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Posted (edited)

Reading more on the testing I found using Rust Reformer, they compared it with Ospho, Corroseal, and other treatments that were meant to be top coated but they did not top coat them. The study was to only test the capability of the converter by itself.  Of the products they tested, only the Rust Reformer was meant to stand alone.  This is probably why it did well compared to the others.

 

Ospho is normally my go-to rust converter. Since it is supposed to be rinsed off afterwards, I am concerned that if it gets into the existing seams it will be impossible to rise off completely given that the cavity is sealed up and I'm not keen to introduce a water into an already rusting cavity with no drainage. I may look into drilling drain holes if I go this route.

 

I did use POR-15 rust preventative paint on some floorboards that were pre-treated with with Oshpo.  So far it appears to be holding up well.

 

I've been doing more research on Finishing.com.  This is a pretty well respected forum full of metallurgist and materials engineers. Phosphating bare or lightly rusted (a.k.a. surface rusted) mild steel (with products like Ospho or other phosphoric acid solution) seems to be the most common recommended process.  Ideally this would be followed by a chromate primer .  Unfortunately chromate is toxic to people and our environment and it being slowly phased out.  We use Super Koropon two part epoxy primer at my work to protect aluminum (after conversion coating - similar to phosphating) but it also good for steel. It's probably the best rust preventative primer on the market but it's expensive (~$200/gallon) and highly toxic. Toxicity is manageable for us since we are not in a production environment - we design/build mostly one-off and experimental type aerospace engineering products. 

 

Anyway, as they say "perfect is the enemy of good enough," so I will need to just pick one that is deemed good enough.

 

 

Edited by rossman
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Long time no post. Life has gotten in the way of the project. It's not dead, just on the back burner for a while.   The exhaust system, including the wastegate dump tube is complete. I'

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5 hours ago, RJ280ZX said:

 

Muriatic acid will eat the rust and leave you with bare metal, the full strength stuff works better but hard to come by.  Be careful, if you leave it on too long, it will eat the metal. 

Here is an example of what the acid can do https://www.youtube.com/watch?v=Tfk2J0fXZzM  full strength version of the acid https://www.youtube.com/watch?v=V2Q7I26cwkU

 

Skyco ospho rust converter will "convert" the rust into something paintable.  You apply it, let it sit 24 hrs then wash it off, then paint it.   I just started doing this method this last year, so I can't offer you any lasting results, but I think it will work better than other methods I have used.  Remember, you need to wash it off after you let it sit or the paint won't stick. 

 

I recommend using POR-15 to repaint it,  they have an aerosol can that can be painted directly to the bare metal.  

 

Thanks for the feedback and links.  I've used muriatic acid (diluted hydrochloric acid) to remove mill scale - it works well and does leave a good surface for painting once it is washed off and dried.  I'm not sure it chemically bonds with the steel like phosphoric acid does to leave a neutral exposed layer.  So it's probably best to coat it again with another rust converter like you did with Rust Reformer.  How did that work out for you?

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6 hours ago, rossman said:

Anyway, as they say "perfect is the enemy of good enough," so I will need to just pick one that is deemed good enough.

 

This has become my philosophy for MOST of my build. Especially over the past year. Keeping this mindset has gotten me more progress on the car in the past year than in the previous 5 combined (that and spending lots of money haha)

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6 hours ago, rossman said:

Anyway, as they say "perfect is the enemy of good enough," so I will need to just pick one that is deemed good enough.

 

 

LOL....I have always heard it as "perfection is the enemy of excellence", basically same meaning I guess.

 

It is one of my favorite expressions, because I have anal-retentive tendencies, and I frequently have to remind myself that perfection is not a realistic goal.

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2 hours ago, Zetsaz said:

 

This has become my philosophy for MOST of my build. Especially over the past year. Keeping this mindset has gotten me more progress on the car in the past year than in the previous 5 combined (that and spending lots of money haha)

 

I'm trying, good enough is how it usually goes.  A good example is the guy complaining in your thread that the VA ac duct is horrible for air flow. That's probably true but the VA stuff is "good enough" in my book and has the benefit that it's much easier to work with. Now, if we were engineers designing climate control ducting for Nissan, we'd probably choose something better...but were're not and I don't know about you, but I don't really have the time or budget to spend on fancy ducting when cheap flex duct just works. That said, I was hoping you found something better and so I could steal the idea :).

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50 minutes ago, rossman said:

 

I'm trying, good enough is how it usually goes.  A good example is the guy complaining in your thread that the VA ac duct is horrible for air flow. That's probably true but the VA stuff is "good enough" in my book and has the benefit that it's much easier to work with. Now, if we were engineers designing climate control ducting for Nissan, we'd probably choose something better...but were're not and I don't know about you, but I don't really have the time or budget to spend on fancy ducting when cheap flex duct just works. That said, I was hoping you found something better and so I could steal the idea :).


Haha, true. Sorry to disappoint. As far as I'm concerned, what I have is better than the original ducting, the new fan is far better than the original, and each vent has a dedicated ducting all the way to the core. I don't know about you, but I've rarely if every had the fans cranked up even in modern cars. The Z is plenty small and some light airflow to keep things cool will be all I need. The lizard skin ceramic coating was already more than enough to keep heat at bay most of the summer except when the car wasn't moving at lights. 

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2 hours ago, Ironhead said:

 

LOL....I have always heard it as "perfection is the enemy of excellence", basically same meaning I guess.

 

It is one of my favorite expressions, because I have anal-retentive tendencies, and I frequently have to remind myself that perfection is not a realistic goal.

 

I too suffer from the a similar problem.  I call it "analysis paralysis." Have to constantly fight it. Sometimes it's a loosing battle.😆

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3 minutes ago, Zetsaz said:


Haha, true. Sorry to disappoint. As far as I'm concerned, what I have is better than the original ducting, the new fan is far better than the original, and each vent has a dedicated ducting all the way to the core. I don't know about you, but I've rarely if every had the fans cranked up even in modern cars. The Z is plenty small and some light airflow to keep things cool will be all I need. The lizard skin ceramic coating was already more than enough to keep heat at bay most of the summer except when the car wasn't moving at lights. 

 

I live near Houston.  The AC is cranked up to 11 in July/August

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Posted (edited)

Did more work yesterday repairing the center section of the sacrificial replacement panel.  Sounds weird I know but it has enough rust that it's thinned out in some sections.  Using this piece will be much easier than trying to repair the original, completely rotted part.

 

I also found evidence of more shoddy repair work on the left (drivers) side rear quarter panel that will eventually need to be cut out and fixed correctly. I don't think anyone makes reproductions of this panel (the exposed metal that surrounds the tail light surround). I'll be on the lookout for someone parting out an s30 to see if they can hack off this section for me.

 

Here are a few pictures of the sacrificial panel (this is the part under the top, lower hatch plate just above the latch/license plate)

 

IMG_20210101_154027.jpg.42b3b1e0e5c974211afc5f44fd0ee6f9.jpg

 

As you can see, it's not perfect. Both sides will need to be fixed.

IMG_20210101_154036.jpg.dd4e64112864ad05a3fa95ca3aa30989.jpg

 

Here it is on the car.  There is a nice 1/2" hole on both panels that I used to align the parts with a center punch. I didn't get a picture but later, I removed the original latch mount so the parts laid flat so I could verify they were identical.

IMG_20210101_133223.jpg.3b0950f763afde0b38ad350b16488003.jpg

 

Here is the start of the repair panel.  I'm using 18 gauge metal to replace the thin 20 gauge stock metal.

IMG_20210101_154048.jpg.d7c9df18e44e74f434d2c2a228175f20.jpg

 

Here is the completed patch panel.  It was all done by hand using an angle grinder, body hammer, vice, and stock tension rod to make the large radius bend. I eyeballed the whole thing and it seems to match up nicely.

IMG_20210101_155324.jpg.d1d453d3b9ea48fb7ec70e300f0ae196.jpg

 

I also started measuring the distances between the interior clips as a reference when I get all the panels welded into place.  The 280z tabs are different.  Anyone have a better idea to get the tabs to line up properly? I suppose I could make a template but maybe there is an easier way. Another option may be to use the panel as a guide but I won't be able to see the tabs with the panel in place.  Any ideas?

 

IMG_20210101_132708.jpg.bab9c38016bbe70d7c8acf4d9bfc074f.jpg

 

IMG_20210101_132757.jpg.a652fda92573eb32d336c209b9544c33.jpg

 

Here are a couple of pictures of the inner side of the left quarter panel.  These were taken from the inside of the hatch looking back towards the tail lights.  You can see the body filler that oozed thru the holes they used to pull out a pretty significant dent from a rear end collision. 

 

Top.  I actually have this replacement piece already but it doesn't capture the bottom section pictured below.

IMG_20210101_122636.jpg.b088903254995459d32ed04add4899a6.jpg

 

Bottom, you can see rust and curled up structural support (behind the out of focus connector)

IMG_20210101_123013.jpg.b4d26343eee6bce54cbb4fde097bd719.jpg

 

Here is the right (passenger) side for reference.  Note the surface rust. I will be treating this as best I can with rust converter.

IMG_20210101_122453.jpg.a0ee67705cb6c6175833e79ad61d1c1c.jpg

 

IMG_20210101_154056.jpg

 

Thanks for looking!

Edited by rossman
clarity and grammar
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Did a little more work this weekend.  I'm ready to start welding this week.

 

The the right side of the replacement center section patch was cut and is ready to weld.

Before:

IMG_20210102_171918_sm.jpg.9c2530b916ae0b6782834554fcab9b1d.jpg

 

After - didn't get a picture of the rusty metal cut out of the replacement panel.

IMG_20210102_171905_sm.jpg.f7b1394c52f8586b3b3baf21fc6bf91b.jpg

 

The center section is cut and ready to weld to the car. I match cut both panels while the replacement was clamped on top of the original - worked great.  I learned this trick from Fitzee's Garage on YouTube.

IMG_20210103_175617_sm.jpg.a3cb9dfd1bfaf0475521d5714411a90e.jpg

 

Thanks for looking!

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Posted (edited)
59 minutes ago, Exposed said:

Great progress so far! Are all of the tabs in good shape that hold the bottom of the rear light panel? If not do you plan of making some, buying them or just leaving it as is?

Are you referring to these tabs?  They appear to be in good shape, although at lease one of the clips that grabs the tail light surround is spread open so it doesn't clip onto the surround panel. I seem to remember that the clip is separate from the tab that's welded to the body.  If so, it could just be replaced.  Either way, I'll probably just bend it closed.

 

InkedIMG_20210103_175617_LI.jpg

Edited by rossman
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Wow, I admire your diligence...while I personally agree wholeheartedly with Zestaz regarding getting a shell in better condition...at the end of the day, when your beauty is all done an driving, you will have a much more visceral connection to her knowing the amount of incredibly detailed work you put into it...

 

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Posted (edited)
11 hours ago, boosted300 said:

Wow, I admire your diligence...while I personally agree wholeheartedly with Zestaz regarding getting a shell in better condition...at the end of the day, when your beauty is all done an driving, you will have a much more visceral connection to her knowing the amount of incredibly detailed work you put into it...

 

Thanks for the kind words but I'm just implementing what I have learned over the years.  This is what I got so I'm going to work with.  It will never be a perfect concours car. I knew that when I purchased it back in 2008 for $4k as a running/driving all original 240z. There are more body issues - so there is more to come after this repair.  I'm already planning how to undo and fix the damage around the quarter panel and tail light.  The current plan is to hand-form a piece of sheet metal and butt-weld it in. I'll take pictures as I go...

Edited by rossman
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6 hours ago, rossman said:

Thanks for the kind words but I'm just implementing what I have learned over the years.  This is what I got so I'm going to work with.  It will never be a perfect concours car. I knew that when I purchased it back in 2008 for $4k as a running/driving all original 240z. There are more body issues - so there is more to come after this repair.  I'm already planning how to undo and fix the damage around the quarter panel and tail light.  The current plan is to hand-form a piece of sheet metal and butt-weld it in. I'll take pictures as I go...


Honestly it's the same even with mine. I'm sure it has some hidden rust, but most of it was sandblasted before paint. There's no rot anywhere that I can see, so I've used internal frame coating anywhere I could reach to hopefully prevent rust problems, but it seems like the smallest bits of exposed metal can spread rust. I'm at a point where I just don't worry about it as much because I just want to enjoy it.

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They ALL have hidden rust.  It's just the extent of the rust that is the question. The only other spot that I can see from the outside is also on the left quarter panel where they rolled the lip - at the very top of the arch.  Hopefully it's minor but I'm not holding my breath on that one! I have done some snooping around and found evidence of filler on the right dogleg behind the door.  I don't see rust there from the outside but I'm sure there is at least some surface rust. The whole reason I have been putting off doing this body work is because I just enjoy driving it more than anything.  But, it's time, I'm going to start stripping paint soon.

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It's been a nasty cold day, so I spent this afternoon working on the car.  I made a little progress.  The center panel is tacked in.  I had almost forgotten how difficult it is to weld on this old car.  The metal is like ~22 gauge.  The 280z replacement panel is slightly thicker ~20 gauge.  Several of those spot welds blew right thru the metal.  I had to relearn the technique I previously used on the floorboards a few years ago when I replaced them - angle the MIG gun and pull back to modulate the heat when needed.

 

IMG_20210110_144524.jpg.8efcb77b3d490006d8d9ac5ba5c29c43.jpg

 

IMG_20210110_124832.jpg.73fb3904dd99ec3da1e0e3e0903eacb3.jpg

 

I fired up my trusty MIG welder for the first time in a while.

IMG_20210110_144501.jpg.b8b9a3725f32966a3b9a3543d9491709.jpg

 

Before I made my first weld, I took a sheet of 20 gage and set up the welder and practice prior to welding on the car. The welds progressively get better towards the right-most clamp.  The first weld on the left was done the settings recommended by Miller - which were too cold.  The last one was using my technique of angling the weld gun to effectively lower the heat.  The welds are far from perfect but good enough since most of the weld will be ground off flat when the panel gap is completely filled with weld.

IMG_20210110_144451.jpg.116addeb1cbbc0db5d0dac1be89c53d7.jpg

 

This spot weld was made with the gun at an angle to the plane of the panel, similarly to what's shown below.

IMG_20210110_140629.jpg.e1522457165bd2497bee4d1940012894.jpg

 

This hole/weld was made with the gun pointed more perpendicular to the the panel.

IMG_20210110_140646.jpg.f4805a0ef454b753f6694a7c6642d483.jpg

 

I also used a magnetic copper backer to "dam" the back side of the joint and absorb some of the heat to minimize blow-thru.  I didn't get a picture of the tool but you can find them on Amazon.  Once there is a tack weld there, it's easier to add more weld adjacent to it.  The existing weld serves as a little heat sink making the panel more resistant to blow thru.  It will still blow-thru if you're not careful but much easier to weld.  The process is slow and a pain in the ass but it works if you're patient, and take your time.

 

I also made a little mandrel so I could form patch panels for the curved lip that holds the hatch seal. This was prior to smoothing out the inside  of the radius.

IMG_20210110_130235.jpg.2fd0dad90448066d5e1701f9e74e03f3.jpg

 

I then cut out a piece of 18 gauge for forming. The offset line is where I cut for the panel to make the lip.

IMG_20210107_194515.jpg.3555de32c0ad2bf8325ea6a0adb48555.jpg

 

Here is the formed piece.  It's not perfect but it's much better than the replacement panels that I can find on-line...which don't exist. The lip is tall but it will get cut ground down to match the stock lip once all the panels are welded on the car.

IMG_20210110_130217.jpg.04e0a5e25286ac70a3c398ab92a845fc.jpg

 

It matches fairly well with the old rotted piece it's replacing. I will not be stepping/lapping the joint as the original was done.

IMG_20210110_150655.jpg.89c496946f5807af2d02707e51ce0526.jpg

 

Next up will be to tackle this mess and weld in the replacement panel.

IMG_20210110_145942.jpg.e7f09d3d11b9cd48cc48be5294d6b10b.jpg

 

 

 

 

 

 

 

Edited by rossman
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3 hours ago, rossman said:

It's been a nasty cold day, so I spent this afternoon working on the car.  I made a little progress.  The center panel is tacked in.  I had almost forgotten how difficult it is to weld on this old car.  The metal is like ~22 gauge.  The 280z replacement panel is slightly thicker ~20 gauge.  Several of those spot welds blew right thru the metal.  I had to relearn the technique I previously used on the floorboards a few years ago when I replaced them - angle the MIG gun and pull back to modulate the heat when needed.

 

IMG_20210110_144524.jpg.8efcb77b3d490006d8d9ac5ba5c29c43.jpg

 

IMG_20210110_124832.jpg.73fb3904dd99ec3da1e0e3e0903eacb3.jpg

 

I fired up my trusty MIG welder for the first time in a while.

IMG_20210110_144501.jpg.b8b9a3725f32966a3b9a3543d9491709.jpg

 

Before I made my first weld, I took a sheet of 20 gage and set up the welder and practice prior to welding on the car. The welds progressively get better towards the right-most clamp.  The first weld on the left was done the settings recommended by Miller - which were too cold.  The last one was using my technique of angling the weld gun to effectively lower the heat.  The welds are far from perfect but good enough since most of the weld will be ground off flat when the panel gap is completely filled with weld.

IMG_20210110_144451.jpg.116addeb1cbbc0db5d0dac1be89c53d7.jpg

 

This spot weld was made with the gun at an angle to the plane of the panel, similarly to what's shown below.

IMG_20210110_140629.jpg.e1522457165bd2497bee4d1940012894.jpg

 

This hole/weld was made with the gun pointed more perpendicular to the the panel.

IMG_20210110_140646.jpg.f4805a0ef454b753f6694a7c6642d483.jpg

 

I also used a magnetic copper backer to "dam" the back side of the joint and absorb some of the heat to minimize blow-thru.  I didn't get a picture of the tool but you can find them on Amazon.  Once there is a tack weld there, it's easier to add more weld adjacent to it.  The existing weld serves as a little heat sink making the panel more resistant to blow thru.  It will still blow-thru if you're not careful but much easier to weld.  The process is slow and a pain in the ass but it works if you're patient, and take your time.

 

I also made a little mandrel so I could form patch panels for the curved lip that holds the hatch seal. This was prior to smoothing out the inside  of the radius.

IMG_20210110_130235.jpg.2fd0dad90448066d5e1701f9e74e03f3.jpg

 

I then cut out a piece of 18 gauge for forming. The offset line is where I cut for the panel to make the lip.

IMG_20210107_194515.jpg.3555de32c0ad2bf8325ea6a0adb48555.jpg

 

Here is the formed piece.  It's not perfect but it's much better than the replacement panels that I can find on-line...which don't exist. The lip is tall but it will get cut ground down to match the stock lip once all the panels are welded on the car.

IMG_20210110_130217.jpg.04e0a5e25286ac70a3c398ab92a845fc.jpg

 

It matches fairly well with the old rotted piece it's replacing. I will not be stepping/lapping the joint as the original was done.

IMG_20210110_150655.jpg.89c496946f5807af2d02707e51ce0526.jpg

 

Next up will be to tackle this mess and weld in the replacement panel.

IMG_20210110_145942.jpg.e7f09d3d11b9cd48cc48be5294d6b10b.jpg

 

 

 

 

 

 

 


 

looking great! I had similar difficulties with heat and burn through. Mine was rusted out more than yours, so there is always something to be grateful for! Here is minE: 

D85EA525-528D-45DD-A795-DC977019ECCB.jpeg

FA74EFAE-4A47-4213-8079-E1F7E0348718.jpeg

A7F77A93-DE85-47E6-8E4A-D412E81F8061.jpeg

F06E9D10-9F3B-40D8-A183-35D1F80B6CFA.jpeg

BDBF75C3-3282-4E94-9B87-14E415EB36D5.jpeg

0AD27C82-BE18-4616-B016-25195551811D.jpeg

7A54EE02-CAF9-47B6-A75F-C112183E6F99.jpeg

CAA6D513-E2A1-4F1A-8EF6-D7BFE4CB9570.jpeg

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