What do I do when my sandpaper keeps gumming up?

by | Sep 1, 2022 | Sand hardwood floors, Sand wood floors, Sanding floors, Wood floor refinishing

We love this question so hard.

Because any time your sandpaper is gumming up, it is not a problem; it is a SOLUTION!

When sandpaper is loading up, it means that the friction and heat created by the paper as it spins on your floor is actually melting off the old protective finish.

This happens mainly when the finish dates back before 1950 or so, when it was more likely that they coated the floor with lacquer, shellac, or even paste wax.

Those finishes melt at a lower temperature than today’s finishes. When they melt, that material clogs up into your sandpaper. This is good because it means it is being removed from your floor, which is the whole goal of this enterprise.

But it’s so annoying to have to keep changing out your paper, right?

There is your problem! If it feels like you are changing your paper constantly because it loads up so fast, you are using too fine a grit.

If your paper is clogging up so quickly that you have to change it more frequently than you were told (and if you weren’t told when to change your sandpaper, get over to Pete’s and let us treat you better) you are using too high a grit of sandpaper grit for your conditions.

Don’t be sad; it’s a solution!

Most first-timers who try to sand their floors are used to sanding already bare wood. Understandably, they believe that 60-grit is a coarse grit, perfect for removing finish from their floor.

While 60-grit is considered fairly coarse if you are working on countertops or furniture, in the flooring world, 60-grit is a considered quite fine.

There is so little space between each of those tiny mineral pieces that even the smallest amount of old finish (even the harder modern finishes) can cause it to glaze over and become useless in seconds.

Coarse sandpaper helps.

That is why reputable floor sander rental establishments should always offer you much coarser grits for your floor sanding needs.

For drum sanders, we always include 16-, 24-, and 36-grit drum belts and edger discs in every customer’s sandpaper kit. Because you can’t always know what your floor is going to need before you start sanding. 

If you start at 36-grit, for example, and the paper begins to gum or glaze over immediately, that is a clear sign to drop to a lower grit of sandpaper. With the brands of sandpaper we sell, we expect a belt to last at least 200sqft and a disc to sand at least 30 square feet before it is glazed over.

And for your most extreme sanding projects, Pete’s sells 12-grit for the edger. Sounds crazy, but if you have multiple layers of old shellac or lacquer in an old closet, you will thank us.

We understand that you think you should start at 60-grit.

We know you are afraid of removing too much wood, or making deep scratches in it.

But if your floor is covered with thick gummy finish, using a coarse grit quickly across that floor to melt off the worst of it will NOT permanently damage your wood.

As long as you don’t keep grinding and grinding with that coarse grit, the mineral particles will barely touch your wood – they will be too filled with finish to reach it!

Trust the grit sequence.

The general rule when sanding these older floor finishes is to not make the wood bare with your first grit. If you start at 16-grit on any machine, you should only expect to remove about 2/3 of your finish. You have several finer grits to worth through. Let them remove the last traces of your finish and begin to grind smooth the wood beneath the finish.

Finer grits are much more efficient at removing the finish or stain that is IN the wood; your coarsest grits are designed to speed up the removal the material ABOVE the wood.

So, as long as you use your coarsest grits to primarily remove the material above the wood, you will save both money and time. Because using a coarse grit as finish remover is always cheaper and easier than using a chemical stripper.