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The Cars => 1969-1970 Shelby GT350/500 => Topic started by: tgilliam on March 26, 2022, 01:01:20 PM

Title: Undercarriage Primer Color; 69 Convertible
Post by: tgilliam on March 26, 2022, 01:01:20 PM
Currently working on body work and prep for a 1969 Shelby GT 350 Convertible, Dearborn built, 01/13/1969 build date, #480202; Car was stripped and dipped back in the 80's so I do not have a clue as to what was original; I have looked for information here and on CM Forum but have not found a clear answer;
What I have seen is the possibility it could be red oxide or dark slop primer; I found one reference that there was a change by Ford in the February 69 time frame; Not sure if that was to start using the slop primer or go back to red oxide primer; I also saw a note that the engine compartment up to the fire wall would have red oxide under the black but from fire wall back would be slop primer. Any help or further information would be appreciated. Currently at the point to actually do the undercarriage painting. Thanks for your help.

Tom Gilliam
tom@jtgil.com
(270) 847 - 8093
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: Coralsnake on March 26, 2022, 01:26:57 PM
The color of the primer changes multiple times during 1969 Dearborn production. Here's a Dearborn car from December 1968. The bottom of the engine compartment frame rails may have been red oxide, but its unlikely the would have sprayed the inner aprons or radiator support to any great extent.

(http://www.saacforum.com/gallery/8-260322133105.jpeg)
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: KerryBWhite on March 26, 2022, 01:32:53 PM
Pete
Has there been any info or time frames established as to primer color changes through out the 1969 production?  If memory serves me right, wasn't the later production cars a grey  ( slop grey)?
Thanks
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: Bob Gaines on March 26, 2022, 01:34:22 PM
Quote from: tgilliam on March 26, 2022, 01:01:20 PM
Currently working on body work and prep for a 1969 Shelby GT 350 Convertible, Dearborn built, 01/13/1969 build date, #480202; Car was stripped and dipped back in the 80's so I do not have a clue as to what was original; I have looked for information here and on CM Forum but have not found a clear answer;
What I have seen is the possibility it could be red oxide or dark slop primer; I found one reference that there was a change by Ford in the February 69 time frame; Not sure if that was to start using the slop primer or go back to red oxide primer; I also saw a note that the engine compartment up to the fire wall would have red oxide under the black but from fire wall back would be slop primer. Any help or further information would be appreciated. Currently at the point to actually do the undercarriage painting. Thanks for your help.

Tom Gilliam
tom@jtgil.com
(270) 847 - 8093
This question would be much easier to answer if it weren't for the fact the early car status .Of course the best course of action with no evidence left on your car would be to find a Dearborn car built close to your build date for confirmation. With that said and considering the time frame I would not be surprised if the red oxide is what was used. Have your documentation and comparisons for what ever you choose if showing your car ln concours like you have done with other cars in the past. Expect push back if you go red oxide because the larger majority of later built Shelby's and Boss cars have been well documented with the batch paint and consequently that will be the first thought what is correct. +1 ,there are a multitude of different batch shades during production depending on the colors mixed in with the gray of a given batch.
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: Coralsnake on March 26, 2022, 02:12:16 PM
So, from the few samples I have collected (fourteen) it does appear the red oxide is in the late January/February time frame and then other colors are much more prevalent.

Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: Special Ed on March 26, 2022, 10:25:48 PM
we have early feb 69 shelby low mile car red oxide.
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: mikeh on March 27, 2022, 07:29:05 AM
480412 Jan build was same as coralsnake reply #1 when I took it apart

FWIW, Mike
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: shelbymann1970 on March 27, 2022, 02:51:49 PM
First week of March Boss 429
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: shelbymann1970 on March 27, 2022, 02:55:52 PM
May 6 Shelby
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: nightmist67 on March 28, 2022, 07:46:48 PM
Currently restoring 480183 (late December 1968 build date).  There is evidence of red iron oxide and slop gray per Coralsnake's reply #1.
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: Bob Gaines on March 28, 2022, 09:05:10 PM
Quote from: nightmist67 on March 28, 2022, 07:46:48 PM
Currently restoring 480183 (late December 1968 build date).  There is evidence of red iron oxide and slop gray per Coralsnake's reply #1.
I would suggest taking numerous pictures of the evidence .
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: KShane on March 31, 2022, 09:20:55 AM
481256 has red primer.  Build date is 2/13/69

Shane
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: J_Speegle on March 31, 2022, 07:28:16 PM
From what I've collected and published the majority of these cars were done with   a batch color from the firewall rearward and red oxide from the firewall forwards after the rear section was done. With that said there were periods when red oxide epoxy primer/sealers were used on the section from the firewall rearward . If I recall correctly have at least four production periods identified with numerous examples of each and for a specific period a time when a batch color was used from the firewall forward.

Looking at other cars I have records, owner data and pictures from I see there was a period in late December which have red oxide but then a return to dark then a light batch from cars finished at Dearborn 06A - 16A -  27A. Red oxide from firewall forward for those two time periods

Likely have more to add to the period. Don't think I've updated that file for a while

Hope this helps in some way
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: Dennis Y on November 18, 2022, 09:11:36 PM
So if my Eminger & Marti report show a January 8 build date, is that when it was built at Dearborn or AO Smith? This would be red oxide underneath?
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: Coralsnake on November 18, 2022, 09:14:50 PM
Dearborn build (Ford) dates on Marti reports.
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: J_Speegle on November 18, 2022, 09:42:51 PM
Quote from: Dennis Y on November 18, 2022, 09:11:36 PM
So if my Eminger & Marti report show a January 8 build date, is that when it was built at Dearborn or AO Smith?

Eminger/shipping invoices I have only show when the invoice was prepared not the real build date. Look to the Marti report for that


Quote from: Dennis Y on November 18, 2022, 09:11:36 PMThis would be red oxide underneath?

Can't be certain but if data that has been shared of cars built before and after Jan 8th were batch from firewall rearward and red oxide epoxy sealer from firewall forward
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: TLea on November 20, 2022, 01:30:12 PM
I think it's important to understand for those who don't know there was no primer called slop gray that was used initially. Slop gray came about as a result of mixing leftover body color and with a primer to use it up and extend the use. So at the beginning of the model year and then again we see in January sometime the vats were started with red primer and then through mixing the other colors in as an artist would know everything would turn towards black or in this case dark gray. Depending on when other colors were put in you can see some crazy wild undercarriage colors. I have seen purple and green
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: 427hunter on November 20, 2022, 02:28:54 PM
Quote from: TLea on November 20, 2022, 01:30:12 PM
I think it's important to understand for those who don't know there was no primer called slop gray that was used initially. Slop gray came about as a result of mixing leftover body color and with a primer to use it up and extend the use. So at the beginning of the model year and then again we see in January sometime the vats were started with red primer and then through mixing the other colors in as an artist would know everything would turn towards black or in this case dark gray. Depending on when other colors were put in you can see some crazy wild undercarriage colors. I have seen purple and green

100% correct, my gt500 slop gray was dark and had lots of metallic in it. Rust Oleum graphite wheel paint was almost an exact match. 
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: Bob Gaines on November 20, 2022, 02:35:23 PM
Quote from: TLea on November 20, 2022, 01:30:12 PM
I think it's important to understand for those who don't know there was no primer called slop gray that was used initially. Slop gray came about as a result of mixing leftover body color and with a primer to use it up and extend the use. So at the beginning of the model year and then again we see in January sometime the vats were started with red primer and then through mixing the other colors in as an artist would know everything would turn towards black or in this case dark gray. Depending on when other colors were put in you can see some crazy wild undercarriage colors. I have seen purple and green
I have seen a in your face Maroon color as my wildest color seen. I am sure there are others but to be clear to others reading for direction they are in the small minority compared to the predominate gray as has been described .
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: J_Speegle on November 20, 2022, 03:55:12 PM
God point Tim. Can see where newbies might think we are describing a specific color name.


As an aside concerning the colors that can be referred to as slop or batch color as mentioned its typically a gray - medium to very very dark often with some metallic and either a green or bluish tint. When you start seeing some very "different" looking colors in 70 Dearborn Mustangs with the introduction and popularity of things like brighter and flashier (thing Grabber) colors

Then when you mix that with a contrasting body color over spray you get some very IMHO unpleasant combinations. Thing Grabber Orange with a light green under carriage. In other cases the color or tint of the undercarriage color is fairly close to the exterior color, leading some in the hobby's early yes to believe that their car had body color on the exterior and under 
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: J_Speegle on November 20, 2022, 04:39:13 PM
Not sure why we forgot to post this link. It might help as well as offer some examples

https://www.saacforum.com/index.php?topic=929.msg6979#msg6979 (https://www.saacforum.com/index.php?topic=929.msg6979#msg6979)

Also thought I would post some examples of the some of range of what the mixed colors produced. There are even odder examples but thought I would stay, at this time, with the more typical colors or tints found. Some of these are from cars O took, others from owners and shops and finally some are from samples of floors I cut out and save in bags so that I don't have to rely on pictures with varying lighting when I can get a sample

(https://www.concoursmustang.com/forum/gallery/18/6-201122163120-18134917.jpeg)

(https://www.concoursmustang.com/forum/gallery/18/6-201122163125-181382279.jpeg)

(https://www.concoursmustang.com/forum/gallery/18/6-201122163125-181371806.jpeg)


Of course have plenty more :)

And some of the examples of the range of what the red oxide color follows were. Notice in both the grays and the red oxide that these are not flat finishes originally though with exposure to the elements they can get that look on some samples. Take notice of the reflection in the one well preserved examples




Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: rcgt350 on November 30, 2022, 12:56:53 AM
When a car was travelling on the line, I understand that the primer was shot up towards the entire bottom, did it not keep applying that same primer right to the front crossmember? From what I've been reading it sounds like it stopped spraying in around the firewall area. If so was the next area up to the front crossmember hand sprayed?
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: J_Speegle on November 30, 2022, 02:16:57 AM
Quote from: rcgt350 on November 30, 2022, 12:56:53 AM
When a car was travelling on the line, I understand that the primer was shot up towards the entire bottom, did it not keep applying that same primer right to the front crossmember?

From what I've been reading it sounds like it stopped spraying in around the firewall area.

The car/unibody was traveling in the direction so that the front of the body entered first so the floor application started at approximately the bottom of the firewall

This produced allot of runs and drips in an effort to cover as much as possible. Vertical surfaces were sometimes thin or nothing more than a mist because of the angle. Also, the jets stopped spraying before they reached the very back of the rear. Just forward of the rear cross member. All of this was to eliminate the raining down of paint and overspray on the car being coated and the car following. Some times a single or multiple jets clogged producing a strip of unpainted floor for a foot or the whole length of the floor. Not common at all IME but did happen. Have seen examples (other plants and years) where it was recoated by hand or not caught by any of the inspectors  :(

Quote from: rcgt350 on November 30, 2022, 12:56:53 AMIf so was the next area up to the front crossmember hand sprayed?

After the rear 2/3rds of the floor area was painted the front frame sections and inner fender panels were coated by hand so that the spray could be controlled. If they had used the under-car spray system from the front cross member rearward all of the jets mounted in the middle and outer edges would have "thrown" their paint upward and not hitting any panels would have rained down everywhere creating a mess to fix and clean up

By applying the hand applied spray second it allowed the painters to cover over the earlier coating of the floor and reduce the chances of leaving a gap between the two applications which would rust quickly in most regions


As a mention the products used were not what most people thing of when they think "primer" so using the term is misleading. Primer is an open surface that promotes attachment of following coats and applications of other produces. They will allow rust to start. Instead a primer sealer was used at some plants that was epoxy based which produces a low to higher gloss finish. For this year and plant a epoxy primer sealer was applied or a base with left over paint from either the last shift or when ever the workers collected the near empty drums and poured the remains into the vats to create a combination that would be used during those production periods

The source that supplied paint/primer sealer to the floor jets was a different source than the one that supplied the hand applied application for the firewall forward.
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: shelbymann1970 on November 30, 2022, 07:40:35 AM
May 6th 1969 Dearborn. clogged sprayer to boot.
Title: Re: Undercarriage Primer Color; 69 Convertible
Post by: shelbymann1970 on November 30, 2022, 07:43:16 AM
April(can get the exact date) 1969 Dearborn Boss 9.