Composite manual

This document is a manual of how to create a composite shape to a given set of plans.  The composite shape I'm going to discuss is the girder in the SHAW 550 yacht that we built in class.  The girder is and important structural member of the boat, it runs from the transom of the boat forward till you get near the cockpit.  The girder serves as a structural part of the cockpit floor so that when your walking along the deck the girder and support some of the load.

Steps:

1-  Make your composite product, don't force yourself to work within a boundry, try and keep it larger "you can always take off but not put back on"

2-  Create a working surface, larger than what you need.  Make it workable to standards of what you need.

3-  Gather and cut the materials that you need.  With the purfirated plastic you can cut that roughy to the size of the girder This will consist of resin, glass, purfirated plastic, mesh, vacuum bag and vacuum tape and have them by your table ready for it to be applyed.

4-  On your table that you have made to vacuum onto, put your vacuum tape around the edge, you would want to put the tape on before hand because that reduces the risk of the edge of the table to be contaminated like if resin goes to the edge of the the table and then you try and put down your tape it will not stick.

5-  Place your foam girder on the table and mix up 4-5 pumps of epoxy resin into a clean container and stir for 2 minutes and make sure that someone records the time that the resin was poured into the container becuase depending on the weather the resin has a pot life and will start to gel if not applyed fast enough.

6-  Lay your glass over the top of the foam girder and start wetting the resin out using squigies.  A good technique is to wet out the centre of your glass so that it can roughly stay in possition while your applying it to the other areas.

7-  Next you put your peel ply over the glass.
8-  Grab you purfirated plastic and lay it over the top of the girder but make sure it is kept within the boundries of the vacuum tape.

9-  Over the top of the purfirated plastic you want to put down your mesh still staying within the vacuum tape.

10-  Now for the vacuum bag, take you bag and work fown one side of your bag, while you are putting down your bag you need to put in some darts.  Darts are massive creases on the bag which helps the bag get around and into corners and tight spots.  You need quite a lot of these darts so dont be shy.

11-  Grab you hose and make sure it has mesh on and in the tip.

12-  While you are putting down the bag make a spot for you to put your hose into, the hose needs to fully sealed so cover it with vacuum tape and make sure it is pressed down onto the bag and the table with prenty of vacuum tape.

13-  Once you have finished putting down your bag and connecting the hose into the mix turn the hose on.

14-  Walk around the vacuum and listen for the whistle noises coming out of the bag which means there is an air hole that needs to be closed up so you can get a full vacuum.

15-  CLEAN UP.

The stack is made of different layers, each with different/similar perposes which are:

Glass- Glass is the external/internal skin  that helps stiffen up the boat in a massive way and protects the surface.

Peel Ply- Peel ply is a cloth that goes over the top of the glass and it soaks up excess resin and also heaps to protect the glass.

Purfirated Plastic- Purfirated plastic is oviously plastic but purfirated plastic has hole in it and this helps the let the air flow though and go out the bag to get a good vacuum.  This plastic also helps with excess resin.

Mesh- Mesh is like a shade sail type material that has larger hole in it and has the same purpose as the purfirated plastic, catching excess resin and heaps with the release of air.

Vaccum bag- Vacuum bag is a large plastic that is much bigger than the project you are doing.  You don't want any holes in the bag or else the bag becomes useless.

EDB240 - Fibre Glass                                                      Peel Ply

Purfirated Plastic                                                               Mesh

Vacuum Tape                                                                   Vacuum Bag

 Vacuuming the girder

Reflection: There were a few things that we can improve on and make better for next time, like when putting in the hose for vacuum you could put the hose at the top of a dart so the when the pump is turned on, the vacuum doesn't pull down the hose and create a bumo or hollow in the laminate.

Another thing we could have done was glassing both side at the same time, this would have been more efficient and saved more time.