---
title: Polygonal mould for sheetpress
slug: polygonal-mould-for-sheetpress
description: Plastic sheets made with a sheet press do not need to be square.

This guide explains how to create an octagonal mold for producing octagonal plastic sheets. The same techniques can be used to create molds of other polygonal shapes, such as triangles and hexagons.

For inquiries or suggestions about the mold, please refer to our contact information.
tags: ["HDPE","mould","hack","sheetpress"]
category: Moulds
difficulty: Medium
time: < 1 day
location: Sukawati, Indonesia
---
import { Image } from 'astro:assets'
# Polygonal mould for sheetpress
<Image src={import('./Screenshot_3-18551b60d58.png')} alt="Polygonal mould for sheetpress" />
Plastic sheets made with a sheet press do not need to be square.

This guide explains how to create an octagonal mold for producing octagonal plastic sheets. The same techniques can be used to create molds of other polygonal shapes, such as triangles and hexagons.

For inquiries or suggestions about the mold, please refer to our contact information.

User Location: Sukawati, Indonesia
## Steps
### Step 1: Gather tools and material

Tools:

- Sheet press set
- Angle grinder
- Welding tools and materials
- Jigsaw
- Sander (for product finishing)
- Safety gear: welding helmet, safety glasses, mask
- Marker
- Ruler

Computer with drafting/drawing software

Materials:

- Steel for mold: 0.78x0.78 in galvanized steel (standard size = 19.7 ft)
- Clean, sorted plastic of chosen types


<Image src={import('./Screenshot_20221228_035519-18557c81e43.png')} alt="Screenshot_20221228_035519-18557c81e43.png" />


<Image src={import('./IMG_5704-18557ab30d8.jpg')} alt="IMG_5704-18557ab30d8.jpg" />

### Step 2: Draw

### Polygon Drawing Tutorial

1. **Drawing the Polygon:**
   - Use any drafting software to create a polygon. This provides precise dimensions for each side. A reference drawing is available in the provided drive link.

2. **Work Area Measurement:**
   - Measure your sheet press work area.
   - Offset the measured area by 2 inches (5 cm) inward to account for space needed around the mold.

3. **Polygon Adjustment:**
   - Adjust polygon dimensions according to your sheet press machine's capacity.
   - Offset by 0.8 inches (2 cm) inward for the thickness of galvanized steel.

4. **Mold Dimension Measurement:**
   - Derive mold dimensions from your drawing.
   - Utilize this drawing for calculating the plastic needed for sheet production.


<Image src={import('./octagonal_sheets-185529f10cc.png')} alt="octagonal sheets-185529f10cc.png" />

### Step 3: Cut

After determining measurements, cut the 20mm (0.79 inches) hollow galvanized steel with an angle grinder.

Use an erasable marker for precision.
Cut using the angle grinder.
Draw a 1:1 template of your sheets with a whiteboard marker to ensure alignment of angles and dimensions, and adjust as needed.


<Image src={import('./IMG_9475-1854bee9b7e.jpg')} alt="IMG_9475-1854bee9b7e.jpg" />


<Image src={import('./IMG_9468-1854beeb2ea.jpg')} alt="IMG_9468-1854beeb2ea.jpg" />


<Image src={import('./IMG_9491-1854beed0f0.jpg')} alt="IMG_9491-1854beed0f0.jpg" />

### Step 4: Weld

With a whiteboard marker, draw a full-scale template of your sheets to ensure angles and dimensions align, adjusting as necessary.

Weld the sides to connect the ends, forming polygonal sheets.


<Image src={import('./IMG_9771-1854d3672c3.jpg')} alt="IMG_9771-1854d3672c3.jpg" />


<Image src={import('./IMG_9795-1854d37704a.jpg')} alt="IMG_9795-1854d37704a.jpg" />


<Image src={import('./Screenshot_97-1854d36eb66.png')} alt="Screenshot (97)-1854d36eb66.png" />

### Step 5: Finishing

Grind excess welding material with an angle grinder. This ensures the mold is flat against the sheets, preventing damage to the steel plate and leakage of plastic.


<Image src={import('./Screenshot_95-18557c67553.png')} alt="Screenshot (95)-18557c67553.png" />


<Image src={import('./IMG_5701-18557c5366f.jpg')} alt="IMG_5701-18557c5366f.jpg" />


<Image src={import('./IMG_5700-18557c53ec1.jpg')} alt="IMG_5700-18557c53ec1.jpg" />

### Step 6: Make your polygonal sheet

### Making a Polygonal Sheet

1. Determine the area of your polygon from the drawing.
2. Calculate the required plastic quantity using this area.

For detailed instructions on sheet pressing, refer to the associated video tutorial.


<Image src={import('./IMG_9900-1854d39cf75.jpg')} alt="IMG_9900-1854d39cf75.jpg" />


<Image src={import('./DJI_0107-1854d39ff9e.jpg')} alt="DJI_0107-1854d39ff9e.jpg" />


<Image src={import('./3-1854d3a11e6.png')} alt="3-1854d3a11e6.png" />