I have seen some recipes that use dryer lint, but I'm pretty sure that I've seen some folks suggest using a layer of Elmer’s Wood Filler over the surface and then sanding. But for really lumpy surfaces, it may be using a mix of different maché materials and perfecting your technique overall.



Here's a previous discussion about it with some great links (Stolloween is a master of paper maché!):
http://www.halloweenforum.com/halloween-props/142967-smoothing-paper-mache.html

 

Sanding is what gets you a smooth surface.

Sometimes you want lumpy so you don't bother sanding, but the only way to get that super smooth surface is to sand it with several grits, start rough then work your way up to the finer grit.

 

In my experience, home made paper clay like you used tends to have a coarse texture compared to commercial paper clay products like Creative Paperclay. You could try making cold porcelain like in this video but sanding might be your best bet. You can always use the paper strips dipped in water, flour and glue method too. That tends to yield a smoother surface.

 

Ive found that if you chop up the paper in a blender first it comes out much smoother. GhoulishCop did a very nice video on it a few years back.
For a pumpkin I just let it be lumpy. Pumpkins are not totally smooth.

 

What did you use to mix it? I use a mixer similar to this Warner-Paint-Mixer and it comes out fairly smooth.

 

I have always used paper mache strips dipped in PVA glue, that way you can get it as smooth or textured as you want and it easily paints over with acrylics

 

I used to have that problem an awful lot, and resigned to doing a thin layer of DAS clay over the top.

But recently, I've started mixing in some drywall joint compound into the paper clay, and it gives me a much better result.

About the smoothest I could get it pre-mud:

With mud in the mix:

 

1 part drwall compound with 6 parts paper mache paste, then add insulation until i reach my desired texture. I apply the paper clay to my buck, then using a paint brush, apply the paper mache paste to smooth in out while the clay is still wet. Works very well

 

I've tried and made a lot of paper clay this year. For the cellulose insulation clay I've followed Scott Stoll's recipe as given by Antrocks above. Yes, you can smooth it out a bit by either brushing on more paste or rubbing it down with some on your fingers or with your hands wet down. I found that if you mix in too much cellulose and go for a dryer clay it's like sculpting tunafish. If you start with a wetter clay (less cellulose) its much easier to smooth. Either way, at best it dries looking somewhat like cement. The cellulose just gives a coarser texture. If it's a little drier to start, it's good for larger projects.

There are quite a few recipes out there if you're looking for a smoother clay to start. Generally I think you'll find that the finer your paper in your recipe, the smoother your clay will be to work with. My most recent I did last night is a modified recipe from ultimatepapermache.com via a Youtuber. this one calls for two rolls of toilet paper, soaked in water to separate, which is then broken down further with a hand mixer. Squeeze out the water, tear it into small chunks and grind it down as fine as possible with the mixer again. Mix with 2 cups pre-mixed drywall compound, 1-1/2 cups PVA glue and a small amount of kosher salt to keep mold from growing. As with the cellulose, watch out for how much paper you add. More paper = dryer/chunkier and not as smooth. You may need to add a little water if the mix is too sticky.

When you use the TP clay, smoothing it with a palette knife dipped in thin paste will give a really smooth finish. The lady at ultimatepapermache.com has a version of the recipe she uses in lieu of strip mache and applies with a knife directly to her armature. Experiment a bit to find out what works best for you. You can always dip a ball of too-dry clay into your paste and knead it into a moister material as you're working as well.

PF

 

I build up with a regular paper and glue method, then for the last layer and any detailed sculpting I mix finely shredded toilet paper (cheap stuff), white glue, and joint compound. Let that dry, then fill and smooth with joint compound straight up, then sand. I get a very smooth, leather-like finish.