those panels?

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