dantastic Posted February 19, 2019 Share Posted February 19, 2019 I'm just about to install some side windows in my 90 in order to be able to see what I'm doing at junctions. Too many brown pants moments after blindly driving out in traffic... I had initially thought I'd just use metal blades on my reciprocating saw but as I went to pick up some blades I read they were for 1.5-5mm. That lower limit concerned me a bit so I didn't get any blades and figured I'd ask here instead. A reciprocating saw is not exactly a fabricator's tool, it's for demolition but I still thought it was the right tool for the job. I'm no longer sure. Can I cut thin panels with it or will it leave rough edges? What to use instead? Angle grinder I presume? I'm just a bit worried my hands aren't steady enough to be using the grinder. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted February 19, 2019 Share Posted February 19, 2019 Jig saw? Clamp a scarificial piece of thin ply behind? Quote Link to comment Share on other sites More sharing options...
dantastic Posted February 19, 2019 Author Share Posted February 19, 2019 The side panels will still be on the car so I don't think I can clamp a piece of plywood to the panel. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 19, 2019 Share Posted February 19, 2019 I'd go in with a 4.5" grinder and slitting disc, roughing out the rounded corners, and finish with a file/finger sander/flap disc. You have much more control with a grinder than you'd think. BOM suggested rubbing a bar of soap on a grinding disc to help lubricate when cutting ali, I've not tried it yet, but does sound like a good thing to do. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted February 19, 2019 Share Posted February 19, 2019 1 hour ago, dantastic said: The side panels will still be on the car so I don't think I can clamp a piece of plywood to the panel. Sure you can! Wedge it in situ on the inside. Quote Link to comment Share on other sites More sharing options...
dantastic Posted February 19, 2019 Author Share Posted February 19, 2019 Hmmm.. right. So angle grinder it is I suppose... 😬 Quote Link to comment Share on other sites More sharing options...
daveturnbull Posted February 19, 2019 Share Posted February 19, 2019 I used a jigsaw with good results. Quote Link to comment Share on other sites More sharing options...
Stellaghost Posted February 19, 2019 Share Posted February 19, 2019 Pneumatic hacksaw would do job very well Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 19, 2019 Share Posted February 19, 2019 Grinder with bacon-slicer disc, drill/hole-saw for the corner radius 1st then join the dots with the grinder. Or plasma cutter if you have one Quote Link to comment Share on other sites More sharing options...
zardos Posted February 19, 2019 Share Posted February 19, 2019 I would have thought a plasma cutter would be no use unless you intend to repaint the whole panel as you would need to grind off too much paint to get electrical contact. I would have thought a grinder with a thin cutting disc would be best, air hacksaw tend to not produce straight lines. Quote Link to comment Share on other sites More sharing options...
dantastic Posted February 19, 2019 Author Share Posted February 19, 2019 The template says a radius of 61mm. I don't have a hole saw that can do that so will have to do that with the grinder as well. bacon-slicer disc, slitting disc. Are these even thinner than regular cutting discs? Haven't seen them at my local disc-monger I don't think. Quote Link to comment Share on other sites More sharing options...
L19MUD Posted February 19, 2019 Share Posted February 19, 2019 I would second the jigsaw approach, did this on a RR to fit Defender spats and it worked well. Probably need to apply masking tape to the surrounding paint to stop the jigsaw scratching though More controlled than a grinder and less likely to make 'run off' mistakes Quote Link to comment Share on other sites More sharing options...
Dave W Posted February 19, 2019 Share Posted February 19, 2019 Jigsaw. Use masking tape to cover the line of the cut and then you can mark the line you need to follow clearly. It will also help prevent the paint lifting at the cut. Make sure the masking tape also covers the area the the jigsaw will be resting on as it will scratch the paint otherwise, especially on the corners as you turn the jigsaw to follow the curve, the back end of the jigsaw comes out a long way from the cut. Remember the strengthening pillars behind the panel though, you either need to cut them out first from the inside or you'll risk snagging or bending the jigsaw blade. For that I'd use an angle grinder - carefully. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 19, 2019 Share Posted February 19, 2019 Bacon slicer discs - 1mm stainless cutting / slitting: https://www.ebay.co.uk/itm/142487240428 Just be careful as if you put side-load on it and break it it's a flying wheel of death - very much for straight-ahead cutting only. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted February 19, 2019 Share Posted February 19, 2019 You don't need to get the corners spot in, anything that can help with a hole saw will be good, but.... If you don't have one, just cut it at 45 degrees across the corner, you will find there isn't much material to remove afterwards. I think you may be over thinking this, and underestimating your skill and achievable accuracy of an angle grinder held in two hands, with your thumb guiding the blade on the guard. watch some the Binky stuff to get an idea Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 19, 2019 Share Posted February 19, 2019 Or take it round to @Shackleton and bribe him with pound notes to cut it out for you and film it for his channel Quote Link to comment Share on other sites More sharing options...
rusty_wingnut Posted February 20, 2019 Share Posted February 20, 2019 Make a wooden jig of the window, clamp on to the side of 90, use a plunge router to cut the aluminium, with a guide bush against the jig. Perfect windows everytime and nice neat cut. Quote Link to comment Share on other sites More sharing options...
dantastic Posted February 20, 2019 Author Share Posted February 20, 2019 2 hours ago, rusty_wingnut said: Make a wooden jig of the window, clamp on to the side of 90, use a plunge router to cut the aluminium, with a guide bush against the jig. Perfect windows everytime and nice neat cut. That's a very good idea! I can screw the template to the panel as I'm getting rid of it anyway. I have a router so this might be the best option! Quote Link to comment Share on other sites More sharing options...
dantastic Posted February 20, 2019 Author Share Posted February 20, 2019 Will I need to trim the brace in the middle of the panel? or will the cutout clear it? Is that spot welded on? Quote Link to comment Share on other sites More sharing options...
daveturnbull Posted February 20, 2019 Share Posted February 20, 2019 2 hours ago, dantastic said: Is that spot welded on? Only at the top and bottom, not to the outer skin. Quote Link to comment Share on other sites More sharing options...
110 V8 Posted February 21, 2019 Share Posted February 21, 2019 1mm cutting disc in an angle grinder and lube with candle wax every minute or so (just cut into a candle with the wheel). Cuts aluminum like butter, does not clog/pick up on wheel and leaves a pretty tidy edge. Andy 1 Quote Link to comment Share on other sites More sharing options...
rusty_wingnut Posted February 21, 2019 Share Posted February 21, 2019 20 hours ago, dantastic said: That's a very good idea! I can screw the template to the panel as I'm getting rid of it anyway. I have a router so this might be the best option! Of course it is, it's one of my own 😏 Quote Link to comment Share on other sites More sharing options...
Sharp Posted September 21, 2020 Share Posted September 21, 2020 You can get slitting discs that are made for cutting ali. I'm not sure how high the risk is but I've been told that abrasive discs can clog up and shatter when they get hot. My guess would be that if you're careful and not leaning into the cut so it clogs and gets hot then it'll be fine but the ali discs aren't much more expensive so I always have some in and they work nicely as well. The recip would probably do it to be honest, I've been surprised how straight a good blade cuts if it's a flat piece of metal but like you say they're brutal beasts and I'd be worried it would jump and make a mess. Quote Link to comment Share on other sites More sharing options...
Stellaghost Posted September 21, 2020 Share Posted September 21, 2020 If you run your normal slitting disc through some candle wax first, the disc then cuts smoother and faster, worlds apart of difference, obviously you need to replenish the candle wax onto the slitting disc periodically regards Stephen Quote Link to comment Share on other sites More sharing options...
Romahomepete Posted September 30, 2020 Share Posted September 30, 2020 You could always do it manually and use a monodex sheet metal cutter, that is how they used to cut van sides to put windows in or the moderne air driven equivalent nibles tool Peter Quote Link to comment Share on other sites More sharing options...
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