Paint Drips on Original Parts? - Here is Why

[PaulGS]

Have you ever wondered why there are paint drips on a majority of the brackets and small parts on your GM classic?

Believe it or not, what GM did back then was to develop a really cheap and effective method to paint these parts as a subassembly operation near the assembly line.

What GM did was have a large tank of water, and they would pour about 1" of cheap black paint on top of the water. The parts came in raw steel, and they were dipped into the paint and hung up to dry on racks. The process was really neat, and the part dipped did not break thru to the water.

I saw this first hand at the GM plant in Framingham in 1972.

It works great - use Rustoleum enamel in the non spray can for best results.

On my Fremont built 70 442, I found drips on pulleys, brackets, and interior parts.

[wkillgs]

It works great - use Rustoleum enamel in the non spray can for best results.
.

Cool, I'll have to try that!:TU:

How thick of a paint layer do you leave on the surface of the water?
And can you get the unused paint back in the can?

[PaulGS]

You need about 1/4" of paint on the surface.

Not sure about reusing the paint.

Try a 5 gallon bucket, just the right size for most parts.

[buick64203]

What does the water do?

[Brad Conley]

It allows you enough depth to dip the part in completely. You will go first through the layer of paint and into the water and as you withdraw the part, the paint will again coat the part. You use much less paint this way.

[william.ali.kay]

So you would dip the part through the paint into the water, then as you pull the part back out, the paint coats the wet part?

Im just trying to understand this. It sounds interesting to me but Im not getting it.

[Brad Conley]

So you would dip the part through the paint into the water, then as you pull the part back out, the paint coats the wet part?

Im just trying to understand this. It sounds interesting to me but Im not getting it.

Yep, that's the idea. Crappy cheap black paint floating on top of the water. That's the way I understand the process.

[william.ali.kay]

The process was really neat, and the part dipped did not break thru to the water.

I must have read the 1st post too fast and missed this. It makes a little more sense to me now.
But now my question is, what purpose does the water serve?

[wkillgs]

Using water simply saves paint.....you could dip a part into a 5 gallon bucket full of paint, or you can get the same result dipping the part through only a 1/4" layer of paint floating on top of water.

[John Stevens]

I've been painting parts like this for a long time, works fantastic for coil springs! I usually have 1/2" to 1" of paint on top of the water, rust-o-leum oil based seems to work the best, just SLOWLY insert the part thru the paint until submerged then SLOWLY pull back out, be sure to have somewhere to hang the part and something to catch the dripping paint so as to not cover your floor. I've tried different ways of saving what paint I didn't use, after painting the parts then sitting the "bucket" outside in the winter and letting the water freeze then pouring the paint off the top seems to work best. Laugh if you want, works great!! :laugh: I normally use a "kitchen" type trash can as its deeper for the springs, put in a trash bag, bungee cord around the top, fill 3/4 or better with water then add the paint, when done you can pull the bag out, poke a hole in the bottom, and let the water come out, if there isn't much paint left it will stick to the bag for zero clean up!! :TU:

[william.ali.kay]

Using water simply saves paint.....you could dip a part into a 5 gallon bucket full of paint, or you can get the same result dipping the part through only a 1/4" layer of paint floating on top of water.

Or I could just pour a 1/4" layer of paint in anything without any water underneath and get the same result, couldnt I?:Do No:
Again, Im just trying to understand why they did this with the large tanks of water.

[william.ali.kay]

I usually have 1/2" to 1" of paint on top of the water, rust-o-leum oil based seems to work the best, just SLOWLY insert the part thru the paint until submerged then SLOWLY pull back out,

So when you do this, the part first goes through the paint, then into the water, and then back out through the paint?

[John Stevens]

So when you do this, the part first goes through the paint, then into the water, and then back out through the paint?

Yes, the paint will stick to the part on the way thru, if you go slowly you will completely cover the part on the way thru. the paint and water will not mix, pull it back thru then hang up to dry.

[william.ali.kay]

Yes, the paint will stick to the part on the way thru, if you go slowly you will completely cover the part on the way thru. the paint and water will not mix, pull it back thru then hang up to dry.

Thank you for clearing this up for me.
I was really lost there for a minute trying to understand.

[mtdman]

Or I could just pour a 1/4" layer of paint in anything without any water underneath and get the same result, couldnt I?:Do No:
Again, Im just trying to understand why they did this with the large tanks of water.

What if the part is deeper than the 1/4 inch? This way you can submerge the whole part, especially if it's a long piece, and only use 1/4 inch of paint at a time instead of a whole bucket.

My question is, why not just spray it?

[william.ali.kay]

The process was really neat, and the part dipped did not break thru to the water.

I saw this first hand at the GM plant in Framingham in 1972.




What if the part is deeper than the 1/4 inch? This way you can submerge the whole part, especially if it's a long piece, and only use 1/4 inch of paint at a time instead of a whole bucket.


Because of the quote from the first post, I did not see any need for the water.
And nobody explained what the purpose of the water was or clarified the process in a way that made sense to me untill John answered my last question.
:idea2:

I get it now, but I think I will stick to spray bombing. :)

[JZRIV]

This is a :gp: . Never fails that I learn something new here. I had heard of this but could never quite grasp the concept of dipping a part into water that you are painting. When spraying I go to great lengths to eliminate any amount of moisture.
Definitely helps explain the appearance of some factory finishes. I'll probably stick to spray cans too but someday may try it just to demonstrate the logic defying process.

[r0ckstarr]

You ever get a drop of water on a freshly painted part and notice how the water beads up, rather than mixing in with the paint? Pretty much the same, just with alot more drops of water. With the paint being oil based, the 2 will not mix together.

[PaulGS]

The water was used because there was 95% water and 5% paint in the tank.

It was a cheap and easy way to coat the parts.

Be aware that the amount of rust protection applied was minimal....just enough to keep the rust away until the car was sold.

The fasteners came in wire sided pallets of thousands. The bolts were black oxide, and sprayed with oil.

The paint dipping station was right down the line from my station, and if I had not seen it, I would not belive it either.

However, the strangest process was the leaded seams process for the A pillars and roof joints....super nasty!

[buick64203]

I read about this technique in one of Jennifer's Mustang Monthly magazines. Someone wrote into Bob Perkins (a noted concours judge and restorer) about the correct black for brackets and fans.

He said that Ford would dump all kinds of crappy, excess paint in the dip tank. So the shade of black varied tremendously depending on what the line workers poured into the vat. Nothing goes to waste in a car plant I guess

[John Stevens]

What if the part is deeper than the 1/4 inch? This way you can submerge the whole part, especially if it's a long piece, and only use 1/4 inch of paint at a time instead of a whole bucket.

My question is, why not just spray it?

Ever tried to spray paint a coil spring? or a boxed control arm and get COMPLETE coverage? If you can I guarantee you will have used A LOT more paint!!! :TU:

[JZRIV]

Ever tried to spray paint a coil spring? or a boxed control arm and get COMPLETE coverage? If you can I guarantee you will have used A LOT more paint!!! :TU:

I'm with ya on the coil spring. Its a real challenge to get full coverage. I have to hold the light at all different angles to see all the places I missed and then a week later I'll be looking at it and see more bare spots!

I'll say it again, this is a great post. Always most interesting to here stories from folks who worked the assembly line.

[r0ckstarr]

However, the strangest process was the leaded seams process for the A pillars and roof joints....super nasty!

I am curious to hear this one.

[skierkaj]

I am curious to hear this one.

X2! How did they do it? :Do No:

[PaulGS]

Leaded seams were applied to all of the cars, regardless if they had a painted top or a vinyl roof.

There were large pots of molten lead by the assembly line. They had propane burners underneath to keep the lead in a liquid state. The workers would use a flux to the joint, then take wooden paddles to spread the lead on the joints and "work it" until the lead was reasonably smooth. Then, the cars went into a large chamber where other workers in space suits (with air hoses) would use air grinders to semi finish the joints. As the car exited the chamber, other workers would use an assortment of files and sanders to get the finish seam completed. Keep in mind that the cycle time for every step was 60 seconds.

The strangest (or worst) thing was that there was about an inch of lead dust EVERYWHERE. A lot of the folks doing this work eneded up with lead poisioning. I never saw any OSHA folks either.

Remind me to tell you about the UAW and what they did to control management.....:shock:

[skierkaj]

Leaded seams were applied to all of the cars, regardless if they had a painted top or a vinyl roof.

There were large pots of molten lead by the assembly line. They had propane burners underneath to keep the lead in a liquid state. The workers would use a flux to the joint, then take wooden paddles to spread the lead on the joints and "work it" until the lead was reasonably smooth. Then, the cars went into a large chamber where other workers in space suits (with air hoses) would use air grinders to semi finish the joints. As the car exited the chamber, other workers would use an assortment of files and sanders to get the finish seam completed. Keep in mind that the cycle time for every step was 60 seconds.

The strangest (or worst) thing was that there was about an inch of lead dust EVERYWHERE. A lot of the folks doing this work eneded up with lead poisioning. I never saw any OSHA folks either.

Remind me to tell you about the UAW and what they did to control management.....:shock:

Somehow I knew that somebody was sacrificing their health in that department.

[r0ckstarr]

Somehow I knew that somebody was sacrificing their health in that department.

Same here. I knew it couldn't be good when he said "lead".

[gstewart]

that is as bad as dipping your t-shirt into a vat of benzene to cool yourself off in the summer..

[skierkaj]

Same here. I knew it couldn't be good when he said "lead".

On a side note; anyone know when they stopped using lead based paint on cars?

[Randy Lutz]

Hi Paul,

Do you know why the seams between the quarter panel and deck lid filler panel were filled and smoothed on convertibles but not on hardtops?

Cheers

[Guy Parquette]

Hi Paul,

Do you know why the seams between the quarter panel and deck lid filler panel were filled and smoothed on convertibles but not on hardtops?

Cheers

Now THAT'S a good question!

[PaulGS]

I believe that hardtops had less body flex, thus the added joint was not needed.

Believe me when I tell you that GM did not add ANYTHING that was not absolutely required....not one thing.

If something is on your car, is is a design requirement.

[PaulGS]

One other thing: when the bodies were spot selded together, every joint got a thick bead of a maroon color caulking between the panels. The spot welding was then done.

If you wonder why the spot welds are evenly spaced, it is due to a fixture that clamped on the parts being spot welded, and it guided the operator to place the spot welds in the same position on every car.

The bodies (from the firewall back) were dipped in a huge vat of primer. The entire body was submerged, and then baked before paint. The hoods and fenders were done separately, and then mounted later.

That is why there may be a slight color difference from the front clip to the rear body......:Dou:

[Randy Lutz]

Hi Paul,

Thanks for the replies. It also explains why my floor pans are red oxide primer.

One more thing, were chalk (crayon) marks applied to the firewall at the Framingham plant? I have looked everywhere (including under the booster mounting bracket) and have not found anything. My firewall appears to be original.

Cheers

[John Eberly]

Using water simply saves paint.....you could dip a part into a 5 gallon bucket full of paint, or you can get the same result dipping the part through only a 1/4" layer of paint floating on top of water.

For what it's worth - this also works with corn on the cob!

Use a quart jar of hot water and melt an inch of butter on top.....

[PaulGS]

The inspectors at GM Framingham did not use chalk. There was a QC (quality control) traveler that each inspector punched using a uniquely shaped punch.

This hung from the cowl, and was used as a final QC when the car left that part of the plant.

The paint daubs were a visual quality control check so someone doing the next operation would know that the prevoius step was completed. This was used anywhere there was torque specs.

The water test area was cool - they had a full size carwash type chamber that the car went thru. Someone would sit in the car and look for leaks. All leaks were marked and corrected.



Hi Paul,

Thanks for the replies. It also explains why my floor pans are red oxide primer.

One more thing, were chalk (crayon) marks applied to the firewall at the Framingham plant? I have looked everywhere (including under the booster mounting bracket) and have not found anything. My firewall appears to be original.

Cheers

[jay3000]

For what it's worth - this also works with corn on the cob!

Use a quart jar of hot water and melt an inch of butter on top.....

Finally something useful:laugh:

[copperheadgs1]

I actually TRIED Pauls paint trick years ago when I read it in a muscle car mag. I used the rustoleum paint and it promptly sank to the bottom. I riuned a can of paint and a 5 gallon bucket not to mention having a toxic mess on my hands. Was my water magic? What the hell happend? I spray everything now. You guys can have your drips.:Do No: >>>>For what it is worth Flint did not use Chaulk on the cars etiher. It was more a type of crayon.

[copperheadgs1]

Maybe it would float better

[69SkyInNJ]

Someone should write Mystbusters as this would be a good myth to (re)prove even-though we already know the results.

[John Stevens]

I actually TRIED Pauls paint trick years ago when I read it in a muscle car mag. I used the rustoleum paint and it promptly sank to the bottom. I riuned a can of paint and a 5 gallon bucket not to mention having a toxic mess on my hands. Was my water magic? What the hell happend? I spray everything now. You guys can have your drips.:Do No: >>>>For what it is worth Flint did not use Chaulk on the cars etiher. It was more a type of crayon.

Must have been that "magic water" Rustoleum have worked perfect for me many times....:TU:

[1967GS340]

Very cool and educational thread!!

I know I'm going to try the corn test!