Technical How to fill pits in bumpers before chrome

Title pretty much says it all. Making a small bumper for the rear of my A coupe. I need to weld a couple of pieces of pipe together on end and I’m wondering the best why to fill the inevitable pits and shrink. I’ve read silver solder works and brazing doesn’t.
Any suggestions would be greatly appreciated

 

I always thought that brazing would work. Who are you going to get chrome it?

 

There’s a place in Fredericksburg that @ Just Gary got his done, came out really nice.

 

Wayne’s? He’s done some for me. Does a nice job and is fairly reasonable.

 

Yup

 

You might give them a call and confirm your choice, since they will have to take it from there.

 

Thanks, I will, just thought I’d ask the HAMB brain trust

 

for what it's worth... I spent a few hours brazing and filling some deep scratches in some handlebars; when I took them to my plater, he said it was a waste of time and needed to be redone without brazing.

 

Thanks for confirming that !

 

Sometimes the chromer will fill with solder after the first copper plate.

 

It may depend entirely on the plater or the plating chemicals they use.
Back in the 70's a friend filled in around the weld on a hair pin steering arm with brass before I had it plated at Waco plating and I spent a few hours filing and sanding it to get a polished finish and all he wanted to know was that it was actually welded with steel and not held on with brass and it turned out fantastic. That was 1974 as apposed to now though.

 

Bing Videos
This is for pot metal but they have different powders for different types of metal.
We have sprayed shafts that were turned down in a lathe at work.

 

X2. Tell him I sent you.

Also, @Moriarity posted great advice a few years ago. Here's what I'd emphasize:

I MIG-welded my axle's pits & divots. I'm told silver solder is good too. Then I filed the welds flat and sanded it down to #400.

Then I thoroughly cleaned it so there's nothing left to contaminate the chrome plating chemicals.

The bumper you drop off at Wayne’s needs to look like its already chromed.

He'll probably redo the filling, grinding & sanding until he's satisfied.

Then it goes into the copper tank. Copper fills tiny imperfections, like fill primer, but not a lot, it's gotta be pretty close to "right" before copper.

Looking forward to seeing the new "jewelry"!

 

I had seen pitted Cushman scooter parts filled with the plater's copper and then chromed. They were great.

 

Talk to the plater. I leave most of that to the plater since they know how they want it and do a great job of it.

 

A good player will fill and polish parts prior to chrome.

 

Just a comment , many plumbing parts are brass , many are plated , is there a chemical difference between brass & brazing rod ? In the past I have brazed brass fitting together so they're compatible .

 

Thanks guys for the info ! I’ll speak to the Wayne before I bring it to him. Appreciate the help !

 

I watched a TV show years ago where they followed the plating process at a high end plater. The plater said they either drill every pit down to solid metal, or drill completely through if it's a deep pit. Then they soldered every opened pit or hole they made.
The owner said if pits are simply cleaned and filled they eventually bubble and ruin the plating.

 

Wonder what solder they used.

 

Which would be a better choice, MIG or TIG ?

 

I used to work at a chrome shop, and nearly every time someone pre-worked over a part hoping to make it nicer or cheaper, we'd have to redo it and it would end up costing the customer more. If you're welding steel, anything big enough to get welded up you can do, but I wouldn't start filling in stuff with braze or solder because your plater might end up wanting to take it all out and redo it, and that'll just eat up more time.

Think of it from a bodyman's perspective. Most shops don't want to paint over someone else's bodywork because even if it looks great on the surface, they can't tell how well it was done underneath. Same thing with plating.

 

This won’t help @Dino 64 with his bumpers but I recall an article in a Rod & Custom annual on repairing and plating pitted die cast. You drill to eliminate any pits and then fill the holes up with Certanium 34C solder. I believe 34C may be banned (hazardous?) in the US but it’s still available in Great Britain.

 

I use Advance Plating and they told me they prefer to do their own prep work, Steve told me they would remove previous work if the customer wanted guaranteed work. HRP

 

Might consider just drilling out each pit and leave it at that. Then the chrome shop can fill with whatever they like and chrome it. Or call the local chromer and ask what they'd want to see?

 

I ran across the article in the old R&C Street Rod Quarterly that I referenced above. Here is what was in the article in case anyone does get some Certanium 34C. The parts must be copper plated before adding the solder.