I do not want to come across as a smart ass, that is not my intent. But wouldn't it be easier to buy a couple of the 24V Rubber self adhesive heaters and use them?
It absolutely would, but I'm pretty broke at the moment, so it has to be a cheap and temporary solution. The plan in the future is to upgrade to a really proper heatbed, either silicone or kapton or pcb, but right now, i just cant afford it.
Been There, done that. Hopefully the day will come when you can afford the upgrade. The idea of using nichrome wire on the aluminum will work if the wire is encased in a high temperature fiberglass tube or possibly even a couple of layers of Kapton with some sort of ceramic insulator to hold the wire close to the bed but not touching it. No matter how you do it, you will have some sort of investment to keep the wire away from the aluminum. Best of luck to you on figuring out what will work the best for you.
I know... And the shop today was sold out of kapton. I've seen a few options. Based on the materials I have, I'm thinking 2-3 layers of blue painters tape and then use thermal compound around it. I've seen that done on a few sites, but I wonder if the tape would burn.
The tape would definitely burn. It is not designed for such applications. You really need to find some kapton tape. A fiberglass mat would probably work but it would be more costly than the Kapton tape.
Sure they would work, but I thought you were going to go with nichrome. Or do up just want to use the nichrome along with the resistors? That would work to. The most difficult part is how to keep the wire insulated from the aluminum and determining the amount of wire to use for a particular voltage and temperature you are trying to achieve. There are web based calculators for the nichrome but I don't remember where they are, a search will find them.
Yeah I've seen a few of them. See I have the 2R2's in place, but I don't know if 4 x 2R2 in series will get up to the required temperatures.
hmmm... I think this might work... or alternatively this: I know they're both above the 15W rating of the resistor, but considering the old ones was WAAAAAY higher, they could be options to consider surely? edit: also, I now have ALL the final print files ready to go. so excited! So close yet so far!!!
You need to generate as many watts as you can without destroying the resistors. Can you put the 2.2 ohm and the 1.5 ohm on at the same time? I don't know or remember how big your power supply is but too heat that large piece of aluminum is going to take a lot of watts, which means a lot of resistors and a lot of current going through them.
Not without drilling more holes. And I don't have the right drill bits. So I would get less heat from those methods because there's less watts than the old setup?
hmmm... its sounding like I may be forced to wait a bit and invest in something a bit more substantial. So then realistically, if I'm trying to keep the costs down, it's either: nichrome 4 x 3.3R 50W (43.64W across each resistor) 4 x 3.9R 50W (36.92W across each resistor) some other cheap solution? Kapton foil heater maybe?
Kapton Foil would be better than resistors if you can find it in a large enough size and high enough wattage.
yeah but they need a tonne of power. Right, I'll get some kapton tape as soon as i can afford it and go with the nichrome, and then eventually go to a 300x300 bed with a 300x300 silicone heater. That seems like my best option, right?
Yeah, this is all just a temporary solution in my mind. Once I can, I'll be going to a bigger bed, with proper heating. Nichrome it is for the moment. I'll get some tape in the next week or so. It is proving difficult to keep focussed on this with so many set backs. But I guess its like that old saying, go hard or go home.
Oh I won't give up. Besides, the help and advice here is excellent, and people here are really inventive.
