Topic: Ford 2100/4100 Carburetor Body & Cover Cleaning

[Countrysquire]

I recently rebuilt the 2100 carburetor on my son's 1970 Bronco.  After vapor blasting the body, I gave it a soak in the heated ultrasonic cleaner with a 30:1 solution of water and Simple Green Extreme Aircraft Precision cleaner.  This darkened the surface a bit and brought out the color of the parts.  Carburetor bodies seem a little too bright to my eyes after vapor blasting, but don't know how they looked when they left the factory in ~1965 before much oxidation had coated the surface.  Morsel has a 4100 coming my way, so I'll post some pics before and after the soak to solicit some expert opinions.

I do have a friend here in the Houston area who is in the dry ice blasting business and I know he would be happy to do a sample for any of you if you wanted to send him (or me) a part to test.  It is an amazing process and works incredibly well on undercarriages.  He just did the '70 Bronco for us, removing the undercoating to reveal (mostly) beautiful factory red oxide primer and Harbor Blue overspray.  One thing that I did notice is that it did not do a good job cleaning the porous sand cast aluminum alternator housing, but I think it will work well on a die cast part.

[Dan Case]

I recently rebuilt the 2100 carburetor on my son's 1970 Bronco.  After vapor blasting the body, I gave it a soak in the heated ultrasonic cleaner with a 30:1 solution of water and Simple Green Extreme Aircraft Precision cleaner.  This darkened the surface a bit and brought out the color of the parts.  Carburetor bodies seem a little too bright to my eyes after vapor blasting, but don't know how they looked when they left the factory in ~1965 before much oxidation had coated the surface.  Morsel has a 4100 coming my way, so I'll post some pics before and after the soak to solicit some expert opinions.

I do have a friend here in the Houston area who is in the dry ice blasting business and I know he would be happy to do a sample for any of you if you wanted to send him (or me) a part to test.  It is an amazing process and works incredibly well on undercarriages.  He just did the '70 Bronco for us, removing the undercoating to reveal (mostly) beautiful factory red oxide primer and Harbor Blue overspray.  One thing that I did notice is that it did not do a good job cleaning the porous sand cast aluminum alternator housing, but I think it will work well on a die cast part.

Pretty bright but not mono-tone.  The process was used during  the 1950s and 1960s for 2100/4100 body and top castings.



All kinds of microscopic and larger visible artifacts of the die casting process leave various surface textures and shades of color, for lack of a better description, all over. Large flat areas can exhibit varying degrees of visual iridescence created by molten aluminum running over the surfaces of the mold.   Castings also exhibit edges of broken off casting flash and drag lines created as the newly solidified part was ejected from the mold.  I have endeavored since the late 1970s to preserve as many as manufactured details as I can on not only die cast aluminum carburetor parts but other Ford die cast aluminum parts that were not originally given secondary operations to produce something besides as cast surfaces.


I just rendered a 4100 carburetor into usable parts. I have not done any cleaning of the body so it would be good for a dry ice blasting test case. I believe you have my email if you care to get something set up for a trial.

Dan

PS The other potential non-destructive method is laser cleaning. If it removes aluminum oxide and does not etch the parent aluminum that method could be interesting but requires another very expensive set of equipment.

[Countrysquire]

Email sent Dan.

Thanks,
Bobby

[Dan Case]

Update 01-21-2022. I will send an as last used dirty 4100 main body to Bobby for a dry ice blast cleaning experiment. I suggested that half the body be cleaned and half left dirty as an exhibit of before and after cleaning conditions.
Dan

[Dan Case]

Update on dry ice blasting experiment.

Bobby Crumpley arranged a dry ice blasting test cleaning job for me. The sample was a Ford 4100-A carburetor main body. I dismantled a carburetor and did no cleaning of the body in any way. The carburetor core was an extra nice one that had no signs of every being chemically or mechanically cleaned before. 

The experiment was to dry ice blast one end of the body and leave the other as received. The results were not as dramatic as I had hoped.

The cleaned areas came out looking like just manufactured everywhere the aluminum was protected from corrosion. Protection could be by a complete gasket seal of a surface, oily grime, tight fit like screw threads, and or fuel varnish. The economy valve boss looks like just machined where the ring gasket for the valve and the valve protected it. The black pressed paper gasket Ford used apparent took up water and allowed the dark gray corrosion film to form on the rest of the machined face.  The dry ice blasting did not remove the rough feeling gray corrosion products.


The yellow and violet blue iridescence left over from the original manufacturing process was not disturbed by the dry ice blasting and locations projected by grime cleaned up well.  Most "cleaning" methods would remove the iridescence.  None of the tiny surface defects from tool marks and molten metal flow lines were changed in any way.



Right side,  all areas with no protection from corrosion darkened in use and are still dark in dry ice blasted areas. Any surfaces protected from corrosion looks very much like they were freshly made and are much easier to see in person.


The experiment was not a total disappointment.  In the past I have tried some kinds of mineral acids and bases to try and remove the dark corrosion byproducts on die cast aluminum carburetor parts without success. Some do little or nothing and some darken everything it touches more.  So the hunt for a great cleaning method continues.