Performax 16/32 Sander and Abranet Abrasive

[Gerald Hurst]

My rough calculations show that the ideal widths and raw strip lengths of abrasive roll to
achieve perfect wraps on a Performax drum which is 16" long and 5" in diameter with clip
access points that are 180 degrees from each other are as follows:

2.50 inches wide, 114.5 inch raw strip length, 6.5 turns around the drum
3.05 inches wide, 96.6 inch raw strip length, 5.5 turns around the drum
3.87 inches wide, 78.5 inch raw strip length, 4.5 turns around the drum
5.27 inches wide, 60.6 inch raw strip length, 3.5 turns around the drum

These strip widths and lengths allow 1" width where the abrasive strip enters the clip
access slot.

To cut the tapered points on each end of any width strip, do not use degree measurements
with a protractor. Instead lay a ruler's zero point at one corner of one end and angle
the ruler across to the other side. When the ruler reads 15.71 inches as it crosses the
other side, use a pencil to mark the line and cut it with scissors.

15.71 inches is the drum circumference, so this ruler procedure and length of the cut edge
is the same for any width of abrasive roll. Of course, make sure that you cut from the
correct corner on each end.

The instruction manual says to cut off 3 inches from the points, which is correct for 5.5
turn lengths. However, you should cut off approximately 4 inches for a 6.5 turn length, 2
inches for a 4.5 turn length and 1 inch on the 3.5 turn length. Best to wrap around the
drum and clip the ends as needed; you need about two inches inserted into each clip
access point.

These are idealized calculations, so take them with a grain of salt, but they should be close.
Use sheets of paper taped together to experiment with first if you want. My actual
finished pieces have been about 92" long using 3" wide paper.

[John Coloccia]

So you wrap the heavy duty just like regular rolled stuff, taper the ends, and performance is better than the red paper? Are many grits available? What source have you found best?

It lasts forever and never burns/clogs. I'm not sure about the grits. I only use 80 grit for precision thicknessing. and that's it. I don't remember where I bought it. It's expensive no matter where you go.

BTW, I DO use the 2 3/4" width. My memory was just wrong. They make a 4 1/2" width, but I use the smaller width. Somehow, I get it to fit.

Maybe I'll try the velcro thing this week.

[Curt Harms]

John, if you need precision thickness velcro may not be the way to go. I considered the same but research said "eh, maybe not". Velcro is soft and by the time you get both hook and loop layers on the drum there's 'give' in the velcro/paper layers. The surface of the sanded stock may not be as flat and level as with nothing between the drum and paper.

[John Coloccia]

I thought that too, but people who use velcro say differently. The same could be said for rubber conveyors, but they work OK too.

The reality is that the entire system is always going to have some give in it. Even now, you can take a piece and run it through multiple times without actually lowering the head. The key is measuring after each pass. I have to do that now anyway. Also, for the final passes, you're set for a very light cut so there is minimal pressure on the system. Velcro may actually be BETTER than just wrapping, IMHO. I believe that the paper moves away from the head slightly because of centrifugal force when spinning.

But I don't know. I haven't tried it yet. It may not even fit without modification of the roller mounts.

[Curt Harms]

I have no experience either and good point about the rubber conveyor. I agree about the paper lifting off the roller, if the clips are supposed to take up any slack and keep the paper taut I'm doing something wrong. Bottom line is if you're getting the results you need what else matters.

[Ken Krawford]

A quick update - I left my old sandpaper on the drum and laid the Abranet over it. I centered it on each wrap so there's 1/4" gap on each side. That approach put the taper exactly where it needed to be. I ran about 75 ft through it and so far so good. In the long haul, we'll see.
Gerald - fantastic calculations. You must have been a math major or engineer!

[Michael Kellough]

I have a Performax 16/32 that I was very dissatisfied with until I made a simple modification.

I work with pine a lot and it loads/clogs/burns the abrasive very quickly. Very frustrating.
I went through a lot of abrasive and had to buy a lot to keep going

At a Woodworking In America show (organized by Pop. WW mag) I talked with Paul Moore (RIP) of STOCKROOM Supply of Canada. Paul was an expert on abrasives but he was also both a creative and analytical thinker. He worked for Klingspor when the guy who designed the Performax inquired about abrasives to apply directly to a the metal drum. Paul told him that was a dumb idea that would result in excessive loading and burning etc. The guy went ahead with his drum sander plan with mixed results. I bought one and have had mixed results. Not too bad with hardwoods but softwoods always overloaded the abrasive.

Paul said even if you could turn the drum perfectly round and straight and used perfect bearings and used the very best abrasive you still wouldn't be able to avoid overloading in spots if the abrasive was tight on the drum. Even with the internally ribbed Performax drum "designed to keep the drum cool", at the speed the drum turns you will get loading and burning with anything the least bit resinous.

Anyone who has stuck a bit of PSA abrasive onto a piece of wood knows you have to keep the pressure low or you get loading and excessive wear at the high spots. If you apply the same abrasive to a cork (or other slightly resilient backing) there is an enormous reduction in loading and if you don't press down hard you still get a sanded surface that mirrors the sanding block. Of course you can't move the block at anywhere near the speed a drum spins...

To improve the performance of a drum sander you just need to let more air get behind the abrasive but it needs to be evenly distributed so the work stays flat.

The simplest way to do that is to use hook&loop backed abrasive. The slight cushion back of the loops will help a lot. You don't even need to apply the hook part to the drum to get a big benefit.

I planned to conver my drum to H&L like Paul's drums that but didn't have the appropriate abrasive on hand. I did have the hook component so I applied that to the drum and used the standard abrasive. The difference was dramatic. No more burning even in pine.

I still haven't tried the full blown version with loop backed abrasive on hook covered drum and I can imagine problems getting the abrasive on evenly enough. I asked Paul about that because he used both on the drum sanders he sold and he said the centrifugal force lifts the abrasive off the drum just enough that it evens out.

So, how does relatively loose abrasive avoid rounding over the edges? The trick is to back the drum away so that the abrasive doesn't touch the work until it's spinning. The drum does not really do what you think it does. It's just a mounting fixture for the abrasive not a mandrel.

As Curt and John point out the abrasive moves out from the drum and does the cutting. You can make multiple passes at the same nominal thickness and it keeps cutting. That is proof that you need to back off and let the abrasive do the work. Wrapping it too tight is a problem. Squishing the abrasive between the drum and the work results in loading.

I can change abrasive pretty quickly with practice but I do wish I had the full H&L system. Too much standard abrasive in stock and now that it doesn't overload it lasts so much longer.

Abranet should be fine. I think centrifugal force will keep the mesh from clogging but I think Abranet is overkill in this application.

[keith micinski]

Hate to say it but I had been meaning to try Abranet on performax basically since this thread came out and just learned the same thing the orignal poster did. At first I thought its smaller so I will just have to wrap it more, but that doesn't work because the taper falls a full inch short of the clip to make it work. I see some people saying they were using the 4.5 inch stuff and I just wanted to make sure that is definitely working since a lot of people in this thread didn't seem to understand the problem of using the smaller Abranet even though he posted a photo.

[keith micinski]

I guess if worse comes to worse I could at least cut the 4.5 to 3" if I had to. The 2 3/4 I have now is going basically just look good on the shelf I guess.

[Keith Pleas]

2.75 inch HD 80 grit Abranet here, using drum clamps not velcro. I modified the hood for 4 inch dust collection. I run hardwoods only with perhaps minor buildup. Lots of hours on this setup.

Sander.jpg

[keith micinski]

Ya, I'm trying to avoid having large gaps in between wraps it leaves to much room for the paper to move around on me. i don't doubt it probably works ok though.

[Keith Pleas]

Ya, I'm trying to avoid having large gaps in between wraps it leaves to much room for the paper to move around on me. i don't doubt it probably works ok though.

I found that the paper doesn't "move around", it moves to the left (in my picture) until it encounters another edge which actually tightens it up a bit. The only thing I have to do is periodically check the tail end and possibly re-tighten. It does work "ok".