Al B. Fuct
once had a dog named
heh, thanks LB.
bula bula!
bula bula!
Bud dryer - manicured to smoke in 3 days
- Thread starter Al B. Fuct
- Start date
LoudBlunts
Well-Known Member
why is your thread closed?
Al B. Fuct
once had a dog named
It had run its course. It was all about a 2-week rotation SoG grow- I covered that any number of times- and the thread turned into 'Ask Al B.' It got so long that people were not fully reading it anymore and I'd get the same questions over and over.
I might start a new thread one of these days, but I was putting too much of my day into it. We'll see.
I might start a new thread one of these days, but I was putting too much of my day into it. We'll see.
LoudBlunts
Well-Known Member
a few questions, al....
how big does the heat sink have to be?
what is the use for the light dimmer if the thermostat is capable of upping and downing of the temps? or do you wire both so you can control it through the thermostat? if not, is there a way to rig it so you can control it via the thermostat?
isnt there different wiring for the fan and the heating and cooling elements on the thermostat? im guessing if im using a fan with a filter on the end i would wire that up on the 'fan' option on the thermostat and have the button switched to 'on' not auto or off, correct?
Al B. Fuct
once had a dog named
oh crap, you would ask that.
I built my dryer with a heatsink that was on hand, not one that I selected for any particular performance characters. So, let's go back to 1st principles and do some hypothesising. If the heat sink's too large, the resistors won't be able to put enough heat into the sink and air coming off it won't come up to 29C even when the resistors are at max power dissipation. If it's too small, the resistors will overheat because not enough heat is being taken off the heatsink into the airflow.
The sink I used is very similar in size and shape to this Jaycar unit (pictured above), which is 150mm x 75mm x 46mm.
I've put in the dimmer to smooth out the temp stability. IF I had calculated the ideal sized heat sink, the dimmer would not be needed. However, in my working example, the resistor bodies warm up very fast and will overshoot their max operating temp rating (80C on the R bodies) before the airstream comes to 29C. Dialing them back a bit with a dimmer slows down the rate at which they warm up, keeping the resistor bodies below 80C.
I've calculated the R values to allow rated dissipation in the resistors (25W) at about 90% of line voltage because even when the dimmer is wide open, the dimmer only delivers about 90% of the line voltage. If I didn't calculate the R values for 90% of line voltage, they could not get enough voltage to come to their rated 25W dissipation.
You could build this without the dimmer but the R values would change. For 240V, each resistor should be 2.3k ohms. For 120V, each should be 576 ohms.
I'm not sure I understand your question. The fans are wired to run at all times that the unit is plugged in. Only the resistors are switched on and off by the thermostat.
Keep in mind that the thermostat you use must either have a remote mountable thermistor (temperature sensor) or you have to modify the thermostat by removing the thermistor and extending its leads so you can mount the thermistor in the warm air stream while being able to mount the thermostat unit itself on the outside of the dryer unit.
Al B. Fuct
once had a dog named
Rats, the heat sink I pictured in the above post would not be the best choice. The fins run in the wrong direction. If you put a muffin fan in the middle of the pictured unit, the fins on the ends of the unit will be 'lazy' and won't warm air that is being drawn through the fan. The heatsink I used has fins running on the long axis, so air being pulled through all fins is being heated.
This Jaycar sink (actually 2 of them pictured) would work better. The fan goes on the end of the two stacked sinks. The resistors could be mounted 3 per sink.
This Jaycar sink (actually 2 of them pictured) would work better. The fan goes on the end of the two stacked sinks. The resistors could be mounted 3 per sink.
LoudBlunts
Well-Known Member
im not understanding where i would put the fan on that heatsink....
nor am i able to find a heatsink like that in the US..... you know im trouble al, but forgive me....could you possibly help me find a heatsink from a US retailer? also the smallest heatsink possible!
and if i understand you correctly....since you are calculating the heatsink i can do without the dimmers? and as long as they are 576 ohms @ 120v correct?
as far the fan question and the thermostat....i know you are supposed to have the fans running the whole time the bud box is drying or plugged in. i just wanted to use the on and off features for the thermostat?
and also you say that the only thing switched on and off by the thermostat is the resistors (excuse me, you'll have to hold my hand as im not looking at one right now)
how does it hook up? is that just on a basic thermostat, b/c i thought thermostat would have contact hookups for the options of 'fan-auto/on/off' -- the heating & the cooling contact hookups right?
if you are still following me, that is where my last question came in at.... like if i wanted to hook all the fans to the thermostat and when i press off all the fans turn off? or it doesnt work like that?
nor am i able to find a heatsink like that in the US..... you know im trouble al, but forgive me....could you possibly help me find a heatsink from a US retailer? also the smallest heatsink possible!
and if i understand you correctly....since you are calculating the heatsink i can do without the dimmers? and as long as they are 576 ohms @ 120v correct?
as far the fan question and the thermostat....i know you are supposed to have the fans running the whole time the bud box is drying or plugged in. i just wanted to use the on and off features for the thermostat?
and also you say that the only thing switched on and off by the thermostat is the resistors (excuse me, you'll have to hold my hand as im not looking at one right now)
how does it hook up? is that just on a basic thermostat, b/c i thought thermostat would have contact hookups for the options of 'fan-auto/on/off' -- the heating & the cooling contact hookups right?
if you are still following me, that is where my last question came in at.... like if i wanted to hook all the fans to the thermostat and when i press off all the fans turn off? or it doesnt work like that?
flipsidesw
New Member
Just wanna say thanks for answering my question!!
NeoAnarchist
Well-Known Member
hey Al, good thread i read the whole thing, and ive been wondering about how to make one of these things, got my RM tub and im probably gonna have to use some p/c fans, or atleast one, i was thinkin of some ideas on how to get some heat in there, but i think im jsut gonna stick without a heat source. but i have some questions 1. will an exhaust fan work to suck the air out, or do u think it would suck the air out too fast? and 2. do the temps in the room have to be below 84f, cuz i try to keep my whole house around 72ish degrees and the RH is around 40ish % depending on where i am in the house. but my closet stays about 82f so im thinkin of puttin the box in there, but im also usin the closet for my OP so the light would be the only problem, but the tub is dark and u cant really see light in it.Your opinion?thnx man.
1. will an exhaust fan work to suck the air out, or do u think it would suck the air out too fast? and 2. do the temps in the room have to be below 84f, cuz i try to keep my whole house around 72ish degrees and the RH is around 40ish % depending on where i am in the house. but my closet stays about 82f so im thinkin of puttin the box in there, but im also usin the closet for my OP so the light would be the only problem, but the tub is dark and u cant really see light in it.Your opinion?thnx man.
Al B. Fuct
once had a dog named
On the end, where you see the fins.
See the holes for fan mounting screws in each corner? Fan mounts on the end and blows air through this pair of heatsinks.
Seeing as how I'm not in the US, it's hard for me to point you. Hit the electronics shops. I'm quite sure you'll find something suitable in the US if you just get out & look.
It's also difficult for me to tell you exactly what size to use. If you can find something about 150mm long x 75mm wide x 45mm thick with fins running on the long axis, you'd be pretty close.
I didn't calculate the heatsink size. I recalculated the R values. I'm a BSEE but I must have slept through the unit on calculating the thermal dissipation of a heatsink!
Ohm's law sez that 120V through 576 ohms is 25 watts, the power rating of the resistors
Not having a copy of the thermostat you are thinking of in front of me, I can't comment.
It sounds like you are thinking of a standard HVAC thermostat, which may not be rated to switch line voltage. HVAC systems usually use a low voltage like 24-36V as a control voltage, which is then used to switch the coil on a relay in the central heating/cooling system. That relay is used to switch the HVAC system on & off.
The tstat I'm suggesting has a relay which has NO and NC contacts, which we're using to switch (only) the resistors on & off. It doesn't have any 'fan-auto/on/off' switch. With the Jaycar Qt7200, if you want to switch the fans, you'll have to add a separate switch in the power lead to the fans.
However, a switch in the supply line to kill power to ONLY the fans is not a good idea, though. It would be possible to have current running through the resistors with the fans shut off. With no airflow, the resistors would overheat. In this design, it's necessary to have the fans running at all times that the unit is plugged in.
It doesn't work like that. If you want to have a switch to shut off the fans to avoid unplugging the unit when you want to shut it off, it should be a DPST type, with one set of contacts used to kill power to the fans and the other connected to simultaneously shut off power to the resistors, turning the entire device off.
This is the schematic for BudDryer v2.0. It has a motor speed controller in the leg feeding the fans. Even this is not a terribly good idea because it would be possible to dial down the fan speed enough to stop them.
This design relies on airflow over the thermistor to control the temp of the resistors. It cannot be organised to switch the fans off when the resistors are switched off. If it shut off the fans at the same time the thermostat shuts off the resistors, it would not come back on again.
LoudBlunts
Well-Known Member
wow...thanks for the schooling! im getting it! slowly but surely!
Hey Al thanks for all the info, i was getting ready to order all the stuff for my dryer, and wanted to see what you thought of my plan.
For the intake i was thinking of using this:
FAN & HEATSINK ASSEMBLY FOR INTEL P4 | AllElectronics.com
And the outake will be another 80mm fan.
For the resistors, i was gonna use:
All Electronics | Electronic and Electro-Mechanical Parts and Supplies at Discount Prices
and im thinking 4-6 of the 600 ohm 25 watt ones, we'll see how they fit onto the heat sink.
For the dimmer, I take it I can just use any generic light dimmer that I find at a hardware store right? As long as its above 600 watts?
For the msc, what do you use and is it really necessary?
For the thermostat is there anything in particular I need to look for in one im buying?
Would one like this do?
Robertshaw 9600 Programmable Thermostat
Im new to electronics and want to start learning and this seems like a good project to start.
I dont have any equipment so i assume ill need a soldering iron and some other misc supplies, any advice on what to pick up woud be greatly appreciated?
For the intake i was thinking of using this:
FAN & HEATSINK ASSEMBLY FOR INTEL P4 | AllElectronics.com
And the outake will be another 80mm fan.
For the resistors, i was gonna use:
All Electronics | Electronic and Electro-Mechanical Parts and Supplies at Discount Prices
and im thinking 4-6 of the 600 ohm 25 watt ones, we'll see how they fit onto the heat sink.
For the dimmer, I take it I can just use any generic light dimmer that I find at a hardware store right? As long as its above 600 watts?
For the msc, what do you use and is it really necessary?
For the thermostat is there anything in particular I need to look for in one im buying?
Would one like this do?
Robertshaw 9600 Programmable Thermostat
Im new to electronics and want to start learning and this seems like a good project to start.
I dont have any equipment so i assume ill need a soldering iron and some other misc supplies, any advice on what to pick up woud be greatly appreciated?
cannabitch
Well-Known Member
Hey thanks for the great info!! +rep
Al B. Fuct
once had a dog named
Way too small.
Think more this size.
should be ok
I don't think that sort will work well.
You need aluminum body resistors with mounting tabs to suit mounting on the flat surface of the heat sink.
Yep, any generic incandescent dimmer. However, 6x 25W = 150W.
I used a continuously variable fan motor speed controller, like this one,
in this case fitted to an extension lead for another purpose. This is an HPM brand MSC, common in Australia. You're sure to find some other branded MSC in your locality.
Yes, it needs to have contacts suited for switching a load at line voltage.
The specs for that tstat say:
This tells me that the switch contacts in this tstat are only rated for a low current 24V control voltage. This would not be suited for switching 120 or 240VAC.
I used one of these:
This tstat will switch 5A @ 240VAC. It also has both NO & NC contacts so it can be used either to switch a heating appliance or a cooling fan, making it immensely useful in the grow. I have at least 6 of them doing various tasks in my op. They are $AUD40/ea and cost about $10 to ship to Nth America (so said a person in Canada who recently ordered one). It costs about the same to ship 3 of them as one, so you might buy more than one. They run on 2x AAA batts (lasts months) and can be modified for remote mounting of the thermistor.
yep, you'll need a 25W iron, some rosin core solder & some small dia (3mm?) heat-shrink tubing to insulate the connections you make.
Hey Al,
I cant thank you enough for helping me out. The fact that you would take time out of your day to help out a total stranger is a testiment to your character. Hopefully my questions will help out other Americans looking for the parts for this, because it has not been as easy as I thought it would be.
So, I have a few more:
I think I've found the necessary resistors:
Resistive and Dynamic Loads, Power Resistors and Rheostats
they are the OMI HT-25 500 Ohm / 25W / 1% Resistors near the bottom of the page. I had to search through several different websites to find these, but im pretty sure they are what you said will work.
Im thinking that I'll need 6 of these? They're not cheap at $8 apeice but if its what I need to get it'll have to do.
I've been looking around at some thermostats, and the cheapest one I've found that looks like it'll work is:
Honeywell T6031A1136 Remote Bulb Thermostat
Is that what I'm looking for?
Will something as simple as the one below work?
ACE SINGLE POLE LINE VOLTAGE THERMOSTAT 11042 LUX PRODUCTS CORPORATION
Im trying to go as cheap as possible, but I dont know how to tell which thermostats I will be able to move the sensor on. Is this difficult? Am I better off just getting a remote bulb, or trying to mess around with modifying one that doesnt have a remote bulb?
Now, as for the msc, will this work?
Motor Speed Control Kit
And what does it do and is it really necessary? If I just pick properly sized fans will I need this?
Ok, on to the heatsink. I looked at the one you posted, and while it looks nice, I would really like to go cheaper than that.
You said the one I posted is too small, so from this I gather that the resistors will overheat, or the air will not warm sufficiently?
It seems like the one I posted was the about same height and width as the one you posted do I need the extra length just to fit the resistors on, or to dissipate the heat from the resistors?
Im really having trouble finding a heatsink like the one you pictured in the US, what if I used 2 of the smaller ones I posted?
What about this one, still too small?
http://www.partspc.com/ProductDetails.asp?ProdID=12845
It seems that all the heatsinks I can find either dont have a fan, or are about the size of the ones I've posted.
One last question, the connection to AC mains in your diagram is just a normal powercord right?
Again, thanks for all the help, it is VERY much appreciated.
-Flow
I cant thank you enough for helping me out. The fact that you would take time out of your day to help out a total stranger is a testiment to your character. Hopefully my questions will help out other Americans looking for the parts for this, because it has not been as easy as I thought it would be.
So, I have a few more:
I think I've found the necessary resistors:
Resistive and Dynamic Loads, Power Resistors and Rheostats
they are the OMI HT-25 500 Ohm / 25W / 1% Resistors near the bottom of the page. I had to search through several different websites to find these, but im pretty sure they are what you said will work.
Im thinking that I'll need 6 of these? They're not cheap at $8 apeice but if its what I need to get it'll have to do.
I've been looking around at some thermostats, and the cheapest one I've found that looks like it'll work is:
Honeywell T6031A1136 Remote Bulb Thermostat
Is that what I'm looking for?
Will something as simple as the one below work?
ACE SINGLE POLE LINE VOLTAGE THERMOSTAT 11042 LUX PRODUCTS CORPORATION
Im trying to go as cheap as possible, but I dont know how to tell which thermostats I will be able to move the sensor on. Is this difficult? Am I better off just getting a remote bulb, or trying to mess around with modifying one that doesnt have a remote bulb?
Now, as for the msc, will this work?
Motor Speed Control Kit
And what does it do and is it really necessary? If I just pick properly sized fans will I need this?
Ok, on to the heatsink. I looked at the one you posted, and while it looks nice, I would really like to go cheaper than that.
You said the one I posted is too small, so from this I gather that the resistors will overheat, or the air will not warm sufficiently?
It seems like the one I posted was the about same height and width as the one you posted do I need the extra length just to fit the resistors on, or to dissipate the heat from the resistors?
Im really having trouble finding a heatsink like the one you pictured in the US, what if I used 2 of the smaller ones I posted?
What about this one, still too small?
http://www.partspc.com/ProductDetails.asp?ProdID=12845
It seems that all the heatsinks I can find either dont have a fan, or are about the size of the ones I've posted.
One last question, the connection to AC mains in your diagram is just a normal powercord right?
Again, thanks for all the help, it is VERY much appreciated.
-Flow
Al B. Fuct
once had a dog named
WHAT!? You're AMERICAN? Oh, no, I cant help YOU. If you were ONLY Canadian or perhaps Cape Verdean...
No, not cheap at all. I think you ought to be able to do better on the price. I pay about $4 each for them. You'd save money ordering from RS in Australia!
I've found 25W alum body resistors on Allied's site, about $2.40/ea, haven't found a 600 [FONT="]Ω[/FONT] unit yet.
that'll do!
that'll do, too!
Mechanical tstats which use a mercury bulb will work fine but you won't be able to extend the capillary tube to the bulb. The Honeywell unit you pictured already has a remote bulb, but it's $50-odd bux.
Electronic tstats are dependent on thermistors, which usually can be liberated from the ckt board and remote mounted on a piece of 2 cond wire.
The speed controller you picture will probably work fine. It's not entirely necessary. It simply allows you to slow the fans down to make them quieter or to reduce airflow through the unit for cool ambient temp operation where the resistors on the heatsink are not making enough heat to get the air temp to 29C. For $6 and change, it's cheap to add the feature.
The one you pictured was a CPU sink for a Pentium4. Too small. The one I pictured was about 225mm long!
You are searching for a heatsink with a fan. Try searching for just a heatsink. You probably won't find a heatsink & fan as a unit, you have to marry them up later, I'm afraid. Computer CPU heatsinks are not going to work, simply too small. Find a heatsink about 200mm x 75mm x 50mm with fins running on the 200mm axis.
yep!
Now, I've given you the basic parameters, done a little bit of shopping for you, but I'm afraid you'll have to do the rest of the shopping on your own. I'm sorry, but I'm buried in work at the moment and really am not very useful shopping for things on the other side of the planet!
Al B. Fuct
once had a dog named
Here's some detail shots of BudDryer v2.0's heating unit.
nylon stocking material acts as a dust filter on air intake.
air intake from either end of heatsink, stocking material on both ends.
Looks like 2 muffin fans stacked- it isn't. The fan next to the heatsink has been gutted of a blown motor and is only being used as a spacer. If there is no spacer, the fan blades passing so close to the heat sink fins makes for a whizzzzzzzzzzzzzzzing noise.
note blue thermistor near bottom of the fan, in the warm airstream. Thermistor has been removed from the tstat housing and extended on a 2 cond lead
6x 25W power resistors in parallel.
nylon stocking material acts as a dust filter on air intake.
air intake from either end of heatsink, stocking material on both ends.
Looks like 2 muffin fans stacked- it isn't. The fan next to the heatsink has been gutted of a blown motor and is only being used as a spacer. If there is no spacer, the fan blades passing so close to the heat sink fins makes for a whizzzzzzzzzzzzzzzing noise.
note blue thermistor near bottom of the fan, in the warm airstream. Thermistor has been removed from the tstat housing and extended on a 2 cond lead
6x 25W power resistors in parallel.