Advice on Sanding my Floor

[JamesW]

No that's not a euphemism.

Hey,

The missus has given me the wonderful task of sanding down our dining room floor. I hired an industrial sander thing and that did most of it, I then hired a skirting board sander and did the rest.

I now have a problem though. The floor is a little uneven, so the industrial bad boys couldn't do some of it. Also I can't get to the corners..

I have tried using my little electric hand sander but that didn't do the trick (basically the floor has like 192 layers of varnish on it). I don't really want to hand sand it all as I would be there forever.

A friend of mine recommended Nitromors (http://en.wikipedia.org/wiki/Nitromors) but not really sure about it.

Does anyone have any awesome tips of how to finish it? I need the brownie points!

Cheers,

James

 

[Jon von der Heyden]

Hi James

What wood are we talking about here? I presume pine. Industrial sanders will eat up pine because pine tends to be a very soft wood (although some pine can be tough depending on the type of fir and the climate the tree grew in, but generally speaking it's very soft).

You can use a paint stripper to get off the varnish, but even then you have quite a bit of work ahead of you. You see you still actually have to scrape up the varnish when you smear it with stripper. So you'd do a surface of like 1M2 and then scape it up when the varnish softens (about 10 minutes). The problem with strippers is that they also tend to discolour the wood, so even after using stripper you will need to sand the wood.

What is your electric hand sander, orbital or belt? I recommend a belt sander. You can use that to smooth out any grooves the industrial sander has left behind. Unsure how good a job has been done with the industrial, but recommend that you start off with a 60 grid sandpaper belt. Any coarser and you run the risk of making more grooves in the wood. Start with a 60, then go up to 80, then 100 for a smooth finish. You can go even finer if you want it really smooth. Remember to sand with the grain. Sometimes it's easier to work out grooves by sanding against the grain, but then make sure you go over it again sanding with the grain otherwise it will look horrible.

A belt sander won't get into the corners either though, I'm afraid. You do get electric orbital sanders designed to get into the corners but in my experience they really don't cut it. The corner tips of the sand paper wears out too quickly. When it comes down to the corners your best bet... ELBOW GREASE! If the varnish is thick then use a paint scraper or a piece of glass (consider using a bit of stripper). Then start with a coarse sandpaper (40 grid), and then when the worst is done use finder sandpaper (60;80;100).

Be sure to seal the wood soon after sanding because any spillage will ruin it and even humidity can affect it (referring to pine). I even recommend sealing with a wood oil after you have sealed it with a couple of coats of varnish (I recommend at least 3 coats, but it really depends on the sealer and how you will apply it). Oil is good for the wood and even good for the longevity of the varnish.

Enjoy it! I really miss working with wood!

 

[JamesW]

Many thanks for the suggestions Jon!

Not sure about the type of wood; the houses were built in the '30s and our nextdoor neighbours said they are pretty crap quality.

I have a little wedge sander (Similar to this.) and I borrowed a belt sander from a pal of mine.

There isn't much left after I attacked it with the industrial ones, only in the bits that are uneven. The bits that are left are small patches of varnish and white paint (I think the last owners painted it, then varnished over the paint).

We arn't too bothered about the quality of the sanding, as we will be varnishing over it with dark varnish when we are done.

Edit: Just a thought... Can we not just varnish over it all now and ignore the bits left over it? Will they be visible?

 

[Jon von der Heyden]

I think it's a safe bet that it's pine. If it's not then I think it would be a cardinal sin to paint it.

Yep, your sander is what I was referring to about getting into the corners. In my experience you {edit}don't{/edit} get through the job much quicker than by hand. I especailly don't rate Bosch green. It's for DIY, Bosch blue is the industrial brand.

You need a belt sander mate. The bigger and more powerful the quicker it will chew through the varnish. And they are great for getting up close to the edges, where as the industrial floor sanders (drum sanders) don't get you close to the edges.

If you are going to use stipper (such as the one your friend recommended) then I suggest you only use it for corners and places you can't get to with the sander. If you start smearing huge patches you will find you will spend heaps of money on it because it really does go very far.

That's my opinion anyway... Or rather, in my experience (safe to say I have probably done 50 floors or more in my time, but admittedly nothing in the last 12 years)...

 

[Jon von der Heyden]

Edit: Just a thought... Can we not just varnish over it all now and ignore the bits left over it? Will they be visible?

Possibly, but I can't say without seeing it. Take a couple of pics and show me. If you are staining it with a dark stain then you might well get away with it... Can you show me a sample of the stain too?

 

[JamesW]

Cheers Jon, I'll try and take some pics over the weekend.

Will let you know how I get on.

 

[Jon von der Heyden]

I'll be in your neck of the woods in April, so if you're not done by then give me a shout.

 

[JamesW]

I'll keep that in mind although if it's not done soon I'll get shouted at

 

[arkusM]

When sanding with a belt sander you can carefully cross-grain sand to remove ridges in the grain, go easy though. You need to follow up sanding with the grain to remove evidence. Like Jon says you should progressivly use finer paper grits.

If you are thinking about a tinted "varnish" or a stain-&-varnish to refinish, any bit of leftover old finish will not accept the new finish. Stains work by penetrating the wood and an old finish would prevent this from happening.
If you are simply try for the "natural" or exsisting colour and are putting clear coat then whatever is there will still be there.

Of note, Varnish is a type of finish that I don't beleive is used much for floors anymore there are tougher finishes out there. Take a look at water based polyethylene floor finishes. I have no idea what is available in the UK in terms of brand, but I have used oil based polyethylene for some tables I finished and I am very pleased with the resistance to water, stains and two little boys banging away. LOL. Though next time may opt for the water based version.
The significant advantage to the water based stuff is the lack of smell (and toxicity, while it off-gases) which is improtant for your home.

Mark

 

[Domski]

My advice...buy a carpet

Dom