Everything below is quoted from a published technical datasheet or a named standard. Where a product does not publish a value, the table says "not published" — that is a statement about documentation, not about performance.
Sealers are developed against different failure modes, and comparing them row by row produces conclusions the data cannot support. The useful comparison is a problem map: start from the failure you have, then look at what each product's published data addresses.
| Product | Designed against | What its published data highlights |
|---|---|---|
| GT-Sealer 501HT | Sealing before a dehydrogenation bake; high-strength fasteners | 250 °C bake without discolouration, corrosion resistance retained after dehydrogenation; 100–400 ml/L; pH 7.5–10 no adjustment; friction 0.13–0.18 |
| FINIGARD 105 | Zinc and zinc-alloy systems with a matching passivation; automotive fasteners | Organic-mineral concentrate; 750–1000 ml/L; 120 °C thermal shock 1 h with 240 h no white rust / 720 h no red rust; friction 0.15 ± 0.03 (DIN 946) |
| 350 WL8 | Zinc passivated surfaces where a low friction coefficient is the priority | Silicate-based organic/inorganic reactive system; 450–900 ml/L barrel / 200–400 ml/L rack; friction 0.08–0.12; stated not to cause hydrogen embrittlement |
Sources: GT-Sealer 501HT technical datasheet; FINIGARD 105 TDS (CN-TDS-03032 C); 350 WL8 product data sheet (1411-CN 02). Products are listed to show different design targets, not to rank them.
| Parameter | Value (TDS) |
|---|---|
| Type | Water-based organic-inorganic sealer |
| Substrates | Zinc, zinc-nickel, zinc-iron, zinc-cobalt, zinc alloys, aluminium (after trivalent passivation) |
| Heat resistance | No discolouration at 250 °C; corrosion resistance retained after dehydrogenation |
| Working concentration | 100–400 ml/L |
| Operating temperature | Ambient to 40 °C |
| pH | 7.5–10, normally no adjustment; top up with concentrate |
| Friction coefficient | 0.13–0.18 |
| Appearance | Silver-white achievable after blue-white or yellow passivation |
| Agitation / filtration | Not required in normal operation |
| Criterion | What it means |
|---|---|
| White rust at 96 h | The barrier lasted 96 h at the weakest point. Sensitive to film quality and passivation. |
| Red rust at 240 h | The zinc was not consumed at that point. Driven mainly by coating thickness. |
| Scribed vs unscribed | A scribe tests under-film corrosion spreading, not barrier performance. Different failure mode, different acceptance rule. |
| GB/T 10125 / ISO 9227 / ASTM B117 | Similar but not identical. A result is only comparable within the same standard and the same chamber practice. |
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