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Post by sf2 on Nov 14, 2007 19:54:00 GMT 10
as part of my plank, I'm making a carbon ballast tube to fit in the wing.The only problem is how to make the shot that goes into it.
I tried to make a plaster cast to pour lead into, but moisture caused boiling and bubbles in the pour, so need to come up with another idea.Thought of pouring lead in to a brass plumbing pipe, but will it stick once cooled ? again any ideas any one.
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Post by thevon on Nov 14, 2007 21:28:49 GMT 10
Hey is this Jeff? With the Lumberjack? It's Andrew here anyway! There's some stuff about this in the Bat thread I think but I recently made ballast blocks for the Bat by chiselling a rectangular hole in a bit of hardwood. Perhaps you could drill into a bit of wood?
But most guys (I think) do use thin walled brass tubing that fits really neatly inside the outer ballast tube, and pour the lead into pieces of the inner tube. Glenn (Zipper) did the ballast tube on my late Drongo and that's how it was done, so he might be able to chip in with what he used. That way even if there are a few bubbles etc the outside is really smooth. Plain lead might be too rough and sticky, making it difficult to slide in and out of the tube - it really needs to be able to slide freely.
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Post by jase on Nov 14, 2007 22:03:25 GMT 10
i hammered some sinkers into cylindrical shapes, but i've made them about 1 - 0.5mm too narrow and there is considerable slop in the tubes with these installed.
not sure if this will affect anything, but i'm going to try and get them a little more fitting better...
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Post by laanguy on Nov 14, 2007 23:58:00 GMT 10
I do alot of ballast slugs and have used the brass tube but normally use aluminium tube that has a thicker wall. Basically I just want the outside diameter to be perfect to slide into the ballast tube. Melt the lead and poor it into the tube (outside with a mask of course). Sometimes the lead will move a little but I normally use my disk sander to get the ends looking pretty and this seems to stick the lead in place.
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Post by sf2 on Nov 15, 2007 8:42:00 GMT 10
No it's not jeff,I met you(Andrew) up at Tamborine a while back, you where there with a mate(sorry can't remember name).With your method, I guess the lead stays in the inner tube and you just cut sections as you want and use as you see fit. Same with Laanguy but using aluminium.Ok I can do that.
I did have a model from the states with lead shot with no casing, which is what I was aiming for, but this sounds a lot less painful, what size (wing permitting) tubing do you guys use and is a regular plummer going to sell it ?(or better where do you get the tubing from ?)
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Post by thevon on Nov 15, 2007 9:43:20 GMT 10
Ah, sorry - thingyon as I remember?? I was up there with Sean, and also Gary turned up later too. Cheers! I have no experience with making my own ballast tubes. But I just measured the dead Drongo's gear and the brass outer casings of the slugs are 15.0mm OD. The OD of the brass ballast tube is 16.7mm. It's really thin walled and quite light - worth considering instead of carbon I would think.
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zipper
> 50
Off The Edge Sailplanes
Posts: 88
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Post by zipper on Nov 15, 2007 12:33:09 GMT 10
The brass tube comes from your local hobby shop in 300mm lenghts. I melt the lead into the pre cut lenghts of brass tube and then finish them off on the lath. You can usualy get lead from a tyre shop (they throw away the old wheel ballance lead). To stop the slugs coming out the ends of the ballast tube, you could use a small split pin at each end of the tube.
I use thin wall tube because you want as much lead in that tube as you can fit, and if you are using thick wall aluminium than you are wasting space with the aluminium.
Glenn
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Post by thevon on Nov 15, 2007 20:09:44 GMT 10
Ar, Ar, this forum has software to pick up suspect words and it changes them to "Thingy"! Like the time Jase wrote Yepp-oon (see if I can trick it). So the above should be Dic-kon, not thingyon!!
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Post by sf2 on Nov 19, 2007 21:38:17 GMT 10
That's great thanks for the help, yes that's correct, it is Dickon, and nicely spelt, most peolpe use an"E" instead of an "O". Just finished installing 3 out of 4(2per wing)carbon rods in the wings, using vise, seems to be working, but might be doing a bit of sanding.
Thanks for the tip glenn, I guess I'll have to visit brisbane to get the tubing local guy never seems to have the stuff. All part of the fun I guess.
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Post by sf2 on Nov 19, 2007 21:40:25 GMT 10
Must pay more attention, correct Andrew Dic-kon
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