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Technical Chrome Plating Aluminum

Discussion in 'The Hokey Ass Message Board' started by Roothawg, Feb 4, 2019.

  1. Roothawg
    Joined: Mar 14, 2001
    Posts: 19,457

    Roothawg
    Member

    i have a set of vintage 7 fin Cal Custom valve covers at the polishing shop. I am hoping for a “show finish “ but I am hesitant.

    Would it be better to have them chromed? Just wondering how this process holds up?

    I know very few people are chrome playing with all 3 steps these days.

    I have time. This project will take a long time to finish.
     
  2. lcfman
    Joined: Sep 1, 2009
    Posts: 206

    lcfman
    Member
    from tn

    Good chrome platers like Advanced Plating others would have no problem chrome plating aluminum and I see no reason it would not hold up.
     
  3. Atwater Mike
    Joined: May 31, 2002
    Posts: 10,013

    Atwater Mike
    ALLIANCE MEMBER

    Think they have to be anodized, then chromed.
    Don Orosco chromed some stainless and then some aluminum on his Pebble Beach '34...said chroming aluminum is 'just fine'.
     
  4. gnichols
    Joined: Mar 6, 2008
    Posts: 10,676

    gnichols
    Member
    from Tampa, FL

    Ditto. Works great. Part must first be polished to perfection, like Advanced does, and the grand prize is that future cleaning can be done with Windex and very little elbow grease. Gary
     
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  5. I've sanded and buffed out aluminum to a high polish before. You will want to seal it when your done though. Either use "Diamond Clear" from Eastwood or have someone powder coat clear em'. I have done both ways with good results.
     
  6. Jack E/NJ
    Joined: Mar 5, 2011
    Posts: 578

    Jack E/NJ
    Member
    from NJ

    If the covers were pressed from extruded flatstock, bright dip anodizing is probably best. Jack E/NJ
     
  7. DDDenny
    Joined: Feb 6, 2015
    Posts: 13,289

    DDDenny
    Member
    from oregon

    Like any process the results will be proportunate to the quality of the prep work but with many parts cast in aluminum they can have inconsistant (pour) quality (porosity).
    My knowledge about casting also has holes in it so best to get the facts from the experts.
    Here:
    http://berntsen-foundry.com/porosity-free-aluminum-castings/

    I've seen many aluminum parts chrome plated but in all honesty I would rather have them highly polished, just doesn't look "natural" to me, just never quite liked that look.
    Not sure why, maybe it's because I know it's aluminum and I've never seen aluminum polish up with that level of lustre.
     
    Last edited: Feb 4, 2019
  8. VANDENPLAS
    Joined: Dec 14, 2009
    Posts: 2,282

    VANDENPLAS
    Member

    I had an O/T aluminum valve cover plated years ago, came out great. Was not cheap as the cover had to be polished to perfection and then a coating on top I don’t remember if it was anodized or zinc ... something along those lines. Then got it “concourse chrome” almost like a black chrome. Looked great.

    But I would have to agree with DDDENNY I really like the look of high polished aluminum, it has a warmer glow to it then chrome. A bit more up keep, but oh well.
     
  9. Roothawg
    Joined: Mar 14, 2001
    Posts: 19,457

    Roothawg
    Member

    I told my polisher the finish I wanted, but everyone's interpretation of "show quality" may be different. He showed me some of the stuff he had chromed for his Harley, that he was super proud of. I would have sent it all back. supposed to be done polishing them this week. We will see. I spent a couple of days prepping the fins myself.
     
    kidcampbell71 likes this.
  10. 41rodderz
    Joined: Sep 27, 2010
    Posts: 4,435

    41rodderz
    Member
    from Oregon

    I have had a couple of chromed over aluminum intakes and like was stated prep and porosity come into play. Both were old jobs but the chrome eventually chipped in a few places and chrome over dibs and waves takes away from what can be a nice show part. I agree with DDDenny chrome doesn't look the same as it would on metal.
     
  11. Mr. Mac
    Joined: May 16, 2005
    Posts: 1,920

    Mr. Mac
    Member

    Chromed aluminum is so much easer to clean than just polished aluminum. All my aluminum parts are chromed on my roadster.
     
    kidcampbell71 likes this.
  12. Moriarity
    Joined: Apr 11, 2001
    Posts: 17,884

    Moriarity
    SUPER MODERATOR
    Staff Member

    If you want show quality chromed aluminum parts they need to be polished, then plated in copper, then the porous parts can be soldered or leaded and sanded and then copper plated again. polish and copper plate until perfect. then nickel and chrome plate... It is expensive when done correctly but looks great. I use AIH custom chrome in Dubuque Iowa
     
  13. A Boner
    Joined: Dec 25, 2004
    Posts: 5,502

    A Boner
    Member

    Polished aluminum valve covers are cool, polished aluminum and chromed valve covers are bling. IMHO
    Polished - race look
    Chrome - show look
     
    scotty t likes this.
  14. fourspd2quad
    Joined: Jul 6, 2006
    Posts: 677

    fourspd2quad
    ALLIANCE MEMBER

    Here are two samples of my cast aluminum tail light bezels for comparison. The bezel on the primered car was chrome plated while the one on the green car is polished aluminum. Definitely a different look.
    20170722_133250_resized.jpg IMG_3722.JPG
     
  15. A Boner
    Joined: Dec 25, 2004
    Posts: 5,502

    A Boner
    Member

    ^^^^Looks more like brushed aluminum.
     
  16. DDDenny
    Joined: Feb 6, 2015
    Posts: 13,289

    DDDenny
    Member
    from oregon

    Boy, that looks good chromed, clearly proves I was all wet as far as a general statement.
    The example I used in my previous post was a pair of LT-1 (1970 style) valve covers that I saw that had been chrome plated. I had a pair of NOS valve covers, OEM polished, not show polished and I loved them (sorry Mark), should have kept them.
     
    The Shift Wizard likes this.
  17. I'll be the contrarian…
    I had a crusty old plater tell me many years ago that plated aluminum is like a teen-aged hooker; looks great when fresh, but doesn't age well. Time has proven him right...

    Plated aluminum can look great and does eliminate any frequent polishing, but you can't let any moisture sit on it for extended periods, and that includes high humidity. If there's any chips, breaks, or thin spots in the plating (and these are all extremely difficult to totally eliminate) and corrosion gets a foothold in the aluminum, it'll start lifting the plating and the only fix is to strip and replate. If you've ever seen a Cragar SS wheel with peeling chrome around the lug nuts, that's the process. Keeping all plating spotlessly clean and waxed is the best maintenance, along with heated storage.

    Same thing goes for any 'coating' over polished aluminum; any corrosion gets under the coating and you'll be stripping and repolishing sooner or later.
     
  18. chopolds
    Joined: Oct 22, 2001
    Posts: 5,719

    chopolds
    Member
    from howell, nj
    1. Kustom Painters

    Can be done, but as DDenny said, crappy castings, like most finned VC's, will cost a bit more to get all the imperfections out of them. MUCH easier to clean than polished, though, and won't oxidize.
     
  19. Advanced Plating does a beautiful job, Steve did all the chrome work on our wagon and he does chrome plate aluminum parts, he did a friends 1952 bubble top aluminum side trim and it turned out amazing. HRP
     
  20. Roothawg
    Joined: Mar 14, 2001
    Posts: 19,457

    Roothawg
    Member

    Thanks, this thread has some good info.
     
  21. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,174

    56sedandelivery
    ALLIANCE MEMBER

    Does the chroming process hold as good to aluminum as with steel? My reason for asking; I had a RARE aluminum Ansen 2 piece, SBC/BBC scattershield for sale. The lower cover had been chromed at one time, but the chrome was flaking after 45 PLUS years of use. The buyer was told this before he committed to buying it; he still "Pissed and Moaned" after getting it. Cost me $100.00 to shut him up, and it was sold through the HAMB Classifieds! I think it was more buyers remorse than anything; he just did't want to pay the price for a RARE part. I should have kept that scattershield!!! I am Butch/56sedandelivery.
     
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  22. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 6,392

    Bandit Billy
    ALLIANCE MEMBER

    If you think about it, every chrome GM alternator is plated aluminum, holds up fine from my experience. I have had a few aluminum parts that due to the cast and material would not polish. The polished said they kept "popping" when they got them hot on the buffer wheel. Those parts got plated and turned out nice.
     
  23. DDDenny
    Joined: Feb 6, 2015
    Posts: 13,289

    DDDenny
    Member
    from oregon

    Hmmm
    I wonder how aluminium connecting rods would look chromed? Just for show of course!
    Inside joke;)
     
  24. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 6,392

    Bandit Billy
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  25. alchemy
    Joined: Sep 27, 2002
    Posts: 15,322

    alchemy
    ALLIANCE MEMBER

    As Moriarity said above, a plater can hide the flaws of whatever they are plating with copper coats and solder in the pits. Aluminum included. And as any plating job requires, whether steel, brass, pot metal, or aluminum, a good prep job and proper procedure will provide a long life.

    And sometimes plating aluminum is beyond the plater's skill level. You just need to find the experienced plater.

    Over ten years ago I had Chromeplaterjosh here on the HAMB do some of my 41 Studebaker taillights, which I normally sell as polished aluminum. That pair still looks great.
     
  26. Chrome plating aluminium should be no problem. My experience is that after a few years it easier
    flakes off than chromed steel. Could be my bad luck or the poor Dutch wetter, but that's my experience.
     
  27. badvolvo
    Joined: Jul 25, 2011
    Posts: 429

    badvolvo
    Member

    I actually prefer polished aluminium vs chrome. Takes a bunch of work to keep that look though, and I don't do well at that kind of maintenance.
    I just got a new intake from Edelbrock, fresh casting 12-2018. It looks so good I want to clear coat it. I am afraid it will just begin flaking off and don't want to deal with that mess.
    Anyone clear coat aluminium engine parts - with long term success?
     
  28. Roothawg
    Joined: Mar 14, 2001
    Posts: 19,457

    Roothawg
    Member

    That's me. I don't wanna spend a ton of time polishing.
     
  29. Chrome plated aluminum can look great, but does need a first-class plating job to hold up. If you have any suspicions about the plater, walk away. A few things to remember...

    1. Chrome plating is porous. While it seals most corrosion out, it doesn't stop all of it. This porosity is why chromed pot metal pits and chromed steel parts rust. Aluminum isn't immune to this. A full triple-plate (copper/nickel/chrome) will help, but not fully eliminate this.
    2. Chrome plating doesn't always apply evenly. During the process, the plating metal will 'stick' to the first part of the item it encounters. If you have holes or recesses, the plating will be thin in those areas and if you have problems, that's usually where they'll start. Wide, shallow recesses can be adequately plated by simply allowing more metal to transfer (as long as the plater isn't too cheap), deeper stuff can be fixtured but that runs the cost up sharply. On your valve covers, it will be thin in the mounting holes and between the fins. I'd paint, or better yet powdercoat between the fins.
    3. Chromed steel will give you warning if the plating is compromised; that's where rust will first appear and if promptly polished off and then waxed, it can be maintained. Pot metal and aluminum won't give you that warning, so preventative maintenance is critical.
    4. The chrome is actually decorative. The actual corrosion-inhibiting layer is the nickel but it tarnishes easily. Failure to apply enough nickel will result in a plating job that won't hold up.
     
    Last edited: Feb 5, 2019
  30. quicksilverart46
    Joined: Dec 7, 2016
    Posts: 460

    quicksilverart46
    Member

    I agree 100%. Polished aluminum looks natural and shiny enough. Clear coating looks fake and will peel in time. Chrome is great for steel but chrome aluminum again looks over done on a known aluminum part.


    Sent from my iPhone using The H.A.M.B. mobile app
     

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