Tip of the Day

[Ben Beacock]

Use a very small amount of loc-tite or a dab of silicone on toggle switches and push button switches. The little bolts don't usually have a positive locking mechanism, and the ring terminals/wiring make it easy for the bolts to loosen off or fall out.

[Ben Beacock]

Use a very small amount of loc-tite or a dab of silicone on toggle switches and push button switches. The little bolts don't usually have a positive locking mechanism, and the ring terminals/wiring make it easy for the bolts to loosen off or fall out.

[Jersey Tom]

Here's a good one that a couple of us didn't know about..

Use MEK-P as a catalyst for polyester resin, not MEK. The former makes it harden fairly quickly. The latter thins the resin out, and leaves you wondering why your fiberglass layup is all gooey the day after.

[Dr Claw]

to go with tom's word of advice.....

USE THE CORRECT AMMOUNT OF MEK-P.

went through 2 gallons of resin in 18 minutes and junked a prepped sidepod mould surface (mould release and primer/gel-coat) on my first FSAE car using the exact opposite of whatever the correct ammount of MEK-P was.

[Travis Garrison]

um...that sounds like a recipe for flaming polyester...

[James Waltman]

I feel bad for nitpicking this one...

MEKP (Methylethylketone Peroxide (yes, I can type that without looking it up)) - is technically an initiator – not a catalyst. I know that everyone calls it a catalyst.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Catalyst: A substance, usually used in small amounts relative to the reactants, that modifies and increases the rate of a reaction without being consumed in the process. </div></BLOCKQUOTE>

In Polyester Thermosets, the initiator becomes part of the resin so it is not a catalyst. There are usually promoters in the resin too (like cobalt napthenate). The monomer (styrene) is there to form the crosslinks (and provide the smell we all love).

Assuming MEKP and MEK are the same is like assuming that Sodium Chloride and Sodium are the same...toss them both in water – I dare you.

That will conclude today's polymer chemistry lecture...sorry for that.

Flaming polyester, huh Travis? What would you know?
I think I have some pictures around here somewhere...

[Jersey Tom]

Well, on the bottles I get from our local composites place where we get all our fiberglass, carbon, kevlar, etc, its labeled 'catalyst'. So I call it catalyst.

Not that it matters. I'm not a composites guy. Yuck. Metal is where its AT.

[RonBurgundy01]

You can make home made napalm by dousing polystirene in petrol then setting it on fire

...Oops, wrong forum

[KevinD]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by James Waltman:

Assuming MEKP and MEK are the same is like assuming that Sodium Chloride and Sodium are the same...toss them both in water – I dare you.
</div></BLOCKQUOTE>

i'll take that challenge, and it looks like richard from top gear beat us to it:
http://video.google.com/videoplay?do...66654801392897

the cesium in water is pretty impressive!
but the sodium in water makes me yawn...

[James Waltman]

That just wasn't enough sodium.
I was thinking something more like this:
http://www.theodoregray.com/PeriodicTable/Stories/011.2...eos/SodiumLake01.MOV
That was only 109.5 grams.

From here:
http://www.theodoregray.com/Periodic...Stories/011.2/

So I should have said: Toss a brick of each in water.

Cesium is much cooler but my point is the same.