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535i Andrew

Soldering Iron advice

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I was trying to solder 2.5mm^2 wire (35/0.3) to make up a loom for the missing three pins in my towbar socket. 

 

I was using an Antex 18W iron and I can't help but think it was just a bit underpowered for the big size of cable being soldered into the replacement socket pins.  The 18W iron was bought for dealing with wires no bigger than 16/02 on my model railway and it's been faultless, but I think it's not able to heat up the bigger sized components in this example. The next size up is a 25W, would that be man enough?

 

 I couldn't tin the end of the wire as this increased its diameter too much to fit into the pin, so I soldered a 'collar' around the end of the pin where the wire goes into the pin and it was doing this that my iron struggled with as it's a big bit of solder, but it's solid. The biggest wire BMW use in these pins is 1.5mm^2. The 2.5mm^2 cable is a snug fit into the pin. I want the big cable for reliability and little voltage drop as one circuit will be for a permanent charge point for my Ctek charger.

 

Or was it due to the fact that I was trying to solder in my garage and it was only a few degrees above 0, the iron is having to do more work?

 

image.jpg

 

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just googled 18w irons and seems a bit weedy looking at the bit. Mines in the garage so can't check but would tin that sort of size wire though outside doesn't help. 

 

Those gas pen blow torches are quite good

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You might laugh at my proposal but I once found myself in a similar situation and managed to improvise a way around it. I do have larger irons myself but had to make do with an 18w. My solution for more heat was a candle! It wasn't pretty but got me out of a hole. Might save you buying a bigger iron if it's only a once off.

Keliuss

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1 hour ago, 535i Andrew said:

I've got a big tip on it, but a bigger tip isn't necessarily the answer as if more heat is needed, you need, and I quote Jeremy Clarkson "more power"I think.

And possibly patience? 

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9 hours ago, keliuss said:

You might laugh at my proposal but I once found myself in a similar situation and managed to improvise a way around it. I do have larger irons myself but had to make do with an 18w. My solution for more heat was a candle! It wasn't pretty but got me out of a hole. Might save you buying a bigger iron if it's only a once off.

Keliuss

 

No you make a good point, it's all about getting the right amount of heat into the object you are soldering. If it's something big it will draw all the heat away from the small location where you want to heat. A more powerful iron can maintain the heat, counteracting the sink effect form the larger object.

 

I'll try it again in the house where the ambient temperature will be 20 deg warmer and I could pre heat the pins in the oven, but don't tell the wife.

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28 minutes ago, pidgeonpost said:

I've used a cheapo Antex 30W iron successfully on car sized wiring. Moving indoors may help, at least it will stop you shivering. ;)

 

 

Yeah that's a good bit bigger than my iron.  

 

You always need more power!  But I've only got two more pins to do so I'll take Duncan's advice an have a bit more patience and go indoors!.  I didn't rush the first one, I just wasn't hugely happy that I had to solder it in parts due to lack of heat.  It wasn't pretty but it will never be seen.

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17 minutes ago, pidgeonpost said:

A couple of weeks back I tried soldering a wire to some 6mm copper pipe with that 30W iron. Not a chance! :lol:

 

You need to roughen (key) the area so the solder can stick. Plumbers solder has a higher melting point and with any soldering iron you have to make sure the tip is properly tinned.

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Gas hob will do it. I use a mix of hot air soldering station as well for large items.

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A good gas powered soldering iron is the way forward. As long as you can get spares your great. Smaller ones usually have an equivalent wattage rating adjustable from 20-60 watts.

You will never look back.

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9 hours ago, jake13 said:

 

You need to roughen (key) the area so the solder can stick. Plumbers solder has a higher melting point and with any soldering iron you have to make sure the tip is properly tinned.

Agreed. I've done plenty of soldering but was in a rush and being lazy as I have a gas torch but couldn't be bothered to go to the shed in search of the proper flux and solder.  :oops:

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23 hours ago, 535i Andrew said:

Thanks for the tips lads.

 

Hmmmm, I've got a blow torch and plumbers solder for soldering copper pipe work.  That might just be too much power! Don't want to melt the wires insulation.

Back when I was a battery engineer we kept the heat on the connector (proper oxy acetylene welding rig) when building charging cables, plenty of flux on the wire then slowly push it into the connector filled with molten solder about 1/3rd full, the copper wicks the heat away so fast that melting the insulation was never a problem. Just make sure to remove the heat source as soon as the cables pushed in. You can put a damp cloth on straight after to pull the heat out faster if you want.

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Annoyingly the pin I'm trying to solder too has a small hole in it at the side which solder may flow out off if I try that trick with filling it with molten solder.........although......It's a small hole and thinking about it, it's worth a try. Thanks. 

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2 hours ago, 535i Andrew said:

Annoyingly the pin I'm trying to solder too has a small hole in it at the side which solder may flow out off if I try that trick with filling it with molten solder.........although......It's a small hole and thinking about it, it's worth a try. Thanks. 

You can push a little bit of foil in the hole with a pin if you need to.

 

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Once you go to a gas iron, you'll never look back.

 

Instant heat up, lasts for ages, can take it anywhere and it fits in your mouth.

 

I've had an Iroda SolderPro 70 for ages and I love it.  Tips are expensive though.

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The Antex 25W is pretty decent if you fancy a moderately priced upgrade. I have soldered some very thick wires with it when putting connectors onto beefy lipos for model aircraft.  However, I feel that if you already have the 18W, you may as well go a bit more powerful than 25W so you can cover a bigger range of jobs. FWIW, I think the Antex irons punch well above their wattage. Makes sure to get a silicone cable on whatever you buy.

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Thanks guys, other things have got in the way before I could drop back on to this project.  I'll use the gas hob to get some heat into the pin first, just don't tell the wife.  I've only got two more to do, so I'll try one more before going up an iron size or two as the 18W is perfect for my normal jobs.

 

Or blag from a mate..;)

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