Removing zinc for another finish? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**71CHEVYSHORTBED402** · 01-29-2018, 02:24 PM

Replacement GR. 8 bolts are generally yellow zinc, so if you want them black then the zinc needs to come off. I'm wondering what you guys recommend to accomplish this, though I may have been successful already........

Image below explains why, but at this point my test is inconclusive. Inconclusive because I used Caldwell black oxide and sealant just to see if successful, but once dry it just wipes right off. This might be because the room temperature of the chemicals was too cold. I'll probably try again in the right temperature using two bolts, one sanded after vinegar.

harpo231 · 01-29-2018, 02:37 PM

Should be done at room temp at least... check with your local gunsmith , see what he does ,,,

**truckster** · 01-29-2018, 04:26 PM

I often remove zinc for welding purposes. I use muriatic acid. The concentration depends on how much of a hurry I'm in. Vinegar is a safer but slower option.

harpo231 · 01-29-2018, 04:41 PM

you neutralize ?

**71CHEVYSHORTBED402** · 01-29-2018, 05:27 PM

Quote:

Originally Posted by harpo231

you neutralize ?

i.e., baking soda? I do.

harpo231 · 01-29-2018, 06:12 PM

**truckster** · 01-29-2018, 06:25 PM

Quote:

Originally Posted by harpo231

you neutralize ?

I generally don't. I use clear water to gradually cut the concentration until it's safe to pour it out, and then a clear water rinse.

harpo231 · 01-29-2018, 06:30 PM

That'll work as long as ya give it a good soaking

B. W. · 01-29-2018, 10:34 PM

Some of my grade 8 replacement hardware was yellow, I bead blasted then parkerized. You have to do a very thorough job of blasting. On some bolts I didn't find this out until after the black phosphate. I use a home brew, exact temp isn't critical but it needs to be hot, I shoot for 180°.

Pics:
1 - bead blasted
2 - black phosphate finish & oiled
3 - home brew set-up - Left can is water, right can is solution. Not shown is can for oil, it's on a different warmer. Once I get rolling I'm doing three batches at one time. It's still a whole lot of work.

**randy.powell** · 01-30-2018, 09:19 AM

A friend of mine swears by citric acid. Buys it as a concentrated powder from one of the web sites. Safe to use, biodegradable, cheap, pour it down the sink when done...

**truckster** · 01-30-2018, 03:44 PM

Quote:

Originally Posted by randy.powell

A friend of mine swears by citric acid. Buys it as a concentrated powder from one of the web sites. Safe to use, biodegradable, cheap, pour it down the sink when done...

Not a bad choice, either. Pretty much any acid will work to remove zinc; it's just a question of how quickly.

**71CHEVYSHORTBED402** · 01-31-2018, 02:00 PM

My question is while the gold color is gone, what if anything was left behind? As mentioned, when I'm up for it I'll do two more, one sanded. My thought is, if simple cold black oxide sticks to it then other finishes will too.

There's a good chance the bolts will be black zinc plated anyway. Fair assumption it will stick.
__________________

**71CHEVYSHORTBED402** · 04-23-2018, 01:09 PM

About 70% vinegar and 30% water overnight on new gold grade 8. I scrubbed one with red scotch bright, and left the other as is, which was discolored, so I had some doubt it would come out nice. Used Caldwell blackening (cold oxide) and sealant on both. The results are about equal and the black sticks, so no doubt black zinc will stick too.

01-29-2018, 02:24 PM	#1
71CHEVYSHORTBED402 Senior Member Join Date: Feb 2009 Location: Northern Nevada Posts: 7,120	Removing zinc for another finish? Replacement GR. 8 bolts are generally yellow zinc, so if you want them black then the zinc needs to come off. I'm wondering what you guys recommend to accomplish this, though I may have been successful already........ Image below explains why, but at this point my test is inconclusive. Inconclusive because I used Caldwell black oxide and sealant just to see if successful, but once dry it just wipes right off. This might be because the room temperature of the chemicals was too cold. I'll probably try again in the right temperature using two bolts, one sanded after vinegar. Attached Images __________________ Tony 71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assm. guide "kit" for restoring it from ground up. With assys, the guide accts for 1000s of OEM identifications and part numbers, all written in short order. 700+ images include assm, illust., charts, and points of interest. Much of the info. applies to all 67-72 GM trucks, and to a lessor degree all 67-72 GM vehicles. My build thread, and more on the guide https://67-72chevytrucks.com/vboard/...d.php?t=730025

01-29-2018, 02:37 PM	#2
harpo231 Registered User Join Date: Nov 2014 Location: Lincoln City DE Posts: 1,292	Re: Removing zinc for another finish? Should be done at room temp at least... check with your local gunsmith , see what he does ,,, __________________ Stan 67 swb BLU MULE posted via flip-fone

01-29-2018, 04:26 PM	#3
truckster Senior Member Join Date: Jan 2001 Location: Orem, Utah Posts: 7,798	Re: Removing zinc for another finish? I often remove zinc for welding purposes. I use muriatic acid. The concentration depends on how much of a hurry I'm in. Vinegar is a safer but slower option. __________________ I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson

01-29-2018, 04:41 PM	#4
harpo231 Registered User Join Date: Nov 2014 Location: Lincoln City DE Posts: 1,292	Re: Removing zinc for another finish? you neutralize ? __________________ Stan 67 swb BLU MULE posted via flip-fone

01-29-2018, 06:12 PM	#6
harpo231 Registered User Join Date: Nov 2014 Location: Lincoln City DE Posts: 1,292	Re: Removing zinc for another finish? __________________ Stan 67 swb BLU MULE posted via flip-fone

01-29-2018, 06:30 PM	#8
harpo231 Registered User Join Date: Nov 2014 Location: Lincoln City DE Posts: 1,292	Re: Removing zinc for another finish? That'll work as long as ya give it a good soaking __________________ Stan 67 swb BLU MULE posted via flip-fone

01-29-2018, 10:34 PM	#9
B. W. Registered User Join Date: Nov 2014 Location: Bigfork, Montana Posts: 1,137	Re: Removing zinc for another finish? Some of my grade 8 replacement hardware was yellow, I bead blasted then parkerized. You have to do a very thorough job of blasting. On some bolts I didn't find this out until after the black phosphate. I use a home brew, exact temp isn't critical but it needs to be hot, I shoot for 180°. Pics: 1 - bead blasted 2 - black phosphate finish & oiled 3 - home brew set-up - Left can is water, right can is solution. Not shown is can for oil, it's on a different warmer. Once I get rolling I'm doing three batches at one time. It's still a whole lot of work. Attached Images

01-30-2018, 09:19 AM	#10
randy.powell Senior Member Join Date: Jun 2014 Location: Bushwood, MD Posts: 510	Re: Removing zinc for another finish? A friend of mine swears by citric acid. Buys it as a concentrated powder from one of the web sites. Safe to use, biodegradable, cheap, pour it down the sink when done...

01-31-2018, 02:00 PM	#12
71CHEVYSHORTBED402 Senior Member Join Date: Feb 2009 Location: Northern Nevada Posts: 7,120	Re: Removing zinc for another finish? My question is while the gold color is gone, what if anything was left behind? As mentioned, when I'm up for it I'll do two more, one sanded. My thought is, if simple cold black oxide sticks to it then other finishes will too. There's a good chance the bolts will be black zinc plated anyway. Fair assumption it will stick. __________________ __________________ Tony 71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assm. guide "kit" for restoring it from ground up. With assys, the guide accts for 1000s of OEM identifications and part numbers, all written in short order. 700+ images include assm, illust., charts, and points of interest. Much of the info. applies to all 67-72 GM trucks, and to a lessor degree all 67-72 GM vehicles. My build thread, and more on the guide https://67-72chevytrucks.com/vboard/...d.php?t=730025

04-23-2018, 01:09 PM	#13
71CHEVYSHORTBED402 Senior Member Join Date: Feb 2009 Location: Northern Nevada Posts: 7,120	Re: Removing zinc for another finish? About 70% vinegar and 30% water overnight on new gold grade 8. I scrubbed one with red scotch bright, and left the other as is, which was discolored, so I had some doubt it would come out nice. Used Caldwell blackening (cold oxide) and sealant on both. The results are about equal and the black sticks, so no doubt black zinc will stick too. Attached Images __________________ Tony 71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assm. guide "kit" for restoring it from ground up. With assys, the guide accts for 1000s of OEM identifications and part numbers, all written in short order. 700+ images include assm, illust., charts, and points of interest. Much of the info. applies to all 67-72 GM trucks, and to a lessor degree all 67-72 GM vehicles. My build thread, and more on the guide https://67-72chevytrucks.com/vboard/...d.php?t=730025



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.