DOMINOX guide
From cut to joint: preparing copper tube
A copper joint fails at the preparation, long before the flame. Three steps come first: a square cut, a clean edge and a tube that is still round. Here is how we do each one.
By the DOMINOX team · sources read 1 October 2026
Cut square, and gently
A wheel cutter beats a hacksaw on copper because it leaves the end square and makes no filings. Tighten the knob a little on each turn and let the wheel do the cutting.
Soft, annealed tube needs the lightest hand. The Copper Development Association puts it this way in its handbook.
With soft tube, care must be taken not to deform the tube end by applying too much pressure.
The same holds for the cutter. Crank the knob hard on soft tube and you squeeze it out of round, and no fitting will seat on an oval end.
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CT-650
CT-650 Tubing Cutter with Deburring Tool
One cutter from 3/16 to 2 inch copper, with a deburring pen in the box.
3/16-2in
Which cutter for which tube
| Feature | CT-650 | JJ1322 mini |
|---|---|---|
| Tube sizes | 3/16 to 2 in | 1/8 to 7/8 in |
| Fits in a tight space | No | Yes |
| Deburring tool in the box | Yes | No |
| Price | $20.99 | $8.99 |
Take the burr off, inside and out
Every cut leaves a lip on the inside of the tube. Water speeds up around that lip, and over the years the fast water wears the wall behind it. A reamer removes the lip in a few turns.
- Push the tube onto the cone and turn to clear the inside edge.
- Turn the tube in the cup to clear the outside edge.
- Tip the tube down and tap out the chips.
- Wipe the end bright with abrasive cloth before you flux.
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CT-211
CT-211 Tubing and Pipe Reamer, 1/4 to 1-3/8 in
Deburrs the inside and the outside of a tube end with a few turns of the wrist.
1/4-1-3/8in
Solder or braze
Solder flows at a few hundred degrees and suits household water lines. Brazing alloys need far more heat and make a stronger joint. Refrigeration lines are brazed for that reason. The heat has a cost, and the handbook spells it out.
When welding or brazing is used to join tubes, the annealed ratings must be used, since the heating involved in these joining processes will anneal (soften) the hard tube.
So brazed hard tube is no longer hard near the joint. Support it, and do not count on its original strength there.
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DM-022CGA
DM-022 Trigger-Start Propane Torch
Our best-known torch head: one press lights it, one button holds the flame.
2,372°F
Where our tools stop
- The wheel cutters take tube walls under 0.1 inch. They are not for steel pipe.
- A hand torch on propane brazes copper up to about 3/4 inch. Larger joints want more heat than it gives.
- We sell no solder, flux or brazing rod. Buy those to match your pipe and your code.
- Local plumbing code decides what joint is allowed where. Check it before you start.
Sources we read
- Copper Development Association: Copper Tube Handbook. Read 1 October 2026.
More guides
- Torch work near wood: Move it, shield it, and keep an extinguisher in reach.
- Before you open a refrigerant line: The charge goes to a recovery machine, never to the air.