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Correct mid 20's Buick rear window detail


Hubert_25-25

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One of the welders took a shot at doing a tack weld.  The first one went well, but dropped a lot of material.  On the second, it bent the tube a little and almost vaporized the rivnut.  I really like the spot weld idea, but the welder did not want to try it.  He likes to talk more than work which was part of the problem.  He did suggest 3m panel bond 08214.  This is a 2 part Urethane.  It really sticks.   Unlike JB weld, it stays semi-flexible.  I have JB weld here, so going to try it next.  The 3M material comes in a larger tube than I really need.   $47 for the 3m tube, and $60 for the gun - yikes.      Hugh

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Edited by Hubert_25-25 (see edit history)
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I can understand the ease of gluing, but would want to make sure that the frame doesn't end up falling off and getting run over by the other Buick behind you.

 

A stud welder is not a tack weld, the stud is put in place being held by the welder snout, pull the trigger and pfffft the stud is welded to base.

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I could not find anyone that would spot weld the rivet nuts to the frame.  They all had excuses - like saying they never used a spot welder with stainless steel.  I did try JB weld.  They took a little effort, but did pull out of the test piece, so I do not recommend using it for this application.

Drill and Tap - I did drill a hole and use a 3mm tap.  This requires a regular tap and a bottom tap.  The hole drilled and tapped with little issue.  I used tape on the drill to ensure I did not drill too deep.  I felt if I drilled thru, the Tig welder could fix it easily and it would file out and polish out and be un-noticible.  A short piece of all thread and a nut and washer would work.  A recommended option.

Silver Solder - I drilled all the 19/64" locating holes by .030 deep.  I put a slight grind on the bottom and sides of the rivnuts for adhesion.  I put flux between the parts and used 2 pieces of galvanized wire to secure the rivnut.  Having never really tried this before,  I appreciate the recommendation on what to use to solder.  I used the "white stay silv" flux and "safety silv 56" 56318LMPOP (uncoated 5 sticks per box).  I followed directions to not overheat the flux.  The silver solder flowed in beautifully.  Using a hammer later to pull them out, I can bend the metal.  A recommended option.  

I thought this brazing video was helpful     https://www.youtube.com/watch?v=no-OWfC5-RY

I plan to use 3M strip caulk to seal around each stud when attaching to the canvas to prevent any water intrusion.    Hugh

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Edited by Hubert_25-25 (see edit history)
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Thanks for posting that video. That is one of the best ones I have seen. Here is another one I like:

 

https://www.youtube.com/watch?v=kIKQ-FL96uU

 

There was once a video showing that on something round, you can form the hard solder into a ring, pre-flux the parts, and just lay the ring in place and heat the base material up. Here is a video showing someone doing that, but in this video he is using soft low-temperature "silver bearing" solder, like you might use on plumbing. Still, it illustrates the technique.

 

https://www.youtube.com/watch?v=EzRQpKVSrbg

 

Another trick is to use Milk of Magnesia as a "resist" coating to keep the silver solder from going somewhere you don't want it to.

 

Cant wait to see that window frame all polished up!

 

 

 

Edited by Bloo (see edit history)
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I was reminded to remove all the excess flux as it can cause problems down the road, so I used emery cloth and sanded around all the rivnuts.  The rivnuts that I used were 3mm x.5.  After silver soldering, some of the solder in a few places had climbed up into the threads and on 4 locations, the hold down wire would not come out of the hole.  A little too much hook on the wire in the hole did not help.  Best to just heat the rivnut tube section and not the base, and the wire will come right out.  I did have to order a regular and a bottom tap to clean out the threads on atleast 1/2 of the holes.   In a couple spots I used a 3/32 drill bit first to remove any excess solder in the hole.  On the last hole I broke a tap so I just broke the threaded part of the rivnut off (they really are held in well) and I drilled the rivnut out and silver soldered a new one in.  You just have to go slow and easy on these little taps. 

Next job was polishing the stainless on my buffing wheel.  Then I got to trade my safety glasses for sun glasses.     Hugh

 

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On 3/4/2020 at 12:51 AM, Hubert_25-25 said:

I was reminded to remove all the excess flux as it can cause problems down the road, so I used emery cloth and sanded around all the rivnuts.  The rivnuts that I used were 3mm x.5.  After silver soldering, some of the solder in a few places had climbed up into the threads and on 4 locations, the hold down wire would not come out of the hole.  A little too much hook on the wire in the hole did not help.  Best to just heat the rivnut tube section and not the base, and the wire will come right out.  I did have to order a regular and a bottom tap to clean out the threads on atleast 1/2 of the holes.   In a couple spots I used a 3/32 drill bit first to remove any excess solder in the hole.  On the last hole I broke a tap so I just broke the threaded part of the rivnut off (they really are held in well) and I drilled the rivnut out and silver soldered a new one in.  You just have to go slow and easy on these little taps. 

Next job was polishing the stainless on my buffing wheel.  Then I got to trade my safety glasses for sun glasses.     Hugh

 

 IMG_0060.thumb.JPG.9ed5df022a1044af7dfaa8ca3e773527.JPG

 

Great work Hugh, when do you start taking orders for these?  ;D

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Don, 

     At this point, I need to finish the rest of the top installation before I consider doing another.  That said, I did make my bending jig where I can substitute different diameter wheels and make regular rectangular frames or D shaped frames.  I do have a couple other frames that I started but I need to correct them and see about selling them.  It will take me less time to correct them than starting over.  These are also not easy to make and it requires 2 people to bend them.  One to heat and one to tighten in the vise.  Hoping that my vise holds out in the process.  

I do not believe anyone makes these frames with the wood on the inside as they were made originally.     Hugh  

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  • 2 weeks later...

There is also a wood frame on the inside of the back window.  This is a 1" tall border of wood and this creates a 3/4" backing outside the metal frame and provides a connection for the 3 1/2" wide jute support straps as the window is heavy being glass with a metal border.  The wood is 5/8" (16mm) thick and I am making this frame from baltic birch marine grade plywood that was sealed with clear penetrating epoxy sealer.  I also had a local engraver use the dimensions below of the Johnston logo,  and they were able to replicate and engrave a sample on a piece of half round stainless.          

Img_8926s.thumb.JPG.5112b076ff28475d0411392ab7b15cec.JPG1390127738_Johnstonlogodimensions.thumb.JPG.88c2bc21c8ff036fc6dfd9867eb91ffe.JPGIMG_8929.thumb.JPG.8c35e289a36b12ab3e80f10912186c05.JPG

 

Edited by Hubert_25-25 (see edit history)
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Great work Hugh!

 I did not see how they have my oval Johnston attached.  Don't feel like taking off the inner curtain until I am sure I can get my top sockets. With the supports documentation you sent I understand since the assembly is quite heavy. The wood frames I showed you when you were at my place are of light Basswood. DSCF5831.thumb.JPG.4726a2dfdff31cbc596881276b9632d0.JPG

The original glass and diecast frame will probably not be as heavy as what you are putting together. The Basswood would have been used so the finishing tacks can be driven into it easily.

 The inner curtain of my friend's original 1927 Sport roadster.

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Edited by dibarlaw
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Larry, 

 Thank you.   I have been editing this diagram some but I want to post it so that you have the entire picture of how this back window is assembled and attached.  I agree with you not to pull yours apart until you are ready to build the frame.  This is from the original top and frame that Brian Meek sent me.  Brian is a lifesaver with this, and I am able to get all the information I need without disassembling this old top and window.   What he sent is fascinating that I am able to see all the original construction details.   I also thought that the glass was held between the wood and the frame, but it is not.  The glass is held in by the tack strip that uses nails (instead of tacks) that is covered in bowdrill - so that you can change the glass out if necessary.    The 3M strip caulk is my idea.  I don't think they were too concerned if it leaked a little bit because I saw no traces of any sealant.  3M strip caulk is non hardening and black.    Hugh

 

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Edited by Hubert_25-25 (see edit history)
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  • 1 month later...

Finally got my car out

 

Here is the window frame I bought last year from Wayne Funk

 

Wayne stressed the importance of the 4 D rings and straps to carry the weight of the glass and frame. 
 

Believe when my current top was done they used Model T rear windows. 
 

So when I sell a kidney to get my top replaced down the road this one will get cleaned up and used. 

287009A1-1784-4EA9-BDEF-B1BB27B940F3.jpeg

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Brian, 

     Relacement window frames came from several manufacturers.  The replacements had an additional metal frame inside the back curtain and eliminated the original wood frame.  You are correct that these absolutely need the straps to support the back glass.  These glass and frames are very heavy.  I have an original Johnston frame with glass that has never been disassembled and is similar in size to my frame.   It weights 4 lbs 5 oz.  The stainless frame with glass and wood weighs 5 lbs 15.6 oz.   4 to 6 lbs would be a lot of weight to hang on the top fabric alone.  The manufacturers tried to not put a lot of stress on the top fabric.  That is why the top has pads under it as well.  It is supposed to take some of the load off the top fabric.          Hugh

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  • 2 months later...

I will add to the convertible top thread when I get caught up on my notes regarding making the "back curtain", but I was able to finish all the back curtain sewing and installing the back window in it this weekend.  I still have to tack the back curtain to the car and install the snap fasteners.  This is how you assemble a wood framed Johnston rear window in a Buick.  Hugh

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Edited by Hubert_25-25 (see edit history)
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