From what I've read about weed burners, a common mistake s trying to or thinking the weeds are killed in one go

I think the idea is to frizzle /wilt the weeds & seeds, and then let the tops dry out naturally, making another pass later, maybe after a week or so

Also, handy for a quick shrivel as any seeds geminate

Saw a tip today,which showed ( before and after)how to get rid of weeds/dandelions/ etc between paving slabs,if this any help.? Poor on boiling water out of a kettle ,then when they are frizzled,sprinkle salt sparingly on the remains.It seemed to work well,and no chemicals used. Not sure if this would be suitable in a border though. Good Luck..

Hello!
I don't know about the electric weed burner. I have a propane weed torch, It really kills the nasty weeds. I found it's best to flame the weed near ground level to really kill it. Flaming it at it's highest point causes a lot of flame but may not fully kill the weed.

Thank you all for your comments. In the end I bought an electric one through Amazon and it certainly does the job. I have to be careful with it - it blows out air that shrivels most things and actually sets fire to grass if I point it in that direction for long enough. Any fire is very localised though and doesn't spread. Reviews of some speak of a cable that is too short, but this one is plenty long enough, but of course needs a good extension cable to reach most of the garden.