A different PID question (i hope)

[bhop]

So i know i need a controller a ssr a tc and a heat sink. my question is what other things can these parts be found in? im going to the scrap yard today and thought i might could maybe find a piece or two there.

[lancem]

Any good chunk of aluminum would probably do for the heat sink but they are pretty cheap on ebay. The other stuff, I'm thinking commercial kitchen equipment, or industrial heating cooling. I wouldn't wouldn't hold out much hope myself finding them.

[bhop]

maybe like an oven?

[bosterr]

For a housing I found a plastic electrical junction box that measures about 6 3/8 X 6 3/8 X 4 3/8 high with a gasketed lid at Home Depot. It holds all the components and has plenty of room to work in. It has mounting tabs at all 4 bottom corners that I attached leveling feet. Price was about $12.

[Lee]

Evel-Bay will have everything you want. And price wize you should spend under $100.00 or you're over-spending ...... Lee

[w0fms]

I spend $8.82 on a 40A SSR and heatsink for the relay last one I bought on flea-bay. The PIDs go for about $25-40 depending on options. So I'd say <$50 actually.. not $100. I added a $5 Wal-Mart mini saucepan and a $16 Amazon Prime Aroma hotplate (with chunky cast iron bottom), a $4 K thermocouple, and that's my casting setup. $60 total...

[bhop]

im going to try to spend as little as possible on it, i would like to see just how cheap i can make one that works good. im hoping to not buy any parts new, i plan on checking the scrap yard and a place here in town that is like a scrap yard for electrical components. and go from there. this adventure is open to donations too guy wink wink lol. i plan on posting about it once im finished. i figure with a baby on the way i can not piss off the emotional s/o at the same time hopefully write something everyone will enjoy reading about and maybe learn something too

[bhop]

wofms- where did you get the $4 thermocouple?

[2wheelDuke]

This thread gave me the idea to check eBay.

http://www.ebay.com/itm/AC-110-240V-...item20d586a96c

This looks like it'd be viable for casting, right? I see people talk about 40a SSR's, but that sounds like overkill to me. My pot is running off a 20a circuit at most, and there's probably other things running there. I don't see how it'd need bigger.

I guess I'm off to search and see if I can find that answer myself.

EDIT: This thread here http://castboolits.gunloads.com/show...ol-temperature lists a 25a SSR. The only thing missing from the eBay package is a heat sink for the SSR. I bought the package I linked, plus a heat sink from another seller for an extra $10. So I've got $40 in parts in my PID build. I should have everything else, but I might have to shell out a few bucks for a terminal block.

[bhop]

but that is a good deal i was looking at that exact one earlier.

[Lee]

w0fms is probably correct. I ain't looked in a while, but when I see PID's setups going for $198 I get agitated.
20amp is OK. As far as I know 40amp is also OK, should make no difference in performance. (The pot will only draw the amps it needs. Heatsink only needs sized for amp draw. Bigger for 40A, smaller for 20A. Ensure you have the correct voltage rating for the SSR output, typically 120VAC.)
Don't rule out Amazon.com either. They just might surprise you.
Thermocouple: SS jacket and be aware that you have Type J and K , as well as a few others to choose from. Others will chime in with details! ..... Lee

[texassako]

Watch out for the knockoff ebay SSR's. I have been looking at components, and it may not be worth risking an ebay SSR(especially a Fotek). There is even a listing trying to educate people on the knockoffs: http://www.ebay.com/itm/SSR-solid-st...item3ccc4d60fa . Problem is some are the real deal, some are not, and some are close enough to the real thing to function adequately.

[Lee]

texassako. WOW! thanks for that info! Anyone wishing to build needs to check this out! I hope evel-bay don't get you in trouble. I hope evel-bay wakes up on these junk items. But don't hold your breath. In any case, with careful shopping, it is still possible to make a PID controller for under $50 - $100. Know that your typical pot will draw less than 15amps. But unless your components (SSR) can handle 15 amps, they WILL fail ...
Typically without damage to any other components, it just won't work ..... Lee

[2wheelDuke]

I guess we'll see. I know that I've got a 20a circuit tops, possibly with other things drawing. I can't recall if it was done with 14g or 12g wire, and what size the breaker is. I'm pretty sure that the hot plate is on the same circuit, and maybe the lights as well.

[Dystaxia]

Got the following from here:

http://www.auberins.com/index.php?ma...=index&cPath=1

Works great on my Lee 20#!


Products
------------------------------------------------------
1 x 1/16 DIN PID Temperature Controller (SSR control output) (SYL-2352) = $45.50
1 x 25A SSR (MGR-1D4825) = $15.00
1 x K type high temperature thermocouple for heat treatment (WRNK-191) = $18.62
Probe Length Option 6" (150 mm)
1 x Panel mount connector for K thermocouple (TCCON) = $5.89
------------------------------------------------------
Sub-Total: $85.01

[el34]

The Lee 20lb pot operating current is around 5.5 amps for the 115V version, half that for the 230V.

A higher-capacity SSR has the probable advantage of being more reliable since it would be running in 'low gear' while being designed for much harder use. Mine is a 25 amp part.

The heatsink choice is a function of output current squared times its internal resistance which nobody knows, and thermal resistance to the outside air which also nobody knows. If a datasheet is available for the SSR it's likely that heatsink requirements are at least generalized.

Bottom line is that the heatsink isn't critical, some people mount the SSR to the aluminum chassis and that's it. Others use a heatsink about the size of the SSR, that's fine too. Perhaps more important is to have an identified path for any SSR/heatsink heat to get outside the chassis it's in.

[blikseme300]

I am a born scrounger but the effort to find bits and pieces for my first PID setup cost me more than expected and consumed too much time. Very few common electrical and electronic items lend themselves to yield parts needed.

My solution was to visit auberins.com and just order the parts. A few more bits from Lowes and an evening of assembling and done. Cost was just under $160 and well worth the time saved.

To me it is a question of what you have to burn. Money if working 60 hours plus/week or time if retired. I could not be happier with PID's and would not hesitate to do it again.

[bhop]

Got the following from here:

http://www.auberins.com/index.php?ma...=index&cPath=1

Works great on my Lee 20#!


Products
------------------------------------------------------
1 x 1/16 DIN PID Temperature Controller (SSR control output) (SYL-2352) = $45.50
1 x 25A SSR (MGR-1D4825) = $15.00
1 x K type high temperature thermocouple for heat treatment (WRNK-191) = $18.62
Probe Length Option 6" (150 mm)
1 x Panel mount connector for K thermocouple (TCCON) = $5.89
------------------------------------------------------
Sub-Total: $85.01

i dont think you read all of the posts in this thread. $85.01 is WAY more than i want to spend. this is about just how cheap i can get one built.

[bhop]

el34- so as long as i can keep the ssr cool i dont need a heatsink? so if i put a small computer fan blowing across it would that be enough?

[felix]

General rule: Keep electrical things as cool as possible. Longevity is the only downfall. If fact, some of the cheap light bulb "brands" blow up on first turn on (at home). About all computer chips designed for maximum storage or speed, depending upon chip destination, are burned in at the factory for quite some time at OPERATING temperature as measured on a chip external, usually on a flat top. In other words, make sure the operating temperature is not exceeded. If you don't know, cool the device!!! ... felix