Over the years, running our aluminum brazing material factory, I’ve received calls from customers facing brazing issues—not because of bad materials, but because of small mistakes in the process.

Here, I’ll share the most common problems in aluminum brazing that I’ve seen again and again—and how we help customers solve (and prevent) them.

1. Poor Wetting or No Flow

This is one of the most common issues. The filler doesn’t flow or spread properly across the joint.

Causes:

• Surface not clean enough (oil, oxide, or dust)

• Incorrect temperature (too low or too fast heating)

• Using bare alloy without enough flux

Solution:
Use flux-cored aluminum wire for consistent flow. We also recommend pre-cleaning the parts—even new tubes need it!

2. Joint Cracking After Cooling

Some customers notice that the joint cracks during cooling or later in use.

Causes:

• Too much gap between parts

• Thermal stress due to uneven heating

• Wrong alloy choice for the base metal

Solution:
Keep joint gaps tight (usually 0.1–0.2 mm is enough), and heat evenly. If needed, send us your base metal specs—we’ll suggest the right alloy.

3. Excessive Residue or Flux Marks

Sometimes after brazing, white or black residue appears, especially when using external flux.

Causes:

• Too much flux applied

• Improper temperature control

• No post-cleaning step

Solution:
Switch to flux-cored wire to reduce mess, and if using powder flux, apply lightly and clean thoroughly after brazing with warm water or a soft brush.

4. Overheating and Burn-Through

This happens when operators accidentally overheat thin aluminum parts.

Causes:

• Inexperienced operator

• Flame held too long in one spot

• No temperature monitoring

Solution:
Use temperature indicators or a pre-set heating cycle for automation. We’ve also trained many customers’ teams to better control the flame and timing.

5. Inconsistent Joint Strength

Some joints are strong, others weak—even on the same product batch.

Causes:

• Uneven heating

• Irregular filler metal feeding

• Dirty base materials

Solution:
Consistency is key. We recommend automatic brazing machines for large-scale production, paired with our stable-quality wires and rings.

Final Thoughts from the Factory Floor

Problems in brazing are usually process-related, not material defects. That’s why we always offer technical guidance with our products—not just ship and forget.

If you’re facing a recurring issue, feel free to send us pictures or a video. We’ve seen it all—and we know how to fix it.

Need help choosing a better wire or solving a brazing issue?
We’re here to support you—just like we’ve supported over 100 clients worldwide.