Topic: Modeling

[bambuhiphop]

Hello,

I want try my hand at modeling a tail section and seat for my bike. I have never done this before and fully expect numerous errors to be made in my quest.

Not sure if I am going to weld pieces together or get really bold and try to make a fiberglass piece.

Looking for advice on what materials are good to use? Clay, foam, metals? Thanks in advance for the help!

[jgger]

Watched a guy on a 4WD forum do some awesome glass work. He made foam shapes for what he wanted then used or built a box around the part. Put some kind of separator on the part and suspended it in the box. Next he used either foam or plaster of paris and mate a mold and laid the glass in that.

He did a dash board and some other stuff and it came out great.

Good luck with the project.

[70CB750]

Often people use flower arrangement foam since it is easy to shape. Styrofoam is another option.  For fiberglass you will need to protect it -  most solvents melt that stuff

[RAFster122s]

Epoxy will not attack most foams but Polyester Resin will.   If you use the blue or pink foam you can shape it easier than some others.  Usually best to go in one direction...Right  to Left, etc. not back & forth... I reduces tear out.  The board you referred to is called a parting board...designed to create a female mold for the fiberglass to be created.  You make one side then you clean it up and then make the mold the other side.  Usually people will do wet seams in the mold for the two parts after the fiberglass is laid up on both sides when they bolt the halves together.  Takes some practice and you make some small rollers to work the overlap from one side to the other inside the mold.  The other option is to take the two halves and trim them after they are cured and then you seam them from the inside after they have come out of the molds.

You won't be using 5 minute or 30 minute epoxy if you want to do any composite work, even with thinning it down.  You need a slow hardener suitable for the temps you will be working in.  Making a hot box to heat cure the fiberglass can be beneficial for some epoxies.  They are a foam board (1") box over a bench setup with a few small light bulbs for heat source.  You need a thermometer you can view what the temps are in the box without opening it of course.  Some folks rig up thermal switches to control the temp between a high point and a low point for the on-off cycles. Once it is up to temp it doesn't take as much on time or wattage to keep it at the elevated temps if it doesn't have holes for the heat to escape.  The use of vacuum bagging is also done.  You can make a vacuum bagging pump pretty inexpensively, believe it or not, with a medium sized aquarium pump, coffee, can, some brass fittings, and a board...  It will pull a vacuum in the mid to high 20s. 

The reason people make a mold is because doing so allows you to have a much smoother surface than doing the layup on top of the foam.  Unless you don't care about putting lots of plastic filler on it (not recommended as it will show itself before too long.

David

[innovativems]

I've used foam from hobby stores on my last three I've done.  I glue them together with 3m upholstery adhesive.  I get the general shape with a hand saw then sand them to finalize the shape.  Once the shape is how I want it, I mask all of the foam and apply a mold release to it.  Then lay down glass.  Keep us posted on your progress


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[MikeSimon]

Why don't you use aluminum? Friend of mine made a mock tank for a Whizzer and formed the aluminum over a wood block that he shaped.

[bambuhiphop]

Why don't you use aluminum? Friend of mine made a mock tank for a Whizzer and formed the aluminum over a wood block that he shaped.

I may as it was a thought. What material did he use to form the block?

[bambuhiphop]

Thanks for all the advice guys!! Really appreciate it. I think I will start with foam. Be a good cheap material to practice with and can take it from there based on how it goes.

[754]

Make it easy on yourself..
Cerealbox cardboard, or posterboard and clear, masking or duct tape...
Mock it all up ..,lots of changes before it looks right..
 Next if you want it in Aluminum or steel, picture it in flat form , and make a pattern to achieve that.
If you are hammerforming, oak is the way to go for long term use..but MDF is easier for a one off..

 I would like to see the Whizzer tank.

[MikeSimon]

I was just looking for the picture of that Whizzer and cannot find it.

[bambuhiphop]

Opinions on this 5 parts series I found on the Youtube regarding process to making a plug with a foam base? Obviously marketing their products but would you say the process and advice solid?

Part 1: https://youtu.be/MAinuf5I_dw