Tech Spam thread - because 1/4" BSP gets 5 hand spans to the jiggawatt

[kws]

These disposable welding gas bottles, are they any good? Do they last any sort of reasonable time? I have a couple of small patches of rust I need to weld, and have no gas/regulator at the moment and thinking of changing from flux cored to solid wire for this job just to have better/cleaner welds.

https://www.machineryhouse.co.nz/O0185

I know the bunnings side D bottles are good value, but $129 + $240 (plus regulator) is a bit much for me since I use the welder once every couple of blue moons.

[tortron]

They might last one panel, I have used them, but imo get the D bottle and have it for every small job for the next 2 years

I think I used one to do a set of 4 cyl headers

[kyteler]

20 hours ago, kws said:

These disposable welding gas bottles, are they any good? Do they last any sort of reasonable time? I have a couple of small patches of rust I need to weld, and have no gas/regulator at the moment and thinking of changing from flux cored to solid wire for this job just to have better/cleaner welds.

https://www.machineryhouse.co.nz/O0185

I know the bunnings side D bottles are good value, but $129 + $240 (plus regulator) is a bit much for me since I use the welder once every couple of blue moons.

They're terrible.  I used them for a while but they just don't last worth a shit,, far more cost effective to go a proper bottle. If you really want to try it I can send you a regulator for them. 

[SOHC]

I welded on one exhaust flange and it was 80% empty when o had to get one in an emergency.

[kws]

So in other words, not worth the money. I suspected as much. Thanks guys.

[Bling]

Yeah it's bad value for sure. One of those 2.2L cylinders probably costs the same as a full size cylinder refill. Costs a bit more up front, but having a cylinder tucked away means you can weld as much as you want. Could pick up a cheap reg off trademe and a cylinder off there too for not silly money. Test every 5 years ~$100 (with co2 fill) and no other costs other than refills. If you really have super limited need, just give someone a Rutherford to bring their welder over and get it sorted. Rental options when I first started were super limited, so I purchased a cylinder. The bunnings deals seem all good now. $250 gets you a 5KG co2 cylinder delivered (trademe) plus ~$70 for reg delivered (trademe). Bit more than the above combo of 2.2L cylinder + a reg. But you'd get 50 times the repairs done i'd say.

 

[Transom]

Yup I fizzed thru a couple of those disposable co2 bottles very very quickly then just got a rental 

Surely you can rent a full bottle local and just return it after a month or 2 ? 

16$ a month and about 60$ for a fill is what I’m paying 

 

[SOHC]

How much pressure should I put in some 10 ply light truck tires? 

[Yowzer]

Well that's all gonna depend on how much weight you plan on putting on them.

Go 4.5bar.

[kyteler]

Check the tyre manufacturer because they can vary wildly depending on the size and application. 

[Roman]

On 18/11/2020 at 19:15, Roman said:

Dear people-who-know-things, 

Any advice on a valve spring removal tool? 

Just to follow up, I'd been massively overthinking the complexity of this job. 

(with head on the bench off motor)

Step 1: place stuff under the valves to stop them moving/bending

Step 2: place a 19mm socket with a magnetic thing on the inside, on top of the retainer

Step 3: hit it with the hammer

step 4: Valve retainer thing is off

Too easy 

Now to try the rope trick and get a knot stuck in it 

Might try on a pick a part engine first haha.

[ajg193]

How do you get it back together without the tool though?

[M.H.]

15 minutes ago, ajg193 said:

How do you get it back together without the tool though?

Assembly is the reverse of disassembly 

[Roman]

Just press it on without the magnets and clicks in place

[kpr]

then hit it with the hammer ?

[tortron]

you press down on it with the hammer, then pull it away real fast

[RUNAMUCK]

Ling, but I've stripped heads for scrap before and just beat the retainers with a hammer on a crooked angle to ping the collets off. (Wear safety glasses) 

 

[kws]

Ive just welded some patches in to remove some rust, and need some bog to smooth out the fuck up from the previous person that tried to fix it. I've never used bog before, so what is the go?

I need to fill and level out where the patches are, and its currently bare metal. Some sort of rust inhibitor would be nice, but dont know if thats a thing? Do i zinc paint it before bog? Im not filling/bridging any holes, so I guess a normal "filler" is ok and I dont need metal or fibreglass? Just this ? https://www.supercheapauto.co.nz/p/septone-septone-car-filler---500g/1332.html#q=filler&lang=en_NZ&start=4

And then its a case of sand sand sand, prime, sand, paint?

[tortron]

Paint thread

 

But

I use evercoat liteweight filler over a coat of sealer

I seal the bare metal with durepox  -epoxy urethane primer

 

Then I have a couple different carmaster primers/primer fillers

 

 

[RUNAMUCK]

Bog is very hygroscopic. It pulls moisture from the air. Where its laid over bare steel, the paint eventually gets a chip/scratch in it, which allows moisture into the bog. The moisture lies against 5he steel, which enables corrosion. As steel rusts it spawls/swells. This forces the bog away from the metal surface. The filler splits, and more water gets in. 

Nutech is somehow different, and doesnt absorb moisture. But I'd just epoxy it before adding filler.