How to grade a circuit board by eye
Refiners and grade buyers price boards in tiers that span thirty to one. Getting the tier right before you ship is worth more than any amount of chemistry.
High grade
Typically $5–20 per pound. What you are looking for:
- Many gold-plated connectors and gold fingers — multiple edges, backplane connectors, dense pin fields
- Ceramic processors, gold-lid integrated circuits and flat packs still on the board
- High component density — many small chips packed close together
- Thick, rigid, multilayer laminate. Count the layers at a cut edge or look through a drilled hole
- Metal rather than plastic processor sockets, edge-plated grounds, gold-plated shields, conformal coating
Typical sources: telecom line cards and backplanes, mainframe and server boards, industrial and medical controllers, Apple logic boards, hard drive controller boards, cell phone boards.
Mid grade
Typically $2–8 per pound. Standard desktop motherboards: coloured soldermask, one processor socket, several gold-fingered expansion slots, a moderate component count, a mix of surface-mount and through-hole, four to eight layers. Laptop mainboards and graphics cards sit at the upper end of this band.
Low grade
Typically $0.20–0.60 per pound. The signals are unmistakable once you know them:
- Brown or tan phenolic substrate visible on at least one side. This is the single most reliable low-grade tell there is.
- Thin and flimsy, single- or double-sided, feels like it would snap if you bent it
- Dominated by large electrolytic capacitors, transformers, heatsinks and big through-hole resistors, with few or no integrated circuits
- No gold anywhere; tin-plated edges and headers
Typical sources: televisions, DVD players, microwaves, power supplies, LED drivers, appliance and automotive control boards.
The test that does not work
Holding a board up to a light does not grade it. This advice circulates constantly and it is wrong — plenty of low-grade boards are completely opaque, and translucency tracks laminate thickness and glass weave, not metal content. Use substrate colour, thickness, component density and visible gold together instead.
Grading is a moving target once you start harvesting
This trips up buyers and sellers alike. A server board is high grade with its processors, memory, sockets and connectors attached. Pull all of those and the remaining laminate is mid grade at best. Sellers routinely quote the pre-harvest grade for post-harvest material.
If you have stripped a board, say so. If you are buying, ask. The difference is often larger than the freight.
Why grade buying usually beats assay for small lots
Assay-based settlement pays you for actual metal content at 97–98%, but it carries a flat lot fee around $350, a per-pound treatment charge, and a minimum lot size in the thousands of pounds. Grade buying is a flat rate per pound with no visible fees and a minimum measured in dollars rather than tons.
For typical mid-grade material, gold alone does not beat the grade buyer even at thirty thousand pounds. Assay wins in two situations: when your material assays materially above what its visual category assumes, or when silver, palladium and copper are a real share of the value — because flat-rate tables credit none of those.
Questions
What makes a circuit board high grade?
Dense small components, gold-plated connectors and fingers on multiple edges, ceramic or gold-lidded chips, thick multilayer laminate, and metal sockets. Telecom line cards and server boards are the classic examples.
Can you tell board grade by holding it to a light?
No. That test is a myth. Translucency tracks laminate thickness and glass weave, not metal content, and many low-grade boards are fully opaque. Use substrate colour, thickness, component density and visible gold instead.
What does low grade board mean?
Thin, single- or double-sided boards, often on brown paper-based phenolic substrate, dominated by large capacitors, transformers and heatsinks with few chips and no visible gold. They typically pay under a dollar a pound.