Removing pitted corrosion in the field — without damaging the substrate?

For light pitting under stripped paint on your Bonanza's wing skin, you have a field-friendly procedure, but laser is not the first choice—and may not be appropriate at all depending on pit depth.

Step 1: Verify damage limits [1]

Consult your Bonanza's Structural Repair Manual (SRM). If any pit or blended dish-out would leave skin thinner than the SRM minimum (typically ~10% of original thickness, or 0.020 in on 0.040 in Alclad), the part requires repair or replacement rather than cleaning. Use a dial-depth or pit gauge to measure pit depth before you proceed.

Step 2: Choose your method [1]

For light pitting (<0.003 in deep):
Hand brush + conversion + paint. Mechanical cleaning is the default, lowest-cost, FAA-approved method for your application. [1][3]

For medium pitting (≤10% of skin thickness):
Mechanical blend with plastic/Tampico brushes and 150–240 grit aluminum oxide cloth—never steel or copper brushes. Fair to a 20:1 length-to-depth ratio, then progressively sand to 400 grit. [1][3]

Step 3: Why NOT laser first [1]

The decision tree in Source [1] places pulsed-fiber-laser cleaning in two specific slots:

Complex geometry, rivet lines, or environmental concerns (like containment of particulates).
NOT as the go-to for open-skin pitting on a wing.

Mechanical cleaning removes less parent metal overall and is already approved in every SRM. [1][3] Heat input is minimal, and you retain full control of depth with hand tools and gauges. [3]

Step 4: If you do consider laser [5]

Run a coupon first and perform an eddy-current thickness check to document zero base-metal loss before touching the aircraft. [5]
Use fume extraction with HEPA/activated-carbon filters. [5]
The Sources do not provide field FP-300 settings for corrosion pit removal; contact Jamie at jamie@aviationlaser.com or (479) 588-1200 for application engineering.

Step 5: Post-cleaning [1][4]

Whichever method you choose:

Chromate or TCP conversion coat within 8 hours of cleaning. [4]
Primer (epoxy) and top-coat per SRM. [1]
Eddy-current or borescope NDI to rule out hidden intergranular corrosion. [4]

Bottom line: For light-to-medium pitting on open wing skin, stick with mechanical cleaning. It's proven, fast, and won't weaken the aluminum if you respect the SRM thickness limit and use soft abrasives. Laser works best when you have geometric constraints or regulatory/environmental reasons to avoid particulate spray.

Sources

[1] Field-Oriented Checklist — Removing Pitted Corrosion
[2] FAA AC 43.13-1B — Acceptable Methods, Techniques, and Practices
[3] Field-Oriented Checklist — Removing Pitted Corrosion
[4] FeatherPulse Laser Ablation — Full Reference Document