A laminate is only as strong as its weakest patch, and the weak patches are almost always the same two things: a dry spot where the resin never fully saturated the cloth, or a trapped air bubble sitting between layers. Both are avoidable with the right resin, the right technique, and a bit of patience.
Start With the Right Resin
MAS Low Vis Resin is formulated as a low molecular weight, 100% solids resin specifically to fully saturate fibre-reinforced fabrics, including carbon fibre and mixed cloths, and it's our most popular choice for exactly this reason. A thicker resin will sit on top of the cloth rather than penetrating it properly, which is how dry patches happen even when you think you've applied plenty of material.
Choosing and Laying Your Cloth
We stock glass biaxial stitched cloth and tape, which wets out cleanly and turns fully transparent once properly saturated — a useful visual check as you go, since a patch that's still opaque or white hasn't wet out yet. It also has good draping qualities, so it lies into curved or complex shapes without you having to fight it into place, which matters because cloth that's been forced or stretched into position is more likely to leave voids underneath it.
Lay cloth in dry and let the resin wick through from underneath rather than pouring resin on top and hoping it soaks down — a simple spread followed by a light roller pass is usually enough. For tape, you can lay it wet or dry depending on the job. Whichever you're using, allow a proper overlap between pieces; a thin or missing overlap is another common source of a weak line running through an otherwise sound laminate.
Working Out Air Bubbles
Air gets trapped between layers most often when cloth is laid too fast, pressed down unevenly, or laid over a surface with texture or edges the resin hasn't had a chance to work into first. A roller worked methodically from the centre of a panel outward, rather than randomly across the surface, pushes trapped air ahead of it towards the edges rather than sealing it in. Take your time on corners, edges and anywhere the cloth changes direction — these are the spots where air most often gets left behind.
Timing Your Next Layer
If you need to stop partway through a multi-layer lay-up, that's not a problem, but timing matters. If you can still mark the cured epoxy with a thumbnail, you're fine to keep building layers directly on top. Once it can't be marked, it's fully cured, and you'll need to abrade the surface with 100-grit paper before continuing — and remember to keep your overlap consistent even across that pause.
Cleaning Up as You Go
Keep your tools and rollers clean between mixes rather than letting resin build up and go off on them, since a roller clogged with partially cured epoxy will leave a worse finish on your next pass. Our Bio-Solv Acetone Replacement cleans uncured epoxy resin from tools and guns effectively without the fumes and flammability of a traditional solvent, and it lasts considerably longer than something like acetone before you need to replace it.
Once your cloth is down and wet out, you can build up further depth with MAS FLAG resin rather than more Low Vis, since FLAG's thicker bond line is better suited to building thickness than saturating cloth.
