Painting and building pinewood derby car questions

[User Name missing]

I’m using a blue metal flake enamel paint in my testors/aztek external mix model air brush. I thinned the paint and played with psi settings from 10 psi up to 40 psi. At 40psi, I get better coverage but the paint still “spits” out. Nozzle isn’t clogged. Do I have the paint too thin/not thin enough or is something else wrong? Painting my daughters with just regular thinned enamel paint came out better, but some of the surfaces isn’t really glossy and has a kind of powdery finish. I plan on wet sanding both and shooting another coat of paint tonight.


The block of pinewood comes with slots precut for the axles. However the design req’d a different axle spacing, so I flipped it over and redrilled new holes using a jig. Is it ok like this or should I recut the slot? I’m afraid of the nail axle busting out the pinewood.

First time making one. Thanx for any help.

 

[swynx]

Not gonna be any help but go find a movie called 'down and derby' goos movie all about your project

 

[hank857]

it could be because it is a metal flake instead of plain ol paint. You said the straight enamel sprayed ok. I think flake requires a bigger nozzle than an air brush may offer? As to the relocation of the axles, need to check on the rules, I dont think the cub scout rules (although you said for a girl) allow changing the wheel base, but it will depend on the organization if there is one running whatever you are building the car for. I have run several races and yes the cars sometimes hit hard and tilt the axels in the slots form being dropped or going off the track. Would probably use a longer nail/axle if just nailing in.

 

[User Name missing]

thats the thing, only thing that was said bout the rules is the max width and length, clearance under body and not to use anything be graphite powder as a lubricant. I briefly talked to one of the guys running the show and he mentioned that he always drill new holes for the wheel. Pretty much, if they say something is wrong, I'll simply state that I wasn't told bout it nor read anything in the Scouting handbook.

I know metal flake paint is a PITA to work with....and now wish I didn't pick it. But its not that big a deal since the car will be black with blue stripping. But it was pissing me the F off trying to get it to work right cause I have til Saturday @ 2 to have these done.

The plain enamel did spit a bit, but not nearly as bad as the metal flake. I just don't know if its too thinned or not thin enough. Probably after this I'm gonna get a better air brush.

 

[hank857]

take a look here, one set states must be in the slots cut at factory, but as they say its up to the locals.

http://en.wikibooks.org/wiki/How_To_Build_a_Pinewood_Derby_Car/Rules

 

[85_Ranger4x4]

The slots are nice to adjust the camber of the wheels.

 

[Scrambler82]

The paint thing I am not sure about unless you are painting directly on the wood, use a primer compatible to the top coat.

On the axles, sand the axle to smooth them out, get some slightly oversized replacements and after cleaning up the axles, measure them and get the wheels drilled to fit. Do a smooth job drilling the axle hole through the wheel, the smoother the hole the easier the wheel will turn.
Sand the outer diameter of the wheels to smooth but not a lot.

Flip the block with the axle slots up and drill new holes based on the new axle OD.
Then I cut the block for a shape that will eliminate the old slots.

Make sure the holes are deep enough and parallel to each other and the bottom of the block.

 

[Defective]

We were able to move our axles but had to use slots, not drilled holes. We also polished them up pretty good and I angled the rear wheels so they only contacted the track on the inside edge. Glue the axles in once you've got them set up perfect. The kids were picking up cars and messing with them at the competition, and by the time we raced, our car was out of whack and weakened. It broke about the third run and due to the amount of competitors and time, they revoked the rule to allow us to repair our cars between races. So we ran on three wheels, backwards just to finish up the day. Painting is about the only thing the kids can do by themselves, so I let them handle most of that. I'm curious, how are the kids contributing to this?