What is that putty on windshield pinch weld

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spankster

spankster

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What is that putty that is used on the pinch weld window frame? Seems it smooths out the rough imperfections on the pinch weld. It's white, painted over and been there for 45 years. Replacing front and rear windshields. Do I need to replace this putty stuff when I install new gaskets?
If so, where can I buy it? Thanks.
 
Pretty much the same bedding and glazing compound used in conventional house windows. Butyl rubber sealant is more common in autos and preferred by most.
I've seen front windows that had the glazing compound where the glass sits in the gasket and butyl where the gasket sits on the fence.
 
I just took out my windshield yesterday and was wondering the same thing.Does a sealer of some sort need to be used with the new gasket?
 
The rubber gasket only serves as a medium or filler between 2 less that perfect planes, the fence, and the glass. A cross section of the gasket looks like 'H' The edge of the glass is a lot closer to perfect but the fence is made up of several pieces pinch welded together. I personally have spent a little time tweaking the fence for a better result.
If the raw edge of the glass stands in water the glass will deteriorate. This causes the milky discoloration seen in old auto glasses.
So... the more butyl sealant you load on the more mess there is to clean up and the less chance of leak.
 
3m makes a butyl bedding compound in a standard caulking tube just for this. You can pump it in the glass and body channels of the gasket.
 
The 3M strip-calk pictured below is the closest I found to that white putty found in our cars.. The 3M stuff is black (might be available in white, never checked) and comes in strips layered in wax paper in the box. When I was restoring my T-top Daytona these were all the products I used for the t-top area.

That 3M strip-calk always stays soft like butyl and is awesome for sealing seams and edges. I need to pick up another box of it for my Swinger restoration.

 
The white stuff you are seeing under paint is probably seam sealer.
Just get the metal flange relatively flat as Redfish said. I filled a couple low spots with a smear of JB weld. Seam sealer takes too long to dry.
Factory body manual does call for sealer in both grooves for glass and metal. I like the 1/4 inch black ribbon seal put in the gasket first where it goes on the metal. I put a fine bead of 3m Windo-weld ( caulk gun) under the glass side of gasket lip after its all settled in place. Manual calls for a 3/8 bead of caulk on top of cowl for lower part of gasket to sit in. NAPA has a butyl caulk that works good for that.
As far as actual install procedures, it will vary by gasket. Some have zip lips, others use fill strip or none, or combination...
 
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