Small tank anodizing

[sage]

Anybody usig the 300W submersible heaters by Caswell? Im trying to boil about 4gal of water in a bucket. Scaling up from my hot plate you see - and I have three of them in the bucket and after an hour it's still only at 180 deg. Pretty expensive way to heat water. Do I have to buy another one and make it 4? This is nuts!

Sage

[cameraman]

Originally Posted by caswellsage

Anybody usig the 300W submersible heaters by Caswell?

I am. I use them two at a time to heat the desmut, dye, and sealant. In winter two would heat the dye up to 140° in an hour and change, now it takes about 40 minutes. I've heated water to 180° to mix up dye. I don't rightly recall if I've gotten them to get the water to a full boil or not, but if not, it was pretty darn close.

[cameraman]

Originally Posted by destroyer125

I just ran across these

That little guy runs on something called a peltier element. It's a magical little device that runs on DC and transfers heat from one side of its plate to the other (to us laymen, one side gets "cold"). Reverse the polarity and the sides reverse.

Originally Posted by luminous

I don't think it would be happy in a sulfuric acid solution

I don't think it would, either.

However, knowing what it is, you can find tons of info on it in search engines. Several companies sell them for all sorts of applications; I don't think it would be very hard to build something that's more suited to anodizing.

The problem with that one is that while I don't doubt that you could get 6-8° out of 10 gallons, the seller doesn't tell you how many days it will take . I had run across them as CPU coolers in a computer store a few years ago and picked up 3 at $5 apiece. They look exactly like that eBay picture except no spout.

The peltier element can develop a pretty fair temperature differential between its two sides, but you have to take into consideration the size of the element versus the mass that you're trying to heat or cool. I have an "electric cooler" that works on one - I haven't taken it apart to see what size or how many elements are in it. It claims to be able to keep something 40° F cooler inside than the outside temp. It takes it a long time to get cold, though. It runs on 12 volts. If I remember correctly, it was something like $40-60 at WallyWorld about 4 years ago.

[M_D]

If you insulate the tanks or buckets you are heating, it will dramatically change how easy it is to heat the solution. Use a lid with some sort of insulation also while it is not in use. Three 300W heaters will bring a 5-gallon bucket to a rolling boil. Make sure you use a circuit with enough capacity and that any extension cords are sized properly, so the heaters get enough power.

[sage]

Ok. I guess it's back to Home Depot again then for styro insulation. This small project has cost me a lot of time. Oh well - all part of the fun I guess.

Next I need to do some powder coating on this project too. Now there's a whole new build-up that I know nothing about.
Guess I'll have to eavesdrop on the PC forum as well.


Sage

[M_D]

There is that sheet foam that is flexible and used for packing, some of it is about 1/4" thick and makes a good insulation. It is easy to wrap around containers and secure. A layer or two of that does wonders to help hold the heat in. Even placing your bucket within another bucket helps.

We use a 55 gallon plastic drum for the sealer, wrapped with foam, and only use 4 300W heaters.

When you get it so the sealer gets up around boiling, it evaporates very fast, so you have to be mindful of that and not let it go dry and melt the buckets and then start a fire.

[sage]

That's incredible. How much of the 55 Gal drum has liquid in it and how long does it take to get to boiling?
I just tried again with 3 heaters - no insulation yet - in a covered 10x14 plastic container with about 3" of water (probably less than a gallon). (I'm doing a plate, one off, so excesive water not required). It took about an hour to boil. I'll search around work for some styro packing material before I buy anything but I'll keep that thin bendable stuff in mind.
I think I'll measure the current to the heaters and see if they really are 300W (they are labeled as such). I'm beginning to doubt it.

Sage

[M_D]

We maintain the drum about 2/3 to 3/4 full. There is definitely a difference in how much heating power you need to rapidly heat the liquid versus maintain the temperature once it reachs the peak. We leave ours on 24/7 because we anodize all the time. When we occasionally change sealer, we do that in the afternoon and the next morning it is fully heated and ready to go.

So if you need quick warm ups because you don't anodize all of the time, then you might want more heating power. But the insulation still helps a lot, the solutions heat up quicker and it requires less heating power.

The kind we use is a flexible foam which comes on rolls. It is commonly used for wrapping and padding products for packaging, and is used a sill seals for buildings.

[RedRiver]

The obvious...

Smaller Tank = Less Working Solution = Less Heat Dissipation
Smaller Tank = Less Working Solution = Faster Heatup Times
Smaller Tank = Less Working Solution = Faster Cross Contamination
Smaller Tank = Less Phyiscal Space = Smaller Parts / Batches
Smaller Tank = Less Physical Space = Smaller Power Supply
Smaller Tank = Less Chemical Required = More Economical

Things to consider when working in the wife's laundry room...

- Young children/pets and chemicals NEVER mix. Avoid this at all costs!
- Moisture/heat is generated from the hot chemical baths.
- Odors can/may be produced which are apt to be circulated by the air conditioner/furnace.
- Potential damage due to mist/splashing and/or spills.

Just my $0.02
- Dan

[cameraman]

I don't think heat dissipation would be too much of a problem because I would only use it for pretty small parts, but pets & chemicals and ac circulation are good points; the room I was thinking about using does have an ac return in it, which would complicate the venting issue - I'd pretty much have to build a cabinet around Sage's vent hood, and would have to do something about the sealant, which I hadn't even thought about before.
Sigh, I guess I'll just put a fan on the patio, maybe do my anodizing at night.