Join in skirting board

[John Brown]

I need to join a length of skirting board to an existing piece, on a flat wall.
I realize it would be better to go all the way back to a corner, but that's not going to happen.
It's a simple bullnose profile in redwood, and will be stained brown, to match the existing skirting.
I have two questions:
Firstly, is it worth doing anything more complicated than a simple butt joint? I have an oscillating multitool, which I used to make a vertical cut at right angle to the wall, but I guess I could knock up a jig of some sort to enable a 45 degree mitre, possibly using the same jig as a guide for cleaning up with a chisel...

Secondly, since this is being stained, can anyone recommend a suitable filler, that will take stain well, or should I trie to find something like Brummer that's close in colour to begin with?

 

[Droogs]

Do a scarf joint. then you can blend it in by sanding smooth

 

[Bingy man]

Butt joint and fill for me as it will be difficult to get an accurate angle on existing skirting unless you remove it which I assume you don’t want to . Regular flexible type -(mixed with water) filler mixed with your stain is usually good for me unless you want an exact match . Fill joint in 2 or 3 applications and sand flat . M H O is to keep it simple.

 

[Doug B]

I prefer a 45 degree scarf joint as Droogs suggest, I simply cut a short bit of new skirting at 45 degrees place this against the old skirting, hold the multi tool blade against the angled cut on the new skirting & cut the old skirting, then cut a piece of replacement skirting to length, glue & fit

 

[John Brown]

Thanks. I'll check if I have enough board for 45 degrees. I thought I'd vastly overestimated when I bought 3m, but there was a bit if damage I didn't notice when I picked it up from TP.

 

[okeydokey]

I like Doug B approach and would follow Bingy man idea about mixing the stain with the filler (which is usually white OR buy one about the right colour to start with) as this would avoid a white line at the joint (however you do it) that the stain might have trouble concealing.
If your new wood is a different thickness (thinner) to the old, then you may need to pack just behind the joint to bring level.