How to Make a Plumbing Capillary Joint

A capillary joint is simply a copper sleeve with socket outlets into which the pipe ends are soldered. It is neater and smaller than a compression joint and forms a robust connection that will not readily pull apart.

Because it is considerably cheaper than a compression joint it is frequently used when a number of joints have to be made and is particularly useful in awkward positions where it is impossible to use wrenches.

Some people are put off using capillary fittings because of the need to use a blow-torch. But modern gas-canister torches have put paid to the fears associated with paraffin lamps and are not dangerous.

capillary joint How to Make a Plumbing Capillary Joint

How a capillary joint works

If two pipes to be joined together were just soldered end to end the join would be very weak because the contact area between solder and copper would be small. A capillary fitting makes a secure join because the sleeve increases this contact area and also acts as a brace to strengthen the connection.

Molten solder is sucked into the space between the pipe and fitting by capillary action, and combines with a thin layer of copper at the contact surface thus bonding the pipe to the fitting. To help the solder to ˇ®take’ the copper needs to be clean and shining. Therefore flux is applied to prevent oxides forming which would impair the solder-copper bond.

Types of capillary joint

The most common type of capillary joint has a ring of solder pre-loaded into the sleeve. It is known as an integral ring or ‘Yorkshire’ fitting – the name of a leading brand.

The ‘end feed’ type of capillary joint is virtually the same as an integral ring fitting, but you have to add the solder in a separate operation. The sleeve is slightly larger than the pipe and liquid solder is drawn into the space between by capillary action.

Instructions: Making a capillary joint

1. Make sure the pipe end is square, then clean it and the inner rim of the fitting with steel wool or abrasive paper until shining.

2. Flux can be in liquid or paste form. Use a brush, rather than your finger, to smear it over the end of the pipe and the inner rim of the fitting.

3. Push pipe into fitting so that it rests against pipe stop, twisting a little to help spread the flux. Remove excess flux with a cloth.

4. When you’re making up a whole pipe run, it helps to make corresponding pencil marks on pipe ends and fittings as a guide for correct lining up.

5. Make other side of joint in same way, then apply blow-torch. Seal is complete when bright ring of solder is visible at ends of fitting.

6. For an end feed fitting, heat the pipe, then hold the solder to mouth of joint. A bright ring all the way round signifies a seal.


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

Powered by WordPress | Maintained by: Expert How | Thanks to Mega HowTo