Scratch-Built Hydro

[FloatDaBoat]

ISO Settings

I checked the EXIF data on the two pics. Using Auto ISO, the camera selected an ISO setting of 80 for the transom shot (taken in bright sunlight using Auto White Balance) & 200 for the servo shot (light source - incandescent heat lamps, I manually selected Tungsten for the White Balance [Tone] setting).


What ISO settings would you suggest ???

[j.m.]

Not sure, they just look grainy... Larger aperature?

[FloatDaBoat]

Here's another pic. I adjusted brightness before resizing. The previous photos were resized before making adjustments. Any Better ???

[j.m.]

Yeah, do you see how the dark shadows are much less grainy? When photo editing programs increase 'sharpness' they really only make them grainy. Try irfanView, it's free.

[FloatDaBoat]

Kool Koils

Fabricated cooling coils for the Leopard 4074 out of two 5/32” pieces of aluminum tubing. Thirty-six inch lengths were the longest size available. Since I had to utilize two pieces, I needed to know what the optimum length should be to connect them together with silicone tubing. I determined that by wrapping a round boot lace around the motor can, & found 33” to be the proper length.

To ensure that the silicone tubing would achieve a sure grip on the aluminum tubes, I added ridges to the aluminum tubing ends. This was done by wrapping 22 gauge single strand magnet wire around the ends & then securing it with epoxy, making sure that there were no sharp projections that would cut the silicone tubing. Small cable tie wraps will also be utilized during final installation to make sure the silicone tubes remain securely attached.


Pics:

[FloatDaBoat]

Silicone Hatch Seal

I used this same method to seal the hatch on my cat, & it didn't leak a drop after being upside down in DaLake for approximately 20 minutes before I was able to ready my rescue boat to retrieve it … it works very well !!!

What I used:

Loctite Clear Silicone Waterproof Sealant, which is not recommended for brass, copper, magnesium, iron, zinc or galvanized metals. Hard to bond plastics such as PE, PP, PTFE, PMMA, PC, or PVC. It has a tensile strength of 325 psi & sticks like a champ to epoxy resin.

How I did it:

Cut strips of Saran Wrap to place around the hull hatch opening.

Applied a very light coat of petroleum jelly to the hull to hold the Saran Wrap in place, then another thin coat on top of the Saran Wrap using a Q-Tip swab (probably not necessary, but I wanted to be sure the silicone wouldn't stick to the Saran Wrap).

Ran a 1/4” bead of silicone around the edges of the hatch. Clearance between the hatch sealing edge & hull opening was 1/8”.

Put the hatch in position, then placed two lead shot filled ankle weights (2.5 lbs each) on top to secure it in place while the silicone cured. I left it undisturbed for 18 hours.

Placed a piece of silicone vacuum tubing over the end of the stuffing tube, gave it a shot of 60 psi compressed air, & the hatch popped off nicely. Severe damage may occur if a pry bar is used to separate the hatch from the hull, as it's a tight fit !!!

Trimmed the excess silicone sealant off the hatch with a new utility knife blade. A razor blade probably would've done a cleaner job . . . .

The fumes given-off from the sealant as it cured caused the brass stuffing tube to become heavily tarnished. I surmise - - DOH !!! - - that's why it isn't recommended for use on brass & some other metals (see above). Definitely don't try this with any electronics inside the hull !!! After 48 hours or so, there's very little residual fumes emanating from the sealant.

DaPic . . . . (my $230 camera will have to suffice, as I'm not able to afford an $8,000 one at this time - - HAW !!!!)

[FloatDaBoat]

Hull Done

I've completed the seemingly endless wet sanding process using 600, 1,000, 1,500, & 2,000 grit finishing paper.


Constructed a Boat Tote with PVC & coated it with plastic Valspar rattle shake paint - - still need to add the carry
straps.


Applied the decals & took a pic . . . .

[martno1fan]

Boat looks great,also like the cooling coils on the motors how the heck did you manage to coil them up that tight without kinking them .
Mart

[FloatDaBoat]

Coiling Aluminum Tubing

Thanks, Mart. Here ya go . . . .


You'll need something to bend the tubing around that closely approximates the diameter of the motor can. I super glued two PVC electrical conduit slip connectors nested together, then glued those onto the end of a piece of old wooden shovel handle. I clamped the wooden dowel in a vise attached to the top of a 4 foot step ladder. This allows sufficient space to maneuver the tubing during the bending process.


Keeping your thumbs close together (no more than 1 inch apart), slowly begin bending the tubing around the mandrel (PVC conduit) using steady pressure. Once you've made almost one circuit, ensure that the sides of the meeting tubes slide against one another (touch on a bias angle) while completing the initial coil, & for all remaining coils. This results in no spaces between coils.


This method also causes the tubing to flatten into an oval shape, increasing the contact patch with the motor can. Filling the tube with salt or fine sand keeps the tubing rounder (& from kinking), but also produces some wrinkling of the inner tube wall.


Now you have a coil, but it's too large in diameter to fit snugly around the motor. Not a problem, as the coil's diameter will be reduced by constricting it around a smaller mandrel. My mandrel happened to come in the form of a butane fuel refill can (with fuel still inside to prevent deformation). Place the coil over the smaller mandrel & twist the coil to tighten it, making sure to apply pressure to each individual section (don't just grab both ends & twist - - you'll warp DaCoil). Aluminum is actually quite springy, so you'll have to compress the coil numerous times to achieve the correct diameter. Check to make sure you don't decrease the diameter too much, or you'll damage the coil, even when using a screwing motion to install the coil over the motor can.

[FloatDaBoat]

Hardware & Power Train Installed

Applied the finishing touches to my hardware & mounted it on the hull.


Also soldered the 5.5 mm bullets onto the ESC & installed it using Velcro. I haven't applied power to the ESC or programmed it, yet. As soon as I've determined the motor phasing is correct, I'll reposition the motor wiring for a neater appearance.


DaPics . . . .

[martno1fan]

Thanks for the info on the cooling coil much apreciated.The boats looking great,look forward to seeing how she goes

[FloatDaBoat]

Mart, you're welcome. I'm always willing to share.


I'm not in any real hurry to finish the build, as I don't know if I'll be able to afford the price of the gas required to drive to the lake - - HAW !!!

[FloatDaBoat]

GT3B 2.4 GHz Radio Tested

I've Tested the GT3B Radio I purchased for this build - - everything works OK. The throttle channel had to be set to reverse for the motor to spin normally using the SeaKing 180A ESC. If channel 2 is set to normal, the Leopard 4074 motor will only spin when reverse/brake is applied to the XMTR trigger.

[FloatDaBoat]

Dang Near Done

Installed the battery tie-downs, plumbed the silicone cooling lines, fabricated & attached the stuffing tube sling guard, & mounted the RCVR/antenna.


Almost Ready to Rip !!!


DaPics . . . .

[FloatDaBoat]

Turn Fin Strike Plate

Since my turn fin's designed to break-away and pivot back in the event of encountering an object in the water (log, 20 pound carp, turtle, dead body, etc.), I've added an aluminum strike plate to the chine to prevent a hull puncture if that should occur. [See DaPic]


Now it's time to get to work modifying, sharpening, & balancing all the props I've purchased from Steven over the winter to get this beast properly motivated . . . .