I was wondering if anyone here has any ideas what material to use to fill pit/holes in metal prior to having it rechromed?

After stripping the metal down to bare metal, does lead work? Will lead desolve in the replating process?

I have some parts I want to fill in some pitting on, and wondered the best filler to use.

Thanks to anyone who takes time to reply.

 

I don't have an answer, but I'm interested in any responses you get, too.

 

I found out that NEVER use lead.

"Steel parts can be filled with steel, brass, bronze, or silver solder. Pot metal parts must be filled with special zink based material usually found at welding supply stores. Never lead!"

This came from a replating company I contacted.

If anyone knows what this "zink based material usually found at welding supply stores", let me know. I think I will try to pick some of this up and see if it works well for minor pitting on pot metal.

It's only $40 to replate a radio face plate. And if I can fill in my own pitting, that would turn out a much nicer finish.

 

The places we've used in the past for re-chroming have used a 3 part plating system that fills in those little pits. Our bumper for the '41 was pitted pretty bad and it turned out great. The only prep work we did was to take it to the chrome shop and write the check.

I don't know if thats true for all chrome shops, but it would make sense since the main reason to have something re-chromed is due to rust, pitting and other imperfections.

I don't see why you would have to do any prep work, unless you just wanted to.

 

Carlene,

The most important step in replating is the prep work.

Plating shops don't do a lot of prep work. It would be cost prohibitive to pay for the labor to prep pitted hardware. They will do some minor prep.

You don't just drop off an item that needs a lot of prep work and expect outstanding results. Of course some may feel that mediocre results are acceptable (for instance on say a bumper). But for detailed show quality work, there is more to it than that.

With regard to pot metal, it is far different than working with a bumper also. Pot metal will have mediocre results at best, generally unless it is handled by someone who really knows how to obtain high quality results. And is willing to put in the time to get those results. It can take many many hours to prep a piece of pot metal. I have 16 hours in on a radio face plate, and it still has a long way to go. If I were to have paid a replating shop to do the work, it would have been stupid expensive...... and would have not made any sense to have the work done.

A lot of folks don't realize that replating is not just a matter of dipping a piece of metal into a magic pot of chrome. The chrome actually is the least critical part of rechroming. The chrome is more like a protective film. The real luster and beauty comes from the nickel plating underneath.

Here is some more explanation on the subject.
http://www.verneschromeplating.com/chrome-plating.html

 

Thanks for the link, but I've already researched chroming before. We just happened to be in an area that had an excellent chrome shop. Our '41 bumper turned out flawless.

Our center hood piece on the other hand is pot metal and we have to send that off to a specialty shop. I believe they do a 7 part system and their advice was to let them do all the prep so we didn't make matters worse. Improperly done and they would have to strip it anyway.

Good luck on you search.

 

Carlene,

Yes the pot metal takes special skills, and time. As you found out, most replating shops do not want to put in the time to prep pot metal. And they turn out rather poor results. Many plating shops work on a volume/production basis, rather than a super high quality process.

I have my parts stripped by the shop, and given back to me, and do much of the prep work in advance of having the part copper plated. If it is a part that needs a lot of attention. The part should be exactly how you want it BEFORE any plating is started.

As you probably found out.... the cost of prep work on pot metal can get expensive. For instance on a radio face plate it might not make sense to pay $600 to replate it, due to the prep work needed. On the other hand if you have the time and tools (dremel works very well), to sand a part and prep it yourself, $40.00 is quite reasonable. Having the zink filler material, helps so that you do not have to remove as much material to get rid of pitting. Generally you have to remove a great deal of material, and in some cases completely alter the contour of the part just to remove the pitting. To be able to use a filler material on pot metal, is quite appealing.

I'd sure like to find that zink filler material that is used on pot metal.

 

Bet you cant find a place that will chrome plate a factory step bumper for a 79 Ford pick up.

 

why is that?

 

When I was pricing at the chrome shop, if it was prepped in any way by the customer there was an invisible surcharge. Nine times out of ten the prep work caused us more work and the piece was charged for accordingly, the surcharge was double if the part was sandblasted.

Pitted bumpers get a treatment on a semi-automatic belt machine with a 50 grit belt to get the nickel off, grinding with a 50 grit disc then finished with 150 belt and 240 - 300 grit polishing wheel.

Before you try welding pot metal with those zinc rods, the pits must be sandblasted out. If you look closely at them, they will appear black, that black is oxidizing and you will get poor results if you try to weld onto that.

Other problems I've run into with pot metal is; the piece will look like it's ok but if you look closely, sometimes there are spots, like age spots of a slightly different color than the rest of the piece. I call these areas rotten because it's almost impossible to get plating to stick to it.

We have used lead semi-sucessfully, after a copper strike, the piece can be filled with lead. I'd say it works 50% of the time as the lead oxidizes very quickly in the plating solutions and causes blisters.

There isn't a step bumper we don't plate. I still work at the shop occasionally so I can say 'we'.

If it's a bumper you're talking about with minor rock pitting, I wouldn't bother doing anything to it cause they'll likely gring it anyway.

As with anything, be very specific as to your expectations and ask questions as to what they actually do to prep the parts and what you should expect. In fact, ask them every question twice at different times to be sure.

 

I've never had anything chromed. I've had plenty of things galvanized and have seen that process.

Do they "mask" off areas like the ports on intakes or say, a threaded whole where a bolt goes? Or do you have to grind or retap those areas? Is there some type of liquid mask they use?

On aluminum, if I wanted to do some prep work, should I stay away from the wax based polishes and stick to wet/dry for the prep?

 

Electrical tape is used the most for masking. chunks of rubber hose can be stuck/screwed into bolt holes.

As for the polishing aluminum, I suppose it may depend on the shop. We used dry first then a grease buffing compound, sometimes applied to the dry compound wheel, to do a nicer job on the soft metal. All parts have to be cleaned in a hot, caustic tank and scrubbed so grease compound diesn't matter.

I've never seen anyone chrome a manifold, only buffed.

 

I've known some Latino guys around here chrome intakes and basically any metal part you can pull off an engine... I always wondered how they kept the mating surfaces and ports clean.

Thanks for the info!

 

I would suspect the aluminum manifolds are buffed; plating takes the path of least resistance in a very noticeable way. deep crevices, like those in a manifold, won't plate with chrome. A light deposit of nickel may be there because of the time the piece in in the nickel tank but chrome dip is only 1 - 3 minutes; this will leave those deep crevices with an ungodly dark yellow color contrasting against the bright chrome. Since the nickel deposit is what gives the pieces that 'smooth as glass' appearance; the lack of plating in the crevices plus the difficulty of attaining a fine degree of finish, compounds the crappy look of the yellowing.

A lot of elbow grease and time and you will get a nice overall bright finish with buffing the entire piece.

 

Thanks for the info FB! I've seen that yellowing on rechromed parts. Sounds a lot like painting, where it's hard to spray an inside corner.

The intakes I've seen chromed are stock cast iron. The amount of effort involved must be something else. For me, I like the contrast of a painted intake, but then, I don't care if my front end can hop either. I like a lifted truck..