Hello,

We're looking to build a self-contained and dust-free drying cabinet with temp. control and a blank capacity minimum. We're on the fence regarding either a chuck or drum set up. Here are a few questions.

1) Would a drum dryer allow the finish to level properly be that the blanks are spinning off-axis?
2) Is there an in expensive source for stable 6-12 RPM motors?

We'd also appreciate any tips or other ideas.

Thank you in advance,
Steve

The finish is treated to the same type trip regardless of what type of dryer you employ. Most companies that need maximum drying capacity per the space and "pieces" use drum type units.

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I would THINK you want to be moving a little faster on a drum than a standalone motor as the path you are traversing is larger.

15-40 RPM depending on the size of your drum seems appropriate, but that is just one guys opinion.

Steve,
I am in the process of checking out the same thing.
You can do some @#$%& site searches for motors of the desired rpm and can often get reasonable prices.
The one thing to be sure to verify for ANY motor that is to be used on a dryer to insure that it is Continuous duty.
Many motors that are available are Intermittent duty and can get very very hot, or shut down - with the thermal protection, if used long term like a drying application.

If building a drum dryer, some folks will use a square piece of aluminum tubing, rather than a round tube. There are a couple of advantages.
1. The square tubing typically exhibits less flex than the round tube.
2. With a square tube, using 9 inch round disks to hold the rods, each of which contain a square hole - there is little need for much clamping on the tube to maintain disk alignment.
It is a good idea to put a clamping mechanism of some sort to keep the disk from moving back and forth on the square tube, but the square tube inside the square hole will keep the disks from rotating on the center shaft.

Another clever idea that was used by one dryer builder was to use a piece of 1/2 X 20 threaded rod - glued or screwed into the end of the square tube. You can use either, depending on your machine skills.
Then, screw a 1/2 inch drill chuck on the end of the threaded shaft. Finally, use the drill chuck, to clamp the center shaft to the drive motor drive shaft.
When the motor needs replacement - and it will eventually, you simply loosen the chuck, take out the motor mounting bolts and wires, install the new motor, and tighten the drill chuck.
On the other end of the tube, simply use a 1/2 inch ball bearing set into the end support to hold the rotating dryer.

Aluminum square tubing is commonly available in most larger cities at surplus metal yards or other similar supply shops.

Take care
Roger

p.s.
There are several rod builders in the area that are using drum style dryers and every one of them are rotating the drums at 6 rpm. They are either a direct drive, or a belt reduction drive to get the speed at 6 rpm.

Note, most of these same builders are also using a high speed device to apply the finish at speeds up to 50-180 rpm.
However, for the actual long term drying, they are all using the 6 rpm number for the blank rotation.


Take care
Roger



Edited 1 time(s). Last edit at 02/09/2009 08:03PM by roger wilson.

Thanks everybody.!

I found a source for mirror (disco) ball motors. They are 5 RPM, self-contained, pre-plugged, quiet, stable and reasonably priced at $10.00. You can check them out here: [www.springtree.net] . We decided on a 2 X 2 chuck setup in a 14" X 14" X 97.5" box that will have an 8' two light fluorescent fixture along the entire bottom for heat. They are low profile, which allowed us to make the box a bit smaller and they should keep a steady temp. in the 80* neighborhood. We've also found a power switch with timer that has 2, 4, 6 and 8 hour settings that will shut the entire box down automatically. I'll post pictures when it's done.