Thread: Drum sander selection advice, please.

Can I suggest a second hand wide belt sander? it seems you have a demand for it.

Drum sander will always be drum sander...

Can't really offer any advice re. a twin drum sander, but if you keep working your Jet 16/32 that hard you will destroy it. First things to go will be the conveyor drive gearing and the drum motor. I've just replaced the conveyor drive mechanism on my 16/32 and the previous owner had already replaced the drum motor. Apparently he gave the machine the kind of pizzling you are giving yours. There are no cheap replacement parts for these machines.

The local Mens Shed has a Dual Drum Carbatec Sander and, from all accounts, if they could get rid of it they would.

I am lead to believe that it is a PITA.

Originally Posted by cava

The local Mens Shed has a Dual Drum Carbatec Sander and, from all accounts, if they could get rid of it they would.

I am lead to believe that it is a PITA.

I've heard a similar report from a private owner, wishes he never bought it.

Originally Posted by Phily

I need to create a fair few boards for a retail opportunity and have been working my Jet 16-32 pretty hard to rough sand them for finishing - via orbital sander. The boards have quite a bit of epoxy resin so I can’t use a thicknesser as the resin is prone to shatter.

this I find more than surprising.
My experience is that epoxy resin less than a month or so old cuts readily with sharp WW blades. Most times it cuts more easily than wood.
Epoxy over a year old tends to chip rather than cut, but can still be cut if you take a very light pass. On the surface, I would expect some chipping that would be eliminated when the surface was sanded. That is unless the final surface is fully epoxy coated.

Which begs the question are your thicknesser blades blunt?

I’m thinking of investing in a dual drum sander to speed up the process. There are a few options on the market: several around the $3k mark and then a jump to the $5,500 mark. From what I can ascertain, the more expensive units have auto feeds that help minimise the annoyance of triping the cut out.

The way I see it, my options are:
Stay with my Jet and go to an even courser grit, then buy a similar second unit with a finer grit to speed up finishing.

Invest in a lower cost twin drum with x2 course grits and use my Jet as the finisher.

Purchase a more expensive twin drum fitted with x1 course and x1 finer grit papers with auto feed. $5k is well over budget for this project but if there is strong justification I might be able stretch.

Any advice on strengths/weaknesses and what factors I should consider, greatly appreciated.

my experience

feed rate and sanding depth are critical parameters. But you have already discovered this.

using a coarser belt won't really speed things up as you loose time changing belts to step up through the grits. When using my drum sander, I'll typically go to 180 or 240 before switching to an ROS. So if I were starting at 60 grit, the sequence would be 60 - 80 - 100 (or 120) - 150 (or 180) - 240 a total of 4 belt changes. Which isn't too bad with batch type production.

dual drum sanders are a real pain to set up.
you must keep both drums exactly parallel -- with parallel measured with sand paper on both drums.
The rear drum needs to be set fractionally lower than the front drum to account for the material removed by the front drum. If the paper tension varies between the drums you will not enjoy setting the drums.
The drums need to realigned every time you change paper, and unless set perfectly, the paper on one drum will wear faster than on the other.
Unless the front drum is cutting to final "thickness" a finer paper on the rear drum doesn't save any time.
The depth of cut per pass is not much different to that on a single drum sander, but dust generation is almost double.


Personally, I think you may be better off with 3 single drum sanders which would allow you to work 3 boards at once.

Originally Posted by ian

Personally, I think you may be better off with 3 single drum sanders which would allow you to work 3 boards at once.

I agree with Ian, that this is your best and quickest option (space permitting).

I would have thicknessed the timber prior to filling with epoxy then just used the right amount of epoxy to do the fill allowing for final finish with the ROS, would have saved a heap of time and expense.

I’ve tried the belt sander route. The concentration level is too much like hard work - a bit too much enthusiasm or loss of focus ends up with a nice groove! I like taking the relaxed approach ��

Thanks for the heads up, I wasn’t aware of the weakness nor expense. I read a post somewhere that suggested restricting each new pass to a quarter turn to minimise jamming. I tried the approach today. Certainly works well, but is slow going!

���� i can believe it. Like most machines, they are great when they work, but .......

I should clarify that I am not unhappy with the 16-32. Actually its been a beast and has cleaned back a huge amount of timber, one of the best machines I’ve owned. It just needs to be treated reasonably gently.

Originally Posted by aldav

Can't really offer any advice re. a twin drum sander, but if you keep working your Jet 16/32 that hard you will destroy it. First things to go will be the conveyor drive gearing and the drum motor. I've just replaced the conveyor drive mechanism on my 16/32 and the previous owner had already replaced the drum motor. Apparently he gave the machine the kind of pizzling you are giving yours. There are no cheap replacement parts for these machines.

sorry, stuffed up my response, see above - thanks for the heads up!

Originally Posted by ian

this I find more than surprising.
My experience is that epoxy resin less than a month or so old cuts readily with sharp WW blades. Most times it cuts more easily than wood.
Epoxy over a year old tends to chip rather than cut, but can still be cut if you take a very light pass. On the surface, I would expect some chipping that would be eliminated when the surface was sanded. That is unless the final surface is fully epoxy coated.

Which begs the question are your thicknesser blades blunt?



my experience

feed rate and sanding depth are critical parameters. But you have already discovered this.

using a coarser belt won't really speed things up as you loose time changing belts to step up through the grits. When using my drum sander, I'll typically go to 180 or 240 before switching to an ROS. So if I were starting at 60 grit, the sequence would be 60 - 80 - 100 (or 120) - 150 (or 180) - 240 a total of 4 belt changes. Which isn't too bad with batch type production.

dual drum sanders are a real pain to set up.
you must keep both drums exactly parallel -- with parallel measured with sand paper on both drums.
The rear drum needs to be set fractionally lower than the front drum to account for the material removed by the front drum. If the paper tension varies between the drums you will not enjoy setting the drums.
The drums need to realigned every time you change paper, and unless set perfectly, the paper on one drum will wear faster than on the other.
Unless the front drum is cutting to final "thickness" a finer paper on the rear drum doesn't save any time.
The depth of cut per pass is not much different to that on a single drum sander, but dust generation is almost double.


Personally, I think you may be better off with 3 single drum sanders which would allow you to work 3 boards at once.

Thanks for the valuable advice Ian, really appreciated. Ref the resin shatter, each board has around $40 of resin and if something goes wrong the whole lot is ruined. Having ruined several pieces I made the decision to take a more gentle approach - even if its more time consuming. Resin is great in the right conditions. After a minus 2 night in the Southern Highlands it tends to be less forgiving than a balmy 30 degree afternoon!
I spoke to Carbatec this morning re their twin drum units and specifically asked about adjustment adjusting to allow for the first cut. I was assured that the drum heights cannot be adjusted. I know they can on other units.
I’m coming around to your point of view of three sanders ����

Originally Posted by Cal

I would have thicknessed the timber prior to filling with epoxy then just used the right amount of epoxy to do the fill allowing for final finish with the ROS, would have saved a heap of time and expense.

Thanks Cal, I have tried several different approaches. The one I use makes it easier to feed the timber. Also I’m pretty careful to only use as much resin as needed. The nature of the job means that I have to remove several mm of resin to get the even, smooth finish. I think the issue is that I need to me more patient!