New Shopsmith DC-6000 Dust Collector

[dusty]

Dusty,

Did you take any airflow measurements yet?

No, I have not. For reasons I cannot control, I have spent very little time in the shop since I bought the conversion kit.

Furthermore, I am seriously considering a dismantle. I want to look closely at all of the mating surfaces that could become air leaks.

[DLB]

I ran a thermal monitoring evaluation on the DC-6000 yesterday. I didn't take pics of how I placed two uncalibrated thermocouples, I'll try to remember to get those as I remove them. Both are near top of the motor, attached with plumbing insulating tape (low R value), one nearer the impeller and one nearer the cooling fan. I reached a level of discomfort and stopped the test when one of the temperatures reached 235F at 70 minutes. The data shows the temperature was leveling off, but that is pretty darn hot. I don't know if the motor is thermally protected or what its max case temp is, I posted a pic of the data label earlier in this thread.

I did find data to support the following: Most motors are rated for a 40C ambient and Class B insulation (which was on the data label) is good for a 80C increase. This means a max temp of 120C (248F) at the windings. I'm not measuring at the windings, nor with only two data points, am I likely measuring the highest case temp. IMO this confirms my opinion that 235F was very hot.

Note: during my eval from about the 15 minute point the temp nearer to the cooling fan and nearer to the main housing grate was the higher of the two. The difference between them increased with time/temp, ending with a +10F difference.

Before removing the thermocouples I'm planning to run the motor/impeller in free air with no motor housing. My thinking is this will help to validate the above observations and any conclusions drawn from them.

- David

[DLB]

After three (might have been four) install/remove cycles trying to isolate the air leak my seals are shot so I've stopped working on this. These are items 19A Motor Seal (three sides) and 19B Short Seal (the thick one for the fourth side) that seal the open end of the motor housing to the main housing. My last evaluation was to tape up the perimeter of the motor housing to fan housing interface with duct tape and this significantly reduced the magnitude of the leak, I estimate 95%. Since both seals were probably damaged on the last installation I think that is acceptable. Whenever I do a final installation I plan to provide more robust sealing for the motor housing at both the main housing and fan housing interfaces.

So far I don't seem to have successfully communicated the problem to Shopsmith. I did get a response yesterday but they seem to feel that the primary problem is the large gap where the Short Seal goes and suggested that I could double up that seal. I think that is a problem but not the primary problem in my case. I still have a bad motor housing.

- David

[dusty]

After three (might have been four) install/remove cycles trying to isolate the air leak my seals are shot so I've stopped working on this. These are items 19A Motor Seal (three sides) and 19B Short Seal (the thick one for the fourth side) that seal the open end of the motor housing to the main housing. My last evaluation was to tape up the perimeter of the motor housing to fan housing interface with duct tape and this significantly reduced the magnitude of the leak, I estimate 95%. Since both seals were probably damaged on the last installation I think that is acceptable. Whenever I do a final installation I plan to provide more robust sealing for the motor housing at both the main housing and fan housing interfaces.

So far I don't seem to have successfully communicated the problem to Shopsmith. I did get a response yesterday but they seem to feel that the primary problem is the large gap where the Short Seal goes and suggested that I could double up that seal. I think that is a problem but not the primary problem in my case. I still have a bad motor housing.

- David

Seals are inadequate here too. I've been debating what to seal with. I'm thinking about packing cotton
rope in the gaps.

[DLB]

Seals are inadequate here too. I've been debating what to seal with. I'm thinking about packing cotton
rope in the gaps.

I suggest checking for that protruding screw first thing. Trimming it won't close that top gap, but might shrink it down to a more manageable size. I included a pic a couple of posts back.

- David

[JPG]

Poke a clearance hole for the screw?

[dusty]

Seals are inadequate here too. I've been debating what to seal with. I'm thinking about packing cotton
rope in the gaps.

I suggest checking for that protruding screw first thing. Trimming it won't close that top gap, but might shrink it down to a more manageable size. I included a pic a couple of posts back.

- David

Do you know what the screw is for. I suspect it might be the spring steel clip that holds the dust collection bag. I have the clips but no screws that protrude into the inside.

I opened mine back up this morning and I now seriously suspect that I have air leaks as bad as yours.

I am unable to close a gap between the Motor Housing and the inside will the the dust collector. I am thinking that this gap is the result of improper assembly as much as inadequate sealing.

I also wonder if it would not be better if the 4" union was installed after the DC is set in place. Doing this would allow the union to be installed into and remain in the opening.

[DLB]

Do you know what the screw is for. I suspect it might be the spring steel clip that holds the dust collection bag. I have the clips but no screws that protrude into the inside.

Yes, for the clips on mine.

I opened mine back up this morning and I now seriously suspect that I have air leaks as bad as yours.

I am unable to close a gap between the Motor Housing and the inside will the the dust collector. I am thinking that this gap is the result of improper assembly as much as inadequate sealing.

There ought to be a "Short Seal" in that gap. Foam rubber with an adhesive surface.(?) It's not present in your pic. Do you have that?

I also wonder if it would not be better if the 4" union was installed after the DC is set in place. Doing this would allow the union to be installed into and remain in the opening.

Yeah, it's not a great fit. I'm kind of ignoring this part for now, plan to seal it up when I believe I'm putting the thing together for the last time. I think this is leaking back into the input, maybe losing some CFM but not losing dust back into the shop on mine.

- David

[dusty]

I have the "short seal" if it will reattach. If not that stuff is available in many different forms.

For the leak (gaping hole" across the top of the motor box, I going to trim some flashing to fit the contour and attach it with double sided rubber window/door tape. It works wonders around window casings - why not here. I am contemplating how I might use the same stuff all the way around the motor housing.

Notice the rope I wrapped around the fan housing. Makes a great handle for pulling this out and putting it back.

I have put it all back together twice and had to pull it out because the power cord was being struck by the motor fan. I had pulled too hard on the two cables when I put it together. That won't be a problem any more. I scrapped the plastic wire clip and put in one that grip the cable so that I can not pull it too far. Whyp pull it at all - because it is barely long enough to reach the power receptacle. Instructions warn about pulling too hard but if the power cord was three inches longer there would be no need to pull.

I do have the interfering screw that you mentioned (I denied having). I just backed it out some and will screw it back in when done with the assembly.

I'm also pondering a slightly longer 4" union so that I can install it from the outside after the DC is dropped into place. The controlling factor will be if that is standard size (4"ID). The piece that came with the kit will slide through the hole in the main housing.

I wonder if these get any sort of production test???

[RFGuy]

IF you guys ever turn these dust generators into dust collectors, it would be nice if maybe you created a new thread with all of the details, including pics, of how you were able to seal up your DC-3300/DC-4650*. I am sure many owners would like to know best practices for how to seal their leaking DC-3300's so a tutorial thread would be helpful (IMHO). I did some work on my DC-3300 in the past, but I don't how well I sealed it up before banishing it to the attic. I am sure it still needed more work to seal it fully. However, my ShopVac™ dust collection system needed some additional seal work using the air-sealing tape like I mentioned here (viewtopic.php?p=287099#p287099). After switching to HEPA bags and HEPA cartridges this wasn't enough so I had to seal the canister to keep the dust inside. Fortunately I have meters for measuring dust particle counts in my shop and I used them to fine tune my ShopVac™ system. Unfortunately I didn't have them when I was trying to seal my DC-3300.

P.S. I coined the DC-4650 name to apply to these upgraded DC-3300's since they are halfway between a DC-3300 and a DC-6000.