P409 testing: Float volume

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P409 testing: Float volume


Post by Cotten » Mon May 25, 2009 5:38 pm

(Continued from "What are you doing today... " topic)

Intro & Review:
Summer blends are traditionally the most digestive, and this year's P4gas (P409) promises to be no less. We have two new molded floats on the market to test along with machined DURABLEs, both old formula and new.

Because one of the new cast floats has its pivot nut molded into it, and a lever firmly placed at offset, I elected to outfit the other four test pieces the same: An old DURABLE, low-density and standard versions of the new formula DURABLE, a molded replica of an 'Armstrong', and what appears to be a molded replica of an Eversure (Dixie) brass.

All are variations of the nitrophyl compound that original 1957 "Armstrong" floats were composed.

Each was measured with a dial caliper, weighed on an Ohaus triple-beam, and finally measured for volume with the simple apparatus shown below:
A plastic tobacco canister has a slot cut in the side to allow the lever to protrude, and air escape as fluid is metered in through a hole for a veternary syringe.
The slot was cut with an exacto knife, and the hole was poked with a leather awl to a tight but removal seal on the syringe.

It only shows how feeble my faculties are when I am shocked and surprised to find a 60cc syringe fills a "2 oz" tobacco can EXACTLY. (duh)
The final reading when fluid reaches the air escape at the lever is the
float's volume: no calculations to make!

Mineral spirits was used because it doesn't foam like local tap water, and it doesn't spot things up when I purge the air from the syringe all over the shop ceiling tiles. And a short blast with air dries everything quickly for repeated tests. (My floats are also routinely washed with spirits after machining.)

Accuracy was still limited by the syringe itself to + or - a half a cc.
This will not be enough to study minor swelling, but it certainly illustrates differences among float productions.

Findings were as follows:
Float gms w/lever vol:cc W/V OD ID HT
Old Durable 8.10 17 .48 2.340 1.520 .490
New Ultralight 8.10 18 .45 2.375 1.525 .490
New Durable 8.10 17 .48 2.350 1.520 .480
Molded #1 9.00 18 .50 2.368 1.620 .558
Molded #2 15.10 20 .76 2.362 1.585 .595

NOS cork 8.75 16.5 .53 2.300 1.535 .535

(Corks data is for reference only; It will not go into the P409)

It doesn't surprise me that my crudely-carved DURABLES vary greatly, but I am perplexed that I missed duplicating the original weight to volume ratio.
(How come they work?)

And one of the newcomers has the home team worried!
The other appears handicapped.

I look forward to comments and critiques,
as well as any other suggestions for studying these floats before they are subjected to P409.

It may be the end of the Summer, or longer, before this experiment is

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Re: P409 testing: Float volume


Post by Panacea » Fri May 29, 2009 12:18 am

I think the surface tension would ruin the accuracy of the coffy can idea, The smaller the better. I like Cottens solution. Mike

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