I have a pair of original ‘55 T-Bird valve covers. I had them bead blasted prior to polishing. They came back with some pin holes that I need to get rid of before starting to polish them. What’s the best way to proceed?
How far are you willing to go time and money wise? Those could be micro welded up, but that ain't cheap and the results may not make you happy. https://amadaweldtech.com/blog/tips-for-laser-micro-welding-aluminum-alloys/ This guy does restoration of pitted and corroded metal parts on OT stuff. www.youtube.com/watch?v=wKzmaPkZkcI I don't know how much pristine covers like that are, but restoration can rack up hours fast.
There’s no getting rid of those oxidation pits that deep or numerous without serious material removal. Deep. I’d polish those as is and call it a day. What level of polishing are you aiming for? Some shiny or show polished?
Welded aluminum usually comes out a different color than the base material when polished. Me, I'd block sand thru multiple grits, buff them out, mask them including thin strips on the top of the fins, paint the area between the fins engine color, pull off the tape, and clean any excess paint off the fins with thinner.
Those are rough man, honest. But I have a fix. You ever been to a swap meet or auto show where one of those carnival barkers are selling aluminum (aluminium for the brits in the room) sticks to repair holes in tin cans? I bought in to the idea one afternoon (drinking) and left with a couple handfuls of miracle rods. I have filled pits in manifolds and heads with them and then sanded and polished with surprisingly good results. It takes a bit of trial and error to master, but the basic idea is to heat the subject with MAP gas and wipe the rod across it filling the hole (s). Much more brazing than welding. I used these rods to "weld" two license plates together that are still holding after much abuse. You have so many pits that it would take a lot of work and patience (of which I have none) to repair all those divots. But, it will work, and polish out once done. Or if you TIG you can do that, but my idea is more fun and experimental.
You're not sanding that out, your best bet is polish them and stick that end up against the firewall so you can't see it. Or fill them with JB Weld sand and paint, then polish the fins
I went through the same thing with the exact same valve covers ? I also had them glass beaded , when I started to grind/sand to polish I noticed that the porosity kept going ? and it was like a mule chasing a carrot? I wound up just polishing them and placing the worst pitted end on the rear side of the engine! also the places in between the fins I painted . They came out looking really Nice
I would find another set of covers. They are available as reproductions for about $650 a pair, or good used, for much less.
Since you already bead blasted them, I would just spray on the Gibbs and be done. Then either like them or sell them. Looks like getting them polished to your satisfaction is going down a rabbit hole.
Those pits are caused by what is known in the casting world as "sand inclusion". As the molten metal is traveling across the mold it picks up loose sand and it ends up at the far end of the cavity where it has nowhere to go.
Looks like 1 end? The pro repair is, fuck it. Sand and polish whatcha got. Do your best to hide in the back as has been said already. I've seen worse on cars well into 7 figures in value, and as counter as that seems you have to accept what was when doing this shit. I'd rather have real with legit flaws vs imports that look fake.
i think if you filled them in with grey jb epoxy then polished they at least would not show up near as bad.
Not sure why no one has mentioned this, but my first step if I was planning to polish aluminum valve covers wouldn't be to blast them. I just start sanding them to get flaws out, then progressively get finer grit until they are almost polished before polishing. As far as the pits, sanding the covers smooth, polishing and hiding the pits toward the firewall is likely the best bet as has been mentioned.
I agree with 4 speed2quad . U] you will never get those fixed. The sand casting is bad and when blasted , that made things worse. Vic
How bad tho? If it is just that spot then go for it. I have some legit Cal Customs for a SBC that had a narf in 1 fin. I very gently shaped it and the rest like it was never there, but my downside was different. The "dark spots" in the finished areas seems to have gone a bit deeper than polishing will remove. I stared at them over a cup of coffee. I'd rather have the legit aged but refreshed look than new from somewhere in the far east. Maybe 1 in 10 could tell the difference but I don't care if anyone can. Raw thoughts...
I think the pits on the ribs will go away with enough sanding. Most of the pits on the corners will also come out. It just comes down to how much effort you want to put into them. I have cleaned up many of my own castings this way however some pits get bigger the more you sand.
Polish and live with it. Worse ends towards the firewall Fill with some metal filler and live with the different colors after polishing Find better ones Run as is
You can also have them powder coated. They have the ability to fill pits and the valve covers are easier to maintain.
I own a powder coat shop. I did these Isky valve covers for my brothers Olds 303. They were pitted, some fill and I used "Builder Primer" powder coat base, Chrome powder coat with clear powder coat top coat. Turned out awesome!
Sign of the times in 1955. Fords motto how many, how fast, lowest cost…I had an original set on our 56 Victoria and replaced them with stamped steel with Thunderbird only decals not available on any full sized cars or trucks. (if you bought a T-Bird without the dressup kit).
JB Weld the holes, sand em smooth, then polish away. Any imperfections are just character that comes with old cast parts.
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