Topic: 67 fastback trap door prop rod finish

[gimpystoy]

What is correct finish for 67 trap door prop rod? bare steel? My orig, doesn't seem to have any residue to guide me.
TY,
Gimpy

[Bob Gaines]

What is correct finish for 67 trap door prop rod? bare steel? My orig, doesn't seem to have any residue to guide me.
TY,
Gimpy

I have always done them in light Zinc phosphate plating. FYI you don't want a faux finish on this part because of the nature of how it is used will tend to scratch through a painted surface.

[J_Speegle]

I have always done them in light Zinc phosphate plating. FYI you don't want a faux finish on this part because of the nature of how it is used will tend to scratch through a painted surface.

+1

[gimpystoy]

Bob & Jeff, TY
Gimpy

[Bossbill]

Gentlemen,

   On this page:
http://www.concoursmustang.com/forum/index.php?topic=7741.msg67294#msg67294
Jeff says he had the 67 trap door handle tested and found it to be phosphate and oil.
Here Bob and Jeff say "light Zinc phosphate".
[Do note that there is black phosphate and oil and zinc phosphate and oil. I have always taken phosphate and oil (aka PO) to be black phosphate and oil]

When I did mine in phosphate and oil (PO), based on the Jeff's post and others, I found that the wire didn't go that black and the the bolt-plate was lighter still -- probably due to the mass of each individual piece. To my eyes, a lighter black phosphate that looks a bit like zinc phosphate.

So, which process was used on this piece?

For extra credit, was the trap door latch galvanized or zinc plated?
Were the tiny bolts that hold the latch in place PO and/or something else that had a red tinge?

[J_Speegle]

Were the tiny bolts that hold the latch in place PO and/or something else that had a red tinge?

Its late so I'll take the easy one right now. Will post pictures of originals later

P&O was the finish. The red die was something used in later years - not in 67. Easy to mix up years if you don't focus and plenty of restorers borrowing details across years and plants so be careful

[J_Speegle]

[Do note that there is black phosphate and oil and zinc phosphate and oil. I have always taken phosphate and oil (aka PO) to be black phosphate and oil]

When I did mine in phosphate and oil (PO), based on the Jeff's post and others, I found that the wire didn't go that black and the the bolt-plate was lighter still -- probably due to the mass of each individual piece. To my eyes, a lighter black phosphate that looks a bit like zinc phosphate.

So, which process was used on this piece?

Think you will find that we often lump both zinc and magnesium phosphate together at times. In other cases (example hood hinges) we do note the difference. Yes both processes will normally turn out different degrees of "darkness"  but other times, especially for the home platter or even professional ones today the results get even more muddied. IMHO the best thing is to focus on the desired tone your looking for and if means that one gets a longer soak, different prep or  different solution that should be what guides you.  Would add that by looking at original examples there are some where the tone or darkness is not the same on both pieces (see below) this may be a result of a poor, old or diluted batch for one of the parts

Here is an original example that shows a different between the rod and the base bracket as you describe.

Notice (lower right of the picture) the difference between the two P&O  parts in this example




Now more typical and consistent finishes

For extra credit, was the trap door latch galvanized or zinc plated?
Were the tiny bolts that hold the latch in place PO and/or something else that had a red tinge?

Have not seen signs on the back side (most protected from the elements) of galvanizing on this part. They appear to be made possibly by the same supplier that made the found down seat latches and the striker attached to the rear most fold down floor section/insert and appear to match in finish

[Bossbill]

Excellent. Thanks again for the pics and commentary.

I didn't see the latch on the MCA list of what finish to expect and than ran into a few ads on some Vendor sites (don't know which) which stated "The original galvanized finish."
The backside of my latch looked more like shiny zinc, so rather than do the perp walk, I asked.

The same thing on the tiny bolts. I didn't see any red on my originals but I was led astray by vendor misinformation.

My trap door rod is identical (after black phosphate and oil) to door number 1.

After getting the manganese and zinc coatings from Palmetto, the two finishes can be very different.
Manganese is charcoal black (depends on material, temp, etc) and is usually imparts a color like fresh, black fender bolts.
The zinc is more of a dull, dark, battleship gray (again, depends on material, temp of material, etc). If you steel wool the zinc it gets shinier and a feels a bit like it's plastic coated. Very slippery. I love this coating.

To put the two in perspective it's almost as if the rod material of the prop rod were done in manganese (Phosphate and oil) and the bolt plate was done in Zinc and Oil.

Again, like  you say, it's really a matter of material, mass, temp of the material before it goes in the soup and many other variables.

Here's my prop rod:


Thanks Jeff!

[Bob Gaines]

Excellent. Thanks again for the pics and commentary.

I didn't see the latch on the MCA list of what finish to expect and than ran into a few ads on some Vendor sites (don't know which) which stated "The original galvanized finish."
The backside of my latch looked more like shiny zinc, so rather than do the perp walk, I asked.

The same thing on the tiny bolts. I didn't see any red on my originals but I was led astray by vendor misinformation.

My trap door rod is identical (after black phosphate and oil) to door number 1.

After getting the manganese and zinc coatings from Palmetto, the two finishes can be very different.
Manganese is charcoal black (depends on material, temp, etc) and is usually imparts a color like fresh, black fender bolts.
The zinc is more of a dull, dark, battleship gray (again, depends on material, temp of material, etc). If you steel wool the zinc it gets shinier and a feels a bit like it's plastic coated. Very slippery. I love this coating.

To put the two in perspective it's almost as if the rod material of the prop rod were done in manganese (Phosphate and oil) and the bolt plate was done in Zinc and Oil.

Again, like  you say, it's really a matter of material, mass, temp of the material before it goes in the soup and many other variables.

Here's my prop rod:


Thanks Jeff!

I think the rod is similar to spring steel and the bolt plate is more like plate steel. The P/O can be absorbed at different rates given the same time exposed in the bath (darker /lighter) depending on materials . I think that is one possible reason why you see the darker lighter portions on the parts in your observations IMO.