Elevator counterweight casting

[Bearhawk535]

i tried my elevator counterweights as described by Eric Newton in his guides but did not like the results. So I melted them out and redid them by sandwiching the tip between 2 pieces of plywood and pouring them vertically. I am pleased with the end results.

[Ray Strickland]

Ditto here, except I used 3/16" plywood held in place with spring clamps. Worked like a charm.

[Battson]

I also used the same "vertical pour" approach.

[JimParker256]

Is 5" from the tips the "common solution" for how much lead to use? I have been having trouble trying to figure out how much lead to use - where do "draw the line", so to speak. I suppose it's easier to remove excess lead later on than to add more after it's covered... but didn't know where to start.

[Mark Goldberg]

Pour more lead than you think you need. Then when you do the actual balancing - remove the excess from the aft side of the lead piece. Mark

[Flygirl1]

Also make sure you smooth it out because if you don't ANY imperfections will show up in the fabric and in the paint. And if your a perfectionist you'll end up cutting off the fabric and starting over because no matter how much filler primer you use, it won't correct it. Donna

[JimParker256]

Is 5" from the tips the "common solution" for how much lead to use? I have been having trouble trying to figure out how much lead to use - where do "draw the line", so to speak. I suppose it's easier to remove excess lead later on than to add more after it's covered... but didn't know where to start.

So, would 5" be "more than I need" or should I pour 6 (or 7, or 8, or...)? Seems easy to remove some as Mark says, but much harder to add... Just want to make sure I'll have enough in there!

[JimParker256]

Also make sure you smooth it out because if you don't ANY imperfections will show up in the fabric and in the paint. And if your a perfectionist you'll end up cutting off the fabric and starting over because no matter how much filler primer you use, it won't correct it. Donna

Good point. Maybe I'll spend a bit of time with the wooden "form" to make sure it's super-smooth, so the edges won't be rough. MDF would probably NOT be the best choice for the mold material - LOL.

[Flygirl1]

Another, learn from my mistake, point--when you epoxy prime, wait the full 7 recommended days before you put your fabric on. Polytak makes a good epoxy primer stripper. D.

[Zzz]

Good point. Maybe I'll spend a bit of time with the wooden "form" to make sure it's super-smooth, so the edges won't be rough. MDF would probably NOT be the best choice for the mold material - LOL.

Why not? Are you afraid it'll combust from the glue?

Seems like tracing the opening shape on your mold sidewalls and routering around it so that it extends slightly into the cavity would help keep it below the effective surface.

[Flygirl1]

Bill, it was not a problem adding some more lead. We just made sure we had something for it to hang onto like another tab or a screw. It doesn't take much lead to do what needs to be done and just as soon as I can get a photo of ours I will. D.

[Flygirl1]

[JimParker256]

Why not? Are you afraid it'll combust from the glue?

Seems like tracing the opening shape on your mold sidewalls and routering around it so that it extends slightly into the cavity would help keep it below the effective surface.

No, I was just thinking that MDF has a pretty rough texture, which would mean the lead surface would be pretty rough as well. As Flygirl1 points out, that means more work when it comes time to cover. Your suggestion to "countersink" the form around the tubing could solve that as well, but I was thinking that a smoother surfaced wood would also address the issue.

[jaredyates]

Any wood product is going to off-gas as it burns. I suspect that a pre-warmed steel or aluminum plate is going to be smoother. Russ Erb Erbman figured out a way to approximate the weight of the fabric by using a weight of a certain mass in a certain place, but I don't have the particulars handy.

[Zzz]

No, I was just thinking that MDF has a pretty rough texture, which would mean the lead surface would be pretty rough as well. As Flygirl1 points out, that means more work when it comes time to cover. Your suggestion to "countersink" the form around the tubing could solve that as well, but I was thinking that a smoother surfaced wood would also address the issue.

I can think of no smoother processed wood product than MDF. Are you thinking of OSB? MDF is extremely smooth, much more so than plywood.

[JimParker256]

Doh! Yes, I was thinking OSB when I read MDF. Geesh. Guess I needed more coffee!

[alaskabearhawk]

http://www.mykitlog.com/users/display_log.php?user=yeeeha&project=527&category=7248&log=219610&row=2

[JimParker256]

But that's balanced just a bit nose-heavy without the fabric. Is that the goal here? I thought they were to be balanced (as perfectly as possible) WITH the fabric...

[alaskabearhawk]

When cast I had the weight hung off the elevator at the position that Russ Erb calculated that simulates the entire weight of the elevator that needs to be compensated for, including fabric. When it's all done, it should be nose-heavy without the fabric. (see previous two log entries)

[JimParker256]

Got it! I should have looked back (didn't notice the "3 of 3"). Perfectly clear now. Thanks!

[Chris In Milwaukee]

http://www.mykitlog.com/users/displa...g=219610&row=2

Nice one, Paul