51 replies to this topic

[team burrito]

... if CA glue was the "hot ticket" for bonding donuts to slot wheels... then all the slot tire manufacturers would be using that process today as it is quicker to use CA versus contact cement.

The only time I used CA was to glue my R/C molded tires. There was no other way to neatly glue the tires and it was a pain to clean the rims. Otherwise, I was using contact cement to glue the foam tires in the same manner as with slot car tires. The only thing I would recommend is buying a box of disposable gloves. Save your hands from the lacquer thinner and glue.

[team burrito]

A tool like this will give you extra leverage when trying to put a .500" or larger dia. wheel into a donut with a small 3/8" hole.

I actually made a tool that can core-out the inner hole to accommodate larger rims. I originally made it to trim the excess rubber on the outside, but it works on the inside as well. It's essentially a needle sandwiched between two fender washers. I use a needle because it's the safest way to cut through the rubber. If you tried using an X-Acto knife, the rubber could grab the knife out of your hand (very dangerous). The result is a nice, clean hole to mount that king-sized rim without the hassle.

[MarcusPHagen]

4) Get some pipe cleaners... fuzzy stuff on a piece of piano wire... you know what I am talking about. Craft stores sell them and they are longer and thicker.

Another good reason to buy them at a craft store - some misguided states (Minnesota being one) have tagged pipe cleaners as "smoking paraphenalia" and require proof of legal age in order to purchase them! Stupid, yes, but I know we had to card purchasers even if it was the only "smoking" materials they were buying.

[MarcusPHagen]

On-road R/C cars, electric or gas, 1/10 and 1/8 scale, run average speeds of 50 mph and often reach 80 mph so your comment about a large slow rotating tire is not accurate.

Mike, I suppose that "slow" here is relative. Since wing cars with much smaller tires post _average_ speeds in the 70-80 mph range, I expect that their tires are rotating anywhere from 4-10 times as fast as those on 1/10 or 1/8 scale R/C vehicles.

[Ron Hershman]

Off-road R/C tires are molded and in most cases used on plastic wheels... CA glue is fine for this as all you're doing is forming a "bead" to keep the rubber on the wheel. I have also seen RC racers CA glue FOAM rubber (the same we use for slot tires) onto plastic wheels and in some case use "double stick" tape as well. This seems to be OK for R/C racing and works due to the lower rotating speed of a R/C tire versus a much smaller slot car tire.

There is a formula for calculating this, but I don't have it.

If a R/C tire is 2 inches in dia and a slot tire is 1 inch in dia... no matter what the actual MPH of the car is, the slot tire is turning twice the speed of the R/C tire going the same speed and distance. If the slot tire is .765" dia, then it's even turning more RPMs and speed than the 2 inch R/C tire.

[MarcusPHagen]

Circumference of a circle = Pi x diameter

The amount of distance covered by a wheel in one rotation is equal to the circumference (assuming no slippage), and therefore a 2" wheel will rotate at 1/2 the RPM of a 1" wheel to move forward at the same speed.

Assume a slot car tire of 3/4" (0.750) per USRA rules (and because it makes the math easier than doing the D3 size)
averaging 70 MPH, and a 1/8 scale R/C car with 3-3/8" (3.375) tires averaging 50 MPH. (I couldn't find any rules for 1/8 scale R/C wheel size when I Googled it, so I assumed a 1/24 "true scale" tire of 1-1/8" would be 3 times as large in 1/8 scale.)

The slot car is moving at (7/5) the speed of the RC car (1.4 times as fast).

The slot car's wheels must rotate at (3.375/0.750) or 4.5 times the RPM to move ahead at the same speed.

The combination of the two (smaller wheels, faster average speed) means that the slot car's tires will be rotating at (1.4 * 4.5) or 6.3 times the RPM of the larger R/C car's wheels.

However, the "centrifugal force" (yeah, I know, I should work out the vectors for the tire at the circumference attempting to continue at a tangent, but I'm too tired right now) increases with diameter, I think that the only necessary comparison is the relative speeds of the two vehicles, since that would determine the speed of the tire surface at the circumference. Since the slot car is 40% faster, and momentum increases by the square of the speed (quadruples when the speed doubles), that means that the relative momentum should be (1.4 * 1.4) for the slot car, or 196% of the force on the RC car's tires.

So an adhesive which might be perfectly adequate for the RC car's tires would be subject to approximately double the force if used on a slot car tire.

I think my head hurts...

[gascarnut]

All of this is interesting theory, but in 1/8 R/C the centrifugal forces are the lesser of the problems. It is the sideways force from cornering that is the issue. The traction levels can get so high that contact adhesive just will not hold the foam onto the rim. CA is the best way to go for most amateur tire-gluers. At least that was always my experience. 1/10 or 1/12 scale electric R/C cars can get away with contact adhesive as the cars are lighter and don't generate the same level of cornering forces in the tires.

Additionally, it is much quicker and less messy to use CA. The R/C guys have special machines to apply the CA - the machines hold the rim still and have an angled pin that creates a gap between the tire and the rim where you can dribble the CA glue.

Remember that RC cars never use aluminum wheels. CA glues are not much good when trying to stick foam to aluminum.

[MarcusPHagen]

Thanks, Dennis. My head feels better now. When in doubt, it's better to rely on experience than theory. The details you supplied about the gluing process are also interesting.

[Prof. Fate]

Hi,

I am guessing I have been using Parma blanks, both regular foam and their tunas, for about 20 years. Before that I was buying blanks from England. I personally use a modeling Railroad guck called "Walther's Goo".

Fate

[Cheater]

I personally use a modeling Railroad guck called "Walther's Goo".

Which is essentially a relabeled version of goodyear Pliobond, which IIRC was one of the original contact cements.

[Ron Hershman]

Which is essentially a relabeled version of goodyear Pliobond, which IIRC was one of the original contact cements.

Made by Goodyear and used in every vacuum cleaner repair shop for gluing hose fittings onto hoses. Great stuff

[JerseyJohn]

While there may some similarities between the R/C and slot tire mounting process... DO NOT and I repeat DO NOT use CA glue for mounting slot tires.

CA glue when it cures becomes very brittle, cracks very easy, hardens and cracks the rubber, etc. R/C tires (very large diameter) have a lot lower rotation speed when compared to the smaller slot car tires. As the rotational speed increases, so does the problems of using CA glue and donuts leaving wheels.

If you don't want to believe this, ask any slot car drag racers about the Pro-Track drag tire problem years ago when P-T was using CA to bond their tires to their wheels. It didn't work then and they switched to contact cement and solved their problems.

And let me make another point here... if CA glue was the "hot ticket" for bonding donuts to slot wheels... then all the slot tire manufacturers would be using that process today as it is quicker to use CA versus contact cement. ALL slot tire manufacturers use contact cement today and have for many years because it's the only way to keep the donuts on the wheels.

Ron, what about using Rubberized CA that stays flexible?

[gascarnut]

Ron, what about using Rubberized Ca that stays flexible?

Maybe if you are mounting new rubber onto JK plastic rims, definitely not if you are mounting onto aluminum or magnesium rims.

The other issue is the process of applying CA glues. The donut must be mounted on the rim BEFORE you apply the glue, and the rubber is pulled away from the rim so the glue can be squirted betwen the donut and the rim. This is much easier to do on the bigger RC tires.

[JerseyJohn]

Maybe if you are mounting new rubber onto JK plastic rims, definitely not if you are mounting onto aluminum or magnesium rims.

The other issue is the process of applying CA glues. The donut must be mounted on the rim BEFORE you apply the glue, and the rubber is pulled away from the rim so the glue can be squirted betwen the donut and the rim. This is much easier to do on the bigger RC tires.

Thanks Dennis, I will stick with 3M Super. By the way I built a F1 chassis based on the Noose Samson chassis. It handles awesome !!!

[aquavelvis]

Interesting topic that I found, what, 2-3 years after it was started. Ah, well...

The tuna/fish/natural rubber thing I think I understand. But what about "wonder" and "speed" rubber? Are the two the same as each other? If different, how? And from whom can they be purchased in donut form?

Thanks, and Happy Thanksgiving, 2010 to everyone!

[Ron Hershman]

Interesting topic that I found, what, 2-3 years after it was started. Ah, well...

The tuna/fish/natural rubber thing I think I understand. But what about "wonder" and "speed" rubber? Are the two the same as each other? If different, how? And from whom can they be purchased in donut form?

Thanks, and Happy Thanksgiving, 2010 to everyone!

Wonder and Speed rubber are two different compounds... Wonder having lots of Natural rubber blended in and Speed has more synthetic materials blended in.

You should be able to buy both Wonder and Speed rubber donuts from Alpha.

[aquavelvis]

Thanks Ron!

[Tangmere]

Breathing life back into the thread. What about urethane onto Cox rims? Granted the rpms aren't as high but some do slip on the rims. 3M is the answer here too?

[Phil Hackett]

Breathing life back into the thread. What about urethane onto Cox rims? Granted the rpms aren't as high but some do slip on the rims. 3M is the answer here too?

 

3M makes dozens of different adhesives that could be used. Most aren't sold into the retail market: they're marked "industrial use only". The glue that works for you is the "right" one. The glue Sonic uses is about $50/quart....

[Dave Crevie]

3-M weatherstrip adhesive (yellow) is what we've been using to mount urethane on metal rims. Sold in a

tube at most auto supply stores.

[Bill from NH]

The yellow stuff is known as "Gorilla Snot."  It now comes in smaller tubes of black too.

[Dave Crevie]

I have found that the black is a slightly different formula. It doesn't hold to the urethane as well. The yellow is my

choice, even though the black makes more sense from a cosmetic standpoint. You just have to be careful to clean

all the yellow "ooze" that gets on the tire sidewalls. 

[MattD]

Guys on HRW switch to urethane from stock rtr tires and they use CYA glue.

[Rotorranch]

CYA glue???

 

     

 

We use a CA tire glue on the R/C cars. I'd think that would work on slots too.

 

Rotor

[Alchemist]

Here's a "Between the Lanes" video, published 2017 on YouTube, by Ron Hershman (Ron - hope you don't mind that I post your video?!) showing how to mount slot car tires/donuts.

 

https://www.youtube....h?v=YygqxXF_mCI

 

Thank you - Enjoy!

 

Ernie