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Sat Feb 27, 2010 4:57 am

Does the "metal blackening kit" also works on zinc plated bolts or only on bare metal?

grtz Michel

Sat Feb 27, 2010 11:21 am

It says to remove all old plating. I will throw a plated bolt in and see what happens. I am assuming that it will blacken it but how well it adheres is the question.

Sat Feb 27, 2010 12:21 pm

Well it appears to work, but I think but I still question the quality of the adhesion. For what it's worth it won't rub off using my hands.
Before

After

Sat Feb 27, 2010 12:34 pm

ZwitterND wrote: Well it appears to work, but I think but I still question the quality of the adhesion. For what it's worth it won't rub off using my hands.
Before

After

AN interesting test would be to carry it around in your pocket for a week, or maybe attach it to your key ring to see what some gentle abrasion will do to it. You could also replace you cuff buttons on your shirt with them, but then you'd have to explain that to a lot of people.

Thanks for all the research and details Bill. I will have to address bolt plating for my '51 soon, and I expect you'll have all the kins worked out by then..... :lol:

Sat Feb 27, 2010 2:01 pm

Thanks for your effort for trying this with the plated bolt.

grtz Michel

Sat Feb 27, 2010 11:05 pm

was crawling around under my June '52 standard split today and remembered this thread and went ahead and noted down all the known original bolt locations and markings, the below list is nearly complete and all bolts I have listed are absolutely factory untouched, I missed a few here and there mainly because I cant attest to their originality and completely left out the engine and trans because they have been replaced, I would encourage any other owners of Original splits to add to the list and include their own vehicles unique combinations, I was going to include a less complete list from my April '55 sunroof but it is nowhere near as untouched as my '52

(can you blame me for finally cutting off this fine ancient hackery)

Sun Feb 28, 2010 8:28 pm

That is great information, Thanks! ...can clean your shop?

Mon Mar 01, 2010 6:23 am

Yes you can, come on over!

actually it is clean, you should see it when its messy, I'm affraid I wont be throwing away of the split or oval parts stacked up on shelves in the back anytime soon though

Sun Sep 05, 2010 11:59 pm

ZwitterND wrote: <Snip>

Basically I dumped the whole lot into muriatic acid (be careful with this stuff boys) let them sit for an hour, rinsed in water, sprayed them with degreaser supplied with kit, dumped them in the blackening solution, rinsed in water, dried, then spray with clear satin supplied in kit. Also used it on the hood handle. Cool thing is you don't lose definition of stampings as with a satin black paint.

<Snip>

The results look very good. Question for you on your process. You say you dumped the bolts into muriatic acid (HCL i.e. Hydrochloric Acid) for about an hour. What concentration? 30% 70%?

Also, acid etching of steel is known to cause hydrogen embrittlement. Not something I'd worry about on a non structural item, but on fasteners? I dunno, maybe I'd be concerned about it. You can drive the hydrogen out of the steel by bringing it up to a specific temperature for a specific dwell time. I used to have those figures rolling around in my head but they escape me now. If I recall it wasn't anything terribly exotic, like maybe 350 degrees F for several hours or so. If anyone is interested, I can look that up.

Anyhow, I am very interested in the concentration of the muriatic acid that you used.

Thanks,

Scott

Mon Sep 06, 2010 6:27 am

johnshenry wrote: AN interesting test would be to carry it around in your pocket for a week, or maybe attach it to your key ring to see what some gentle abrasion will do to it.

another test i have been doing (ongoing) is to leave some plated hardware outside, exposed to the weather and see how the plating holds up. i am mostly concerned about the bolts rusting after plating. i've had some stuff black oxided in the past, and it rusted quickly. i've had some other stuff black oxided (by a different company) and it has shown no signs of rusting here in the humid south. i have had no real problems with the black zinc and clear zinc as of yet. the black phosphate has held up well, but seems to be rather porous.
i don't really mess with the "at home" kits, since i have a good plater near my house who does good work for cheap.

i have used muriatic acid to clean LIGHT rust off hardware and parts in the past. there are much better ways to clean heavy rust off parts than letting them soak in muriatic acid. i often use 100% muriatic acid for a very short period, like maybe 10 seconds or so. sometimes i use a concentration, maybe 50-50 for a slightly longer period of time. i have not ever had a problem with embrittlement as in the bolts have not broken or nuts have not stripped, etc. but i really feel that timing is important. i would not leave a bolt in muriatic for an hour unless it was very diluted. i've done more damage to hardware leaving it soaking in coca~cola or lemon juice for extended periods of time than i have using muriatic carefully.

Mon Sep 06, 2010 8:30 am

It would sure be great if there was a decent "at home" system. The problem with using a plater is that you alwyas seem to miss a few items and notice just after you get them home. Unless you know your plater very well, it can get expensice stopping in to throw 5 items in every so often. Mine unfortuantely said $100 minimum per go.

Mon Sep 06, 2010 8:57 am

bwaz wrote: It would sure be great if there was a decent "at home" system. The problem with using a plater is that you alwyas seem to miss a few items and notice just after you get them home. Unless you know your plater very well, it can get expensice stopping in to throw 5 items in every so often. Mine unfortuantely said $100 minimum per go.

i agree, and losing parts does happen. the very first time i took parts to my plater, he was pretty upfront about it. he told me that while they try to be careful about not losing things, it does happen. he also told me that if i had hard to find items, or irreplaceable items, i should keep them separate and clearly mark them. that has worked out well so far, for the most part, although losing parts has happened to me recently. cost me about $40 to replace one small part that was lost. i talked with my plater about it. he was apologetic and he spent a few days looking for the lost part, but did not find it. for the next batch i took to him, i made a very detailed list of absolutely everything that was in the pile. when i got everything back, there were no parts missing. i plan on continuing my pre-plating inventory, just to see how things go.
my plater is cool, he is willing to work with me on "small" batches of parts. i don't rush him, he does my parts when he can, and a couple week turnaround time is fine with me. i clean everything very well before i take things to him, so his prep time is kept to a minimum, and the results are more consistent.
a $100 minimum is more than i would pay. i've had expensive plating done in the past, which makes me even more grateful for the very reasonable plater i have easy access to now.

the most recent batch, pre-plating:

plated:

Mon Sep 06, 2010 5:18 pm

[/quote]
Anyhow, I am very interested in the concentration of the muriatic acid that you used.[/quote]

The acid I use is 31.4% from local hardware store ( I learned that different places such as Home Depot will sell stuff that's 14% so you should, as always, read the label)

I haven't heard the term "Hydrogen Embrittlement" in years, that brought back memories. We had an issue with H.E. on some special pins we were making for a track system. The pin had three heat zones within 1.5" ranging from 55 to 80RC. There was a threaded end on the pin and we had nuts breaking off after assembly, many broke off later as the tracks were sitting in storage racks, warehouse folks were contemplating wearing hard hats. I believe the solution was to bake the parts for about 4 hours to get the hydrogen out. As you referenced, H.E. is a concern for critical structural parts in tension, the parts I coated are for fenders, body, etc. I wouldn't suggest it for engine or drive line hardware.

In my opinion the kits from Eastwood may not offer the same quality you will get from a professional plater. I enjoy doing all the work myself on my restorations and I learn something new all the time. Each time I plated I learned the importance of cleaning the parts, correct solution mixtures, etc. May not be perfect but then again parts I have gotten back from so called "professionals" have not been perfect either. But in the end I get the satisfaction of knowing I did it myself. The best part about running your own race is you always come in first. :D

Mon Sep 06, 2010 11:15 pm

ZwitterND wrote: I haven't heard the term "Hydrogen Embrittlement" in years, that brought back memories. We had an issue with H.E. on some special pins we were making for a track system. The pin had three heat zones within 1.5" ranging from 55 to 80RC. There was a threaded end on the pin and we had nuts breaking off after assembly, many broke off later as the tracks were sitting in storage racks, warehouse folks were contemplating wearing hard hats. I believe the solution was to bake the parts for about 4 hours to get the hydrogen out. As you referenced, H.E. is a concern for critical structural parts in tension, the parts I coated are for fenders, body, etc. I wouldn't suggest it for engine or drive line hardware.

Yes, Hydrogen embrittlement is more of a problem with higher strength engineering grade steels, and you do see more problems with HE in tensile and shear loads. I agree completely that I wouldn't give a moments thought about it with respect to fender bolts. What's the worst that could happen? One of your fender bolts pops? Hell, if they all popped at the same time (a very unlikely scenario) and you lost a fender it wouldn't be the end of the world. I might be slightly more concerned about it for the pan bolts, since that pan will see some twisting moments as each wheel transverses little hills and valleys in the road, not to mention the occasional deep pothole, but I serious doubt it would be a issue. Now, on hardware used to mount the engine to the tranny or the tranny to the frame, I start to have some concern. But, you can always bake the hydrogen out of these critical parts without too much trouble.

Thanks for the info on the HCL concentration. At a 1 hour soak in ~30% HCL - do you feel like you are dissolving much "good" (i.e. solid non rusted steel) during that soak? I might worry that I'd be loosing enough bulk material that the major dimension (i.e. thread to thread outside dimension) of the bolt might loose enough material to get a little on the "skinny" side. I suppose you could mic your bolts before and after treatment to answer that question.

Once again, the finished product looks very good. It will be interesting to see how the finish holds up for you.