Models and Electronics
Tech Tips
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There are 18 tips - hope they help!!| Tip about | Tip | Submitter |
| Cutting Carbon Rod | It is easy to disturb the surface fibres of carbon rod whilst sawing it. To prevent this saw gently and rotate the rod whilst doing so. | Allan |
| Flex drive for speed 400 sports use |
Ingredients: 2 mm stainless steel multi-strand cable (hardware shop) This normally has the wrong lay for anticlockwise rotation but it still works in practice for short shaft lengths. 4 mm i/d brass tube 3 mm i/d brass tube (sliding fit in above) length of thin push rod snake cable (outer) 3 mm i/d x 2 mm bore or brass tube of same dimensions (I couldn\'t find it in Spain) 15 x 4 mm brass screw. Glass fibre circuit board approx 2 mm thickness. Slow-curing epoxy Method: Cut the 3 and 4 mm brass tubes to approx 2 cm length, with a Dremel or similar and cut off wheel, remove the head of the screw. Wrap some turns of insulating tape around last 7/8 mm of the screw and hold in chuck of electric drill. Switch on drill and with flat file remove threads until stub is a tight push fit in 3 mm brass tube. Wrap tape round multi-strand cable and cut to approx length with cut-off wheel. Solder ends to avoid fraying (n.b. clean ends with meths/acetone to remove traces of tape adhesive from cable). Thread the cable into 7 mm length of snake cable. Push filed screw into one end of brass tube with slow-curing epoxy glue and multi-strand cable and plastic snake into the other end. Leave to set in a warm place (I leave it on top of a reading lamp). For strut, cut 2 cm wide strip of cb and cut in half lengthways. File a bevel of approx 60º in one end of each, coat with epoxy and join two pieces together so that there is a 120º approx "V". Epoxy 4 mm tube into this "V" and tape to support the assembly while it sets. When set, with a triangular file or cut-off wheel cut small notches in 3 mm brass tube for grease and then remove any burrs with fine emery paper. If you can find PTFE tube, use it over multi-strand cable (I wrapped PTFE plumbers tape several times up and down the cable and it's still holding, but I first put a bushing for the stuffing tube at the stub end). One greasing per run is needed between the stub and strut and the stuffing box bushings and cable. A fair bit of work, but so far so good and the cost savings are significant. For the stuffing tube I used rigid air line type pvc tube, with a wire inside to shape, immersed in boiling water for 5 minutes and then left to cool, which fixes the shape. I don’t know how long the set up will last, but for the moment it’s fine. Long drive lengths and more powerful motors would test its limits. | Martin Rickards |
| Flex shaft storage |
Most flex shafts are made from steel and will rust if not dried out. If they are left in a boat, over a period of time they will set in the shape in which they are left. For best performance, after use - remove the shaft from the boat and dry thoroughly, ligtly oil with a PTFE laden oil. Hang vertically so that the shaft remains straight. Examine and replace the thrust washers and bearings as necessary. Make sure that the bearing surface of the shaft is clean and polished before re-use and replace the bearings as necessary. | Allan |
| Motor securing bolts | The bolts themselves can be diifficult to find as they are non metric. I found that the cable clamps in electric plugs to be just the right size for a speed 400 (2.5mm). My motor\'s mounted on a removable mount, undo one bolt and motor comes out with mount attached. | Guiri |
| Motor securing bolts | Motor securing bolts are usually difficult to get out and put in so use Allen bolts ..... then get a spare key and cop it to about 3/4" long, glue it in to a suitable brass tube and glue a short piece of flex on the end of that. You can then use this contraption to place and screw up the bolts - finishing with a real allen key. | Allan |
| 4mm Banana Plugs | Heres my tip. Stretch silicone tubing over your 4mm plugs. It stops them coming into contact with things they shouldn't and also slides over the socket when you plug it in, making the connection less likely to pull apart. Neil | Neil McGrath |
| Painting!!!!????? | I usually try to avoid painting my boats and prefer to decorate them with Fablon or some of the self adhesive trim available from most model shops. Sometimes I have to spray the hull if I have had to sharpen up the edges or used filler, but most of the time I leave it in its natural base colour. Detail is picked out using a brush and standard Humbrol paints. Neil | Neil McGrath |
| Painting | When spraying two colours next to each other - DON'T mask but paint/spray the first colour feather edging it beyond where the final mask for the second colour will be. This negates the need to accurately butt the two masked lines or the possibility of a step showing through the second colour applied. | Brian Oldford |
| Painting | When painting GRP or plastic surface, rub down with very fine wetordry paper then wash with water and washing up liquid (fairy is very good!). This will disperse static electricity and remove grease. Dab dry - don't rub as rubbing will re-introduce the static. Keep your fingers off the surface. This is especially useful when spraying. Static can stop paint even reaching the surface. Grease will stop the paint adhering as will a shiny surface | Allan |
| Painting preparation | Painting preparation: Don't try and short cut preparation on painting - if you do then it will show. Wooden hulls need a grain fill. A modern wall filler can be used watered down until it is fluid (e.g. polyfiller fine). When dry sand and you will have a mirror finish ready for your primer. | Allan |
| Cutting Shiny/Polished Surfaces | It is often the case that you have to make cuts in hulls etc. that are made from ABS or GRP etc. This can be a tricky task but if you first place masking tape on the surface you can then draw the line/shape to be cut out on it. When you do cut use a flexible wood/metal baton as a guide. Use light cuts - this with the Masking tape will prevent the blade slipping and damaging visible areas of the piece. | Allan |
| Prop Shaft Hull Exit | Run the shaft through a small length (1/2\" - 1\") of silicon tube that is placed in the exit hole. The hole should be large enough to take the assembly but small enough to compress the Silicon. With flexible shafts a short length of brass or aluminium tube can be used. Use waterproof tape to tape the join in to the tail shaft bearing hosing - this will seal it completely and prevent water being pumped in to the hull. (Ernie Lazenby) | Ernie Lazenby |
| Hull materials | I'm building wood riggers now using mahogany over balsa. The balsa provides an easy glue surface inside the boat and overcomes the mahogany's tendency to split with the grain. For flat surfaces I laminate the woods together prior to assembly. For curved surfaces, the balsa goes on first, followed by the mahogany (steamed as necessary to enable bending). Mahogany is very strong, and provides an excellent surface for finishing due to its hardness. Besides, the boats are much prettier. Oh yes, and I use thin CA to join the woods, applied from the outside of the balsa (it seeps through to the mahogany quite nicely). | Andy Kunz |
| Hull Materials: | Thin balsa laminated to 0.4mm marine ply with thinly spread Epoxy glue provides an extremely light tough hull medium that does not need a lot of internal bracing. For curved surfaces apply the sandwich to the final shape before the Epoxy is fully set and hard. | Allan |
| Water Proof Servo's | A standard servo can be near waterproofed by releasing the joins very slightly and rubbing silicon sealant in to them (just enough to cover the jointing surfaces) and under the screw heads before tightening it up again and allowing to set. The top where the drive shaft exits should be treated with a silicon based grease. So long as the shaft exit is regreased regularly the servo will remain waterproof for a long time. Not only is this a lot cheaper than a waterproof servo but the seals can easily | Allan |
| Glitching |
There are a number of reasons for glitching so don't give up!!
1. Ensure that your motor is properly supressed. High frequency speed controllers require better supression than low frequency/resistance based ones do. Manufacturers supression is rarely good enough particularly on cheaper motors. 2. Keep motor and control wiring seperate. run it down different sides of the boat. 3. Use the whole length of aerial - don't wind it up under the deck. Get as much vertical run as possible - it it may not look really good but it does work. 4. See comment about TX/RX batteries on QandA page. If using nicads, use a 5 cell nicad receiver pack and up to 2 extra nicad cells in the transmitter. | Allan |
| Applying Self Adhesive Plastic Decals | These have a habit of trapping air bubbles etc. To avoid this and to allow easy positioning; after removing the backing from the decal dip it in a small bowl containing dilute washing up liquid. This will prevent immediate adhesion and allow correct positioning and bubbles to be smoothed out. Once the water dries out the decal will adhere in the normal way. | Allan |
| spray painting - masking lines | when spray painting multiple colours, after masking spray back with the base color and allow to dry before spraying with the top colour. Doing this seals the masking and prevents bleed through. and ma | Allan |
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