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Paint stripper safe for pot metal? - Printable Version

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Paint stripper safe for pot metal? - Brad Winder - 02-16-2023

Hey everyone,

I wasn't sure where to post this question, since it isn't directly about wood or plastic cabinet restoration, and not a Philco either...

I am restoring a RadioLamp and the center of the lamp is made of cast metal; I'm assuming a pot metal of some sort being it's from 1939. Possible it's aluminum, but I doubt that due to when it was made. I need to strip off the sloppy coat of paint a past owner applied. But I am hesitant to use just any old paint stripper, knowing how pot metal seems to deteriorate. 

Anyone have a suggestion or experience taking paint off this type of metal?

RE: Paint stripper safe for pot metal? - GarySP - 02-16-2023

Have you considered trying electrolysis? I cleaned up a brass table lamp that way. The only grey area is how it would react with the metal your lamp is made out of. If at all possible I would disassemble the lamp to its' individual parts for treatment. Just my dos centavos. Take care and BE HEALTHY! Gary

RE: Paint stripper safe for pot metal? - Chas - 02-16-2023

Any petroleum based solvent paint stripper will work O.K. So "should" citrus, but check for any reactions in a hidden area.

Any "pot" metal of aluminum, zinc alloys metal will react with base chemistry strippers such as sodium hydroxide. Acid or alkali baths to attempt electrolysis will be destructive as well and may actually penetrate stress cracks and do its damage over time.

Many solvent strippers have gone away so choices are getting limited..

May find that a 'gel' stripper is a good choice and that for cleanup, animal bedding made of wood shavings works well to wipe off spent stripper and will not scratch the surfaces.

If the lamp body proves to be pot metal, seal the interior as well as the outside to reduce the absorption of moisture in the micro cracks.

Pot metal generally gets as hard and as brittle as pottery, cannot be drilled to any extent and should not be heated with a torch or heat gun. Any divots can be filled with Bondo and smoothed before a sealer coat and then finish. Consider a toner or antique like finish, helps to hide any flaws and avoids the look of a "paint job".

GL

Chas

RE: Paint stripper safe for pot metal? - Arran - 02-16-2023

I would not try electrolysis on what you might think is pot metal, zinc, aluminum, etc, it apparently will not take well to it so I would not experiment on something you care about. I usually use washing soda, some use baking soda, which are fairly benign, but it is not the chemical that does the damage but the current flow from the electrolysis itself since it is an alloy. By 1939 the formula for pot metal was largely sorted out, it was very commonly used in trim parts on cars during the 1940s and 50s, pitting is common, but not deforming, and disintegration like in late 1920s radio parts. Apparently what causes the problems in 1920s radio parts was contamination with lead, which may explain why some parts fall to pieces whilst others fair much better on different examples of the same makes and models of radio. I would stick to chemical strippers (not lye based), you might also try boiling or steaming the cast parts. I'm not sure about brass, I don't think it will be harmed though, but the process is usually for steel or other ferrous metals. The condition of this radio lamp is what made it an easy pass for the price, in my opinion, but the deal is done now.
Regards
Arran

RE: Paint stripper safe for pot metal? - GarySP - 02-16-2023

Thanks guys. As I said, I wasn't sure how it would react with the lamp metal. I know it works well with brass and steel. The base looks to be pressed and stamped steel looking at the rolled edge base and cutouts. I would look at the ease of disassembling to clean each different material involved. Let's not forget that quartz (I'm hoping) embellishment between the two. If it is stone GOJO and 0000 steel wool should clean it up nicely without scratching. If it wont come apart easily, do the best you can. Take care and BE HEALTHY! Gary

RE: Paint stripper safe for pot metal? - radiorich - 02-16-2023

Hello brad,
I have antique Floor lamp that I want strip the spray paint off of too.
In the past I have used Citrus Strip with good results !

Sincerely Richard

RE: Paint stripper safe for pot metal? - Brad Winder - 02-17-2023

Yes, I have the lamp disassembled and I am stripping each piece separately; the picture is when I first received it last year. The lamp mount is plated, but the rest of the lamp was painted a bronze colour under the heavy coat of gold-ish paint. The lower grille area around the base looked like it was plated to match the top lamp mount, but once I took the lamp apart, I found that it was sprayed with a toned colour to approximate antique brass colour. 

Information is hard to find on these lamps. Actual pictures of each of the lamp models featured in the ads is almost impossible to find. I'm going to restore it based on the description in the ads, brochure, and what I found when I took it apart. 

I will take more pictures today!

RE: Paint stripper safe for pot metal? - falcon123 - 05-20-2023

have you tried lacquer thinner or xylene to remove the paint? its just a thought but it certainly shouldnt damage anything. xylene isnt as volatile as l. thinner and if it works would hang around longer. sold exorbitantly priced as "goof off" its also a reducer for some enamels like AERVOE brand paints

RE: Paint stripper safe for pot metal? - MrFixr55 - 05-20-2023

Xylene is the active ingredient of GumOut carb cleaner and is also used in tissue processing for microscopic examination. Use caution as Xylene is a carcinogen and is easily absorbed through the skin and through inhalation.

If it is cheap spray paint, laquer thinner will take it off easily. It is enamel that takes work to strip. About 20 or so years ago, I stripped a 64 Lincoln down to bare metal. Was a LOT of work. I used a gel type stripper. Top coats of paint (bad re-paint job) stripped right off. The original enamel, primer and zinc chromate primer was a lot more work! Unfortunately, there was no way to strip off the bad re-paint job without ruining what was left of the original jo. I put a coat of red primer on the bare metal, but will have to strip that off, as i am not sure that it is appropriate for bare metal. There are more modern paints for cars nowadays and correct metal coat, primer coat, color coat and if used clear coat is important to prevent reactions and short life. In the case of your lamp, a primer appropriate for pot metal and the desired color should do it for you!