Pouring elevator counterbalance lead

[FinnFlyer]

Anyone have experience pouring the lead?

Trying to keep tail as light as possible I figure that if I pour the lead all the way out into the front of the tip it should reduce the amount of lead required.

Drill up a hole in E403 to 3/4 or 1" near tip, put alum foil in the fiberglass tip, clecko it on, cover inside of tip with a board, tip pointed down and pour the lead into inside opening between board and E403.

The question is: how well does lead flow and how fast does it solidify? Would a 3/4 or 1" hole in E403 be enough for the lead to flow from inside to outside of E403 and fill up both sides to same level before the lead stops flowing?

Finn

[airtractor8]

Anyone have experience pouring the lead?

Yes, I built an early RV6 kit and we had to do that.

Drill up a hole in E403 to 3/4 or 1" near tip, put alum foil in the fiberglass tip, clecko it on, cover inside of tip with a board, tip pointed down and pour the lead into inside opening between board and E403.

A 3/4" hole will be more than enough. Molten lead flows just like water and you will have heaps of time to do what you need to before it solidifies. I did not do this with mine. I just poured the inner and outer side of the rib separately.

The problem you will have is final balancing and securing the lead to the elevator rib. The plans probably show this( don't know, I built a RV6 ) but you need to secure it with two AN3 Bolts at least. Lead is easy to drill if you go SLOW on the drill speed. I used a wood arbour bit like this one https://ffsupply.com/product/wood-bit-arbor/ to cut a level surface countersink on the inboard side of the rib so the bolt heads would clear the horizontal stab outer rib. It will cut easily if you use low speed and low feed.
Make sure you over balance it to allow for the weight of the elevator paint and trim servo( If you have one).

Good Luck
Cheers
Graham

[Marc Bourget]

Check and then monitor your temps. Don't get too high. Once it flows well, stabilize the heat

[FinnFlyer]

Thank you Graham.
That is encouraging.

The (old) drawing show two 1/4" coarse bolts and nuts embedded in the poured lead.
https://drive.google.com/open?id=1jB...fkx7NAT1TaF88l

Between the 3/4" hole, the opening at the tip (removing baffles there), and possibly a few additional smaller holes in E403 connecting the lead on both sides, I think the lead will stay firmly in place. The lead will be fully supported by the skin and fiberglass tip, so the connecting areas of lead will only be to hold outside/inside parts together. Still probably would be a good idea to add a couple of bolts and nuts.

Thanks for the the tip on the spade bit for drilling (or removing lead later).

I will have the servo and mechanism in place, as well as additional 5 oz for vinyl or paint, when determining lead needed.

3M 1080 vinyl is 150g/sq m or 0.5 oz/sq ft. I don't if a light paint job could be made lighter?

I do intend to mount a 3/16" or 1/4" rivnut on the outside in case I later need to add more weight (big washers).

Finn

[FinnFlyer]

Originally Posted by Marc Bourget

Check and then monitor your temps. Don't get too high. Once it flows well, stabilize the heat

I've never worked with lead before. This particular lead is "Lead Ingots from Wheel Weights".

No clue what the temperature should be. I guess I'll put it a small coffee can, heat it with a propane torch until it flows to an even level in the can and then pour it? Or should I get a cooking thermometer and heat to what temp?

Finn

[abwaldal@gmail.com]

No cooking thermometers in lead. It melts at 640 degrees. Poof goes moms thermometer. pours easily wear safety glasses, gloves, don't drink whats left over. ha ha
Used to make sinkers bullets etc for past 60 years. Ain't dead yet don't breath fumes.
Oh by the way its hot and burns easily

[Christopher Murphy]

Just rivet in a small ?dam? where the plans indicate use the 2 course thread bolts and skip the large hole. Make a single pour for each side (4 total)

Works good lasts long time. And its easy

Cm

[Robin8er]

Be careful with wheel weights, most of them aren't made out of lead any more. The old ones are.

Obviously use in a well ventilated area and try to to breath it.

[rvbuilder2002]

Originally Posted by FinnFlyer

Drill up a hole in E403 to 3/4 or 1" near tip, put alum foil in the fiberglass tip, clecko it on, cover inside of tip with a board, tip pointed down and pour the lead into inside opening between board and E403.

I haven't ever personally tried this method but my guess is that even with alum foil, you will end up replacing the fiberglass tip after you are finished........

I recommend following the instructions.
No need to measure the lead temp. Heat until it is melted and then (carefully) pour.

[FinnFlyer]

Thank you all for the data and advice to follow instructions.

Obviously the fastest would be to follow plans, but this is supposed to be recreational/educational. And I really want to save weight where possible (without spending a fortune on a titanium tail spring).

So fiberglass (resin) deformation would be a real issue. Getting fancy I could coat the inside of the tip with fiberflax sheet (I think that's what it's called) and then the alum foil. Or submerge the tip in water (heatsink). Or put the tip in a small container with gypsum (sheetrock compound) and let that harden -- that should hold the shape of the fiberglass tip. BTW, these are old gel coated tips.

Finn

Originally Posted by rvbuilder2002

I haven't ever personally tried this method but my guess is that even with alum foil, you will end up replacing the fiberglass tip after you are finished........

I recommend following the instructions.
No need to measure the lead temp. Heat until it is melted and then (carefully) pour.