I have just blasted a jack from a 71. Any recommendations on the correct finish/brand to use. I was going to use a gloss black. Also looking for correct paint to use on alternator. Thanks


[Modified by mulchie, 8:46 AM 12/27/2001]

 

Shark jacks should be semi-flat black. Mask off the screw and thrust bearing as they should be natural. Be sure that you clean all the grit completely off the screw and threaded portion before you prep the jack for paint.

If you like, you could "breathe" a little clear on the thrust bearing to keep it from rusting, but I would just apply a light coat of wheel bearing grease to the screw and work it into the threads thoroughly...you never know...you might have to use that jack someday. :D

Alternators were not painted. They are natural "as-cast" aluminum, and it is impossible to duplicate that look with any paint. If your objective is not the judging field, then there are aluminum paint products like "Aluma-Blast" that is supposed to duplicate raw aluminum finish, but I doubt that you will fool anyone.


[Modified by Chuck Sangerhausen, 8:22 AM 12/27/2001]

 

Disclaimer: The above description is what I observed on my own original jack. Further research this morning revealed a 69 jack in the NCRS 70-72 judging guide with more gloss; it's either semi-gloss or a thin, poor gloss paint. Another reference shows a 69-72 jack photograph closer to semi-flat. No reference is made to gloss level in the 70-72 judging guide...only the date and "Ausco" stamp is discussed.

 

Chuck, thanks for the info. I have two more questions. You stated that the thrust bearing and threads are not to be painted, what about the screw bolt. Also, this particular jack is an original Ausco but it only has a 1 stamped on it (for 1971) with no month code. I'm certain it is the original jack. I've never seen one without the month code. Any thoughts on that? Thanks

PS regarding the alternator color. I simply degreassed the housing and it looks great without paint.

 

Your questions made me dig out my jack, and revisit what I did, and it doesn't make sense from this point in time. I think I gave you a bad answer, and I hope this isn't going to confuse you beyond help. :D

From my references, I believe that the thrust bearing was natural, but I am not convinced that the screw should be natural as I implied in my earlier posts. I am now thinking that the "screw bolt" was also dip painted black, but in a separate step from the scissors assembly. I masked the screw threads off because the grease was going to make a real mess on the painted threads, but painted the center unthreaded portion of the shaft. After examining my jack closely, I will need to redo it anyway. Aaarrrrggggguuuuhhhh!

Since the thrust bearing is natural, the screw and the scissors assembly must have been put together after both components were painted. Unusual for them to have an additional manufacturing step, but they really could not dip the entire assembly...the thrust bearing would be gummed up bigtime.

Your date is unusal if it is an original jack. My date is stamped on the bottom scissors arm on the left side nearest the hex end of the jack screw. It is the usual year/month format. If it were me, I would ask myself how I know the jack is original. Unless you have confirmed that none of the previous owners bought a replacement jack, you can't be sure.

I would probably restore the jack and use it without further thought. If you have the car judged, the judges will check the date...it might be interesting to see what they say. The deduct would be minor in my opinion. Sorry for the confusion.


[Modified by Chuck Sangerhausen, 12:52 PM 1/3/2002]

 

I took a close look at the jack before I blasted it. The threads did appear to be natural. The shaft appears to have been dipped up to the point where the threads start. The thrust bearing is definately natural. I agree with you. The shaft was dipped then assembled. Probably a wide variety of permuations as to where the paint is applied, considering the human factor.

The jack is definately stock. Only a "1" appears on the side. Maybe someone forgot to stamp the month code. Wouldn't be the first time. Sometimes I think we learn more about peoples work habits when we rebuild these damn things. I will be curious to see what the judge has to say...Thanks for your help.

 

Maybe my threads were either natural or could have gone either way; its not like me to make any compromises for function in this restoration stuff. You have to remember that with use, any paint that was on the threads of an original jack may pretty much be gone by now. The references I looked at appear to show the threads as painted.

 

I checked out my friends 71. It is a Bloomington and NCRS top flight car. The thrust bearing is natural (installed with shaft in a seperate operation it appears-just as you thought). The threads are painted!! This particular jack has never been used. It does have a crappy factory paint job with runs and drips.

 

LT1man, presuming that your friends 71 jack is an unrestored original, would you please do me a favor if you get the chance to see the jack again?:

(1) Check the finish on the hex end of the jack screw: Is it also painted black or is it a dark natural steel as after forging?

(2) Check the shaft of the jack screw just behind the scissors assembly block it passes through: There is an upset there that keeps the jack screw from being removed from the jack...Is there any evidence that this upset was made after the screw was painted, i.e. flaking of the paint?

I would like to confirm that the parts were painted and then assembled, rather than be dipped as an assembly. Of course, if he has restored the jack, don't waste your time.

Sounds like a dip paint job; fast, adequate, but ugly. You can usually identify the "hanging point" by observing the direction of the runs. If you follow back up the direction of the "run", there will usually be a hole or some other feature that allowed the part to be hung easily on a rack. Unless the dips and runs hit some kind of curvature that they follow, gravity pulls them straight down. The "hanging point" would also be interesting information to have.


[Modified by Chuck Sangerhausen, 10:07 PM 1/5/2002]

 

Just spoke with Chuck Berge (NCRS judge for 70-72). He stated the following:
1. the entire thread shaft was natural (including the hex head)
2. the upset on the block (that keeps the thread shaft from coming out) was made after assembley. He did not comment on the condition of the paint in this area, however,
3. Each component was dipped in semi-gloss black before assembley so I would assume that some marks would be visible in some applications.
4. I also confirmed that some jacks were touched up after assembley, therefore, overspray on the various components would not be objectionable.

I'm going to re-blast and paint with the thrust bearing and shaft masked off (best way to do it according to Chuck). A good zinc primer will give it a deeper sprayed-on finish to closely mimick dipp painting. I may even attempt to put in some directional drips by hanging the jack upright when I paint. A good amount of grease on the screw shaft and thrust bearing. I think thats as close as we can get.

 

This answer raises skepticism in my bones; pictures in my references seem to show painted threads. I painted the unthreaded center portion of my shaft black, and it must have been based on my observation of the original jack before I bead-blasted it. Perhaps there is variation in jack finish details over the years that "muddys up the water" for the purist trying to determine only "one way".

Touch-up of paint on jacks??? Nawwww, gitouttahere! :D Ya gotta be kiddin'! That would fly in the face of GM manufacturing efficiency. I have been wrong as hell before, but I simply can't believe that GM cared if the jack, which was out of sight and mind, had a perfect paint job. :D

Mulch, I got to say, I think you are as bad off as you were when you first asked this question. The longer you talk to us, the more confusing it becomes. I think Chuck Berge is the 68-72 Team Leader, and if that is the case, you can always appeal a deduct to the Team Leader and be assured of winning the protest.

BTW, if you are thinking of using a zinc-enriched primer, I would reconsider. That cold galv primer is just like galvanizing when it comes to paint sticking, i.e. paint don't stick to it. Been there, done that.


[Modified by Chuck Sangerhausen, 1:53 PM 1/7/2002]


[Modified by Chuck Sangerhausen, 1:54 PM 1/7/2002]

 

I just looked at the unrestored jack that I refered to earlier. The bolt head on the screw is natural (kinda bluish). The shaft is also natural. The threads are natural. Drip marks are all over the place. I would suggest the various compenents were dipped prior to assembley. No signs of overspray anywhere. No signs of upset operation on block that secures the screw. These are my observations on an original jack. Wouldn't be surprised if finishes and mehtods varied from shift-to-shift.

 

Hey Chuck. I'm curious about your comments on zinc primers. I have used the OEM GalvZinc primer under Bowman (fast dry Industrial Finish) on several applications like pulleys etc. It seems to have worked fine. What are your experiences? Zinc primers can be an excellent base for painting when the surface is prepared properly. A zinc primer enriched with actual zinc particles can serve as mechanical anchoring sites for paint adhesion. Not to mention the zinc undercoat protects from creep when the paint surface has been compromised. The automotive industry has used zinc (electro and hot dipped) as well as NiZn-electro for multiple automotive applications such as body panels. They have also used aluminum rich paints and zinc rich paints as primers on fuel tanks that are painted after welding.

My experience is very thin coats of paint on top of zinc primers. Heavy coats will not adhere as well.

What is your preparation method for painting an item such as a pulley???

 

I used Rustoleum 'Zinc-Sele' cold galvanizing compound, which appeared identical to industrial coatings that I was accustomed to seeing in plants.

I hand-cleaned a heavy duty trailer hitch by wire brushing it thoroughly, and applied two heavy coats of 'Zinc-Sele'. I then topcoated the 'Zinc-Sele' on the hitch with two wet coats of Rustoleum gloss black without runs. I am not sure if these details are exactly correct, but that would be my usual process for the super-duper, corrosion-resistant paint job; this was twenty years ago.

In use, I found the black flaked easily off the zinc primer; any kind of stike or heavy contact with the finish left you with primer gray shining through. Surface preparation, while not ideal, met the manufacturers directions. But, the problem was not with the primer adhereing to the metal; the black was not adhereing to the primer.

In trying to analyze what happened to this manificent paint job that I had so carefully applied, I read the rest of the instructions on the back of the spray can: "If a PROTECTIVE COATING (their caps, not mine) is to be applied over the top of 'ZINC-SELE', a coat of 'GUTTER SHIELD PRIMER' should be applied first".

This is exactly the procedure that must be followed if you attempt to paint unweathered galvanized metal gutters. If you don't prime them with a special primer first, your paint is not going to stick. The real old-timers used a vinegar rinse, but it never worked for me. Like you, I also felt the relatively rougher texture of the zinc primer would improve adhesion. I found this was not true in practice; it had more to do with the zinc than it did the surface "tooth".

I have no arguments with your statements that zinc enriched primers have been used widely and successfully. The key words are "when the surface has been prepared properly". The premium DuPont coating system in petrochemical plants was sand blast to white metal, apply 3 mils zinc-enriched primer within 8 hours, apply 2 mils intermediate primer (I don't remember the name), apply 3 mils DuPont Imron epoxy enamel.

I am not a coating specialist, but I suspect that if you skipped the intermediate primer coat, the Imron would not stick. Why else would the companies go to the significant expense to apply the intermediate primer unless it was to take advantage of the properties of the zinc-enriched primer, and retain the durability of the epoxy top coat?

OEM's zinc primer may be a different formula with different zinc composition, and I have no experience with this product. If the instructions on the OEM can say it can be topcoated directly, or even make no mention of special requirements for topcoating, I would assume that it can be topcoated with no problems.

I personally no longer use zinc-enriched primer on any part that must be topcoated. My standard practice in refinishing restoration parts has been to bead blast to white metal, prime with either one or two coats of DP-90 epoxy primer, and then apply the topcoat of choice within 24 hours. If the originals would last 30-50 years; then my parts should last 100-150 years. :D

 

This debate will probably go on forever, but the jack was hung on an overhead conveyor after assembly at Ausco by screwing the exposed end of the threaded shaft into a "nut" on the conveyor carrier and was then dipped in a tank of black paint. Who knows what happened to them over the years, rusting in the storage well. The runs and drips are from dipping, not spraying.

 

John, dipping the assembly would seem most likely to me, but that doesn't explain how the thrust bearing remains natural or bare zinc plate. That shiny natural thrust bearing under the hex end is well documented. Around what time period did you make this observation? Do suppose Ausco later revised their paint process?


[Modified by Chuck Sangerhausen, 6:51 PM 1/8/2002]

 

I agree. My 70-72 vette jacks do not appear to have been dipped as an entire assembley. A recent unrestored jack that I looked at has the thread shaft, hex bolt and thrust bearing as natural, albeit a little rusty and blackened from grease. Mulch stated earlier that NCRS claims this area was unpainted too? John Z, where did you get that info. Because if your right than everyone I've talked to is wrong (it's happened before). Again, I go back to what I have seen in unrestored originals.

 

Mulchie, my intention was not to call John's credibility into question; his credentials are beyond reproach. If an NCRS "expert" tells you one thing and John says it wasn't done that way, better listen to John because he was there for an entire career. I was just trying to determine if the procedures may have changed after John's observation. :D

In this Corvette restoration thing, there are always "exceptions" and "anomalies", and all the evidence we have today, excluding those clear cases of restorative molestation, has to hang together consistently. I am kind of like the TV detective Columbo; there is always "just one more question that's botherin' me", until I resolve all the inconsistencies. I also have been burned by "experts" that didn't do their "forensics" thoroughly.

If you have original, unmolested examples of original jacks, and YOU ARE SURE they are unmolested, then that is the way to go if the car is in the same year, and probably if it is in the same year class.

On many parts, it is very difficult to find runs; there are NO runs, because the paint sheeted off the part quickly enough that the paint did not begin to "set up" before all the excess paint that would create "runs" had already run off. My opinion (not to be confused with expertise) is that the paint used was made deliberately "thin" to achieve this effect.

 

Oops! Being a C1 guy, forgot to shift gears for a C3 subject - the process I described was used for all C1 jacks; C2/C3 jacks were made by a different supplier, probably different process. Sorry :(


[Modified by JohnZ, 1:10 PM 1/9/2002]