The Stovebolt Site Forums The Shop Area Paint and Body Shop Frame color/finish

While sandblasting the frame on my 1.5 ton truck I notices that the original finish under all of the brackets was black. I have also seen factory photos that show the frame and sheet metal in a black finish from the supplier.

I did read the paint FAQ at http://bobstory.tripod.com/faq.html but my year of manufacturer isn't really clear... best guess: Acrylic lacquer (black)????

Any idea what type of finish it really is?

There was a recent thread that went into paint vs chemical blackening (dip) vs bare metal.

I believe it was chemical dip and have since found black finish under riveted on brackets. There is no way paint could ever reach there and equally there is no way that all the parts were blackened before assembly. I stand by that. (for this '48 2 ton)

Here's a photo of the frame rail in question. The big hole is for the steering box shaft and the black vertical bars are the original frame finish from the tapping plates used to hold it on.

Frame Rail

I haven't taken out any rivets, but just about every bracket that I can unbolt (spring stops, etc) have this black finish.

I would think that the FAQ I referenced is accurate, just want to get a solid confirmation (photo of frame in a paint booth, or in an acid dip).

This was also part of the FAQ:
"All the major manufacturers use a form of a seven stage process before priming.1. Hot detergent wash to remove grease and oils. 2. Water rinse to remove the detergent, since the detergent interferes with acid. 3. Acid wash to remove scale and open pores in metal. 4. Water rinse to remove acid. 5. Zinc phosphate acid treatment for corrosion protection and paint adhesion. 6. Water rinse to remove acid. 7. Bake dry.This is followed by a primer coat of melamine polyester resin (Japan), polybutadiene (Europe), or a polyester or epoxy ester system (USA)."

But its not clear if this is a modern technique or from the 40-50s time frame.

Way too complicated for manufacturer of work trucks in the 40's-50's. That would take longer than building the truck.

They were looking for the fastest least expensive processes for production.

pretty clear to me that description is modern, and if your frame had been treated like that and coated with an "epoxy ester system" as stated, you wouldn't need to do anything but wash it

Bill

Well, after I sand blast it to bare metal I need to know what to put back on it.

If anyone has ever seen the 'Master Hands' videos made on the GM lines at youtube



fast forward to the 20 minute mark for close up of bare steel frames. Then at 21:17 they show a mostly assembled frame, in black, with other, uncoated parts and plain steet / cadmium plated bolts.

They seem to skip the one step I am looking for info about

use whatever you consider a good quality satin black paint, or spring for some expensive stuff like POR

Bill

One thing you can be sure is that the procedures used in 1936 (pre WW-2) and 1947, after all the years of war time mass production, were different.

When possible, I have the frame powder coated and do the rest of the parts in Eastwood chassis black to match (65-75% gloss or 85% gloss) depending on the powder coat chosen.
Otherwise all paint, either the "extreme" or the Ceramic.

You only want to do this once in the life of the vehicle, use something that will last.

Powder coat would be completely out of the question... as would any epoxy based paint.

I would rather try to get the frame as factory correct as I can. Its kinda a big deal... even though no would but I would know until I sell it, then I can take off a frame bracket and say 'yep, just like the factory'.

The frames are painted. The paint comes off, a chemical treatment would not wire brush off easily. I know from experience that a phosphate treatment, especially on rusted areas is not easy to remove even with media blast. It was not painted with a very high quality paint, main reason it doesn't stay on. Krylon semi gloss black is close and likely just as good as what the factory used.

That seems like what I am experiencing with the frame now... its not hard to remove. Although have used phosphoric acic and it will turn black, but its not the same sheen as what was there before.

Semi gloss seems about right. Are there any purpose made primers (with say, a zinc chromate base) that come in semi gloss black?

I found no evidence of paint on the frame of my 50, in fact even the bed sides under the fenders didn't look like they were painted body color. I found paint runs on the bed sides in that area. ORIGINAL red paint runs

I did paint my frame with eastwoods satin black chassis black paint. I got better results with rustiolum semi gloss thinned with acetone and sprayed with cheap HF gun.

Opinions differ here on this site as to if the frames were painted at the factory.
You stated the finish Is" Kinda a big deal" for you
If your a member of the Vcca you can try their forum. I believe there are judges there that might be able let you know what they look for in the frame area.

Good luck and post some pics when you finish the frame.

Thanks for the lead to another forum.

The videos I posted, and period, factory GM photos I have clearly show the frames and sheet metal as being black (well, a very dark color). Plus my own frame (of which I have 3 1.5 tonners) all have the same black color under removable frame brackets.

I took the running board brackets off my 52 frame and found really nice black finish that looks like paint to me on the surface that was tight against the frame. I also removed the bolted-on cross member under the transmission and the same black finish was there as well.