Router Plane

Monday, December 9, 2019

FLW Cabinet - #28 Grouting the Stained Glass Panels

This post falls outside the general woodworking I usually cover in this blog but is an integral part of this project so here goes.

When I built the stained-glass panels that will go in the doors back in the late 90’s the glass was not grouted or cemented in the zinc came.  That’s because since they were mounted in sliding glass doors any moisture condensation that accumulated between them and the door glass would have a way to escape.  That worked well in that situation but now since they will be mounted in an operating cabinet door, I need cement or grout the well over 500 pieces of glass per window solidly in place in the zinc came to help provide rigidity for the door assembly. 

The process starts out by laying one of the panels on a piece of carboard to protect my workbench as cementing or grouting can get a bit messy.

In their original installation in the sliding glass doors there were 6 copper tabs on each panel that were used to mount the panel in the door.  The left photo below has a pencil pointing to one of them and the right is a closer view of the same one. 

Because they will not be needed when they get mounted in the doors they need to removed.  Since they were soldered on a little heat with the soldering iron removes them.  In the left photo I am heating the tab and in the right one it has been removed.  I did do a little cleanup on the joint after the photo was taken to make the result look a little better.


Next is to do the grouting which will fill the gap between the zinc came and the glass.  The drawing below shows a cross section through a typical piece of zinc came plus the glass.  The left side is before grouting while the right shows the final grouting.  This will anchor the glass in place and make the whole window more rigid and stronger. 

It has been a long time since I did any window grouting and the materials have changed since then.  Since nothing was available locally, I was left with ordering the material online.  Previously the grout was like cake batter while the current grout is very thick, more like a putty.  Because of the material change the grouting process changed too.  This meant there was a bit of learning curve (2 days) before I got any proficiency in putting it on.  With that in mind here is the process I am currently using to install the grout.

Step 1: Using a 2” wide putty knife a small quantity of the grout is applied to the glass/came joint and pressed into it until no more can be packed in.  For me holding the putty knife near the tip with both hands gives good control and allows me to easily apply sufficient pressure to really pack the material in.  One thing to remember is that the idea is to fill the gap between the glass and the came so the direction of the applied force is parallel to the surface of the glass.  Minimal downward force against the glass is used to prevent scratching or worse cracking a piece of glass.  

This worked well where the lengths of the came were longer than the putty knife.  However, there are a lot of narrow or just small pieces in the window.  Moving to a smaller 1” wide putty knife helped but still did not allow me to get in the smaller spaces.  My solution was to take a couple scrap pieces of wood and rip them down to half and quarter inch wide strips then bevel the end.

Here is what it looks like when I get that done in an area.  For this window a square foot takes just under an hour.  Areas with mostly large pieces take less time.


Step 2: Trimming the grout is next.  That cleans up the joint and gets rid of the excess grout.  There are a couple of specialized tools that can be used or in my case I took a scrap of oak and turned it to the profile I wanted in the lathe creating my own “pick”.

The pick is run around each piece of glass and.  In use the pick is held 90 degrees to the glass tight to the came then run around each piece of glass which trims off most of the excess grout leaving a fairly nice edge.  At the same time each glass to came joint is checked to make sure it has grout and was not missed.  Any missed spots are fixed.


Step 3: Cleanup is next.  There are a couple of materials that can be used to clean the excess grout from the came and glass.  One is whiting or calcium carbonate and the other is very fine sawdust.  The sawdust is not what you would get from a tablesaw or similar tool but the very fine, almost flour-like dust that is the result of sanding.  As it just so happens my thickness sander makes this type of sawdust in copious quantities that is sucked up by the dust collector.  When starting the grouting the dust collector bag was about half full which gave me over a 5-gallon bucket of just what I needed at no cost. 

Here is what the window looks like after liberally sprinkling the sawdust over the just grouted area.

A moderately stiff natural bristle brush is used with modest pressure.  Too much and you risk the chance of breaking a piece of the glass.  The sawdust and scrubbing cleans off the excess grout turning the sawdust a darker color.  When it looks like the excess grout is mostly combined with the sawdust a shop vacuum is used to remove most of the sawdust/grout mix.  Some will still be packed into corners.

Another pass with the brush is done to remove as much of the sawdust/grout mix as possible then vacuumed away followed by gently sweeping the surface with a soft brush and blowing it off with compressed air.  Since I generate more sawdust than I can use I don’t bother trying to reuse it. 

Step 4: Tool or detail the came/glass joint.   With the sawdust and excess grout removed I check again for any missed areas or grout that needs to be fixed.  Once any repairs are done it’s time to finish the came to glass joint.  At this point the grout will probably have a little bit of a bevel between the glass and the zinc came.  Below on the left is what that looks like and on the right is what is wanted. 

Step 5: Last step is to take a soft cloth like an old cotton tee shirt and clean any of the odd remaining spots of grout off.  Below is what a finished section looks like which is pretty much the same as before.  Start to finish it takes about an hour and 20 minutes per square foot of window.  There is a bit over 12 square feet per side of window so that works out to roughly 16 hours per side.  Yes, you have to do both sides.

As mentioned earlier I made a rough guess on how much I needed and ordered the largest size available.  As it worked out, I used about ¾ of the container on one window so will need to order more.  That’s OK as I am really tired of grouting so will wait on doing the second window and move on to making all the pegs.

Next up – Pegs

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