[mattpatt]

Now that's a jolly good idea. Epoxy's not a problem as we make fibre and carbon parts, so no worries there.

Looks like I'd better get my a$$ into gear seeing as you guys have taken away all my lame excuses not to do this properly

[D.L]

Cool idea dinosaur!

[dynosor]

Epoxy's not a problem as we make fibre and carbon parts, so no worries there.

This is fairly obvious, but to minimize burring while face milling your epoxy casting, cut counter-clockwise around the edge where the "hole" is - at least for a finishing cut. Also use the hardest availble epoxy or it will smear rather than cut cleanly. Don't cut too fast or the epoxy will melt onto your cutter.

Plaster of paris will be dusty, but should not bur - it might chip though unless you also cut towards the body of material from any edge.

[D.L]

I wonder if you could set up a sandblasting gun at a port with a very coarse abrasive and get a port shape through erosion of the restrictions?

[3v0]

I may have missed it but if you are going to do porting you may want to look at building a flow bench too. A while back people found out you could provide the air with vacuum cleaner motors. Just google for DIY flowbench.

[mattpatt]

I built myself a flow bench following instructions found on the net. Made all the parts such as the cabinet, flow orifices, inclined manometer etc. It worked a treat. Yes I used 8 vacuum cleaner motors in it.

The biggest problem was that I was using it in my workshop at home, and seeing as I don't usually get home until late evening, the neighbours were getting a little upset at the noise. It was like Concorde on full bore with all 8 motors running :-)

I gave it to my mate, who modifies BMW's, and just use it when I want to now.

One thing I found the flow bench very useful for was finding the choke point in four stroke ports. Oh and when testing two stroke reed valves it was very interesting to see different velocities, and also the shape of the flow.

As for sandblasting. I'd rather use my grinder as I can then see where and what I'm cutting. Some do you this method though.