cutting aluminum storm windows

[Beap52 2,517]

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 48,257]

I'm thinking the more teeth the better.

[gwest_ca-(File Mod) 12,512]

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 17,601]

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 32 minutes ago by Handy Don

[JimSraj 590]

Are these typical triple track storm windows with mitered corners?

[wh500special 2,465]

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 2,517]

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.