A thrash logo has to do two contradictory things at once: read instantly from four feet away in a record shop, and look illegible enough at close range that wearing it on a shirt means something. The bands who solved that problem are still selling merchandise on it forty years later.
This is how the thrash logo works, who designed the important ones, and why the good ones have outlived most of the sleeves they appeared on.
The two jobs
Job one is the rack. In 1986 a record was seen at an angle, at a distance, among two hundred others, by somebody who had never heard the band. The logo had to be the thing that stopped them, which pushes towards high contrast, a strong silhouette and a shape that reads before the letters do.
Job two is the badge. The same mark had to work on the back of a denim jacket as a signal to other people who already knew, and there the requirement inverts: the harder it is to read, the better it works, because decoding it is the point.
The great logos solve both. Metallica's reads at fifty feet and is still unmistakably a specific shape rather than a typeface. Slayer's sword letters are legible and aggressive at once.
Testament

One of the best executed in the genre: sharp, symmetrical, readable, and with just enough spike on the terminals to place it. It has barely changed in forty years, which is the highest compliment a logo can be paid.
Slayer

Fully formed on the debut and untouched since. The letters are constructed from blades, the S resolves into a hook, and the whole mark is symmetrical enough to be tattooed. It is arguably the most reproduced logo in heavy music after Metallica's.
Sodom

The German approach, which is spikier and less stable than the American one. Sodom's mark changed shape repeatedly across the eighties, and the version on Persecution Mania is the one most people picture.
The other essential marks
Metallica's extended M and A, drawn by James Hetfield, which is the single most recognisable logo in heavy music. Megadeth's angular script with the drop shadow. Anthrax's block capitals, which are almost aggressively plain and work for exactly that reason. Kreator's clawed K. Exodus's fractured letterforms. Overkill's skull, which is a mascot doing a logo's job.
| Approach | Bands | Characteristic |
|---|---|---|
| Readable and sharp | Metallica, Slayer, Testament | Works at fifty feet and on a shirt |
| Plain block | Anthrax, Overkill | Refuses the spikes deliberately |
| German spike | Sodom, Kreator, Destruction | Changes shape album to album |
| Illegible by design | Much of the underground | Belongs to death and black metal after 1990 |
Where the spikes came from
Two ancestors, and neither is metal.
The first is the horror film poster and the paperback cover, which is where the dripping, carved and blade constructed letterform tradition actually lives. A great many early metal logos are straightforwardly borrowed from that vocabulary.
The second is the punk fanzine, which supplied the opposite instinct: hand drawn, urgent, done with a marker pen at speed. The German logos in particular have that quality, and it is not an accident that the labels behind them came out of the anarcho punk scene.
What the thrash bands added was symmetry. A punk logo is deliberately ugly and a thrash logo is deliberately balanced, because it has to survive being embroidered, screen printed, carved into a school desk and drawn from memory on the back of an exercise book.
What happened next
Thrash logos were the last legible generation. Death metal took the same vocabulary and pushed it until reading the band name became a puzzle, and black metal took it further still, to the point where a logo is a shape rather than a word.
That progression is a straight line and it runs out of the German thrash marks rather than the American ones. The spikier and less stable the source, the more illegible its descendants.
Meanwhile the American logos have barely moved. Metallica, Slayer, Anthrax, Testament and Overkill are all using marks that were finished before 1990, and every one of them still functions on a shirt in a shop today, which is a better outcome than almost any commercial design of the same period managed.
A related visual tradition, and one that several of these bands committed to much harder, is in the Christian thrash bands, whose iconography had to solve a different problem entirely. The full map of the bands is in the bands you need to know.
Who actually drew them
Frequently a member of the band, which is a real difference from most commercial design and explains a great deal about why the marks feel like they belong to the music.
James Hetfield drew the Metallica logo. Away drew everything Voivod ever used. Several of the German marks were done by the same illustrators who did the sleeves, which is why band and artwork match so closely in that scene. Where a designer was hired at all it was usually somebody local, working fast, for very little.
The consequence is that these logos were not tested, focus grouped or refined. They were drawn once, printed, and either worked or did not, and the survival rate of the good ones is a reasonable argument that the process was not a bad one.
What a logo is worth now
Considerably more than the records, in several cases, and that is not entirely a joke.
A band who sold forty thousand albums in 1986 can now sell shirts to people who have never heard a note, because the mark has escaped the music and become a piece of visual shorthand. That is a strange fate and the bands mostly regard it with amusement rather than resentment; a shirt sold is a shirt sold, and it is more money than the original pressing ever generated.
It also means the logo is frequently the only part of an obscure band that survives at all. Somebody sees a mark on a jacket, looks it up, and a record that sold two thousand copies in Wisconsin in 1988 acquires a new listener. The badge does the work the distribution never did.
Sources and notes
Design attributions follow the credits available on original pressings, which for logos are frequently absent. Descriptions refer to the marks as used in the 1980s.