Wednesday, January 25, 2012


Alright those who may be interested, let me take you on a sweep of my process and "logic" of/in surface prep.
My words are certainly not the final words on the subject but a view into my practices and what seems to work for me.

-Surfaces with Nicholas Nelson
You have your rough lumber, do whatever you need to do to get it down close to size over a period of time.
Stress and/or moisture can often be less than stable in a plank, or the plank has some sort of "equilibrium" of forces keeping it in shape. Cutting away material can let loose these forces.
Don't cut it down to final dimension right away!
I try to take time with my lumber. Let it acclimate  to the shop as much as possible. Give it some time to settle after milling away material. And so on.

So, keep it a little fat. I joint the pieces on the jointer again, follwed by the planer again. I mill to "final" dimension when I feel the time is right, or I can't wait any longer.
Though some machines perform better than others, I have yet to see a jointer/planer give a perfectly smooth, flat surface. You will get little ripples by way of the rotating cutter head. However fast it spins it does not apply a continual cut. Usually there is some level of snipe as well.
Enter the hand plane.
A very old tool indeed. A plane is just a jig that holds a blade. The sole of the plane acts as registration for the blade. The sole will ride over bumps and valleys in the surface in a way that the position of the blade will remain "planner" to the surfaces over which the plane is traveling.
Sanding devices do not have this advantage. While one can sand out the ripples and other defects left by machines, the fact is that planes were designed to create and maintain a flat and planner surface. Sure, it is easier said than done. Just like any discipline, accurate hand planing takes practice and accumulated knowledge which will lead to skill.
The hand plane also accomplishes what the typical jointer or planer cannot. A continuous shearing cut the length of your work piece. In my opinion, there is usually nothing better than a freshly sheared, friendly wood in terms of surface quality.
When faced with more difficult woods I will opt for my high angle plane. If that doesn't work I'll try a scraping plane. If not that, then I go to sand paper.

When working with friendly woods like Maple, Walnut, Cherry, etc I typically don't do anything more for prep beyond wiping any dust off with a clean cotton rag before finishing. Another plus for the hand plane/shearing tools, one step surface prep. When working with less friendly woods, such as this Red Elm, I find the surface will be slightly fuzzy, or gritty if the wood contains a fair amount of silica.
This Elm planes fairly well with my high angle plane. I just need something to take care of the small fibers and silica left.
I have used steel wool but Nick B had a good concern that I had forgotten about. Which is the possibility of iron particles trapped in the pores of the wood rusting, depending on finish. I don't really use water carried finishes. Shellac gets methyl hydrate, or I use oils. I'd like to be careful though.
I don't particularly like using the 1000+ grit sand paper that would do the job. It creates more fine dust, clogs quickly, and doesn't perform especially well over rounded surfaces with plane/spokeshave facets left like edge treatments or pillowed legs.
I picked up some non-woven pads by Mirka. These are often used in the automotive paint industry commonly referred to as "scuff pads". I chose their finest "grained" pad which they call "micro fine". I took it on some test runs with an Elm off cut which I'm also using for a finish sample of the oil I plan to use. It seems to be doing the trick! Only problem is, these pads aren't as cheap as steel wool. I imagine I may switch back to steel wool after the the second coat of finish is applied.

Well, I think that about does it!


mckenzie said...

Is the mirka pad like skotchbrite pads? I use those a lot but mostly in the finishing process (mostly maroon).

I think it should be said that a well made and properly set up jointer and planer will give you zero snipe.


Nicholas Nelson said...

I couldn't say on the skotchbrite pads. I haven't used them. I would think that many of these scuff pad makes will do the trick.

I didn't say that there will always be snipe. Jointers seem a bit better on that. I just have yet to work on a machine (especially planers) that consistently yield absolutely zero snipe. From my portable planer to Powermatics to Olivers and Northfields set up by a machinist, to General international and domestics.
This is a little beside the point though. The post is simply of my experience/reality and how I work with it.
However to carry on, what kind of machinery are you using and do they treat you well?

Jason Herrick said...

Good article Nick. Thanks for taking the time. I too believe the Mirka products are just like the Scotchbrite pads. I'm sure they have some marketing bla bla that makes seem special. I do know that Mirka also makes the 6" wet dry sanding pads up to 8000. They're about .125 thick and are loved in the automotive finish industry. In your hands I bet you could do well with them.

What generally is the first plane you grab once your machining is done. A #4 or equivalent? Besides my lack of hand tool commitment of time, I also think I don't always know which tools is best in each specific case. Feel free to school this boy. I trust you.

Nicholas Nelson said...

Hey Jason, sorry for not getting back!
Oh gosh, best tool for the job heh. That's sort of a tricky one. Wehn it comes down to it, I think experience and preference will guide your tool selection. The tricky or time consuming part is of course starting out and learning the nuances of each tool in a particular situation.

I would agree that my first go-to for planing a flat surface after machining is a smoother/equivalent #4 plane. I can at least say that ha.