I’m not beginner by any means, I’ve been painting my models with an airbrush for more than 30 years. I have run into a Zamak Cary E7A body that won’t except paint. Everything I’ve tried has failed. I’ve tried Automotive primer, Self Etching Primer, Zinc Chromate Primer, Tru-Color Primer soaking it in Vinegar, roughing it up with sandpaper and nothing works. I’ve had toughies before but this one is really bad.
I bought the shell off eBay and it is new old stock in the Cary box unpainted, looking at the info sheet and box I’d estimate it at about 1970. I’ve stripped it 5 times and have it soaking in vinegar ready to try a sixth time.
At this point I’m very open to anything but a hammer, that will happen on #7.
Are you sure it is a Cary shell. As far as I know the Cary shells were made out of lead . The Hobbytown shells were made out of Zamak.
The lead shells are much heavier tham a zamak shell of the same size.
As far as why paint won’t stick I am not sure. I do sometimes see a lot of Hobbytown Zamak shells where paint chips off.The only thing I can suggest is lightly scour off any zamek oxidation with super fine steel wool before your vinegar bath. If it is lead the lead is much softer so be careful.
Thanks for your input. The Micro Scale site info on Microprep doesn’t say that it will work on metal so I called Micro Scale and I didn’t get a $16 answer. I need more than a “Try is and see” answer to spend $16 on a product that “might work”.
Have you tried it on Zamak?
This is my 7th Cary E7 body and I had some difficulties on one of six earlier bodies but a good cleaning and Automotive primer did the job. The other five went pretty easy.
This is the first time I’ve ever had Zinc Chromate fail on anything.
I do think it’s a Cary shell, it came in a Cary box with a Cary info sheet and it weighs the same as my other Cary E7A bodies. The reason I said it was Zamak is it isn’t a clear pour like my others were, the texture looks like Zamak.
I have two Hobbytown of Boston Shells and like you said they are lighter than a Cary. The Hobbytown shells also have castings inside tapped for screws and the Cary’s don’t.
I just checked the Bowser web site.They picked up the Cary line a few? years back. Their Cary page says they are zinc die cast but the shells are discontinued. All the Cary shells I have on Hobbytwn drives look and feel like lead. I could be wrong. If anyone asked what do I know,I would say for my first 7 years of 44 working for Ma Bell I was a cable splicer. Back then a lot of telephone cables were covered with lead sheath, I spent many a day cutting, sawing ,melting, casting, and soldering lead cables and sleeves .I do know the look and feel of lead ,perhaps Cary or Bowser changed material. Maybe someone on the forum knows. Of course the real issue is what your paint stick problem is. I sure don’t have an answer again maybe someone has the answer.
Yes, my first try was Rust-Oleum Primer, second was Rust-Oleum Automotive Primer. Third try was Rust-Oleum Self Etching Primer. Fourth was Zinc Chromate, fifth was TCP Primer.
A good soaking in Vinegar between forth and fifth.
Mel
Modeling the early to mid 1950s SP in HO scale since 1951
That shell sounds like the same material, the 50’s Ulrich trucks were made out of and is badly oxidized. I had a couple tank trailers still in box from the 50’s, (1.95 for kit,by the way) the trailers almost looked liked lead. I used double #00 steel wool with lacquer thinner, the real one, literally soaking it in the thinner and scrubbing with the steel wool, then washing with hot dish detergent water with a toothbrush, blew dry with air-brush and used Floquil reefer white as a primer and used Vallejo scarlet red and Insignia yellow, for the main colors, followed by a coat of Vallejo satin varnish, which is 100% Acrylic resin. The paint all held up great, don’t chip, flake.
I believe You said You can’t breathe lacquer thinner though…so!!
Carbontetrachloride would have worked beautiful…but they took that off the market for consumer use.
Got rubber gloves? Diluted Muriatic acid would also work.
Good Luck! Bring it to Me…We fix em’ anything…according to my youngest 35yr.old.
I found an MR Trade Topics review of the Cary E6 body casting and it is described as an antimony lead alloy. I suspect their other E unit bodies were the same stuff. The Hobbytown E6 was reviewed way back in January 1951. They describe it as a one piece zamak body casting. Lead, zamac or zinc alloy - it should take paint regardless – generations of modelers were able to paint all of those models and materials.
I wonder if that shell was stored near certain chemicals (or oils, such as cooking oils?) that have permeated it and made the paint unable to stick.
Years ago I remember reading about the old old MR club layout, the MR&T, back when it was on 1027 N 7th St in Milwaukee. They found they could not paint a backdrop on the walls because years of printer ink and the solvents used to remove printer ink had permeated the walls and made paint unable to stick.
The diluted muriatic acid idea that Frank mentions might be effective, but that still assumes there is something on the surface of the metal that resists the paint.
I wonder if an electrical charge method of painting might work too – I once watched guys repaint old filing cabinets by spraying while an electrical charge was applied to the filing cabinets and the paint flew to the metal like magic. Of course that was steel and already had (chipped) paint on it.
I have some recollection that some modelers who wanted to solder things onto zamac / zamak bodies of diesels or steam engines – which ordinarily cannot be soldered – would have them plated first. I wonder if your shell could be plated and then painted? If it is lead that would likely not work. It should be easy to tell if the shell is lead by trying to scratch into it with a nail (on the inside of course).
I’m not the one with breathing problems, I think that’s Rick. I’m going to try one more time using the Rust-Oleum Automotive primer in the morning. I worked it over pretty good this evening with vinegar and the metal ended up with a slightly different look, I don’t see the imperfections in the metal now.
I’m going to try baking the primer, tomorrow we go back into the triple digits again with an expected high of 103°. I’m going to shoot it about 10:30 and set it in direct sunlight for a couple hours. That has worked for me in the past with difficult paint jobs. If that doesn’t work I’ll try again Sunday at 107° with a different primer.
If my attempt fails tomorrow I’m going to try Muriatic Acid and cooking it in the Sunday sun at 107°, I came close to trying that a couple of days ago but chickened out.
It’s getting close to the 3 pound hammer time.
Mel
Modeling the early to mid 1950s SP in HO scale since 1951
About 94’, I had a close friend got in a accident with His Volvo semi tractor. He knew I did pretty good work, glassing and painting. Body shops wanted 2,000 $$, to repair it. It’s an all one piece fiberglass hood/with fenders that swings off of front end to get at engine. Anyway long story short… I had to repair one of the fenders, where headlight is…completely ripped off…luckily He had the ripped off piece and other pieces. I was able to rebuild that whole section and the front where the grill would go, with fine fiberglass mesh and resin. Had it all sanded and primed ready for paint and My compressor took a crap…so…I went out and bought a case of rattle can rust-oleum pure white enamel paint and put four coats of it on the hood in 100 degree temp. and let it sit all day & night…next day. I wet sanded the whole truck and buffed it out with Imperial Machine Glaze by 3M. when He picked it up that nite, He did not believe that I rattle canned the paint job…It looked that good!!! The Sun makes for a great baking oven.
Didn’t mean to ramble, but I believe You are on the right track with Your approach.
Mel keep us up to date with what happens on the paint job.I am sure interested in how it comes out! If you should decide on the 3 pound hammer post a picture!
I think zamak has a sort of tendency to out-gas if the metal is contaminated? I’m not completely sure though. I have an old American Flyer zamak tender with contamination, and all the old paint is flaking and peeling off. A couple little tiny spots have cracked off too, like contaminated metal does.
What if you went over the whole thing with a fine wire wheel? That might help get surface oxidation out of all the little pits and cracks, which could allow the paint to hold on better?
Mel if all else fails, I have just been introduced to a product called “STIX”. It is a water bourne primer that will even cover ceramic tile or arborite before painting.
My use was for vinyl wrapped base boards that I wanted to paint white.
I just lightly scuffed them up and and wiped them down with a rag dampened with TSP and then primed with STIX and then painted with a latex paint with primer included and it worked great.
Now you would have to experiment a little to see the consistency that would be needed to air brush the product, but this gives you another idea to try.
I found the product at a Benjamin Moore paint Distributor.
I want to thank everyone for all the good info and ideas!
I have #6 sitting out in the Bakersfield sun cooking. I gave the shell a vinegar bath for about four hours late yesterday and a good washing then let it sit overnight. This morning I shot it with Rust-Oleum Self Etching Primer and set it in the sun at 10:20, by 2:00 it should be pushing 100°. I’m going to let it set overnight and see what happens on Sunday.
I’ll let you know what happens Ron, I’m keeping the hammer and camera handy near my workbench.
Mel
Modeling the early to mid 1950s SP in HO scale since 1951
Interesting thread. Hope try number six works. I would have thought the vinegar and zinc chromate primer would have worked; that is what I would have tried. I have a friend who is a custom painter who bakes his paint jobs in a low heat oven (scalecoat paint on brass models) but your weather certainly should suffice. We had a cool day; 96, first day under 100 this week.
The four hour vinegar soaking and 8 hour cooking at 100° procedure has apparently worked with the primer. It got cooked pretty good yesterday, I forgot to bring it in so it cooked in the sun for about 8 hours. This morning the 3M masking tape did not lift the primer. That’s one in a row!!!
After my masking tape test I shot the primer with the SP Daylight Scheme orange stripe using TCP-107 SP Daylight Orange. They are predicting 107° today so as soon as my drying spot is in the sun I’ll cook it again.
I’ve temporarily hung the 3 pound hammer back on the tool board, wishful thinking.
