honestly never looked... I had spilled some lead on some cured glass scraps when i was pouring footy bulbs and was impressed with the way it help up... the MSDS say the boiling point of the resin and hardener separately are > 400* f Physical properties of cured epoxy Specific gravity · · · · · · · · · · · · · · · · · · · 1.18 Hardness (Shore D) ASTM D-2240· · · · · · · · · · · · · · 82 Compression yield ASTM D-695 · · · · · · · · · · · · 11,500 psi Tensile strength ASTM D638 · · · · · · · · · · · · · 7,300 psi Tensile elongation ASTM D-638· · · · · · · · · · · · · · 4.5% Tensile modulus ASTM D-638· · · · · · · · · · · · · 4.60E+05 Flexural strength ASTM D-790 · · · · · · · · · · · · 11,800 psi Flexural modulus ASTM D-790 · · · · · · · · · · · · 4.50E+05 Heat deflection temperature ASTM D-648 · · · · · · · · · · 123°F Onset of Tg by DSC · · · · · · · · · · · · · · · · · 126°F Ultimate Tg · · · · · · · · · · · · · · · · · · · · 139°F Annular shear fatigue @ 100,000 cycles · · · · · · · · · · 10,100 lb I'm going to pull a second bulb tonight or tomorrow... I think another option would be to make a small wooden box and fill it with silicone and make a mold with silicone I did make a mold once with plaster of paris...but even after a week and baking in a oven, the mold still cracked real bad... The problem with the glass mold is you still need to spend a fair amount of time sanding for smoothness which is one of the bad things... sanding lead, dust, handling, ect... for my IOM bulb I will probably get some pourable silicone
I've always liked the idea of pourable silicone but have been horrified at the cost. Cheapest method (although time consuming) has got to be Claudio's 'layering system'. Alternatively, you could always buy one - although there's definately something satisfying about melting lead down and pouring your own. Maybe it's the excitement owing to the potential danger.......!! Cheers, Row
30 bucks for 2lb worth of silicone... or buy a bulb for 80 bucks... I have thought about using tub/tile silicone caulk just to try it... even a silicon mold will only last a few times... my larger problem is my lead pot only holds 4 pounds of lead... so from an IOM stand point. I may end up only doing 1/2 a pour and then using the milling machine to mill it smooth and epoxy the two halves together... but yeah I do enjoy trying to make as much as I can... hence the reason for buying the milling machine. over time I hope to be more self sufficient, and provide stuff for the guysin the club...
Quote " over time I hope to be more self sufficient, and provide stuff for the guysin the club... " Glad your picking up the slack... :-> Time to hit e bay for a bigger pot. Keep up the good work ! Craig
I made my last mold with a 50/50 mix of Plaster of Paris and Portland Cement. So far I've poured 6 bulbs and there is no damage. CAUTION This mix sets up faster(by far) than Plaster of Paris so work fast. It also takes just as long to dry. I gave it a month or so behind the stove. Don
RTV Silicone (Room Temperature Vulcanizing silicone) is also used as Black Silicone Gasket used for engines with different variations, these have and have temp range -80 to 500 deg F. For sure there are other higher temp brands available. Price seems reasonable but quantity per tube is questionable, may give it a try by coating bulb with something like 5 mm RTV silicone layer and bed it in cement for support, save wasting to much silicone & see how it works out ? Marc, when using plaster/furnace cement I found it pays to put some reinforcing in the mix, I used chicken wire. The mould holds together for 4-5 pours, handling it gently. Cheers Alan
can't let you do all the work... my Huge "hunk-o-lead" went missing I've only got about 10lbs of lead before I start scavenging from work again... Still along way from the IOM bulb...
gooseneck/vang off the mill... part # 1 a "copy" of the micro magic vang/gooseneck assembly... not bad for a first try... I'll use for one of the rigs for my trip to texas...
just laid up null number 2. I was happy with Hull #1 but wanted to fix a few of the "rough" edges... also pulled out bulb #2 from the fiberglass mold 595 grams with slot cut...
more pics... getting very close to putting in the rails for the servos...maybe tomorrow night... Dark Matter is getting close
Well I finished albacore hull #2. RTS weight 1245 grams hull with rudder and electronics no rig no battery 420 grams bulb with fin 695gm fingers crossed for no pinholes... sail on sunday
37* no ice a few flurries and some light winds... hulls kisses water for the first time (aside from tap water from wet sanding) put the battery amidships set her on the water. hits the waterline at the bow, but the stern is about 1/4" low... : ( with what little breeze, the transom did come out of the water and settled in nicely but then the bow sinks down about 1/4". trims easily. only one to two clicks on the rudder to trim it out.... hope to try it out against a couple other RG's next weekend. so I have options I can put in the light keel to change the waterline. or shift the battery aft. but need some breeze to see what she can really do... I feel with the battery further aft in a breeze the stern will still come out of the water... cell phone pics, not the best...
about a month not real quick. but I did incorporate several time savers 1. reused original foam plug which allowed me to alter the hull shape some... 2. used heli rotors for keel fin 3. reused rudder from albacore #1 4. reused entire rig from albacore #1 5. Used IOM deck plug for the deck layup... I still need to build two more rigs and make sails... but that is a bit more straightforward...I've gotten to where I can cut the sails in about an hour now...
Marc, How do you like using the heli blade as a rudder ? And how did you attach the blade to the bulb ? Manny
Manny, I think using the heli blades is simple and easy. they probably have a bit more camber than what would be ideal...these blades are 5.5mm thick... usually the blades are either foam or balsa cored so its easy enough to hollow out an area for the rudder post. I used my milling machine and cut out a section of the bulb where I wanted the blade to be. once I got the depth i wanted I then drilled two holes through the bulb and the fin from left to right. and then used small pins to hold the fin in place and then filled the gap with epoxy.. look at post 38 in this thread I have a couple pics of the milled slot and pins... the rotor blades can be found for pretty cheap at hobby king these are the ones I used... http://www.hobbyking.com/hobbyking/store/__10818__500_Size_Fiberglass_helicopter_blades_430mm.html with the heavy bulb there is some deflection in the fiberglass blade. I am going to order a carbon set for more stiffness...and less deflection...