Buyer's guide

How to choose a surface profile gauge

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This page is an unofficial buyer's guide. It is not affiliated with or endorsed by Amazon, AWS, API, or AMPP. It is not a review written for hire. Links below are placeholders. They are not live, and they are not product recommendations.

This page is for someone who has to measure the anchor pattern left by abrasive blasting, and is choosing the instrument. Profile is the roughened shape that gives a coating something to grip. Too little may not hold the film. Too much can leave peaks standing through a thin film. The range that separates those is in the project specification or the product data sheet. This page does not print a universal range, and it does not copy a test method from a standard.

There is no best profile gauge on this page. There is a method your specification allows, and there are tools that perform that method honestly.

Three methods, and you do not average them

Replica tape. A foam tape is burnished into the profile and then measured. The tape maker tells you what to subtract for the backing that does not compress. Use that instruction. Do not use a subtraction you half remember from a class. The burnishing tool is the one the maker names. A thumb is warmer, and it is the wrong tool.

Tape is sold in grades. Each grade covers a band of depth, printed by the maker. Buy the grade that matches the profile you expect, and carry the neighboring grade. A reading that sits on the end of a grade is a reason to check the next grade, when the maker says so. Forcing a number off the stop of the scale is how fiction gets written in a steady hand.

A digital reader that measures the same tape is a convenience around the same method. It is not a new kind of physics. A bad burnish still makes a bad number, faster.

Depth micrometer. A pointed probe measures peak-to-valley directly. You zero it the way the maker says, on the flat they trust. The point wears. A worn point lies with confidence. Plan on the maker's replacement point, and on a zero check, as part of owning the tool rather than as a surprise.

Visual comparator. A disc or a plate of reference patches. You compare the steel to a patch under the light the method describes. It is a comparison. It is not a dial. Some specifications allow it. Some want a number from tape or from a stylus. If your specification wants a number, a comparator does not become a number because you stared harder.

If two methods that the specification allows disagree, write both and follow the specification's rule for disagreement. Do not average them into a third number nobody measured.

What to buy as a kit, not as a single object

For tape: the grades you will actually use, the burnishing tool, and a micrometer or a reader the maker intends for that tape. For a depth micrometer: the instrument, a way to zero it, and a spare point if the work is remote. For a comparator: the disc the specification names, not a disc from a different method that happens to be cheaper.

A kit that cannot tell you which method it is performing is a kit to leave on the shelf.

What to check before you pay

• Which method your current specifications allow. Buy that method first.
• The depth band printed on the tape grade, compared with the profiles you actually see. Not a guessed band.
• How the maker wants the tape burnished, and whether the reader assumes a subtraction. Read that page before you depend on the reader.
• How the depth micrometer is zeroed, and what a worn point costs in time as well as money.
• Whether the comparator is the reference your specification cites. A different disc is a different comparison.
• A case that keeps tape flat and a micrometer honest in a truck.
• Calibration or a verification step, if the project requires a certificate on the micrometer. That certificate is often a separate purchase. This page does not arrange one.

Mistakes that waste the purchase

Buying only a comparator when the specification wants a measured depth. Buying one tape grade and using it past the end of its band. Burnishing with a thumbnail. Averaging a tape reading and a stylus reading to settle an argument. Writing "good profile" with no method, no place, and no unit.

What this page will not do

It will not name a model as the one to own. It will not state a profile range. It will not claim a price, and it will not claim that a given tool is listed on Amazon. Names you recognize from a data sheet are examples of the category, not an endorsement.

Follow the project specification and the maker's instructions. Where this page is quieter than those documents, the documents are the authority.