Other resources

There is a group on Facebook called Brass Model Paint and Repair.  The entire group is focused on Painting and repairing Brass Locomotives (makes sense to name it that) but one of the other chemicals suggested is Aircraft remover, no ultrasonic cleaner needed.

Ventilation is the biggest concern

I have several pieces waiting for lacquer thinner but I have not yet set up a strong ventilation system. Ultrasonic cleaners do not spark; they do add energy and the liquids are slightly more volatile, which means more foul fumes.

In the video they cleverly use a tall glass cylinder to contain long, thin locomotive bodies, it is simply set into more fluid, probably water, in the ultrasonic cleaner.  It is not easy to find a long cleaner within my price range, the glass cylinder is a good solution.  Until I have many brass pieces to strip and paint, I will continue to use a pan and scrub brush.

Only water in ultrasonic cleaners

Only put water or water based cleaners in an ultrasonic cleaner.  To use a solvent put it in a separate container inside the bath like a Pyrex glass container.  Ultrasonic cleaners are used routinely in chemistry labs as an aid to dissolving various materials.  The ultrasonic "action" readily transmits to the contents of the glass container.

Robert

Cleaning solvents

And I know of at least one very good brass rebuilder who uses Jasco paint remover to clean brass models, and the only drawback is that it also dissolves any epoxy that might have been used to make repairs or attach small parts, so he has to carefully make sure that everything gets found when he removes the model from the solvent.  But the brass is clean!  Putting it into a big enough Pyrex dish, and then putting the dish into the ultrasonic cleaner, sounds like a great idea.  Motors, of course, shouldn't be cleaned this way, but he usually re-motors everything anyway.  Remember, if it isn't metal, it's gone!

Fire

The ultrasonic cleaner will atomize an already volatile fluid.  Do Not do indoors.  ANY spark source (static, furnace, light switch, etc) could (would?) ignite the fumes.

Use only outdoors.  Those chemistry labs have hood fume enclosures that draw out any fumes.

stripping clear coat and paint

Another method is to boil the brass model in a solution of sodium carbonate (washing soda). Washing soda is available from Walmart or Amazon online; you generally won't find it in stores (although it's an ingredient in most laundry detergents).  About a cup of soda in 1/2 gallon of water, in a pot large enough to hold the brass parts, and boil for 2-3 hours.  You can also use baking soda (sodium bicarbonate), but you'll need twice as much because half the bicarbonate boils off as CO2 and water (leaving a solution of NaCO3). No dangerous fumes. The paint flakes off, but may still require scrubbing in detail areas. You can pour the liquid down the sink, but catch the paint flakes in a sieve. Sometimes you need to do it twice, possibly in a stronger solution of soda.

Downside is that bad solder joints may come loose, as well as glued/epoxied joints. Bad solder joints are easy to re-solder, so not really a downside.

DO NOT boil any wheels or any plastic or fiber parts or electrical parts. DO NOT use the pot for cooking food anymore!

This also works for painted household hardware such as hinges, doorknobs.

J. Gerritsen

FYI - Washing Soda

We have it available at Meijer in the laundry detergent aisle. We use it to make homemade detergent.