SAAC Forum

The Cars => 1968 Shelby GT350/500/500KR => Topic started by: shelbymann1970 on December 12, 2021, 10:48:39 AM

Title: SHOCK TOWER CAPS
Post by: shelbymann1970 on December 12, 2021, 10:48:39 AM
Here is something weird. While blasting these caps this was the end result. The caps are pretty nice but have what appears to be copper on them. At first I thought it was bondo but when I filed it it was metal. The areas on the one cap where I filed it is misleading as it looks white but it isn't. Any thoughts?  Gary
Title: Re: SHOCK TOWER CAPS
Post by: Bob Gaines on December 12, 2021, 11:29:41 AM
Washers are brazed on.
Title: Re: SHOCK TOWER CAPS
Post by: shelbymann1970 on December 12, 2021, 11:39:12 AM
Quote from: Bob Gaines on December 12, 2021, 11:29:41 AM
Washers are brazed on.
so someone got messy with the brazing?  Also they are in bare metal and those welded areas are definitely welding rod and not brazing rod.
Title: Re: SHOCK TOWER CAPS
Post by: Bob Gaines on December 12, 2021, 11:47:08 AM
They are not typicall brazed but I have seen a mess like that before on various years of what appear as unmolested cars.
Title: Re: SHOCK TOWER CAPS
Post by: shelbymann1970 on December 12, 2021, 01:10:26 PM
Quote from: Bob Gaines on December 12, 2021, 11:47:08 AM
They are not typicall brazed but I have seen a mess like that before on various years of what appear as unmolested cars.
Thanks. I do not know if the paint I blasted off was original on these caps but they are really nice sans the braze rod mess. Gary
Title: Re: SHOCK TOWER CAPS
Post by: shelbydoug on December 12, 2021, 01:15:12 PM
I too have seen them both was, brazed and welded. Welded seems to be more common.
Title: Re: SHOCK TOWER CAPS
Post by: 98SVT - was 06GT on December 12, 2021, 06:46:00 PM
Those look welded. The filler is the same color as the welding not gold as brass would be. I wonder if they had been chrome plated at one time which would account for the copper in the odd areas.
Title: Re: SHOCK TOWER CAPS
Post by: Coralsnake on December 12, 2021, 08:17:19 PM
Not weird or unusual. I have seen it on a dozen 1968s, I have restored over the years. I cant tell you the process, but since the caps get painted its not a big concern.
Title: Re: SHOCK TOWER CAPS
Post by: J_Speegle on December 12, 2021, 08:43:31 PM
Wonder if this is more of a 68 thing and possibly a different supplier since those were installed on the other side of the country
Title: Re: SHOCK TOWER CAPS
Post by: TLea on December 12, 2021, 11:11:35 PM
It's called oven brazing gents
Title: Re: SHOCK TOWER CAPS
Post by: shelbymann1970 on December 13, 2021, 11:00:15 AM
Thanks guys as I never saw that on my 70 caps for the 2 70s I had owned or my 68. When repainted they came out great. A nice set and they are pit free.
Title: Re: SHOCK TOWER CAPS
Post by: shelbydoug on December 13, 2021, 11:39:16 AM
Is there a reason to braze them rather then weld?
Title: Re: SHOCK TOWER CAPS
Post by: pbf777 on December 13, 2021, 11:41:39 AM
Quote from: TLea on December 12, 2021, 11:11:35 PM
It's called oven brazing gents


    In 'welding', this is the process whereby the parent materials are melted, and as witnessed in this case (but not always required) welding wire stock is added to the liquefied pool, forming a melded structure.

    In 'brazing', this is of a lesser heat involved process where the parent material is not intended to be liquefied but rather bonded with the use of particular "brazing-rod' materials.  Also one often will witness this brazing material about the periphery of the seam of the joined units, which here I don't see (maybe a better photo would aid in this observation) as I would expect, but?

    In the case of the pictured, I feel confident in saying there is a welding process presented, but is one saying that then, post welding, perhaps deemed insufficient, these assemblies incurred a further brazing effort; surly seems terribly in efficient?   :-\

    Scott.

   
Title: Re: SHOCK TOWER CAPS
Post by: KR Convertible on December 13, 2021, 01:31:53 PM
This is just a guess.  Is it possible that the threaded pieces were oven brazed.  The washers look welded.
Title: Re: SHOCK TOWER CAPS
Post by: Bob Gaines on December 13, 2021, 01:51:51 PM
Something to keep in mind is that the vast majority of the shelby shock tower caps do not so evidence of the brazing. My guess is that it was a fix for caps that didn't pass inspection for proper welding.
Title: Re: SHOCK TOWER CAPS
Post by: CharlesTurner on December 13, 2021, 02:32:00 PM
Quote from: KR Convertible on December 13, 2021, 01:31:53 PM
This is just a guess.  Is it possible that the threaded pieces were oven brazed.  The washers look welded.

I think those were spot welded.
Title: Re: SHOCK TOWER CAPS
Post by: shelbymann1970 on December 13, 2021, 03:09:49 PM
Quote from: CharlesTurner on December 13, 2021, 02:32:00 PM
Quote from: KR Convertible on December 13, 2021, 01:31:53 PM
This is just a guess.  Is it possible that the threaded pieces were oven brazed.  The washers look welded.

I think those were spot welded.
As a person who has welded for our die operations for a short window of time but have dealt with details being welded for over 40 years by my journeymen Tool and Die Welders I can say that these caps-like the ones on my 70- are welded as in a filler "like"  material was used and the washers with the filler material were liquified in the "bonding" process. You can see the edge burn off on the washers. One of the nuances when I learned to weld tool trim steels is to not have an edge burn off where the weld ends you still have an edge with the virgin steel. Too hot welding and stopping creates a melted edge on the virgin material right where you stopped. Why I usually tig welded and not arc or mig. In todays environment we are going towards laser welding and hardening for our tool and die operations. We will get a new machine in our facility by next summer. Again I'm not an expert welder but one who knows enough to be dangerous and honestly have never seen the process of brazing like has been mentioned by PBF777  :) :) :)
Title: Re: SHOCK TOWER CAPS
Post by: gt350shelb on December 13, 2021, 06:49:13 PM
looks just like mine
Title: Re: SHOCK TOWER CAPS
Post by: pbf777 on December 13, 2021, 06:51:46 PM
Quote from: Bob Gaines on December 13, 2021, 01:51:51 PM
My guess is that it was a fix for caps that didn't pass inspection for proper welding.

   Possible, but it would seem odd to have components in original engineering outline to be welded, with the caveat that if these pieces should fail Q.C. then a brazing operation would be incurred as a suitable 'fix' substitution? :-\

   My experience in the past with F.M.C. is that they would have just tossed them out!  But now, if this had been Chrysler, well............ ::)

   And I'm not saying what is or was, but rather inquiring only on the if. ???

   Scott.
Title: Re: SHOCK TOWER CAPS
Post by: tgilliam on December 14, 2021, 02:14:21 PM
Having a bit of experience in manufacturing and fabrication I believe it is possible the "copper colored" spots on the OP's caps may be due to a fixture to hold the caps and washers for welding. The contact points for the fixture may have been copper in order to ground the part. The appearance could be influenced (more or less noticeable) due to too high a temperature setting on the welder. Basically, during the welding some of the copper was transferred to the part due to current flow. I have seen similar type results on other parts (not automotive) that were machine welded.
Just my two cents.

Tom Gilliam
(270) 755 - 6417
Title: Re: SHOCK TOWER CAPS
Post by: Coralsnake on December 14, 2021, 02:23:32 PM
Thank you Tom, I enjoy reading constructive and educational information.
Title: Re: SHOCK TOWER CAPS
Post by: shelbymann1970 on December 15, 2021, 11:21:50 AM
Quote from: gt350shelb on December 13, 2021, 06:49:13 PM
looks just like mine
Mine had a hint of blue paint on one like yours does.
Title: Re: SHOCK TOWER CAPS
Post by: shelbymann1970 on December 15, 2021, 11:25:04 AM
Quote from: tgilliam on December 14, 2021, 02:14:21 PM
Having a bit of experience in manufacturing and fabrication I believe it is possible the "copper colored" spots on the OP's caps may be due to a fixture to hold the caps and washers for welding. The contact points for the fixture may have been copper in order to ground the part. The appearance could be influenced (more or less noticeable) due to too high a temperature setting on the welder. Basically, during the welding some of the copper was transferred to the part due to current flow. I have seen similar type results on other parts (not automotive) that were machine welded.
Just my two cents.

Tom Gilliam
(270) 755 - 6417
Thanks for your expertise Tom. That makes total sense now.  I have used copper before to use as a "base" for welding up broken off surfaces on cast iron dies. I also have used copper plates as a base for welding(grounding) as the regular tables(beat up and such I have seen the parts on them "arc" and leave the surface with a "prick punch" like surface if that makes sense. I have also used copper for filling in holes in parts like when I make 68 BB frame mounts from 68-70 SB frame mounts.  :)  Gary
Title: Re: SHOCK TOWER CAPS
Post by: gt350shelb on December 15, 2021, 09:56:33 PM
Quote from: shelbymann1970 on December 15, 2021, 11:21:50 AM
Quote from: gt350shelb on December 13, 2021, 06:49:13 PM
looks just like mine
Mine had a hint of blue paint on one like yours does.

I remember when i bought the car the brackets were bare metal and the paint daub was visible the copper was very  visible then . on a side note there is not black paint under  the blue ....... granted this may just  be weird early car thing . but they may never have been painted black originally on  my car  .
Title: Re: SHOCK TOWER CAPS
Post by: pbf777 on December 16, 2021, 01:15:43 PM
Quote from: tgilliam on December 14, 2021, 02:14:21 PM
..............it is possible the "copper colored" spots on the OP's caps may be due to a fixture to hold the caps and washers for welding. The contact points for the fixture may have been copper in order to ground the part. The appearance could be influenced (more or less noticeable) due to too high a temperature setting on the welder. Basically, during the welding some of the copper was transferred to the part due to current flow.

     Seems a reasonable argument, particularly in the O.P. photos presenting "spots" of copper deposited, but in the second examples (post #17)?  In either instance the required welding execution was of the relatively small and limited area of what I would say are tack-welds; these requiring somewhat short duration application of current, and realizing the the potential heat required to heat the steel and melt and flow the copper particularly the sum in the second example..........well, I just don't see the current load in these tack-welds as being sufficient.    ???

     Of course in this discussion we have 'assumed' that the discoloration is 'copper', sure looks like it, but............ :-\

     But if all is so, then it surly was a F.U. execution!   ::)

     Scott.
Title: Re: SHOCK TOWER CAPS
Post by: Bob Gaines on December 16, 2021, 01:27:46 PM
Quote from: gt350shelb on December 15, 2021, 09:56:33 PM
Quote from: shelbymann1970 on December 15, 2021, 11:21:50 AM
Quote from: gt350shelb on December 13, 2021, 06:49:13 PM
looks just like mine
Mine had a hint of blue paint on one like yours does.

I remember when i bought the car the brackets were bare metal and the paint daub was visible the copper was very  visible then . on a side note there is not black paint under  the blue ....... granted this may just  be weird early car thing . but they may never have been painted black originally on  my car  .
The current conscience is that the brackets with the reinforements were painted black while the non reinforced brackets were not painted (Dearborn,Metuchen ) because if not painted the welding would flash rust in short order. Regardless finding a original reinforced bracket originally unpainted is likely not a wierd early thing . Most likely it is in the weird anomoly catagory.