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Posted By: Speedracer Pits in metal - Wed Jun 17 2015 07:49 PM
Hi all,

I was thinking about trying to refinish some heavily pitted parts, instead of always buying re-pop parts. I was wondering if anyone has had any luck using an expander wheel, wire wheel or some sort of abrasive wheel on pitted parts that have contours (such as the 300 hose guard part in the picture)? I imagine it will take about 1/32" of material off overall (before the buffing process), but would probably be un-noticeable.

If you've had any luck, please let me know what you used.

Thanks,
Steve


Description: 300 hose guard mounting bracket
Attached picture IMG_1591[1].JPG
Posted By: JimT Re: Pits in metal - Wed Jun 17 2015 08:06 PM
If Im not mistaken ,isnt that the plating that is pitting?
Posted By: Speedracer Re: Pits in metal - Wed Jun 17 2015 08:28 PM
It may be caused by plating, however it does 'eat' away the metal. When pieces are pitted like this, some are rather deep. As an example, if you look closely along the bottom edge, a small piece is missing (to the left of the red paint). That is from pitting, not a ding.
Posted By: TheGriffin Re: Pits in metal - Wed Jun 17 2015 08:57 PM
For those I've been sanding them down some and using a silver hammered finish spray paint. Ends up looking pretty good without having to buy repops
Posted By: gasmansgp Re: Pits in metal - Wed Jun 17 2015 09:14 PM
A good chrome shop will copper plate these, buff off as you would with primer and re-plate enough to fill the voids. Once that is smooth, then they re-chrome. Always looks better than paint. Paul www.severngaspumps.com
Posted By: model72 Re: Pits in metal - Thu Jun 18 2015 01:53 AM
What Paul said. Not sure about pump parts and the acid copper pricing, but it is expensive to have acid copper process on classic car chrome parts. The process will fill the pits.
Posted By: MORE RUST Re: Pits in metal - Thu Jun 18 2015 09:26 AM
An even better chrome plating shop would fill the pits with solder then go through the plating process. For that part, it would be more cost effective to go aftermarket.
Posted By: Craig Osbeck Re: Pits in metal - Thu Jun 18 2015 01:04 PM
Doing this right now and have done many as we in the Northwest deal with a lot of moisture. You can either 1st have the chrome stripped at a plating shop where the chrome is just chemically taken off. Then you either start sanding by hand or use somekind of hand held grinder or moto tool. You will then grind all the metal to get the pits outs which are usually pretty deep. Sand with either 80-100 grit paper till smooth, going down in paper till you get to about 600. Polish or buff until smooth and shines.
Now the other way is just to hand this to the plating company and say fix it which will go through the same steps except they will fill with copper and sand and polish. They will repeat these steps until all is filled and they can then put on the final plating which is going to be copper, then nickel, or chrome whichever you want.
Most shops will tell you that it is not worth their time or your money if the pieces are like yours. We have no choices on some of the stuff for pumps.
You can do this your self and then just give it to the plater after you polish and they can put the final platting on it for a much cheaper price, you did all the work.
Posted By: Speedracer Re: Pits in metal - Fri Jun 19 2015 02:53 AM
Thanks for all of the reply's. I do not want to paint them and chrome shops around here are very expensive. I brought a bunch of trim from 5 pumps to 5 different chrome shops for quotes about a year ago, thinking I would get some sort of small quantity discount. Wrong. This part alone would cost around $40-$60 each to have done!! $200 just for four hose guard brackets!!! (Not to mention the other trim on the pumps)

Craig, I will try your route. I was just trying to avoid buying re-pops all the time and I have never attacked any of them yet. I think I am just going to try to grind them with a moto-tool and then throw them on my buffer. I wasn't sure if anyone had any luck with some specialized wheel on there grinder/buffer and wondered what they used (such as 80 grit greaseless compound or maybe some kind of wheel that has some give like an expander wheel).

Also, I am curious why you have the chrome stripped first, instead of just grinding it off?

I will let you know how it goes.

Thanks,
Steve
Posted By: st.rod Re: Pits in metal - Fri Jun 19 2015 12:28 PM
Once you sand/grind enough to get the pitting/plating off just buff. Its pot metal. It'll shine. Just won't hold a shine so you will have to polish them ever so often.

Larry
Posted By: Craig Osbeck Re: Pits in metal - Fri Jun 19 2015 12:30 PM
Chrome is a very hard metal and with the stripping is much easier to then sand. You can still grind on it first, but when you get through the chrome the amount of material in that area goes down quickly and unevenly. Such as corners or rounded surfaces. It is time consuming as you will find out. You will be surprised at how deep those pits go.
Posted By: carolinaskies Re: Pits in metal - Fri Jun 19 2015 01:19 PM
Chrome plating is a time consuming process if chrome is already on the part and repair of pitted parts is required. That's why the chroming shops charge so much.

It is possible to de-chrome your pieces at home with either lye or muriatic acid baths rather than mechanical means. Then do any basic repairs and fills. The pieces then could be sent for rechroming. It would save on some cost, but whether it would be cheaper than buying repro parts I don't know.

Also, if the parts aren't available repro rechroming is the only way to go if you want a quality result.

I talked with one fellow who use to work out a trade of his time at a chrome shop for getting his parts done. These days that might be more difficult.

BTW, There are chroming kits you can buy...
http://www.caswellplating.com/electropla...ating-kits.html

And if you've got a lot of smalls that might be a way you could go if you're willing to strip you own parts anyway. Long pieces would require some ingenuity in designing a submersion system, but for anything that could fit inside a 5 gallon bucket I think these would work.
Posted By: Rabbitman Re: Pits in metal - Fri Jun 19 2015 01:37 PM
I go the polishing route on those parts also but I never have chemically stripped any of them. I just start with sandblasting them in the cabinet that I keep a real aggressive media in to strip the chrome and copper off. It is usually already starting to flake off and pretty thin layers so the blaster will take it off if you do it slowly. Then I sand in stages til smooth, using 1500 final grit, and then polish. Like Larry said, they will tarnish in time but I use Autosol to final polish them by hand after buffing and then spray them with Eastwood Metal Protect to preserve the shine. I have parts that have been done for four or five years that look like the day I polished them. They are indoors, not outside though......
Posted By: Craig Osbeck Re: Pits in metal - Fri Jun 19 2015 07:04 PM
Good idea on the spray Rabbitman, where would you get the eastwood metal protect ? Have used thinned lacquer on brass but that is new to me.
Posted By: Rabbitman Re: Pits in metal - Fri Jun 19 2015 08:19 PM
I get it direct from Eastwood. I get the Autosol paste from them also. There are probably other places to get it but I buy quite a bit from eastwood as they have a lot of powder coating supplies and coatings that I like. Here's a link:

http://www.eastwood.com/ew-metaprotect-14-oz-aerosol.html

If you join their preferred club for $29.95/year you get free shipping on most stuff all year. It's a good deal if you order more than a couple of times....GB
Posted By: Paul Bell Re: Pits in metal - Sat Jun 20 2015 11:49 AM
Speed racer, you mention if there are any special wheels you can use for this. There definitely is. My first thought would be to use a scotchbright wheel. It's one of the most handy things I have in the shop, use it all the time. Just attaches to your bench grinder like any other wheel but has a lot of cutting power. Lots of varieties out there, but the one I have is dense grey color if that's helpful. I know it'll work on your application as I've done the very part your doing before. Easier than a dremel or roto zip. (Hate hate those tools) The wheel will leave a semi rough finish that will require additional sanding or buffing with less agressive wheels.

Sometimes with pot metal you just keep finding more holes but I think you'll be good. If you want to seal it with something after polishing I've had some luck with power sealer by wizard, although I can't attest to long term results.

Once you realize how handy these scotchbrite wheels are, you end up spending considerably less time using the sandblasting cabinet or DA sander.
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