New tool (to me) help.

[TominZebulon]

I just inherited an older model Craftsman 3x21 belt sander. I have never had one before so I am not sure if my problem is with the sander or technique. I am building some of those cutting boards features in one of the recent Wood mags and was not careful enough when I glued it up, therefore very uneven surfaces. I thought the belt sander would be a perfect way to flatten them. In case you did not see that issue, the surfaces are end grain. I went to Lowe's and bought some 50 grit belts for the sander and started flattening. Everything seemed to be going well, then a belt failed. I put on a new belt, and it failed also, then another one. I tried to pay attention to where the belt was riding, but even when I was sure the belt stayed in the center, the seam of the belt kept failing. What do you guys think? Is it me and my technique (or lack thereof) or just trying to use the wrong tool for the job? Or is it a tool problem, i.e old sander using not very good belts?

Tom

 

[Canuck]

Had a similar problem with my Craftsman! Kept breaking belts - at the seam. I was using mine to strip paint off of a concrete porch. When I opted for a better quality belt (Norton) and payed real close attention to the tracking when i mounted the belt, the problem went away.

You may want to see if you can take a little tension out of the belt when you mount it to the sander as well. I found that if I over-tensioned the belt it would fail after a couple of laps!:BangHead:

I bought my Norton belts at my local HD.

HTH.

Wayne

 

[Travis Porter]

Is the belt tight/snug on the sander? Are you letting the sander do the work (as you should) or are you pushing it down? Are you running the belts in the right direction? Even if not marked, I believe the seam is supposed to be oriented in a certain direction. Check the platen (metal plate at the bottom) and make sure it is "whole" and won't grab the belt any way. Some are smooth steel, and some have cork. If it is messed up, replace it. They are pretty cheap.

By the way, 50 grit seems a bit "agressive" to me. I used to sand my glue ups with the belt sander, but I don't think I ever went below 80 grit.

 

[Joe Scharle]

Mine is a 1980 model and a couple of quirks are:
Belt direction: Critical, should be an arrow on inside of belt
Tracking: (first couple of minutes it needs tracking adjusted as belt stretches)
Platen: smooth with no sharp edges

Hope that helps, Joe

 

[Ray Martin]

Tom,

Belt direction is the best bet. They are unidirectional.

Once you get the direction correct, the next consideration is keeping the belt clean. Home Depot and Lowes carry this thing that looks like a giant easer... if you can remember the little brown gum erasers from back in school... looks like a large one of them. After you sand for a while (short while if you're stripping any kind of finish) you then rub this eraser like thingie against the belt as the sander runs. It will clean a lot of junk out of the belt and make it last a lot longer.

Ray

 

[Mike Wilkins]

I had the same concerns with multiple belts braking at the seams. It was a whole box of them. Have been told that it is not uncommon for belts and the adhesive that holds the seam together to fail over time. Got some new belts from Lowes and problem went away.

 

[TominZebulon]

Thanks everyone! This gives me some ideas to try. I did look for an arrow or something on the belts after the second failure and could not find one, but maybe overlooked it somehow. I will try some different belts next time and also check the platten to see if maybe I need to change it or smooth it somehow. I t did not look rough on visual inspection, but there may be something causing problems. Again I appreciate everyone's ideas and will keep you informed what I find.

 

[McRabbet]

Indeed, belt direction is very critical -- the seam line on the face of the belt must face the front of the sander on the bottom face so it is the following edge to the work surface (Belts usually have an arrow on the inside to indicate travel direction). In addition, I've found that belts that have been subject to storage in humid space will lose the adhesion on that seam line -- I busted 5 belts when doing end grain on my wine cellar project due to that factor. All of my stationary sander belts are kept in a tight lidded plastic storage box with a few dessicator pouches to keep them fresh.

And, if you are trying to be too aggressive on coarse sanding of end grain, they will heat up and fail as well. :roll: HTH.

Rob