cutting aluminum storm windows

[Beap52 2,519]

I've got a question about cutting aluminum storm window.

 

The church,  that I mentioned I was helping freshened up the outside, has storm windows that are mounted on the outside of the trim instead of the blind stop.  Not only does it not look nice, water running down the wall can run behind the storm windows.  I don't caulk storm windows because this makes them very difficult to remove plus many of them arn't very weather tight in the first place.  In addition, the storm window frames are barely big enough so that many of the screws split the wood they are fastened to.  I'm not sure if the photo helps, but zooming in may show storm windows before work began.  By the way, the steps and ramps are now gone and replaced with a deck and new ramp.

 

So, I would like to take about 1/2" off of the perimeter of the frames so they will set back against the blind stop.  I've never sawn aluminum but see there are saw blades that will fit table saws specially for aluminum.

 

I have a 10" portable table saw that I plan to take to the jobsite so I can cut (and adjust the aluminum frames as needed) 

 

 Is there an advantage of using a 10" (100 teeth) over 7 1/4" (60 tooth) blade? 

 

thanks, Phil

[squonk 48,261]

I'm thinking the more teeth the better.

[gwest_ca-(File Mod) 12,514]

I would use the 7-1/4" blade and just take your time because they are less expensive. Rim speed of 7-1/4" blade is about 28% slower than 10".

[Handy Don 17,605]

2 hours ago, squonk said:

I'm thinking the more teeth the better.

Absolutely agree, especially when being used on thin stock. 

Pro installers tend to use a compound miter or chop saw as it lets them hold the stock firmly while making the cut. 

 

Is your goal to make them narrower and shorter and reduce the glass area as well? Every storm window I’ve encountered was assembled with cast aluminum corner pieces crimped into a tubular extruded frame. These are not easily disassembled without damage. 

 

I get not wanting to caulk, for sure.

If this were me, I’d seriously consider:

- router the inner edges of the outer wood trim boards to the size of the outer edge of the aluminum window frame. This creates a recessed mounting surface and removes the splintered current mountings. Use a router bit with a guide bearing set properly.  (Some manual chiseling to “square” the corners would still be needed)

- then, because the “ledge” is still too narrow, add a ledger strip (use weatherproof glue and nails) to create a more secure (and now weather resistant attachment)

- lastly, maybe, add a bit of aluminum flashing to re-direct rain coming down from the upper trim piece out away from the aluminum frame. 

Edited 14 hours ago by Handy Don

[JimSraj 590]

Are these typical triple track storm windows with mitered corners?

[wh500special 2,468]

Aluminum cuts surprisingly well with woodworking tools.
 

We used to have several 10” woodworking miter saws at work stationed throughout the shop in individual workcells that were used to cut aluminum for cut-to-fit applications where we can’t do it ahead of time in a better cold saw.   I don’t remember the tooth count, but it’s in the 100-tooth range for most extrusions like 1/8” thick angle and channel.  Thicker stock got fewer teeth.  We used to use the piranha blades but changed to a local place that also sharpened them when needed and made them with flatter plates.  The piranha blades were just thrown in the scrap when they dulled. 
 

there was enough of a degree of halfassery with these setups that we largely phased them out, but cut quality was always good and aside from the flying chips it was no less safe than a lot of other processes. The weld shop guys still keep a miter saw handy for their use. 
 

I haven’t cut aluminum for a long time on a table saw, but I’ve cut up to 3/4” plate a few times using just carbide tipped blades.  It works well but the flying chips are a real hazard.  I never had an issue but I would think the kickback danger is increased compared to wood if things aren’t nicely aligned or your technique drifts. 
 

it even routs pretty well with a handheld router, but it can get away from you if you take a heavy pass. Depending what you’re doing, a pass over a carbide tipped spiral bit on a router table might work too. 

 

soft aluminum - like 5052 - will stick to the teeth.  Harder aluminum like 6061 is much more forgiving.  There will be some magical feed rate that will get the best results.  If it’s sticking, you may have to cut faster.  The guys at work apply some kind of stick wax to the cutline at times.  

 

I have no idea what storm windows would be made from. Seems like most extrusions would be 6000 series.  
 

best of luck and be careful. 

Steve

[Beap52 2,519]

1 minute ago, JimSraj said:

Are these typical triple track storm windows with mitered corners?

These are typical storm windows and I believe the mitered corners are welded.  I don't have them here to actually verify but I looked them over when we removed them thinking I could cut them to fit. 

[Beap52 2,519]

4 minutes ago, wh500special said:

Aluminum cuts surprisingly well with woodworking tools.
 

We used to have several 10” woodworking miter saws at work stationed throughout the shop in individual workcells that were used to cut aluminum for cut-to-fit applications where we can’t do it ahead of time in a better cold saw.   I don’t remember the tooth count, but it’s in the 100-tooth range for most extrusions like 1/8” thick angle and channel.  Thicker stock got fewer teeth.  We used to use the piranha blades but changed to a local place that also sharpened them when needed and made them with flatter plates.  The piranha blades were just thrown in the scrap when they dulled. 
 

there was enough of a degree of halfassery with these setups that we largely phased them out, but cut quality was always good and aside from the flying chips it was no less safe than a lot of other processes. The weld shop guys still keep a miter saw handy for their use. 
 

I haven’t cut aluminum for a long time on a table saw, but I’ve cut up to 3/4” plate a few times using just carbide tipped blades.  It works well but the flying chips are a real hazard.  I never had an issue but I would think the kickback danger is increased compared to wood if things aren’t nicely aligned or your technique drifts. 
 

it even routs pretty well with a handheld router, but it can get away from you if you take a heavy pass. Depending what you’re doing, a pass over a carbide tipped spiral bit on a router table might work too. 

 

soft aluminum - like 5052 - will stick to the teeth.  Harder aluminum like 6061 is much more forgiving.  There will be some magical feed rate that will get the best results.  If it’s sticking, you may have to cut faster.  The guys at work apply some kind of stick wax to the cutline at times.  

 

I have no idea what storm windows would be made from. Seems like most extrusions would be 6000 series.  
 

best of luck and be careful. 

Steve

Thanks,  These aluminum frames are probably 40 or fifty years old--maybe older.  I'm going to give it a try.  

[Racinbob 13,235]

Based on one of the projects I did this summer I would go with the 100 tooth 10". Keep in mind that saw blades are total teeth, not teeth per inch. I was very apprehensive about taking a saw to some very expensive railing and post wraps this summer but was thrilled to see how well it sawed. I used a 100 tooth 12" in a sliding miter. A 100 in a 10" is better yet. More tpi. You don't need a 'special' aluminum blade. It will state that it's good for non-ferrous metals as most fine tooth blades are. It sounds like you will need to rip long edges so it would easily be my choice to use a 10", 100 tooth in your table saw.

BTW.......wear goggles, not just safety glasses. Better yet, a full face shield. You'll find out why. 🙂

[JimSraj 590]

How big is your table saw table? If you have a way to support the frame as it is passed through the saw Using a table saw with a 100 tooth blade made for cutting metal (negative hook angle) will make the cutting go pretty easy on the sides. Top and bottom will need more support. 

[Beap52 2,519]

46 minutes ago, JimSraj said:

How big is your table saw table? If you have a way to support the frame as it is passed through the saw Using a table saw with a 100 tooth blade made for cutting metal (negative hook angle) will make the cutting go pretty easy on the sides. Top and bottom will need more support. 

I've got two table saws.  One is portable and the other stays in my shop.  If the portable struggles or is too awkward , I'll use the larger stationary shop saw.   The reason for the portable is that I can make accurate cuts on the jobsite and fit the 100 year old windows openings.  Most of the aluminum windows have the added extensions added  to the bottom so I may not have to cut the height only the sides.  

 

Like I would expect from the fellows on this site, I'm getting good advice.  Thanks to all

[953 nut 69,952]

Bless you for taking care of a house of worship. Are you going to have to replace or recut the glass or do you think the aluminum is wide enough to trim a little off each side? The majority of storm window frames are a channel and if the outside were removed the sides would fall off.

Not knowing all of the details I am inclined to think @Handy Don idea of routing the openings to fit the storm windows is the best way to go. Attach a temporary guide board to each side of the window and select a flush trim router bit with a bearing that will give the depth of cut you need. Set up a temporary scaffold or other safe work platform and trim each side to fit the storm window. The router will ride on the Temporary Guide Board so a secure work platform is very important since tilting the router in either direction would give you an improper cut.

Give the fresh wood some oil based primer and a topcoat of latex exterior paint.

Here is a drawing of the before and after router work.

[Beap52 2,519]

17 minutes ago, 953 nut said:

not knowing all of the details I am inclined to think @Handy Don idea of routing the openings to fit the storm windows is the best way to go.

I like that idea but I'm thinking I'm going to hit a lot of nails holding the exterior trim to the window frame.  There are twenty windows.  The size is about 34" wide and five feet tall.  I may end up cutting them on my shop saw that has a much bigger table.  In worse case scenario, I'll re-attach them like they have been for all these years.  I suppose I could run a bead of caulk across the top of the windows, that way the next person could cut the caulk with a utility knife before removing the window.  I had four window sills that needed attention, possibly in part due to the storm windows allowing water behind them. 

 

Personally, I like the looks of the windows without the storm windows but the added protection from weather and for weatherization they are necessary.  The church doesn't have money to replace the windows or even the storm windows and there is something about old wavy glass windows--kind of like patina on a Wheelhorse.   Below is the front of the church with new deck.  The tall posts are for the new porch that we are going to build. 

 

This is likely the last hurrah for this old building.  The small community is dwindling.  The  2x4 oak rafters on the building have bellied some 6 to 8".  (I can't believe the roofing supplier loaded all of the shingles on that one valley.)  The  rim joists are about shot (we replaced the one across the front of the  building and around back a piece of metal was nailed over a hole where the rim joist was missing).  I replaced a fair amount of the clapboard siding,  made window drip cap for the windows that needed it.  My goal is to keep a much water out that I can.   One neighbor lady came up and donated $2,000 because she appreciated saving the building.  Concrete apron will be poured at the end of the ramp and a sidewalk where the steps will be in front of the doors.  An interesting note:  The foundation is poured concrete.  There are no footers.  When we dug for posts next to the building, we never found a footer.  We dug our holes for the posts deeper than the foundation was buried in the ground.