Need Cheap Capacitors (For Coilgun)

[ZIGGY_DAN]

Hello, i have recently made a coilgun, i have seen some posts about coilguns and was wondering if anyone knows of a cheap source of high voltage high capacitance capacitors?

I am currently using two capacitors, 200V 1000uF each, the are joined in parallel to give 200V 2000uF, i have calculated this to be 40 Joules of energy (Not enough!! )

If you need any specifications, just ask.
Thank You

 

[dknguyen]

Ive had this link bookmarked for a while but haven't bought anything from them. Giantest capacitors I've seen.

**broken link removed**

You can get ~33mF@200V.

Be careful with your project, now.

 

[ZIGGY_DAN]

Thanks dknguyen, they do have some rather large capcitors
no prices though , they look expensive

Thanks

 

[dknguyen]

Yeah, I bet they cost a ton lol. You could parallel a ton of 1000uF caps. Lower inductance.

 

[ZIGGY_DAN]

Be careful with your project, now.

It'll fire a large nail, 35mm x 5mm right through a aluminium can from about 3 to 4 feet. Or bury the nail in polystyerene from up to 12 feet (limited by length of workbench)

The ricochets are pretty nasty though, and iv'e been shocked a few times across the finger(faulty wiring, now fixed ) that shock made me move some though LOL.

 

[hjames]

I would guess that most switching power supplies have 1-2 ~450V, ~x00uF capacitors in them. Find some oldish computer power power supplies, and scrap 'em.

 

[HarveyH42]

I've got 6 that are about as tall as a 16 oz beer can, liitle bigger in diameter, rated 37,000 uF 75/95 volts. If I got these were I think I got them, can get 2 more (been sitting outside for years though). I work in a warehouse, and we put labels on everything. When they upgraded from dot matrix to laser, they were just going to throw these huge ass machines in the dumpster (weigh about 600 lbs each). I hauled all three home for parts. Only took one apart, took months to totally dismantle it (all the screws were slot-heads, and very tight). IBM quality...
It use to be a great place to work, now they throw everyhing away, almost makes me cry sometimes.

 

[ZIGGY_DAN]

My mate has got several that he pulled from several redundant power supplies, they are 400V 330uF each, he won't let them out of his sight lol.

He put them on some Veroboard (stripboard) and he made a mistake with his connections (charging them from regulated mains without any means of current limiting) the Veroboard blew apart and tripped his breaker!!

I was laughing LOL

 

[hjames]

If you're in the US, there's a handful of surplus places that sells cheapie capacitors.

The Electronics Goldmine is one that I've ordered stuff from (many years back - and some of their inventory is apparently *very* slow moving)

https://www.goldmine-elec-products.com/products.asp?dept=1222
I don't know if the link will keep on working, but just dig into their electrolytic caps /snap in category. They're selling capacitors like the one you've described for ~$1.00

 

[ZIGGY_DAN]

I'm in the UK, will they ship to the UK (without charging a fortune!!??)



thanks for the replies

 

[adaminc]

eBay is a great place to get large capacitors!

 

[ZIGGY_DAN]

ebay is great, but the postage usually costs more than the capacitors!

for some reason this makes me feel like i'm being ripped off

thanks for the replies