Salvaging a Failed Vacuum Infusion: How We Saved a Boat Floor

This week’s floor came in two parts — the hatch first, then the floor itself, built around the hatch as its own mould. Between cold weather, a resin that turned out to be genuinely dodgy, and a vacuum that wasn’t quite there, it didn’t go entirely to plan — but it’s a good example of how an infusion failure actually gets rescued rather than scrapped.

Using the Hatch as a Mould

Rather than building the floor’s recessed hatch lip separately and hoping it lines up, the finished hatch itself becomes the mould. A 1mm silicone spacer wraps around the hatch’s edge, stretchy enough to peel away cleanly once cured, leaving a perfectly matched 1mm gap for the hatch to sit into later. It’s a genuinely satisfying process to watch — the spacer stretches thin as it comes away, and the result is a recess that fits the actual hatch rather than an approximation of one.

Worth mentioning too: the Teflon release tape used in this process gets reused wherever possible — not from any pretence of being a fully green process, but because reusing it once cuts material use and cost in half, and a third use cuts it further again. Every reuse matters when the alternative is treating each piece like a single-use plastic bag.

When an Infusion Doesn’t Go to Plan

This particular infusion ran into three separate problems at once, and it’s worth being honest about all three rather than glossing over what went wrong. It was cold. There wasn’t enough vacuum. And the resin — a fresh tin of polyester that came out visibly the wrong colour, the first sign something was off — had drifted in its formulation enough to shorten the gel time unpredictably. Any one of those three issues alone might have been manageable; together, they meant the infusion didn’t fully wet out.

Repairing an Infusion, Rather Than Starting Over

The fix for a partially-failed infusion is what’s sometimes called an infusion repair: identifying exactly where resin didn’t reach, then setting up fresh feed lines and flow mesh specifically over those dry sections and infusing again. This particular floor needed that treatment twice before it was fully done — three infusion passes total on the same piece. Not the smoothest process, but a genuinely useful one to document, since it shows that a partial infusion failure doesn’t mean starting from scratch.

Peeling back the peel ply afterward makes the problem visible in a way that’s hard to argue with: fully wet-out sections show peel ply stuck firmly to the laminate underneath, while the sections that didn’t infuse properly show peel ply that’s wet but not adhered — a direct, visual map of exactly where air got trapped and resin never fully reached.

Getting the Hatch Weight Right — Without Compromising Durability

Comparing two hatches built this way surfaced a useful lesson about what “lighter” actually means. The first hatch came out stiffer than it strictly needed to be — plenty strong, genuinely overbuilt. The second used a thinner bottom skin specifically to shed some of that unnecessary weight.

The nuance worth understanding here: the minimum skin thickness on a part like this isn’t set by strength requirements at all — it’s set by durability, what’s sometimes only half-jokingly called the seagull problem. A hatch panel can be structurally stiff enough for its actual loads while still being too thin to survive everyday wear and impact — something landing on it, being stepped on, general damage tolerance over years of use. It’s not a strength calculation; it’s a durability one, and the two aren’t the same question.

More on This: A Members-Only Deep Dive

A question that comes up often after posts like this one: is infusion always better than vacuum bagging, wet lamination, or even compression moulding? The honest answer is that the question itself is framed the wrong way — none of these methods is categorically better than another. They’re different processes for reaching a specific final product, and on plenty of parts, more than one method gets used together to get there. This post lays out the basics — for the fuller discussion, with real detail on when each method actually makes sense, see Advanced Resin Infusion: Avoid Close-Outs in the Members Library.

In This Series

Salvaging a Failed Vacuum Infusion is one part of Paikea’s floor replacement. Follow the rest of the build here:

Follow the rest of Paikea’s interior transformation on the Paikea’s Refit page.