Frank L

iTrader: (148)

Every car breaks arms now and then. I have only raced the 6t 2x so I dont really know if its an issue or not. But I have spare front lower arms and what I broke is the rear. Thats just the way it goes.

shanty140

iTrader: (5)

I haven't broken a A-arm yet on my Mugen.

dishsoap

iTrader: (8)

Well I just started to do the boiling method. Arms and Diff cases.

So far no boiled parts have broke.

The question I have is it worth while to tear the whole car down and boil the used parts. At this point I have only boiled new parts.

Great thing about the Mugen though is when you do break an arm it is usually a crack and not a full shatter. Although I have broke it has never caused me to not finish.

Redvet79

iTrader: (2)

We used to boil white plastic/nylon parts to dye them. Also I was told it puts some moisture back in them to help make them less brittle. RC10 And chain drive dominator I think it helped for whatever reason.

morgoth

I have a broken front A arm on my mugen (not boiled I think) and it's broken in the rear. The arm is just being hold together with that 1 piece of plastic in the front. I drove a practice day with it, 1 day race and 2 race days on a big track with big jumps It won't break... The arm is slighty bend now so I guess I'll put my spare arms on the car

And it was totally my fault when I broke the arm. I almost never break parts when racing a quali or a main. But I'm when I'm practicing, my driving is more aggresive and this don't go that smooth.

drewmugx5t

iTrader: (21)

Frank as a mugen guy I will say that the 6t is going to be a little more fragile than your losi. Although in 2 years of racing the 6 I have only cracked 1 rear arm. Like the other guy said it didn't put me out of the race just realized it was broken after the race. The fro arms top and bottom on the 6t aren't "weak" but they are probably less durable than the losi stuff. I would boil the front end arms for sure.

gabor szilagyi

iTrader: (12)

Redvet79

iTrader: (2)

A little ragu would help that. LOL

Stubbs

iTrader: (58)

The concept of boiling plastic parts goes back to the material that the parts are made from, which is mostly nylon impregnated plastic, specifically Nylon 6 or Nylon 6/6. The process is better known as conditioning. It does not make the part any stronger overall, it simply allows it to be more flexible, and absorb impact better. "Tougher" would be a better description that "stronger".

Nylon 6 or 6/6 has the ability to absorb moisture, more so than polymers like polyethylene. As a result, the introduction of moisture into the finished part can reduce the brittleness. Be careful though, if the part is brittle due to low moisture content, this will be a good way to increase flexibility. However, if the problem is more related to material degradation during the molding process, conditioning the parts will increase flexibility, but only temporarily, and the brittleness can return over time, once the part is put into use. Murphy's Law says that this will probably happen about half a lap before you do a cart wheel over a big triple

Assuming the part is sound coming out of the mold, it will reach equillibrium naturally through exposure to the atmosphere. If the parts are left in open air, especially in a humid environment (like your spare parts bag in the hot, humid summer months), the process of moisture absorption will occurr by itself, but it will take longer. Conditioning simply accelerates that process.

If you're interested, and like to read techincal papers, there's a very detailed explanation of this process here.

If not, below is the "reader's digest version"...enjoy.

Conditioning plastic parts

Originally by Plasticar

Adding water to the gears works because the material used to make them is nylon. Nylon absorbs moisture, which makes it more flexible and resistant to impact, both of which help it be less likely to break. A common trade name for nylon used in hobby and sporting goods is Zytel, but there are many other brands also.

It is not recommended to actually BOIL the parts, as the higher heat can degrade the material. Rather the suggestion to bring the water just to a boil, then either pour it into another container, or take off the heat and add the parts to sit is a better one. It doesn't take very long to improve the toughness of the gears (or any other nylon parts). 20-30 minutes should be plenty.

This method will not work with any other types of plastic. Delrin, Lexan, none of these are improved in this method. Fortunately, most of the structural parts in RC cars are nylon.

This process does happen naturally, but takes 6-9 months in open air. Once the moisture has been put into the part, it will continue to adjust the level, but this is a permanent condition, as it is mearly accellerating a natural process.

The nylon gears and other parts will not melt in the boiling water. They don't melt until over 200ºC, so unless you have them sitting on the bottom of the pan on high, you are OK. Rather, it is the hot water itself that is the problem. If the water is hot enough for long enough, it will start to break down the plastic itself.

A few mintues on the stovetop should be no problem at all, but you are best as described to remove from heat and let the parts sit in the very hot water that way. That will be more than sufficient to properly condition the parts.

BTW, the majority of the black plastic used in the chassis, drivetrain, suspension pieces is probably nylon and can be conditioned this way if you like. Any of these parts will be harder to break, but will be more flexible. Eventually they will get that way on their own, you are just speeding up the process for your own benefit.

pitpop

If you boil stuff, take the whole pot off the stove and let the water cool with the parts in it. You want all of it to cool slowly together. Someone asked about the negatives. The only negative to this is that the arms will become more flexible. If you race in very hot weather, you might not want rubbery arms.

pntmachine

Theres nothing like some front Kyosho A arm stew