The Ford Barn

fourfords · 03-10-2025, 04:17 AM

I have a '28 Double Venturi Zenith bowl in very bad shape. Casting is good, brass parts are almost welded in place. What is the best technique to loosen up these brass parts?

Joe K · 03-10-2025, 08:28 AM

In general, electrolytic rust removal would be my "go-to" in matters like this.

Cast iron responds VERY well to electrolysis. Copper bearing alloys are more resistant to the bath so these should be fine.

One thinks of the zinc "sacrificial anode" used on boat propellers - and the electrochemical series. Cast iron is below bronze is what makes this so.

Electrolytic is noted for "loosening up parts" which I do a lot on the more complex Model A assemblies. I've even used it on an engine block which I resolved I didn't care if it loosened the babbitt since it was going to be rebabbitted anyway. Final result - it didn't touch the babbitt that I can tell. But the rest of the block was clean for painting.

A good write up with pictures is at https://www.instructables.com/Electr...val-aka-Magic/

He uses "washing soda", but I use regular "Lye" which is otherwise known as Sodium Hydroxide, or "Crystal Lye Drain Cleaner" on Amazon. Its VERY cheap and probably more available than washing soda. And you use "less" of the chemical. After placing or reattaching parts in the bath (electrolysis shut off) your hands come out VERY clean. You'll know your hands are in the bath from your small cuts, but if you wash off quickly there will be no damage done.

DON'T use "Draino." Draino is like 96 percent sodium hydroxide, but contains aluminum powder which is designed to react with the sodium hydroxide to create HEAT, which helps the de-grease in pipes, but COULD be hazardous to your person unconfined.

After electrolysis, to neutralize the caustic and catch any "rust bloom" I use Phosphoric Acid which used to be sold as "Prep & Etch." The same company now sells it as "Concrete and Metal Preparation" as it is used for both, and is the same stuff. Available at the big box hardware stores.

Joe K

johnbuckley · 03-10-2025, 11:40 AM

I usually soak it in cellulose thinners for 24 hours, if that doesn't do it then I use heat with a gun ( propane/actylene mix canisters are available over here)

Gary WA · 03-10-2025, 08:02 PM

Quote:

Originally Posted by fourfords

I have a '28 Double Venturi Zenith bowl in very bad shape. Casting is good, brass parts are almost welded in place. What is the best technique to loosen up these brass parts?

I clean all excess materials then Heat jets screws ect really hot, Propane is not hot enough hit with cold water and remove jets screws etc- may have to do it a couple of times then bead blast.Send it to me i will clean it up just for postage..

Gene F · 03-10-2025, 08:07 PM

Sponsored Links (Register now to hide all advertisements)

And heavy rubber gloves, not surgical gloves (Harbor Freight sandblasting gloves???), and safety glasses!!!!!!!!!!!!!!!!! Have a garden hose handy, as water is your go-to in an accident involving people.

No Draino!!!!!!!!!!

03-10-2025, 08:28 AM	#2
Joe K Senior Member Join Date: Jul 2010 Location: Cow Hampshire Posts: 4,611	Re: 1928 Double Venturi bowl In general, electrolytic rust removal would be my "go-to" in matters like this. Cast iron responds VERY well to electrolysis. Copper bearing alloys are more resistant to the bath so these should be fine. One thinks of the zinc "sacrificial anode" used on boat propellers - and the electrochemical series. Cast iron is below bronze is what makes this so. Electrolytic is noted for "loosening up parts" which I do a lot on the more complex Model A assemblies. I've even used it on an engine block which I resolved I didn't care if it loosened the babbitt since it was going to be rebabbitted anyway. Final result - it didn't touch the babbitt that I can tell. But the rest of the block was clean for painting. A good write up with pictures is at https://www.instructables.com/Electr...val-aka-Magic/ He uses "washing soda", but I use regular "Lye" which is otherwise known as Sodium Hydroxide, or "Crystal Lye Drain Cleaner" on Amazon. Its VERY cheap and probably more available than washing soda. And you use "less" of the chemical. After placing or reattaching parts in the bath (electrolysis shut off) your hands come out VERY clean. You'll know your hands are in the bath from your small cuts, but if you wash off quickly there will be no damage done. DON'T use "Draino." Draino is like 96 percent sodium hydroxide, but contains aluminum powder which is designed to react with the sodium hydroxide to create HEAT, which helps the de-grease in pipes, but COULD be hazardous to your person unconfined. After electrolysis, to neutralize the caustic and catch any "rust bloom" I use Phosphoric Acid which used to be sold as "Prep & Etch." The same company now sells it as "Concrete and Metal Preparation" as it is used for both, and is the same stuff. Available at the big box hardware stores. Joe K __________________ Shudda kept the horse. Last edited by Joe K; 03-10-2025 at 08:42 AM.

03-10-2025, 11:40 AM	#3
johnbuckley Senior Member Join Date: Jul 2010 Location: United Kingdom Posts: 1,557	Re: 1928 Double Venturi bowl I usually soak it in cellulose thinners for 24 hours, if that doesn't do it then I use heat with a gun ( propane/actylene mix canisters are available over here)

03-10-2025, 08:07 PM	#5
Gene F Senior Member Join Date: Mar 2012 Location: Ohio Posts: 2,476	Re: 1928 Double Venturi bowl Sponsored Links (Register now to hide all advertisements) And heavy rubber gloves, not surgical gloves (Harbor Freight sandblasting gloves???), and safety glasses!!!!!!!!!!!!!!!!! Have a garden hose handy, as water is your go-to in an accident involving people. No Draino!!!!!!!!!!