Restoration of Civil War era iron cemetery fence

A. Hi, Paul. There is a technique that I have heard of from time to time over the decades, but I have never seen it and never read an authoritative paper about it. It is called, I believe, electrolytic restoration or reverse hydrolysis. The theory is that the material has rusted due to electromotive forces and if you overcome them and reverse them, you can convert the rust back to metal. Theoretically and ideally, the metal forms again from the rust at the exact point where it originally was. For bronze artifacts in seawater it works great.

I'm sure that it can't really work well in your case because some of the rust has run down the drain, and mechanical forces and movement has displaced some of the corrosion products, but it is the only thing I can think of that has a prayer of partially restoring the fence. For a very light and non-scientific coverage of the process, Randy Wayne White's outstanding novel "Dark Light" includes scenes of the protagonist practicing this procedure on some artifacts.

Hopefully one of our readers can point you to a paper on the subject, and advise whether it has any merit on iron.

Regards,

A. Don't use acid. It will remove the rust but the rust will start in again within three minutes of removing it from the acid bath.

Unbolt the corroded fence panels, and strip the paint, using a gel type/methylene chloride stripper. Wire brush off the loose rust. Then, do your bondo work.

Now, give it a treatment with a nice phosphate wash primer, and repaint.

A. One answer is to contact an on-site powder coating company. As this new process is used more in the USA than most other countries you should have no problems in locating one.
They should be able to offer shot blasting to remove the rust, fill with polyester filler damaged areas and then coat using either a thermoplastic or thermosetting (new) primer followed by powder top coat. The principle is to apply the powder using flame technology. The finish is not as smooth as standard powder coating but is ideal for your situation. It could be quite costly as it is very slow application process, but should offer another >20 years life span.

A. The rules concerning lead are strict and just became tighter. I would have a paint shop that knows the procedure do the work. Removing to their shop makes sense.

Consider Chloride removal because the surface must be contaminated.

No need to mix metal into the epoxy. Today's epoxy will expand/contract with the iron.

Let me know if I can advise more.
Regards

A. Sorry, Paul, all I have on this is heresay and one or two lines from Charles Faust's ASM "Electroplating Course". I agree that it sounds like it would work better on small items than large. I also assume it would work better on non-ferrous items, where the corrosion products are relatively stable, than for an iron fence where some of the rust has washed away. I only mention it because if you are determined enough to restore it that you are willing to experiment, that's one area for experimentation. Good luck.

Regards,

A. OSHA says:
http://www.osha.gov/SLTC/methylenechloride/
MSDS:
http://www.jtbaker.com/msds/englishhtml/M4420.htm

Regards

A. That is a job for a professional metal conservator -- try AIC (American Institute of Conservation) website; there you can you find a list of certified metal conservators. Hope it helps and good luck!

A. You could also try a product called Peel Away [affil links]

It's a Mg(OH)2/Ca(OH)2/NaOH paste. It is caustic, but gives off no fumes. You apply it, cover it with a paper that they provide, leave it for 12 - 24 hours, then scrape it, and the removed paint, off.

It's lots more labor intensive than methylene chloride type products but more environmentally friendly.

A. The most simple process is to take the fence sections to a company which does stripping of auto bodies for restoration. They use alkaline processes which remove all rust and old paint, but which do not attack sound metal. This will give you nice clean metal ready for priming and paint.

Bondo on an historic restoration? Horrors! After stripping, have the badly rusted sections cut out and new metal welded in, then a coat of good quality primer and several coats of good quality color.

Done right, and with proper maintenance, your restoration will last another 100 years.

If you use Bondo, It'll be junk in 25.

A. Try
cool-palimpsest.stanford.edu/byform/mailing-lists/cdl/2002/1478.html
For conservation.
Then a good quality paint job

I'm glad to see all the responses since I last checked this thread. I just wanted to thank everyone who posted a response. All of the advice has been a great help to me. Thanks, again.

A. As a custom ornamental metal fabricator I have researched this matter in an attempt to win some of this restoration work.
The lead is the greatest concern initially. The awarded firm must engage a Certified Industrial Hygienist (CIH) up front and submit to them for approval a comprehensive plan for eliminating the lead based paint hazards from start to finish.
Soil testing must occur prior to doing any work to establish a benchmark level to measure the amount of existing lead, and the remaining lead paint which still hangs on the fence must be encapsulated. A painting contractor needs to seal coat it in a shellac or sprayed wax or other simple sticky coating before the fence is handled.
Then the panels can be removed to a location where they can be dipped into a chemical stripper. The waste from this process has to be documented and disposed of with manifest provided to a federally controlled Hazardous waste dump site. (Federal Regulations on this too but your consultant will help you) FYI, it costs about $550 per 55 gal. drum to dispose of this kind of waste.
Finally, now with the paint, stripper, tainted gloves and rags and lead gone (and the consultant now too), the restoration work and refinishing work can begin. Follow standard finishing practices here (epoxies and urethanes etc). Galvanizing may be possible and especially helpful in humid and or salt air environments.
The posts which remain on site must be stripped on site and waste disposed of properly. Do everything possible NOT to atomize or disrupt a crusty finish which contains lead. Blasting is the LAST thing you want to do. Once stripped they should be primed immediately if not painted.
There is more to be discussed in terms of restoration or replication, when is the product too corroded to repair, how joinery affects the final finish, (welding vs bolting) handling the product in the field and in transit and touch up on site (paint vs. powder) not to mention what the problems are associated with using modern steel in place of wrought iron which are two different alloys and wrought iron weathers better but that starts to have less to do with finishing and more to do with fabrication.
Thanks,

Hi Doug. Thanks for the exposition proving that when we demand zero risk, zero can be produced.
We may fool ourselves that we can do it if we just spend enough money on it -- but then we remember that actual money is the product of production, so society can't buy its way out of such knots :-)

Regards,

A. Go to vintage metal, inc. website and you can learn a lot from this company. Call people who have already done historical restoration work and "pick" their brains.

Hi folks. I now see this book on Amazon .

I don't have a copy and haven't read it, but Amazon's "Look Inside" feature reveals that it seems to cover the subject in exhaustive depth. Good luck.

Regards,