Tried to upload pictures to my folder last night and got the error message that the C drive was full?
Cut the fiberglass strips (about 1 inch wide) and laid them in the channel (after first coating the channel with epoxy). I use EAS slow setting epoxy with fiberglass filler to thicken it into a paste. Makes for a very stong connection. Pictures when I can upload them tonight.
Here are the pics. Sand the channel so the epoxy has something to grab on to. Cut the fiberglass into strips, doesn't have to be pretty. [] Coat the channel with epoxy, soak the fiberglass in the epoxy and then lay it into the channel. Can't put to much in there.
This makes it a true fiberglass ship. No wood to waterproof, less work and keeps the weight down. Today I am working on a new gearbox for the 390's, it's based off of Battlersconnection 550 gearbox. This one will be smaller so it can easily fit in the cruiser. Resin for the body and covering, and the same fiberglass board for the backer. You need to use this as resin will crack after cranking down the screws into the motor body. The new design will use the bottom of the hull as the base plate to allow the shaft to be put in at a shallow angle to help with thrust.
Made the master and molds last night, was able to pull off the first copy this morning. It will have a durable back plate just like the BC 550 gearbox. This size will enable me to get the motor lower in the hull and help with stability. I plan on fiberglassing the water channeling and the motor base will be a part of it.
sweet, thats a good looking gearbox. Any chance you could do a how to on casting sometime? (what materials to use and general things youve learned) did you use the smooth on 30 for those as well or did you cast them out of something else?
Smooth on 30 shore hardness. I will post a "how-to" next week. This month I will learn how to use brush on molds and hard external shell. This will have less usage of material, but greater detail. The material for the plastic is something new for me, it is very durable and requires a 16 hour demold time. Worth the wait!
Good news, the second side of the hull has been cut. I hate cutting the hull. [] Now I have to fiberglass the sub deck to the hull on that side. Next is to start the water channeling.
This will show you how I make a two part mold of the dummy props. Second part will be tomorrow (it has to set up today). Use sulfur free clay and embed half the prop into it. Make sure to get clay underneath the blades. Use a dowel or pen to make a series of holes. Those will become indexing markers. Make a box out of scrap. Doesn't have to be pretty. Seal all the edges. I used super glue. This is mold max30 silicone. Great stuff. Fill the box with rice. This will tell you how much product to use. Notice the seams were filled with clay to help prevent leaks. Fill a disposable cup with the rice, mark the sidewall. Use a small scale, place the cup on it first before starting it, it will automatically zero. Get your total (82.3 in this case). It is a 10:1 ratio, so now add 8.2 ounces of activator (red bottle). Fill the box and wait a day. Tomorrow I will finish the other side. Hopefully dummy props on Saturday. Now is time to set the new gearboxes in the hull and place the struts and shafts.
Ohh. Very nice, I cant wait to see the rest and how it turns out. I love this hobby so many fun this you can do with it.
Working on getting the props, shafts, and gearboxes in place. I start by setting the prop on the shaft and using my "mark-1" eyeball, cut the hull. Use a drill bit for each end of the cut, then finish with the dremel tool. My goal is to get the prop blades as close to the hull and each other as possible. This helps in turning as I try to get as much thrust as possible over the rudder. The shafts are placed parallel to the bottom of the hull to help in starting and stopping. If I angle them down too much the bow of the ship is actually pushed down. Now that I have them tacked in place, the struts will be made of brass strips and a collar, silver solder them together and epoxy to the hull. I cut the hub of the propeller off so the rudder can get as close as possible. The first shaft is the longer hole, once the angle was correct a shorter hole was cut for the second shaft. The shafts are equal to each other. The gearboxes set closer to the stern than the full size version. This helps in space issues as more stuff can be moved around in the middle of the boat.
Primary shafts are in place. I used brass and solver solder for a good joint. Cut a length of the next larger tubing. Then cut it on one side, this will serve as a backing hole for the strut and allow you to slide it over the tubing. Drill holes in the hull for the braces to pass through, they will be epoxied on the inside of the hull. This is a finished brace ready for paint. Now drill holes for the other side, try to make them symmetrical to the other side. Cut a length of tubing, and two pieces of brass stock. The key is to sand the brass to remove the oils. Then use the flux and "tin" both pieces. When you place them together, you will simply apply the heat and the solder will merge. I use silver solder for a strong joint and it only takes 400 degrees to melt it. You can now get silver solder at home depot. Both shafts are done.
Used a two part epoxy putty to set the prop shafts. No way they will come loose or have vibrations. The rudder is complete and will be installed next. Here is the second part of the mold. Plastic square tube was used to be the flow point. Remove the plastic tubes and separate the two halves. Now mix the plastic, pour into the bottom mold and lightly coat the blade area. Now attach the top half of the mold and pour the rest of the plastic. Here's the complete set. Copies are in the background. You can still see the flash on the blades and it looks like I cut one too close and lost the shape. More cleanup time on the next batch. Overall I am pleased with the results. If you have any questions, please ask.
Those look like they turned out well. So after the first half of the mold rubber dries you take the clay out and leave the props stuck in the first half of the rubber. Flip the mold upside down and pour in the second half of the mold and have the pour tubes installed. Once that half dries you peal the two molds apart and remove the real props. Then pour enough casting material in to lightly coat the bottom half, put the other half on and then fill through the holes left by the tubes. Did I get that all right? You are using mold max 30 to make the mold from but what are you casting the parts from, what material? Do you always use the same casting material or do you have a few to choose from depending on what you are trying to build? Thanks for showing that, I remember we talked about it some at NATS 06 but its nice to have the refresher and actually see the process.
Take the base plate off the mold. Remove the clay. If you dislodge the props, you have to start over. This already happened once. Problem is once the grip is broken, the pouring of the second half will either get under the prop or actually cause the prop to rise. Now you place your pour sprues and add the second half. If I just put the two halves together and poured from the top, the air does not have enough time to escape and you get voids or thin pieces. I could have added additional pour sprues, but cleaning all that up was not appealing to me. So I fill up the hub area and lightly coat the blades on the base piece (not too much or it goes everywhere), then add the top of the mold and slowly add material through the pour vent. Use a fast acting plastic, this was Alumilite. If you have a Hobby-Lobby near you, check the website and wait for a 40% off coupon. Then pick it up from there with the discount, makes it affordable.[]
Now starting on the rear water channeling, this one is going to be different. I plan on making it out of fiberglass with a gel coat, just like a full sized boat. Right now the wooden template is being constructed. The solenoids will be set into it to help keep the weight down. I prefer to work from the stern to the bow first. Pictures later.
Well, spent the money on gel coat and was not happy with the test piece. So I will use epoxy paint for a nice smooth finish. I used two strips of basswood to mark the channel, kept them parallel by using a scrap piece of lumber in the center. Bought a can of expanding foam and filled her up. I'll use a serrated knife to cut it to the correct shape tomorrow. Nice and lumpy! I will cover the foam with 1/32 fiberglass board.