Tips for making a 45-degree glued joint

[teach]

To get a perfect 45 degree joint... do your best on the drop saw (or other) on the two sections of wood..'best' means the joint will not be perfect..right?. Start with two pieces that once joined will be too long.... Ok so glue them clamps and all nice and aligned.. (result yuck)..when the glue is done setting and not before...Return to the saw. Cut again the 45 down thru the centre line of the glued yuck joint....now you should have two perfectly matched cuts and go back to the gluing task again... If it fails...the extra wood allows this to be done again..!! 

[Noyade]

Sorry @teach  - just not grasping your glue and then cut routine?

Any photos - before and after - to show us?

[teach]

to grasp or not to grasp that is the question...no pics just words..your first 45 joint in the 6x2 expensive bits of dressed Tawa ( find some if you can ) and then you glued them ever so carefully...rats the end result is not perfect...chances are it won't be...the cuts did vary!

Now re cut down thru the poor joint, that'll be a 2mm blade cut...the poor joint will be sawdust and now you have to glue again but the cuts will be a perfect match.   

[Noyade]

Thanks @teach 

Now grasped.

[Noyade]

I'm in the process of giving this a go - but admittedly with smaller cheaper wood. 😁

Deliberately made imperfect mitre to begin with...(but maintaining 90 degrees).

[Noyade]

Glued - whilst still maintaining 90 degrees...

[teach]

Yes...once the glue dries hard...you could cut again thru the centre of the poor joint but only if you left enough

wood at the start. My work was to make one long plank from pieces. Using metal plates on the back to strengthen the result. I was not making a corner joint. Also I find the biscuit joiner way not to be helpful and the biscuits are a sloppy fit, allowing movement and a fail.

[Noyade]

Morning @teach 

"My work was to make one long plank from pieces"

"I was not making a corner joint."

Ah - I see now - fully grasped.  😊  Sorry, I should have asked you earlier what the application was, as I went down the window/door architrave and picture frame pathway. I was thinking if we keep going back to the same saw with the same inaccurate 45 degree cut, it won't matter how many times we glue and cut  - we'll never get that perfect 90 degree angle required.

Any chance of seeing a photo of your completed plank -  with the brackets inserted?

Cheers!

[Noyade]

"biscuits are a sloppy fit"

Until recently I never had a problem with biscuits (wood variety). I sourced them from my neighbour who purchased them from the US and they were soaked in water for 30 minutes prior to inserting. Very tight fit.

Then I bought these from Bunnings on a clearance trolley. Never again. What brand are you using?

Far too loose.

[teach]

No fault..no worries..the plank became the backsplash and is well fixed in place..picture would not help anyone..but I did screw 8 x 2 galv steel plates to the three joints that enabled the 3m length. About 18 screws to each plate. They were set into a routed opening some 4mm deep. I was surprised it all worked! I can see your corner joint would present problems using my daft process..the accuracy needed for the 2nd cut is clearly critical..good luck trying it. I did discover the expensive 2mm circular crosscut blades are not to be used when ripping...they wonder with any grain. Big fail.