Drywall dust and top hat?

[shawn_s]

I've been reading/lurking for close to a year now. Lots of great designs and interpretations have been produced. I'm planning of building a tophat unit for my DC in my shop, I will try to avoid a questions thread when I get to that. There is loads of amazing information already here and a lot of it has been answered in the last year.

I am also considering a smaller one for my shopvac, probably to place on a 5gal. bucket.  The primary use of my shopvac is sucking up drywall dust as I'm sanding. I'm not always fortunate enough to be renoing a place where the dust can just "fly".

So does anyone have any experience with this set up and drywall dust? What are some thoughts....would it work, a bit, not at all...? I'm not looking for perfection, just longer work times before the filter needs to be banged out. I'm thinking the slot in the bottom of the top hat probably could be reduced to 3/4" wide. Or would it be better to keep it wider, like in the 1" range?

Any advice/help/ideas are welcome.

[galerdude]

I'd always read a few years back that builds had been successful capturing fines with a narrower slot so when I built mine I went with a 7/8" slot. Have been very happy with that choice. 80% of my dust is CNC generated, other 20% is table saw and a little bit of planer. I rout quite a bit of MDF and that generates fine dust, not like plaster though but like I said, I've been real happy with the results. If I were after the results you mentioned I'd sure try the 3/4" slot, maybe configure it so you could slide in a 5/8" slotted baffle just to compare.
Just my opinion and those with more experience and knowledge might have better suggestions  ;).

[giovanotti]

You can see my (full metal, 5 gal) design in other post. Since, I am dealing with very fine ash dust, I went with 10mm (~0.4 inch) gap. I plan to test it with dry wall grinder in the near future as well.

After few trials (I promise to post some quazi scientific research results) I can say following:
- bigger/heavier particles can be separated easier than lightweight ones.
- I still suspect, that very fine particles will still have to be filtered by paper/non wowen filter. Definitely need to change bag or shake the filter is already reduced.
- Question for me is, how to efficiently measure particle size and weight and consequently adjust separator dimensions.

[phil (admin)]

In my testing with both my separator and a cyclone, drywall dust was a challenge.  Even more of a challenge was the dust I got when grinding my basement (concrete) floor before painting it.  In fact, I decided that it just wasn't worth it when grinding the floor and installed a drywall bag in the vacuum and didn't use any type of separator, and was astonished at how much rock dust made it through the bag!

Some of the drywall and rock dust seems to behave almost like smoke particles.

[Bulldog8]

Last year I remodeled our laundry room. I put new sheet rock on the walls and ceiling. (8x10 room) When I was getting ready to clean up the dust, I used a shopvac and my 5 gallon side inlet separator. It did better than I expecting. I was able to clean the room without clogging the filter, but in my experience it wouldn't do for all day work as you would have to clean the filter several times to keep the vac working.

In the past few weeks I've considered trying it out with ash from the pellet stove. Currently, I use a normal shopvac and am able to get the stove cleaned, but the filter is completely clogged by the time that I am done.

Steve

[galerdude]

Last year I remodeled our laundry room. I put new sheet rock on the walls and ceiling. (8x10 room) When I was getting ready to clean up the dust, I used a shopvac and my 5 gallon side inlet separator. It did better than I expecting. I was able to clean the room without clogging the filter, but in my experience it wouldn't do for all day work as you would have to clean the filter several times to keep the vac working.

In the past few weeks I've considered trying it out with ash from the pellet stove. Currently, I use a normal shopvac and am able to get the stove cleaned, but the filter is completely clogged by the time that I am done.

Steve

This doesn't pertain to using a Thien Separator but for the last 10 years I've had success just using a bag with no filter in my 8 gal. Shop Vac to clean out our pellet stove in the house. We only burn about a 40lb bag per day and I clean it on the weekends usually. A vac bag lasts the whole winter season. Have never experienced any blow by. I'll bet with a separator a guy could really get some mileage out of a vac bag  ;)

[shawn_s]

In my testing with both my separator and a cyclone, drywall dust was a challenge.  Even more of a challenge was the dust I got when grinding my basement (concrete) floor before painting it.  In fact, I decided that it just wasn't worth it when grinding the floor and installed a drywall bag in the vacuum and didn't use any type of separator, and was astonished at how much rock dust made it through the bag!

Some of the drywall and rock dust seems to behave almost like smoke particles.

Thanks Phil. From your tests, do you remember if one (separator or cyclone) performed better than the other?

"like smoke particles" is a very neat way of describing it. I can say I do know what you mean though.

[Bulldog8]

Last year I remodeled our laundry room. I put new sheet rock on the walls and ceiling. (8x10 room) When I was getting ready to clean up the dust, I used a shopvac and my 5 gallon side inlet separator. It did better than I expecting. I was able to clean the room without clogging the filter, but in my experience it wouldn't do for all day work as you would have to clean the filter several times to keep the vac working.

In the past few weeks I've considered trying it out with ash from the pellet stove. Currently, I use a normal shopvac and am able to get the stove cleaned, but the filter is completely clogged by the time that I am done.

Steve

This doesn't pertain to using a Thien Separator but for the last 10 years I've had success just using a bag with no filter in my 8 gal. Shop Vac to clean out our pellet stove in the house. We only burn about a 40lb bag per day and I clean it on the weekends usually. A vac bag lasts the whole winter season. Have never experienced any blow by. I'll bet with a separator a guy could really get some mileage out of a vac bag  ;)

I am a one time per week stove cleaner as well. I may try the separator and the bag and see how it goes. I use a pleated filter in the vac an the suction drops off very noticeably during the cleaning. When I dump the ash, I fine the filter completely caked.

[shawn_s]

Last year I remodeled our laundry room. I put new sheet rock on the walls and ceiling. (8x10 room) When I was getting ready to clean up the dust, I used a shopvac and my 5 gallon side inlet separator. It did better than I expecting. I was able to clean the room without clogging the filter, but in my experience it wouldn't do for all day work as you would have to clean the filter several times to keep the vac working.

Steve

Steve, your findings are encouraging. It is pretty rare that I am doing a large enough drywall job that I'd be sanding all day. I do still expect to have to clean the filter. I just would like to have to do it less than I do know.

I'm thinking I might still go ahead with making one. If for nothing else it'll be a good "practice" unit for when I do my larger one. Plus it'll still be handy to have for regular clean ups.

[phil (admin)]

In my testing with both my separator and a cyclone, drywall dust was a challenge.  Even more of a challenge was the dust I got when grinding my basement (concrete) floor before painting it.  In fact, I decided that it just wasn't worth it when grinding the floor and installed a drywall bag in the vacuum and didn't use any type of separator, and was astonished at how much rock dust made it through the bag!

Some of the drywall and rock dust seems to behave almost like smoke particles.

Thanks Phil. From your tests, do you remember if one (separator or cyclone) performed better than the other?

"like smoke particles" is a very neat way of describing it. I can say I do know what you mean though.

I didn't test enough to draw comparisons.  I will say that cleaning the cyclone was a giant PITA though because the drywall dust stuck to the thick and got up to about 1/32" thick and reaching up through the bottom with a towel wrapped on a dowel didn't work that well to remove it, just shove it around.

I had tried putting chips through it while it was running, the drywall compound dust was like glue.

[shawn_s]

In my testing with both my separator and a cyclone, drywall dust was a challenge.  Even more of a challenge was the dust I got when grinding my basement (concrete) floor before painting it.  In fact, I decided that it just wasn't worth it when grinding the floor and installed a drywall bag in the vacuum and didn't use any type of separator, and was astonished at how much rock dust made it through the bag!

Some of the drywall and rock dust seems to behave almost like smoke particles.

Yeah Phil, drywall dust can be unbelievably stubborn, especially when given a chance to "pack" on.  I had thought about the cleaning issue, and had wondered if  a removable top or bottom might work. Just would have to make sure it had a good seal.

Thanks Phil. From your tests, do you remember if one (separator or cyclone) performed better than the other?

"like smoke particles" is a very neat way of describing it. I can say I do know what you mean though.

I didn't test enough to draw comparisons.  I will say that cleaning the cyclone was a giant PITA though because the drywall dust stuck to the thick and got up to about 1/32" thick and reaching up through the bottom with a towel wrapped on a dowel didn't work that well to remove it, just shove it around.

I had tried putting chips through it while it was running, the drywall compound dust was like glue.