Age Cracks in Headlight Door/Surround 1928 Cadillac

[Ken Andersen # 21420]

I have discovered that I have several age cracks in the headlight door/surround of my 1928 Cadillac headlights. Can anyone advise what is the best method of fixing this problem permanantly.

[Porter 21919]

Ken,

I feel bad for you because the 1928 Cadillacs are so rare that not many forum members contribute to your questions.

Whta is the composition of the part in question with the stress cracks ?

Porter

[JIM CLC # 15000]

05-30-05
Ken, hope you answer Porters question about "what the part is made-of.
Assuming its made of sheet metal. Can it be re-enforced with patches welded over the cracks? If it is sheet-matel, a good "gray-haired" body man can make you one/some.
If it is "pot-metal". Go to a "county-fair", there is always some-one there selling welding rods that will wild-up any thing, but, "the crack-of drawn & a broken-heart".
All kidn aside, they claim it is very good on alunimun & pot metal. They will demo. for you> Could be that you could the person weld your part as part of his demo.
Either way, Good Luck, Jim

[Wayne Womble]

I am not familiar with the 28, but if it is like the `31, it is  brass. It is a very common occurence for them to split. Parts like this are work hardened when made and then with age and stresses they crack. They can be soldered up and replated with good success, but you should check with your plater. He will probably want to make the repairs himself so he will use the correct type solder.

[Ken Andersen # 21420]

Hi Porter, Jim & Wayne,
Firstly many thanks for your replies.  The item is the rim or door as they call it in the parts manual. It does not look as if it is brass, but rather sheet metal. It is that part that the headlight lens sits into.  Behind the "rim" or door there is an internal expansion ring which  is removable, and it looks like the expansion ring does two things. It helps to keep the shape of the outer "rim" or door, but also gives it rigidity. It is quite difficult to remove this expansion ring, and once removed, the age cracks actually close up to almost nothing.  I do believe that the cracks can be fixed by either solder or welding.  Would you first file out the crack, in order to clean it up to accept the new solder or welding medium?  Should this be performed with the expansion ring removed or in place? Should the solder and weld be performed on both side? These are but a few of the questions. I do have another set of headlights (not for Cadillac) that have the same problem so I would be able to use these as a "test" to see which method (which ever) is the best option.
Thanks again.

[Johan Boltendal # 158]

As said already, better leave it to the chrome guy, he will
be familiar with the problem, all head lamps this age have the problem. They will be repaired with the expansion ring not in place, when heated for repair, they will deform with the ring in place, you already noticed the split almost disappeared with the expansion ring out.
If you tackle it your self you might come into trouble with the chroming process afterwards.I would strongly advise to talk to the chrome guy first , good luck Johan

[Matt Mersereau]

If in fact they are constructed of sheet metal (steel) and not sheet brass, yes, you will want to remove the cracks prior to welding them up. I used to weld engine parts for a major airline before I bid into the NDT department. If you try to weld over the cracks without removing them first, chances are good that you will just chase the crack into a previously uncracked area of the part. It has been my experience that the older the part, the more likely it is that this will occur. I would use an abrasive cutting disk on a Dremmel type rotary tool if the part and the cracks are relatively small. You must use the TIG welding process for repairs like this as it offers a much higher level of control, and is much more precise than any other welding method. A good welder will leave you with very little blending to do prior to refinishing or replating the part. You really dont want to grind down a bird turd looking glob of weld from a semi-delicate part as this will surely warp said part.

If they are sheet brass, just stop-drill the ends of the cracks, solder them up, and blend to the original contour.

[Wayne Womble]

A simple test with a magnet will tell you if it is steel.

[Ken Andersen]

Many thanks guys for your wise words of wisdom.  I will now be able to take it to the next step and make some enquiries with both panel beaters, electroplaters etc.  Again many thanks.