I have aluminium covers that have black paint peeling off them. I don't have acess to a media blaster. Whats the best thing to remove the paint with? :conehead

 

Be careful here!!! Are you sure they need doing? I'm in the middle of painting the alloy covers on my '81. If I'd known what a PITA it was going to be I wouldn't have even tried. The paint will strip off with a paintstripper such as Nitromors. The problems started when I tried to repaint them - fisheye was so bad that it was more a case of seeing where the paint had actually taken. I've rubbed down the covers with wet-or-dry & have used various degreasers & thinners (including stuff used for cleaning large printing machines that removes all oils & silicons - & blows your head off!). I still got fisheye when I try to paint them. The problem is that the covers are porous & soak up oil. I've hit them hard with a blowtorch to try to boil the oil out of the metal. This had a good effect in that a lot of oil/grease bubbled out (even after all the prior cleaning). Cleaned that off & still got fisheye. At this point I've had enough & the covers are now soaking in an industrial heated solvent bath. They are staying in there til tomorrow (put in yesterday) & will then get bead blasted. I'll pick them up tomorrow night & try painting them over the weekend. If the paint takes OK I'll post here on Monday. If it doesn't I'm just going to give up & buy some chrome covers!
You didn't really want such a negative sounding reply did you? :lol: To give an idea of the time I've spent on these covers: since I started on them I've also cleaned & painted the front & outer sides of the heads, the front of the block, the front impact bar (including the honeycomb that fits to it), the impact bar side supports, the air ducting over the rad, the radiator shroud etc, etc. The same thinners & degreasers that I used on those parts aren't working on the valve covers.
Good luck with them!
Paul

 

Holy cow Paul.. you have the patience of a saint...I would have thrown them across the garage days ago!! It's unbelievable how aluminum can absorb so much oil/grease. Is the printing solution you used Raykoline (sp?) If I remember corectly, (worked in print shop years ago) it's like lacquor thinner. Nasty stuff.. works good and gets you high!! I bet the hot solution will do the trick for you. I'm also in the process of painting the radiator, support, etc.. while waiting to select my engine mod parts. I'm a soft wire brush on a drill guy when it comes to stripping paint and rust. The degreaser from POR-15 has served me well, and all my painting has come out great. Keep us informed on your progress... Good Luck!! :cheers:

 

yeah, normally those valve covers would have gone into low orbit weeks ago, but we're talking my dream car here! When I get to the "Hit it with a big hammer" stage, I just go have a beer or start on another job (& then have a beer :) ).
It sounds like that stuff could be Raykoline. I asked the GF to ask the Printers what it was (hoping I was about to get my hands on some Trichloroflouroblahblahlene), but she said it was really difficult getting any sense out of them. After using it, I understand why - they're all on another planet :lol: I was thinking that it would be a good replacement for the beer until the headache kicked in - ouch (that may explain why the Printers at the GF's works are always going out & getting into fights!).
I hope the hot solution works: if not, those valve covers are gonna pay a heavy price! I'll post here on Monday.
I got my rad support frame powder coated. Came out nice & to prevent rusting from the inside I sprayed Waxoyl down between the layers of metal. The plan is that when it gets warm the Waxoyl will spread out & coat all the metal, protecting it for years. After what's been happening with the valve covers, I'm expecting the Waxoyl to melt & run all over the radiator, clogging up the cooling fins & sticking all sorts of rubbish to it such as general litter & small birds ;)
Careful with how much you start painting - I started off doing more or less what you're doing. I've now got the entire front end of a C3 dotted around the house & various other places, and now the sun has come out, the temp is in the 70's & I'm missing all the fun :lol:
:cheers:

 

A78 -- On my L-82, I did not remove any of the original black, but I did scrape down any loose paint and scaling areas. I cleaned the covers good and degreased them, then cleaned them again. I shot on Krylon semi-flat black straight from the can. Once the paint had dried, I hit the tops of the fins with 320 wet/dry paper and brought the ribs back up. Stubborn areas of black got the once over with lacquer thinner applied by a piece of old tee shirt over my finger. New crossed-flags emblems were added and the covers went back on the engine. It's been several years now and they still look good. Dirty again, but better than they were before I restored them.
:)

 

[Quote] Trichloroflouroblahblahlene [Quote]
:lol: :jester :lol: :jester :lol: :jester :lol: :jester :lol: :jester :lol:
[Quote]Careful with how much you start painting - I started off doing more or less what you're doing. I've now got the entire front end of a C3 dotted around the house & various other places[Quote]
:yesnod: :yesnod: :yesnod: :yesnod: :yesnod: ME TOO!!!!!

 

Update on valve covers:
I went to pick them up on Fri night. They'd been in the cleaning tank for 2 days & as the place were using black etch primer on another job, I got them to spray the covers in it. The result looked good & they said that they would be using a 2-pack lacquer on Saturday, so they'd lacquer the covers to give a nice finish. So I went down there on Saturday & guess what? The etch primer had flaked away from the covers in exactly the same areas that I was getting the worst fisheye. Other areas that I had problems with were covered OK. The place is an industrial metal finishers & they are :confused: The owner has taken it as a personal challenge & said "What the hell is on these things? I'm not gonna be beaten, leave them with me". Next installment (or new chrome covers :lol: ) coming shortly!
Paul

 

Quote: "It's unbelievable how aluminum can absorb so much oil/grease."

Note that the valve covers on a 1981 "L81" corvette engine are NOT aluminum. They're some kind of magnesium or something, but not aluminum! The top edge of the fins are painted/coated with a cream / off white kind of paint, and the covers are painted a gloss black.

 

John,
You're absolutely correct. The valve covers are some sort of Magnesium alloy (to save weight, I read). If they were Aluminum I'd just polish them up, but magnesium alloys very quickly go a dark grey (gray?), so I thought it would be less effort to "just" paint them black :lol:

 

On my 79 L82, first I washed them good in a tub of warm water and dawn dishwashing detergent with a big old scrub brush. Afterwards, I cleaned up any loose paint etc. with steel wool then washed them again. Then I painted them with black semi-gloss engine paint. Here's a tip though. Once you paint them, put them in the oven to bake the paint. The first time it heats up, the paint will become tacky, so you want to avoid touching them or having that happen on your engine where crap can get stuck in the paint. This was a tip that someone on this forum passed on to me, and they were right. :cheers: :crazy: :smash:

 

79:
It may have been me that said to bake the paint (definately if you're using Sperex engine enamel). I found that out the hard way - try riding a m/cycle with tacky paint on the engine (when it cures the 1st time it gets hot) & you'd be amazed at the sorts of things that stick to it, along with all the dust that turns it from high gloss black to flat grey within 2 miles :yesnod:
After cleaning my valve covers with solvents etc, I left them in the kitchen sink for 24 hours soaking in a strong solution of detergent & washing powder (the deal being that I did all the washing up that needed doing at the end of the 24 hours :( ). When I heated the covers to dry them, oil started bubbling out of them, which would have ruined any paint that would have been on them. These covers are turning into a nightmare :mad The infuriating thing is that I've painted all sorts of engine castings & covers (iron, steel, aluminum, monkey metal) in the past without any problems. These magnesium covers just don't want any paint on them!