Silver Solder or just regular plumbing stuff?

Yellow Ballad

Yellow Ballad

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I need to make a new dip tube for my diesel tank for my diesel heater. I have the fitting 3/8 brass elbow to fit the union on the tank, I've got a brass "plug" with a 5mm hole in the middle and some 5mm brass tube.

What's the best way to stick them together? I have regular plumbing solder here, I don't mind buying some silver solder if needs be but thought I would ask on here first. Obviously it's not something structural but I don't want any air leaks from the joint.

Over to you...

20211010_204824_copy_612x816.jpg
 
Yellow Ballad said:
I need to make a new dip tube for my diesel tank for my diesel heater. I have the fitting 3/8 brass elbow to fit the union on the tank, I've got a brass "plug" with a 5mm hole in the middle and some 5mm brass tube.

What's the best way to stick them together? I have regular plumbing solder here, I don't mind buying some silver solder if needs be but thought I would ask on here first. Obviously it's not something structural but I don't want any air leaks from the joint.

Over to you...

View attachment 123899
Click to expand...
Silver solder every time for this job. Much more robust.
 
I would always either silver solder ( not the plumbing lead free stuff ) or braze. For some regs and insurance all fuel lines must be either brazed or compression fittings.
Solder suffers brittle fractures.
 
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Soldered central heating joints don't generally leak if well made and they are subject to thermal cycling for decades. I would expect a joint made with lead solder to be adequate for this application as it is only supporting the weight of the dip tube. It is much easier to do a good soldered joint unless you have the right equipment for silver soldering or brazing.
If the metal is really clean and the surfaces are tinned first and the overlap is over 10mm there is no way that you will be able to pull it apart.
Don't use lead free solder as it is more difficult to achieve a good join.
5mm seems quite small for a dip tube as the ID must be about 4mm which could block quite easily.
 
I'm not massively worried about mixed metals in my fuel system, it's a small tank and gets drained and cleaned annually.

Andsarkit, that was my thoughts but for the sake of a tenner I don't mind doing it a "better way". I have a half decent propane torch (rather than a old school blow lamp) and some fire bricks knocking about but I hope it's not going to be too hard. I have the other 6mm elbow to practice on.

The dip tube is for my diesel heater that only uses 3mm delivery hose, I didn't want to go too big incase the pump couldn't lift it, if it blocks/the joint breaks it'll not be the end of the world.
 
Yellow Ballad said:
I need to make a new dip tube for my diesel tank for my diesel heater. I have the fitting 3/8 brass elbow to fit the union on the tank, I've got a brass "plug" with a 5mm hole in the middle and some 5mm brass tube.

What's the best way to stick them together? I have regular plumbing solder here, I don't mind buying some silver solder if needs be but thought I would ask on here first. Obviously it's not something structural but I don't want any air leaks from the joint.

Over to you...
Click to expand...
I made a similar dip tube for my eberspacher heater using 3mm bore copper and a brass fitting. I used araldite to bond the tube into the bore of the fitting. Been good for 7 years so far......

Www.solocoastalsailing.co.uk
 
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I got itchy fingers and decided to have a go with the leaded plumbing solder I had.

Firstly I thought I would have a go at joing two pieces of the rod together, overlapped. I held the small part in the vice and couldn't breat it by hand. Two knocks with the hammer did it and you can see where the solder let go.

20211011_141432_copy_979x1305.jpg

Happy with that I tried the actual fittings, intentionally over filled the one I'll be using just in case!

So thank you for the input but I did what every good forum user does and ignore the majority ?.

20211011_141357_copy_979x1305.jpg
 
Yellow Ballad said:
I got itchy fingers and decided to have a go with the leaded plumbing solder I had.

Firstly I thought I would have a go at joing two pieces of the rod together, overlapped. I held the small part in the vice and couldn't breat it by hand. Two knocks with the hammer did it and you can see where the solder let go.

View attachment 123920

Happy with that I tried the actual fittings, intentionally over filled the one I'll be using just in case!

So thank you for the input but I did what every good forum user does and ignore the majority ?.

View attachment 123921
Click to expand...

Chances of that falling out are about zero, same as if you'd have used epoxy.
 
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