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The HINZIC LP6138-M is a 10-pack of straight copper couplings listed with a 6.35 mm (1/4 inch) inner diameter, a 0.8 mm wall and sweat ends with a rolled tube stop. A HINZIC copper coupling suits small HVAC or refrigeration copper tube repairs when you already know your tube size. It does not give a pressure rating, so it is not a substitute for a rated fitting.
Quick Facts
| Item | Detail (per the listing) |
|---|---|
| Brand and model | HINZIC, LP6138-M |
| Pack | 10 straight couplings |
| Inner diameter | 6.35 mm (1/4 inch) |
| Wall thickness | 0.8 mm |
| Ends | Sweat ends with a rolled tube stop |
| Listed uses | HVAC, air conditioning, refrigeration, hydraulic lines |
| Not stated | Pressure rating, temperature rating, certifications |
What a HINZIC Copper Coupling Is For
The coupling reconnects or extends a straight run of copper tube of the same size. The rolled stop gives each tube a defined insertion point. The listing points to air conditioning, refrigeration, HVAC and hydraulic applications, but without a stated pressure or temperature rating you need your own documentation to decide whether it suits a given system.
Before You Order
- Measure the tube’s outside diameter. These couplings are meant for 1/4 inch (6.35 mm) tubing.
- Confirm the tube is round, clean and undamaged.
- Decide on the joining method (soldering or brazing) based on the system. Refrigerant lines are usually brazed.
- Check local code and any certification needed for refrigerant work.
Joining Tips
- Cut square, deburr, and clean the tube and fitting until bright.
- Insert the tube to the stop and heat the fitting evenly, not just one side.
- Feed filler into the joint and let it flow by capillary action.
- Leave the joint still until it cools, then clean and test it as the system requires.
For technique, see how to braze HVAC copper lines without leaks.
Pros and Limitations
Pros
- Ten matched couplings for service stock.
- Wall thickness listed at 0.8 mm, slightly thicker than some similar sets.
- Simple straight design.
Limitations
- One size only; no reducing or turning.
- No pressure, temperature or approval ratings stated.
- Listing variant details (finish and size) should be checked before ordering.
HINZIC vs the Wvapzwr Set
The other 1/4 inch option we covered is the Wvapzwr 1/4 inch copper coupling fittings, which list a 0.7 mm wall and 16 mm length. They are the same nominal size, so compare price and what the listing states. For filler metals, see our BCuP-2 copper brazing rods review.
Frequently Asked Questions
What does LP6138-M mean?
It is the model number on the HINZIC listing for this 10-pack of 1/4 inch straight copper couplings.
Do these fit 1/4 inch tubing?
They are listed with a 6.35 mm (1/4 inch) inner diameter, so they are meant for 1/4 inch outside diameter tube. Measure your tube to confirm.
Can I use them on refrigerant lines?
The listing mentions refrigeration use, but it gives no rating or approval. Follow the system manufacturer, local code and certification requirements.
Is a rolled tube stop important?
It gives each tube a set depth in the fitting so the joint is positioned consistently.
Bottom Line
A reasonable pick for a stock of 1/4 inch copper couplings, provided your tube size and joining method match. Do not use them where a rated fitting is required.
