Any question answered...

Why doesnt copper make sparks when you grind it?

It's partly to do with how energetic the oxidation reaction is, and partly what the work of fracture is. The first drives the temperature rise as the fragments burn up in the atmosphere (assuming they do), the second drives the starting temperature. Copper is soft, so it takes little energy to fragment and it comes off the grinding wheel quite cold. It is also not very reactive, so it oxidises slowly and doesn't heat up much in doing so. In order to make "sparks", material fragments have to get up to a high enough temperature to emit a lot of visible light, and that just doesn't happen with copper.

Also high thermal conductivity works against copper, as the energy generated at the fracture surface rapidly dissipates through the body of the fragment, lowering the surface temperature so that combustion never gets a chance. By comparison, for example, Ti is a poor thermal conductor and is more reactive and harder than copper, so it has almost ideal characteristics for creating very bright white grinding sparks.

Thanks tester. Interesting and informative as ever.

How shady/ dangerous is AliExpress?
I know it's (all?) snides, but will my credit card be stolen I'd I buy something from there?

Mine hasn't and I must have bought over 30 items in the last few years.

Driving, at a crossroad junction, the sign says Give Way. Should I give way to people from both sides, or just to my right like a roundabout?

Just buy an Audi and pull out into traffic at will.

Cars turning right from a minor road should give priority to the major road and to cars going straight or turning left from the minor road opposite. And so cars coming from the opposite side should give priority to you if you're turning left or going straight over should they wish to turn across you
No special rules for unmarked 4 way crossroads but all bets are off as to what the other people will do afaik

From both sides. This is obvious if it's a narrow carriageway that allows only one vehicle to pass, irrespective of the manoeuvre you undertake.

If the main road is a two-lane road that's wide enough, you may be able to safely turn left while there is someone else coming from the left, but in general it's better to wait, because that person may want to turn right, too, which could put you into conflict. If you're turning right or going straight across, you of course have to give way to people coming from both sides. On multi-lane roads, a person approaching may want to change lanes, so again it's better to give way.

In my case I was on the major and going straight across and to my left on the minor they were also going straight across (from their POV). They are told to Stop. I am told to Give Way. We both sat there for way too long.

👍
Cheers

Depends what you’re buying. Certain products are available cheaper, but you also get what you pay for, so if something is unreasonably cheap I wouldn’t expect too much.

I’ve just ordered my new coffee grinder from there. I’ll let you know when it arrives. Saved about £20, shipping is obviously slower than from somewhere UK based. I also have little comeback if it breaks. I figured it was worth the gamble and slightly longer wait for the 30% savings (which seemed reasonable considering it’s a Chinese product made in China).

I know it's (all?) snides

Not necessarily, I searched everywhere for a tap and die in an obsolete pre ISO French metric size.
Found it on AliExpress delivered for about £17, came from Taiwan, quality is excellent.

Ti being such a poor thermal conductor is what makes it such a bastard to work. Machining it takes copious amounts of cooling fluid, and if you’re not generous enough it goes badly wrong. Mike Burrows has a souvenir piece of titanium that he was turning into a BB axle; he was boring it out and the drill bit spot-welded itself inside the piece and the drill shank shattered. He mounted on a piece of wood as a reminder.

Ti being such a poor thermal conductor is among the properties which make it such a bastard to work

 FTFY

Not sure if this is the right place to ask. Any recommendations for a DVR?

Had an ageing Humax 9300 which I loved. Things I liked about it (ooh, a list):

1. Simple setup
   
2. Fast to respond
   
3. Skip button (set to 10, 15, 30 seconds forwards or backwards). Made it excellent for watching Giro/Tour/Vuelta and F1 highlights
   
4. Excellent TV reception even on a poor aerial
   
5. Intuitive layout on the remote
   
   

Replaced it with a Humax FVP-4000 which I hated. Things I hated about it:

1. Poor TV reception
   
2. Slower to respond
   
3. Bloated features
   
4. They took the skip button off. It was the best bit about Humax products FFS!!!
   
   

Maybe if there's one which also plays DVD/Bluray, I can also eliminate having another box.

They took the skip button off

Sigh.

https://www.youtube.com/watch?v=DC3yxP6zRJk

With the plan of learning to drive this year, I need to update the address and my surname on my provisional driving license.

After hearing horror stories about turn around time with the DVLA, is there any reason for me not to just hold off updating it if I want to start learning sooner rather than later?

I've more recently noticed people on car forums commenting how quickly the DVLA have been processing things like logbooks during Covid. Personally, I've never had a problem. Their normal turnaround time is about 3 weeks.

Oh! I'd just seen stuff like this:
https://www.theguardian.com/money/2021/jun/26/uk-drivers-dvla-licences-delays

Updating the address on my full licence during the pandemic didn't take long. Also, I never returned my old one so I assume you'd still have that.

I need to buy something from a website with awful customer service.

Checkout is via PayPal. I have an amex and another credit card. Idk yet if they'll take amex, but will using PayPal checkout do anything to get in between me claiming off my credit card if it fucks up?

Cheers.

will using PayPal checkout do anything to get in between me claiming off my credit card if it fucks up?

PayPal deals with fuck ups quicker and with less hassle than your card issuer, so you don't need to worry about it.

Are these creepy crawly eggs?

1 Attachment