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MANUKAU MODEL POWER BOAT CLUB Inc

 

Web Sites:

HTTP://homepages.paradise.net.nz/nickbree/mmpbc/

Venue: Wattle Farm Rd Pond Manurewa

2nd & 4th Sunday of each month from about 10.30 am

 

Secretary:        Glen Sayers                 Editor   Chris Breen

                        9 Reyland Close                       12 Sunset Rd

                        Manurewa                               Glenfield

                        Ph 267 2607                              Ph 4445 482                              July 2002

 

EDITOR’s Special Note

Not a great deal of racing since last newsletter what with the pond a dust bowl in all, plus I have not been inundated with content to put in this edition. Anyway here is what I can offer……..

HOT NEWS

BOAT SHOW (30th May to 3rd June)

 

The club set up and manned a display at this year’s boat show over Queens Birthday weekend. We had about 10 boats on display plus an endless video that drew many spectators. (Sorry photos are crap, but it was only a $16 camera !!)

A special thanks to Brent, who organised arrangements and took Thursday & Friday off work to set up the display stand at the Boat Show.

Thanks also to: Peter Wright for making up the business cards. Merv for the video tapes, Tony for the incredible MMPBC sign and to Chris, Adrian, Brian, Graham, Phil Duthie, Bruce, David, Brent, Tony and Myself for helping out on the stand and running demonstrations on the Hutchwilco Lake over the five day period.

We had an allocated time off 4:00 p.m. Approx. every day to run, before the barefoot water-skiing, but we also managed to run the boats whenever the lake was calm enough.

It was a shame that we only had one Hydro to run on the lake as the organizers of the Boat Show were hoping to see a demonstration of 3 or more Hydro’s.

There was an amazing amount of interest in the stand with hopefully quite a few potential members to turn up at our lake when it is refilled.

Hopefully we will get a chance to put on a display at the Boat Show next year with an even better turn out of boats and members, as I feel this is the best publicity our club has had in years.

For those people that helped out we have allocated 20 points to there club points total.

Jason Lester

Editor’s Note : I have had numerous calls from people who picked up one of the cards that Pete Wright prepared – well done Pete, excellent idea.

Also our lake is full once again.

Driver’s Stand

STILL being “considered” by the Council but we are optimistic – even though they appear to have lost two set of the plans now, and have requested a third set… Club members have already boxed up the launching area and it looks much safer than the old canyon. A bit more gravel is planned to ease the step down into the water. Well done guys & special thanks to Phil Leach for materials.

Still more thanks

Still more thanks are in order for Mr Burns (Bruce's dad) who has donated a set of new tires to the club for the trailer.

Editor’s Note: Bruce is now the proud owner of Grahams Doggett’s blue “Victory” off-shore cat – I guess you had better buy a bigger can of fuel Bruce. I also understand that we will soon see a new Sport 40 hydro ???

TECH NOTES

Anodizing Aluminum

by Ron Newman

The following procedure is for anodizing aluminum parts. Anodizing will protect the aluminum parts by making the surface much harder than natural aluminum, aluminum oxide is grown out of the surface during anodizing and is extremely hard. The porous nature of the anodized layer allows it to be dyed any color that is required. The method I describe is type II anodizing (room temp) and gives a anodized layer of .0002" to .0006". Type III or hard coat anodizing is done at much lower temperatures at higher current levels and gives a anodized layer up to .002 but is normaly at .0005" (Mil spec) in most anodizing shops. Type 2 anodizing using the home brew hanging wire method can be done quite easily at home with materials found at typical hardware and auto parts stores. I wish to share the procedure that has worked for me over the years.

I also include a section on re-anodizing existing parts. This may be of interest for restoring or changing the color of any anodized part. The sample part in this case is a freshly machined Crayford tube. (Editor’s note: I know what that is but I bet most of you don’t !!! Sorry No clue photos. E-mail me if you think you know what it is and HOW IT WORKS. It is not part of a model boat)

My anodizing station set up-- Plastic tank for sulfuric acid in a sealed vented wood box, Power supply, AC unit, and dye.

Before we get to the anodizing part lets talk about preping the aluminum part first----------

Anodizing hides no sins, so put a good finish on your parts before anodizing them. For the most part, what you see is what you get after the part is anodized; however, anodizing does tend to slightly magnify the surface texture, so lean toward a smoother finish when prepping the part, knowing that a small amount of the gloss will be lost after it is anodized. For a glossy surface on your anodized part, steel wool or wet sand it, and then polish with a buffing wheel using tripoli compound. For a matte finish just steel wool or sand it. You can also achieve a very uniform low reflective matte finish by sand blasting the part before anodizing it. There are other non manual ways to prep the parts surface before anodizing. I use vibratory tumblers with different grades of media for sanding and polishing the parts before anodizing. This allows a large quantity of parts to be done easily. But for quick "one off" parts, buffing on a polishing wheel using tripoli compound is the quickest. Or you can just anodize the part right after machining it, just make sure you clean it first.

-----Striping or restoring existing anodized parts-----

You can strip off the anodized layer of any anodized part by placing the part in a Lye (Editor’s Note – What the hell is that ??) solution for an hour or so. Just mix up a few table spoon of lye and water in a plastic container. Wear eye protection and rubber gloves for this procedure!! Place the part in the solution and monitor its progress.

The lye will dissolve the old anodized layer, about .0005" thick. It takes a while for it to start breaking through the layer. It's a little slow at first so the first ten minutes or so not much action will be seen. Bubbles and smut will rise up to the top as an indicator of its progress.

It's a good idea to help the process along by wiping the smut off of the part to allow the acid to get to fresh aluminum. Just wipe it off with a rag every 5 to 10 minutes until the old layer is completely gone. Only bare aluminum should be seen when it is finished.

When it is completely uniform (no remaining spots) just rinse it off and buff it back to a shine. Striping aluminum this way will create a matt finish. Polishing it back to it's original surface is up to you. At this point the part can be reanodized and dyed any color just like a freshly machined part. Note: if the aluminum part has other metal steel parts press into it Do not reanodize the part. Metal other than aluminum will desolve away during the anodizing process. I have removed broken taps this way just by anodizing the aluminum part. The steel tap is gone after anodizing the part. It just burns it right out.

OK. Enough about prepping and striping parts. Let's get to the anodizing part.

 

PROCEDURE

The aluminum parts need to be clean. Oil from machining, polishing compound, and fingerprints from handling the parts must be cleaned off. I use dish detergent with hot tap water and scrub the part. Use a tooth brush to get into any tight corners if needed. You can use any degreaser you want. just make sure the part is really clean!

Next, I connect an aluminum hanging wire to the part. This will provide the electrical connection when anodizing. I force thread the wire into an existing tapped hole. Just double the wire up, or pound it to a point to fit your tapped hole. This connection must be very tight or it will fail during the anodizing process. Use pliers if needed to crank the wire into the hole. The wire is softer than the aluminum alloy and will simply take the shape of the hole with out damaging the threads in your part. Remember, wherever the wire touches the part, it will not anodize and will not take any dye. Pick the connection spot so it will not show on the finished part.

You can buy aluminum 12g wire from Radio Shack for this purpose.

Mix up a solution of sulfuric acid in a plastic container. I mix about 2 gallons of battery acid to about 5 gallons of water. Then measure the specific gravity using a battery acid tester. It should display about 1100. That reading, if testing a real battery would indicate a discharged battery. Adjust the solution as needed. You can source sulfuric battery acid at your local auto parts store. Wear Eye protection and rubber gloves when working with sulfuric acid!

A battery charger or a DC power supply capable of providing at least a few Amps of current is required. A small set up can use a 12 volt 6 amp battery charger, but I use a 12 volt 50 amp charger/starter on the large tank. It puts out about 20 volts on the highest setting and will provide up to 50 amps. The larger the current draw, the faster the part will anodize. But to much current can burn off the hanging hookup wire. Anodizing at high current can also burn the part. Well it's not really burning it, the problem is caused by the bubbles etching the top or an edge of the part making it look pitted. High current anodizing also causes higher temps in the tank that can also cause the parts to pit. So don't try anodizing to fast at high curent levels unless you have some experience with the process.

I anodize multiple parts at a time, drawing between 5 to 12 amps on most occasions. That seems to be a good all around range for the size of parts I do. It takes about 65 minutes no matter how many parts I do at a time with my setup. The more parts I add in the tank the more current is drawn from the Power supply.

The tank also has an electronic temperature gauge to provide a means of monitoring the temperature of the acid to make sure it does not exceed more than 80 degrees F while anodizing. The temperature of the acid typically raises about 7 degrees for each hour of anodizing, depending on how much current is being drawn and how large the tank of acid is. The anodized part will not take the dye well if the temperature of the part is too high while anodizing, or if it is rinsed with hot water after anodizing. The ideal temperature range is between 65 and 75 degrees for type II anodizing, and around 40 degrees for hard coat anodizing. If the temp gets to high while anodizing the parts may start to pit. I have an AC unit blowing into the sealed box to cool the acid down as low as I can before starting an anodizing run. Once the acid reaches about 65 degrees I know I can start and complete a large number of parts before the temp gets into the high 70s and forces me to stop and wait for it to cool down again. You don't need to have an AC unit like I do if you are only doing a few parts. Just place some ice cubes in the acid to get the temp down before starting. Anodizing in the summer time in a garage can be a challenge.

Put a piece of lead in the tank of acid and connect it to the negative side of the charger. If the lead does not stick out of the acid you can use a heavy gauge ALUMINUM wire connected to the lead plate to provide an electrical connection above the acid. I used two lead plates, one on each side of the tank wired together. No metal of any other kind should touch the acid.

Suspend the aluminum part in the acid using the attached aluminum hanging wire. Connect the positive terminal of the charger to the wire holding the part and turn on the charger. The part should not touch the plastic container or be placed too close to the lead in the tank. Don't place the part directly over the lead plates due to the bubbles rising up from the lead.

If the electrical connection to the part is not tight, it will fail during the process and only the aluminum hook up wire will be anodized, not the part. The current should rise then level off in the first few minutes of anodizing. As the anodized layer builds on the part you may notice a small drop in current. This is normal; however, if the current drops suddenly during the process that indicates that the connection to the part has failed. If the current is too high, the connection wire may burn off. Use a 12-gauge wire when possible for the hanging wire. If the current keeps rising as the part anodizes then check the temp. The hotter the acid gets the more current will be drawn. Remember the temp has to be kept with in limits or your part may become pitted and won't take the dye well.

Bubbles will start foaming off both the lead plates and the part. I would advise not breathing the hydrogen fumes and bad vapors, and would suggest some way of venting them away from your work area. I put the plastic tank in a sealed wooden box with a fan to vent the fumes out a nearby window using a simple dryer hose. Some anodizing kits provide fume control balls that take care of the problem. I have not tryed them, but hear they work well.

Figure out how long to anodize the part using the following rule- 900 amps per minute per square foot of part.

The Crayford tube has 42.4 sq " of surface and is drawing 5 amps according to the meter on the power supply. 900/5 =180 amp min, and 42.4/144 = .294 sq'. So 180 times .294 = 53 minutes in the tank. This part anodized for 1.2 hours. Give extra time for parts that have a matte finish. Due to the larger surface area of a matte part, it will take a little longer to anodize then the same size part with a polished surface. To be honest, I don't even bother to figure out the time required for parts any more. I know my set up well enough to just set the timer for 65 minutes and let it go. The current will automaticaly adjust for more or less parts. Other anodizing set ups will differ due to different battery chargers and tank sizes. So calculating the time would be a good idea until you gain a little experience.

Notice the color of the anodized part. It should have a pale lemon tint if it is a 6000 series alloy, or a chalky whitish look for other types of aluminum alloy. Don't pull it out of the tank until it changes color.

Rinse the part with COLD water after removing it from the acid tank. Do not use hot water as it will start to seal the pores in the aluminum oxide layer before you have a chance to dye it.

Once the part is rinsed well in cold water, it is time to dye the part to your desired color. I use different colored anodizing dyes from Caswell, but the bulk of my anodizing is done in black. Click below to see the different colors that they offer. They also sell anodizing kits, plating kits and vibratory tumblers as well.

 

(Editor’s Note: I am advised any household dye will work)

 

Heat the dye to about 140 degrees F. Hang your anodized parts in the dye bath for 15 minutes. Mantain the temperature while the part is dying. Anodizing dye will last years if you are careful not to cross contaminate it with sulfuric acid from the anodizing step.

Now, it is time to seal the pores and lock in the dye by boiling the part in water for 20 minutes. You can also steam the part for 30 minutes by suspending it in a pot with a little water boiling under it. Steaming helps to avoid water spotting problems. If spotting is a concern, use distilled water in the dye bath and for sealing.

After the part has boiled for 20 minutes, rinse it off and remove any dye powder residue that may be on it. Polishing compound or wax can be used to help remove any remaining residue or water spots.

 

Editor’s Note – Sound just too easy to be true ??? But I certainly intend to try it !!!

Web-sites

Here are some recommended web sites:

http://www.scintilla.utwente.nl/~edwinm/links_main.htm

http://www.rocketcityracing.com/ (Check out FAQ <> Affiliated Program)

http://www.bolly.com.au Check out the pipe and motor tips.

Club Points Standings (2002/2003 year)

No change from last time

FOR SALE COLUMN

ANTARES For Sale if anyone interested – say $250(complete other than radio). Call the Editor. Dumas mono type hull, OS 20 FP motor (plane type with cooling jacket)   Excellent beginners boat – very reliable

 

 

Hydro Regatta

The Hydro/Offshore Regatta in July is now to take place on Hamilton Lake

Apparently the local Rotorua Tangata Whenua are being difficult – Entry form attached

 

That’s all folks

 

C Breen – Editor

F:\My Documents\CHUFFS\mmpbc\july2002\july2002newsletter.doc


THE NZMPBA PRESENTS THE

WORLD CUP HYDROFEST

ROUND 3 NZMPBA SCALE HYDRO HI-POINT SERIES

VENUE:                           Lake Rotokawa, Rotorua ,Main Rd, Opp Airport,(follow signs)

                                          NOW AT HAMILTON LAKE

DATE:                              27th & 28th July 2002

HOST:                              Bay of Plenty Model Power Boat Club

ENTRY FEE:                   $5.00 per event, Maximum fee $15.00

ENTRIES CLOSE:         17th July 2002

LATE ENTRIES NOT NECESSARILY ACCEPTED.

ALL COMPETITORS MUST BE CURRENT FINANCIAL MEMBERS OF THE NZMPBA.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

WORLD CUP ENTRY FORM

Name                                                                      Phone

Address                                                                 NZMPBA No.

Events

Pref. Freq

Alt. Freq

A Hydro Matrix

   

B Hydro Matrix

   

C Hydro Matrix

   

1 Hour Semi Scale Off Shore (4 x 15 min heats)

   

Sport 45 Hydro

Boat Name

Scale Judging           YES         NO

   

C Scale Hydro

Boat Name

Scale Judging             YES          NO

   

Conditions of Entry

NZMPBA Racing Rules will apply.

Entry Fee must be paid before racing starts.

I agree to the conditions of entry.

Signed:           _________________

Return to:                Steve Trott

                                 50 Gravatt Rd

                                 Royal Palm Beach

                                 Papamoa 3003

                                 Fax   07 572 1567