First car sanity check

Secrets, tips, tools, design considerations, materials, the "science" behind it all, and other topics related to building the cars and semi-trucks.
User avatar
Vitamin K
Master Pine Head
Master Pine Head
Posts: 979
Joined: Sat Apr 20, 2013 7:26 pm
Location: Montgomery County, MD
Contact:

Re: RE: Re: First car sanity check

Post by Vitamin K » Fri Feb 10, 2017 8:14 am

derbypain wrote: Where do you buy the 1/64" Birch plywood? Having some difficulty in the Dallas area finding it. Not at Hobby Lobby or any of the major hardware locations.

Since you are using basswood for the body and not pinewood do you not have a body twist concern? ... I noticed many will put in Balsa ribs or even blocks in the large hollowed area of the Pinewood so just curious.

Last question do you drill your axle holes prior to attaching the 1/64" birch plywood or after?
I get the plywood at Michael's. It's not super cheap (like, 5+ bucks for a piece that I can get 4 pieces out of), but if you get a 40% off coupon ahead of time, it's a little more reasonable.

I find that the bodies stiffen up quite nicely after the plywood has been glued to the bottom. I'll also have a top cardstock layer as well, which will add a little structure. That said, inserting balsa inserts is definitely not a bad way to go, and really does make the car feel a lot more solid without adding much in the way of weight at all. Something else I've done is to cut support ribs out of balsa skewers and epoxy them into the hollow space. Super light and super strong.

I drilled my holes after, but I'm also a goofy bent axle guy, so I'm not as paranoid about warpage ruining my alignment. Giving the thin basswood "skeleton" a coating of CA glue after cutting might help reduce the warp effect.



derbypain
Pine Head
Pine Head
Posts: 75
Joined: Thu Jan 05, 2017 1:30 pm
Location: Plano, TX

Re: RE: Re: RE: Re: First car sanity check

Post by derbypain » Fri Feb 10, 2017 8:20 am

Vitamin K wrote:
derbypain wrote: Where do you buy the 1/64" Birch plywood? Having some difficulty in the Dallas area finding it. Not at Hobby Lobby or any of the major hardware locations.

Since you are using basswood for the body and not pinewood do you not have a body twist concern? ... I noticed many will put in Balsa ribs or even blocks in the large hollowed area of the Pinewood so just curious.

Last question do you drill your axle holes prior to attaching the 1/64" birch plywood or after?
I get the plywood at Michael's. It's not super cheap (like, 5+ bucks for a piece that I can get 4 pieces out of), but if you get a 40% off coupon ahead of time, it's a little more reasonable.

I find that the bodies stiffen up quite nicely after the plywood has been glued to the bottom. I'll also have a top cardstock layer as well, which will add a little structure. That said, inserting balsa inserts is definitely not a bad way to go, and really does make the car feel a lot more solid without adding much in the way of weight at all. Something else I've done is to cut support ribs out of balsa skewers and epoxy them into the hollow space. Super light and super strong.

I drilled my holes after, but I'm also a goofy bent axle guy, so I'm not as paranoid about warpage ruining my alignment. Giving the thin basswood "skeleton" a coating of CA glue after cutting might help reduce the warp effect.
Thanks for the response... Stupid question what is CA glue? Is that the glue you use to attach the plywood as well or is that epoxy?

Sent from my Note 5 using Tapatalk



derbypain
Pine Head
Pine Head
Posts: 75
Joined: Thu Jan 05, 2017 1:30 pm
Location: Plano, TX

Re: RE: Re: RE: Re: RE: Re: First car sanity check

Post by derbypain » Fri Feb 10, 2017 8:22 am

derbypain wrote:
Vitamin K wrote:
I get the plywood at Michael's. It's not super cheap (like, 5+ bucks for a piece that I can get 4 pieces out of), but if you get a 40% off coupon ahead of time, it's a little more reasonable.

I find that the bodies stiffen up quite nicely after the plywood has been glued to the bottom. I'll also have a top cardstock layer as well, which will add a little structure. That said, inserting balsa inserts is definitely not a bad way to go, and really does make the car feel a lot more solid without adding much in the way of weight at all. Something else I've done is to cut support ribs out of balsa skewers and epoxy them into the hollow space. Super light and super strong.

I drilled my holes after, but I'm also a goofy bent axle guy, so I'm not as paranoid about warpage ruining my alignment. Giving the thin basswood "skeleton" a coating of CA glue after cutting might help reduce the warp effect.
Thanks for the response... Stupid question what is CA glue? Is that the glue you use to attach the plywood as well or is that epoxy?

Sent from my Note 5 using Tapatalk
Also when gluejng together the body and plywood... How do you clamp to get get a tight bond without breaking / putting too much pressure on the body?

Sent from my Note 5 using Tapatalk



User avatar
Vitamin K
Master Pine Head
Master Pine Head
Posts: 979
Joined: Sat Apr 20, 2013 7:26 pm
Location: Montgomery County, MD
Contact:

Re: RE: Re: RE: Re: First car sanity check

Post by Vitamin K » Fri Feb 10, 2017 8:36 am

derbypain wrote: Stupid question what is CA glue? Is that the glue you use to attach the plywood as well or is that epoxy?
CA glue is a cyanoacrylate glue. Otherwise known as "superglue". For porous woods like bass or balsa, it makes an excellent sealant.

I attached the plywood with wood glue, since it was a wood-to-wood bond. Epoxy probably would have worked too.
derbypain wrote: Also when gluejng together the body and plywood... How do you clamp to get get a tight bond without breaking / putting too much pressure on the body?
I just sandwich the body and the plywood between two flat pieces of wood (discarded body candidates, in my case) and then clamp them with a few harbor freight ratcheting clamps. This is especially important with wood glue, since it's an expanding glue, and you want to train it flat while it is drying.



derbypain
Pine Head
Pine Head
Posts: 75
Joined: Thu Jan 05, 2017 1:30 pm
Location: Plano, TX

Re: RE: Re: RE: Re: RE: Re: First car sanity check

Post by derbypain » Fri Feb 10, 2017 9:06 am

Vitamin K wrote:
derbypain wrote: Stupid question what is CA glue? Is that the glue you use to attach the plywood as well or is that epoxy?
CA glue is a cyanoacrylate glue. Otherwise known as "superglue". For porous woods like bass or balsa, it makes an excellent sealant.

I attached the plywood with wood glue, since it was a wood-to-wood bond. Epoxy probably would have worked too.
derbypain wrote: Also when gluejng together the body and plywood... How do you clamp to get get a tight bond without breaking / putting too much pressure on the body?
I just sandwich the body and the plywood between two flat pieces of wood (discarded body candidates, in my case) and then clamp them with a few harbor freight ratcheting clamps. This is especially important with wood glue, since it's an expanding glue, and you want to train it flat while it is drying.
Thanks again... My son keeps asking the questions and I don't have all the answers so I figure if he is researching and willing to ask I can at least help him figure out some answers.

Sent from my Note 5 using Tapatalk



adayzdone
Apprentice
Apprentice
Posts: 9
Joined: Fri Feb 03, 2017 12:52 am
Location: Westchester - NY

Re: First car sanity check

Post by adayzdone » Fri Feb 10, 2017 10:27 am

Vitamin K wrote:I don't see why this body would be illegal for any ruleset. I haven't seen anybody banning "thin" so far. If you can't use basswood, you can do the same with pine.
I am sure thin is allowed, but can you use additional materials such as card stock?



User avatar
Vitamin K
Master Pine Head
Master Pine Head
Posts: 979
Joined: Sat Apr 20, 2013 7:26 pm
Location: Montgomery County, MD
Contact:

Re: First car sanity check

Post by Vitamin K » Fri Feb 10, 2017 11:02 am

adayzdone wrote:
Vitamin K wrote:I don't see why this body would be illegal for any ruleset. I haven't seen anybody banning "thin" so far. If you can't use basswood, you can do the same with pine.
I am sure thin is allowed, but can you use additional materials such as card stock?
Most derby rulesets allow for accessories to be added to cars. If you can put a sticker on your car, I don't see why you can't use a cardstock overlay.

You don't have to use cardstock. Some people just use vinyl or monokote, or even brake-light tape.

If you wanted to keep everything wood, you could always use a second plywood piece.

Another option is to use the plywood as the top piece, and then just seal up the holes in the bottom with clear tape (and probably a piece of silver foil tape to wrap around your tungsten cubes). A lot of league racers do something similar to this.



User avatar
LightninBoy
Master Pine Head
Master Pine Head
Posts: 201
Joined: Mon Feb 20, 2012 10:09 pm
Location: St. Paul, MN

Re: First car sanity check

Post by LightninBoy » Fri Feb 10, 2017 12:51 pm

Speedster wrote:I'm presently using LightninBoy's shape. How much does the wood weigh that was cut out of the large section? How much does the wood weigh that it will take to cover it up. I'd like to keep the car as strong as possible and don't really want to cut that section out. Will I really gain anything by removing that piece of wood?
Its not critical to remove all that wood.The primary reason I take out so much wood is to make up for all the material that the X3 style fenders add. So if you don't plan on adding fenders, then its even less critical to take out all that wood.

If you do, you should strengthen the frame by adding a plywood top (as VK shows) or by adding crossbeams which create the well known "ladder" design.

A third option - which I think is a good compromise for scout cars - is to fill in those voids with solid balsa. The resulting body is super strong yet light enough to take the full X3 fender treatment and still allow an aggressive COM.



User avatar
LightninBoy
Master Pine Head
Master Pine Head
Posts: 201
Joined: Mon Feb 20, 2012 10:09 pm
Location: St. Paul, MN

Re: First car sanity check

Post by LightninBoy » Fri Feb 10, 2017 3:03 pm

Vitamin K wrote:[
Some people are capable of routing out beautiful bodies and leaving a thin layer of wood below. I am not one of those people. :)

You can indeed drill a thin body with the Bullet. Whether to do the weight pockets before or after the drill seems to be a topic of some debate. Do whatever Lightninboy recommends for that. ;) Also verify your alignment after the drill AND after the weight pockets are cut (If you drill before you cut out the weight pockets, that is.)
Yeah people definitely have their preferences here. I drill the axles first, then scroll out weight pockets. I then take steps to "lock in drill" which includes gluing in the first row of weight on both sides of the axle spar, a coat of CA around the joints, and (if my OCD is really overactive) gluing on the birch plywood top. I only use the plywood to cover the weight pockets.

After reconfirming the axle alignment, I then scroll out the body pockets.



User avatar
Vitamin K
Master Pine Head
Master Pine Head
Posts: 979
Joined: Sat Apr 20, 2013 7:26 pm
Location: Montgomery County, MD
Contact:

Re: First car sanity check

Post by Vitamin K » Fri Feb 10, 2017 3:09 pm

LightninBoy wrote: Yeah people definitely have their preferences here. I drill the axles first, then scroll out weight pockets. I then take steps to "lock in drill" which includes gluing in the first row of weight on both sides of the axle spar, a coat of CA around the joints, and (if my OCD is really overactive) gluing on the birch plywood top. I only use the plywood to cover the weight pockets.

After reconfirming the axle alignment, I then scroll out the body pockets.
I could be wrong, but it definitely seems like there is a strong correlation between racer OCD and track success. ;)

It has been suggested to me that there is no one key thing to top speed, but rather it is paying careful attention to a number of small details, each of which contribute to the final result.



adayzdone
Apprentice
Apprentice
Posts: 9
Joined: Fri Feb 03, 2017 12:52 am
Location: Westchester - NY

Re: First car sanity check

Post by adayzdone » Fri Feb 10, 2017 6:26 pm

Vitamin K wrote:I could be wrong, but it definitely seems like there is a strong correlation between racer OCD and track success. ;)
My OCD is getting the best of me now. I need help.

I had read that you can use the pro body tool to drill pilot holes and then use the silver bullet to drill your canted holes. I drilled all of the pilot holes, insert it into the block, and the pilot holes are half covered by the lip used to hold the wood in place. What did I do wrong? What are the recommended heights?

Thanks.



User avatar
whodathunkit
Pine Head Legend
Pine Head Legend
Posts: 1913
Joined: Sat Apr 25, 2009 5:56 pm
Location: Forgan, OK

Re: First car sanity check

Post by whodathunkit » Fri Feb 10, 2017 9:54 pm

adayzdone wrote:
My OCD is getting the best of me now. I need help.

I had read that you can use the pro body tool to drill pilot holes and then use the silver bullet to drill your canted holes. I drilled all of the pilot holes, insert it into the block, and the pilot holes are half covered by the lip used to hold the wood in place. What did I do wrong? What are the recommended heights?

Thanks.
You're in luck adayzdone, and :welcome:

Here is where I think you went wrong ... you said you used ( the pro body tool!)
It's the single axle hole drilling tool right ? If it's the tool I'm thinking of just by the name of the tool given.
You are only drilling at a height of 1/16'' to the center of the axle hole.

(The pro body jig tool)
The tool that uses the long square bar down one side and also has the two jig drill bock's that will adjust for different wheel base's
will let you drill the axle holes higher.. at a height of 1/8'' to the center of the axle hole.

The lip that is on the block and or the older silver bullet tool..
For holding the car block is also at a 1/16'' height to the top of the lip ..so that's why you're seeing the half covered axle holes.

The newer silver bullet mini tool that's out on the market.
( Is a hole different breed of cat.. and type of axle hole drilling tool that will let you drill 3* cambered or straight axle holes.)

Anyhow don't let that OCD get the best of you.. I'v been there my self with the tools!

Hope the info help's you out!
Whoda.
Last edited by whodathunkit on Sat Feb 11, 2017 9:36 am, edited 1 time in total.


What type of automobile can be spelled the same forwards & backwards?

User avatar
Vitamin K
Master Pine Head
Master Pine Head
Posts: 979
Joined: Sat Apr 20, 2013 7:26 pm
Location: Montgomery County, MD
Contact:

Re: First car sanity check

Post by Vitamin K » Sat Feb 11, 2017 8:01 am

I wonder if you could just extend the rear end of the block just far enough out from the side of the Bullet to be accessible by the drill. Shouldn't need to protrude more than an inch or so for the rears...



User avatar
whodathunkit
Pine Head Legend
Pine Head Legend
Posts: 1913
Joined: Sat Apr 25, 2009 5:56 pm
Location: Forgan, OK

Re: First car sanity check

Post by whodathunkit » Sat Feb 11, 2017 8:57 am

VK 's way of drilling lower into car body block makes more since to me!

However.. just to touch on some tool mod's here!
I have also seen where some builders will work over the tool lip by notching out the axle hole areas in the tool for drilling lower into the car block as well.


What type of automobile can be spelled the same forwards & backwards?

Post Reply