# 🚫 NEVER LASER THESE MATERIALS

### <span style="color:rgb(224,62,45);">**These materials should never be used in the laser.** </span>

##### <span style="color:rgb(224,62,45);">**This is not an** </span><span style="color:#e03e2d;"><span>**exhaustive list. If you are not sure, don't use it and find out.**</span></span>

## <span style="color:rgb(224,62,45);">**[![No.png](https://wiki.leicesterhackspace.org.uk/uploads/images/gallery/2026-07/scaled-1680-/no-png.png)](https://wiki.leicesterhackspace.org.uk/uploads/images/gallery/2026-07/scaled-1680-/no-png.png)**</span>

#### <span style="color:rgb(0,0,0);">**PVC, vinyl, neoprene, pleather, PTFE (Teflon)**</span>

<p class="callout danger"><span style="color:rgb(224,62,45);">**When heated, these materials release chlorine or similar gases. This is a respiratory hazard, but also combines with moisture in the air to create acids which will seriously damage the laser through corrosion.**</span></p>

#### <span style="color:rgb(0,0,0);">**Polypropylene sheet and foam**</span>

<p class="callout danger"><span style="color:rgb(224,62,45);">**Highly flammable and likely to catch fire whilst cutting**</span></p>

#### <span style="color:rgb(0,0,0);">**Coated carbon fibre**</span>

<p class="callout danger"><span style="color:rgb(224,62,45);">**The resin coating can give off toxic fumes and is a significant fire risk**</span></p>

#### <span style="color:rgb(0,0,0);">**Mirror-finish metals**</span>

<p class="callout danger"><span style="color:rgb(224,62,45);">**The mirror finish is likely to reflect the laser straight back along the laser path and damage the optics. A CO<sub>2</sub> laser will not cut or mark metals anyway.**</span></p>

#### <span style="color:rgb(0,0,0);">**ABS plastic**</span>

<p class="callout danger"><span style="color:rgb(224,62,45);">**Emits cyanide fumes when lasered and is likely to melt and burn rather than cut cleanly**</span></p>

#### <span style="color:rgb(0,0,0);">**HDPE plastic (e.g. milk bottles)**</span>

<p class="callout danger"><span style="color:rgb(224,62,45);">**Likely to melt and burn rather than cut cleanly**</span></p>

#### <span style="color:rgb(0,0,0);">**Chromium tanned leather**</span>

<p class="callout danger"><span style="color:rgb(224,62,45);">**Releases toxic chromium oxide fumes during laser cutting**</span></p>

<p class="callout info"><span style="color:rgb(53,152,219);">**Use vegetable tanned leather instead**</span></p>

#### <span style="color:rgb(0,0,0);">**Fibreglass**</span>

<p class="callout danger"><span style="color:rgb(224,62,45);">**Both glass dust and resin fumes will damage the machine and cause respiratory problems**</span></p>

#### <span style="color:rgb(0,0,0);">**Expanded polystyrene/polystyrene foam**</span>

<p class="callout danger">**<span style="color:#e03e2d;">Very high fire risk, with toxic smoke</span>**</p>

<p class="callout info">**<span style="color:rgb(53,152,219);">There are some foams, e.g. EVA, that are laser safe alternatives</span>**</p>

#### <span style="color:rgb(0,0,0);">**Cured epoxy resins**</span>

<p class="callout danger">**<span style="color:#e03e2d;">High fire risk, with toxic smoke including cyanide and chlorine</span>**</p>

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