Shaping the bottom of the car?

derbydentist

Council Champion
Pro Racer
Feb 27, 2017
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I have assumed for a long time that the top racers and most racers are leaving the bottom of their cars flat and just tapering the top of the car to get it as narrow as possible. Is this true or are some racers shaving the bottom of the car upwards?
 
Thank you B Regal I appreciate the response- this is what I have been doing but this was one of those things I have been assuming and assuming has burned me before with these cars. Just making sure
 
I have seen some bottoms shaped too...
??? But wouldn't this contribute to the front of the car being higher off the track than the back which seems like it would create lift in the front. Have you seen it done with speed gains ?
 
Are we still talking about pinewood derby cars? Haha
Okay so new question since I think bottom shaping has gone stale- I haven't found much about Delrin washer polishing. Anyone polish theirs or just use as is? I know to make one side rough so it will glue in well but curious about polishing the other side?
 
Thank you ! Do you follow up the sanding with any of johns black ice steps? Or something else?

No I don't use anything else besides fine sand paper. Maybe someone else will chime in on the matter. But it seems like you could use a polishing compound. I use ultra fine sand paper so I never considered using a polishing compound.