Drum sander - finishing touches.

[pavliku]

Hi everyone,

I'm just giving the finishing touches to the drum sander I've been making over the past couple of weeks.
I have a couple of questions if you don't mind.

1: Should I seal the wooden drum with anything (it's pine)?

2:What is the best product to use to stick the paper to the drum?

3:Will I need to use a cloth backed paper - most stores sell the Norton brand "Bear, Master Painters" in 10 m rolls - so this is an easily found non-cloth backed paper. Will this be ok?

4: What grit paper is best?

Thanks very much,
Paul.

[jjh]

On the sander I made I did seal the drum it was MDF and I used shellac, as to sticking it to the drum I use Duct Tape to secure each end, I have used both the Norton cloth and paper with success, though I warn you I have had the paper tear and abrade away a small section of the bed where as the cloth just wrinkles, and as to grits I tend to use 60 and 120 grits

 

[pavliku]

Thanks jjh,

I would prefer to stick the entire paper to the drum for exactly the reasons you have described ie. tearing of paper. Although by sticking the paper to the drum I don't get the choice of changing grades - for this reason it is worth considering the duct tape opition.

I was thinking to seal the drum with a thinned-down mix of poly. Anyone have an oppinion as to whether this is a good idea?

Has anyone used the range of Ados spray on glues? Will I have a hell of a job on my hands when I want to remove spent paper?

Thanks,
Paul.

[Mark Fogleman]

Depending on the stock you will be thicknessing you will need to change the abrasive fairly often. Rosewoods (Cocobolo especially), Ebony and other oily-waxy woods used in instrument building will clog the abrasive and will need to be cleaned and/or changed often. I don't have experience with a DIY wooden drum sander but my drum sander uses cloth backed (Y Weight) rolls http://www.woodworkingshop.com/product/pe69060/ and a spring tensioner to keep the abrasive attached. This abrasive has a Polyester backing which allows it to be cleaned in a tub of soapy (Simple Green) water and scrubbed w/a brass bristle brush and re-used. Paper backed rolls are not waterproof and have to be discarded if the crepe rubber eraser doesn't work.

My previous sander needed the tape treatment because the spring tensioner was too weak to keep the abrasive tight. I used what we call Strapping Tape. It has fibers running lengthwise imbedded in the tape and is very tough. Much better and cheaper than Duct tape.

[pavliku]

Thanks Mark,

You detail some very good points about the clogging and re-use of paper.

Have a look at the method here www.ukuleles.com/BuildingHowTo/sandthck.html has anyone done it like this?
I dissmissed initialy because I was worried that the leading edge of the piece of timber being sanded might catch the lip on the drum - are my fears justified?

Paul.

[Mark Fogleman]

Thanks Mark,

You detail some very good points about the clogging and re-use of paper.

Have a look at the method here http://www.ukuleles.com/BuildingHowTo/sandthck.html has anyone done it like this?
I dissmissed initialy because I was worried that the leading edge of the piece of timber being sanded might catch the lip on the drum - are my fears justified?

Paul.

I would think that would work well with a type JF (thin and flexible) Cotton cloth backed abrasive. The E paper types are very stiff and could crack or tear at the crease. This could cause a lifting of the abrasive and blemish your workpiece. Another concern I didn't mention before is with heat build up and whether the adhesive used to make the abrasive would last. The metal strip would definitely need to be below the surface. It would sound funny but would be an option vs PSA abrasive or Tape.

Here's an excellent reference on the different types of coated abrasives: http://www.klingspor.com/ref_asktech_co ... basics.htm

[DarwinStrings]

Thanks Mark,



Have a look at the method here http://www.ukuleles.com/BuildingHowTo/sandthck.html has anyone done it like this?
.

I reckon David Hurd has Paul but he has not posted here in quite some time.

Have you looked at spiralling the paper onto the drum. The method used on a 400mm Performax. You would have to work out a clamp method as the Performax uses a spring tension device at one end and spring clip at the other but some sort of wedge in a wooden drum may do it. I use a paper by "Hermes" (SB 316 80grit) as it is made for this type of sander. It is 75mm wide and spirals and clips on, no glue.

Jim

[Alastair]

That's what I've done on my little drill press sander:

Spiralled on the cloth backed abrasive, (cut from a suitable sized belt sander). Ends taper to a point with the spiral. Secured with a staple right in the tip of the point, straight into the wooden drum. Tightly wound and same in the other end point. Staples then punched down below the level of the abrasive.

Working so far.

A

[Alastair]

That's what I've done on my little drill press sander:

Spiralled on the cloth backed abrasive, (cut from a suitable sized belt sander). Ends taper to a point with the spiral. Secured with a staple right in the tip of the point, straight into the wooden drum. Tightly wound and same in the other end point. Staples then punched down below the level of the abrasive.

Working so far.

A

Like this:

[pavliku]

Thanks for the pic Alastair - do you think that arrangement will work on a larger scale? (480mm, 110mm diameter)

Hey Jim, do you reckon you could take a pic of the tensioning device and spring clip on your sander? - I have absolutely no idea how to visualise this arrangement.

Paul

[Alastair]

Thanks for the pic Alastair - do you think that arrangement will work on a larger scale? (480mm, 110mm diameter)

Hey Jim, do you reckon you could take a pic of the tensioning device and spring clip on your sander? - I have absolutely no idea how to visualise this arrangement.

Paul

Paul, I would think it would depend how tight you spiral it on under tension. Also at that length, temperature and stretch might become an issue.

With the first loading, I also sprayed the drum and cloth back with an aerosol contact adhesive......... not saturated, just tacky. I did not have any movement on my small drum, and it peeled off without drama when I removed it. Second time around, with a stiffer belt, I did not bother, and to date no sign of movement.

That said, yours is a lot bigger....

[DarwinStrings]

The devices used on the performax work cause the drum is hollow aluminium. I reckon Alastair's method would be good enough for the bush. If the abrasive gets a little loose then just re-staple it.

Jim

[pavliku]

I think your right Jim, I'll give Alastair's method a go.
Thanks.
Paul.

[Taffy Evans]

I used a shop built sander for about 18 years using a steel drum I made up. To attach the sandpaper I used Disc Cement. It holds the paper but can be pulled off when needed, the drum stays sticky so I just had to re-coat the paper with the same cement. I used it to glue the paper to the disc sander too. Anybody want a steel drum complete with bearings?

[pavliku]

Thanks Taffy,

Is there much difference between disc cement and other types of spray on adhesive - ados, or selleys "quick grip"
for example?

Paul.

[vandenboom]

I also put paper on in spiral fashion. Just in case you are not sure how to cut it, wrap a bit of string around the drum to get the circumference, then lay it on the sandpaper in following fashion to get the cut angle/line.

spiral cut.gif (1.94 KiB) Viewed 26628 times

I just wrap a circle of masking tape around each end - quick and simple.
Also, I use velcro backing and while it works well and is obviously very easy to swap paper, I would prefer to have the paper directly on the drum.
Frank

[pavliku]

Nice simple tip - thanks Frank.

I have been running around all morning looking for disc cement - no one has it, nor have they heard of it , which is a bit strange as Holdfast (an nz glue manufacturer) make it - at least according to their website.
Farmlands sell a product for glueing on sanding discs used for sharpening shearing blades - it's not a spray on product but I think it might be ok- sticky, but not too sticky.

Paul

[Alastair]

I used a disc cement (many years ago) which was a friction melt onto the running disc?

[Nick]

If you can wait or are willing to shop offshore Paul, this crowd sells the stuff. I haven't been able to source a local supply yet .

[Nick]

A bit of a google search has turned up these guys, if you sent them an email I'm sure if they didn't stock the stuff they'd know of a supplier for it?
Typical NZ site though, no provision for browsing their products they just list the brands & want you to contact them if you need anything further.

[Tod Gilding]

Hi Paul, no experience with the drum sander but I recall reading about them somewhere,could have been an earlier post on this forum,that the velcro attachment was prefered as this gave a spongey type surface that seemed to work better. also the ease of changing abrasives.

[TKAY]

The glue for emery discs for sharpening shearing tools is coated on both surfaces and pressed together in a clamp. This would not be necessary for a drum sander I think.To remove, it peals off on the break line and is possible to rub off both surfaces with effort. Heiniger is probably the main supplier,at least in Aus.
In the past,plus 15 years, Davis HHG was used for the same job and the same materials.
I do know of one farmer who had a violin fall to pieces and he used shearing glue to fix it!!Asthetics were lacking but it seemed to work.

Tom

[pavliku]

Yea, Heiniger is the brand I looked at. It didn't really say much on the bottle - it did say that to get the old paper of work the thumb down behind the paper.
I might give it a test - it's cheap enough - $12 for 500ml.
Paul.

[lauburu]

I made a drum sander with mdf discs and originally glued paper backed 80 grit sandpaper to the drum with contact cement. Worked really well until the paper needed replacing. It was an absolutely horrendous job peeling off the old stuff which I had to spread over several days as frustration levels soared, blood pressure peaked and the party language reverberated around the neighbourhood. I vowed I would never go through this again. Trued up the drum, polyurethaned it good and proper and then bought some velcro with adhesive backing which I attached to the drum (spiral wound again). (For the technically minded ask for 305mm x HTH 805 PS 9914). A place called V Tapes in Onehunga Auckland have the stuff and are very helpful. Then I organised to get velcro backed sandpaper in various grits through the local power tool centre. They had to order it in special from Norton.
The result is extravagantly expensive but now I can change sand paper grits at will and replace worn sand paper very easily. It's better for the blood pressure and the neighbours are beginning to talk to me again.

[Kim]

Tip

Don't throw ur worn drum sander belts away...soak them in a bucket of water over night and then hose them off in the morning and they will be good to go again.

You can add some mild detergent if you like and for 'really' burnt on black stuff you may need to soak a day longer and then scrub lightly with a stiff nylon bristle brush. But its a quick and easy job after a soak. I then drape them over the clothesline (I go right across the top of the hills hoist so they don't kink) and when dry roll them up ready for next change....

Yeah I know...but regardless of what your thinking right now, once you give this a try you will not look back and will save heaps on abrasives. Of course cleaning them this way will not restore the belts to 'as new', nothing can do that, but they won't be too far off for the first few times and if you have not done this before you will be surprised how well this works even when the belt looks to be a lost cause....I use a Gurney to clean mine these days, soak and blast, hang and ready rolled

Cheers

Kim