Paint removal...

[Ynot]

One of my planned jobs for the dark time over the summer was to lift and replace the MDF stage floor covering that was laid about 3 years ago as it is starting to look a bit weather beaten. However, taking a look the other day it's clear that the major problem there is going to be locating all of the screws that were driven in, and then getting a clean enough grip on them to pull them out... There have been untold coats of paint layered on the boards in that time.

 

Therefore that idea has been shelved as a bad one for now.

 

So - still considering the fact that the floor needs some TLC, I'm now looking at options for taking the layers of paint off and getting a better surface at the same time without removing the boards.

Quite a few years ago we did hire a heavy duty sanding machine (looked like a squat lawnmower contraption) with a large sanding belt, but that didn't really do a great deal before it got clogged with the emulsion it was removing. I'm guessing that an industrial rotary sander would suffer the same problem.

 

One of the lads said he uses an electric plane with the blade set just outside the plate to pull layers of paint off work he does, but he did admit that doing that over an area of 35 by 24 foot would be at best laborious!

 

So - any ideas for something that DOES work? I used to have some sanding pads for my orbital hand sander which weren't sandpaper but some sort of gritted affair which didn't clog but did a great job of smoothing out rough timber - anyone any idea if a similar option exists for large belt or orbital sanders?

 

As usual, please only real-world experience answers - I've speculated far too much myself already!

[paulears]

Tried the plane idea myself, and it worked fine, until it 'discovered' one of the screws just below the surface - wrecked the blade, and a new one was more than I paid for the cheap plane!

[Ynot]

Yep - that's the other downside I meant to mention of the plane idea...

 

:(

[J Pearce]

I've seen hardwood floors planed back when heel dents and other scrapes have got too much, but you would need to guarantee the screws were deep enough to miss the blade.

 

Might be easier to lift the boards out with wrecking bars and then relay fresh boards. Once you get going it is pretty easy to pull the screws through the board and then get the screws out with appropriate removal tool or a grinder if they are properly stuck in.

You might have to do a depth limited plunge cut to get an edge to start on if it is laid flush to walls though.

[bruce]

How thick is the MDF? Are you planning to scrap it? What length are the screws/

 

If it's being scrapped, and it's reasonably thin, you could rip it up with a claw hammer or similar, leaving the screws behind to tackle with a screwdriver (if slot is accessible) or mole grips if not.

[Ynot]

Don't recall exactly but it'll be either 9 or 12mm at a guess.

 

I had considered the 'rip-it-up' option, and yes that may still be considered although there are a LOT of (1.5" I believe) screws in random spacings as it was needed to 'iron out' all the creaks and squeaks. (It had slipped my mind how many were driven in until I iinvestigated. So whilst it may be viable to do that it could well end up with it being a LOT of work prying up the boards in smaller pieces instead of just the 8 x 4 sheets.

 

:(

[ImagineerTom]

you've considered a maget hung from a length of string (pendulum style) to locate the hidden screws? You can then get drill bits designed for drilling/digging out problem screw heads.

[bruce]

Could you just lay another layer of 9mm MDF on top? It does mean, of course, that in a few years time when you come to do the job properly, you'll have twice as many screws to find and remove.

 

Or just keep laying more MDF every few years, and accept that your stage is going to get an inch higher every decade :)

[Robin D]

If you are going to sand the floor, you need one of the huge machines the real pro's use rather than the little ones the hire places all have. These have on-board vacuums that suck the dust away from the edges as well as from the dust ejecting end and weigh a ton (about 100KG I think). They take a lot of controlling and the personal protection needed is high, but they do fabulous job without clogging or leaving vibration ripples on the floor. I'm not sure where you would hire one though.

 

I've only every used one once with the professional showing me how and frankly wouldn't go near one now. You might find that its cheaper and cleaner to get a pro in to do it for you.

 

I've also got a set of these and can vouch that they work well, most of the time. ;) Not sure how long they would last with a large number of screws though.

[andy_s]

hot air paint strippers and scrapers are an effective but very laborious way of cleaning back a painted floor. Many hands are needed, and many days. You might decide ripping up the boards and going on a screw hunt is a quicker option.

 

(Speaking from experience, having tried the large drum sander approach on a planked floor with at least 8 years' worth of paint. With the hot air strippers, we peeled off "sheets" of paint that were probably 4mm thick. I think it took about a week for a stage measuring about 10m by 10m, but that did include a day of fannying about with a sander)

 

The floor sander was ineffective because paint pooled in the tiny gaps between the planks, and over the years created little ridges, which meant that the sander more or less "floated" above most of the paint rather than actually sanding it down! I suppose eventually the ridges would have been levelled and the rest of the paint would have been removed, but we had no idea how long that would take, so found a faster (albeit still very time consuming) method.

 

This is why if an architect ever proposes a beautiful maple floor for a new theatre space, this foolish idea must be fought to the last man by the people who have to maintain the space. If you inherit a planked floor, and expect to paint it on regular basis, campaign for a top covering of MDF or hardboard at the earliest opportunity.

 

(but beautiful planks are fine for concert halls)

[adam2]

Presuming that you wish to remove the MDF and not just the paint, I would go for levering up with a crowbar such that the boards break up and leave the screws exposed and thus easily dealt with.

Removing the FIRST board may be tedious, try to start with a part one, but after that it is very quick. An old screwdriver is useful for slightly lifting the board so as to give space to insert a proper crowbar.

 

Take GREAT CARE not to step on the exposed screws, wearing footwear with safety SOLES would be sensible.

[Ynot]

Presuming that you wish to remove the MDF and not just the paint, I would go for levering up with a crowbar such that the boards break up and leave the screws exposed and thus easily dealt with.

Well, that was the original plan, and replace with nice virgin MDF. But then, as I realised (or rather recalled) just how many screws were in there, I fell back on the idea of stripping back the paint instead.

 

Take GREAT CARE not to step on the exposed screws, wearing footwear with safety SOLES would be sensible.

Hmmm...

I think I'm rather long enough in the tooth to have worked that one out should we go that route... B-)

 

When all's said and done, I've had words with our local Buildbase and queried the options available on their industrial sanders.

 

The one in that link is similar to the one we hired ten or more years ago - one of the other guys hired it before and it came with whatever was on the drive.

Buildbase say that theirs will come with a selection of sanding belts based on the job as described to them, and after I told him what we needed, he was most emphatic that using their coarsest belt to start with then stepping down to a medium then a fine-ish grade to finish would do the job nicely.

 

So, maybe our last attempt failed simply cbecause of the wrong attachment for the job. So methinks this is the route I'll take and see how we get on.

[Hilary Watts]

When all's said and done, I've had words with our local Buildbase and queried the options available on their industrial sanders.

 

 

I don't want to be unduly pessimistic but that was just the sort of thing we hired last year and it didn't really do the job for exactly the reasons set out in the post above by andy_s. Although the sander was quite heavy to lift it simply seemed to skate across the top of the paint even with a plentiful supply of new sheets of abrasive. We resorted to the hot air guns/paint scraper approach which andy also appears to have used. (I hired a similar sander for some old floorboards at home and it made a superb job - it's just the multiple layers of paint which it doesn't like)

 

The sander was fine for finishing off the oak floorboards in the theatre once the 'sheets' of paint had been removed and also for smoothing the edges of the areas of paint which were still left when we finally gave up after about 3 days worth of work. We now have a surface with 'gentle undulations', which is better than the state it was in 12 months ago but by no means perfect. If we'd been willing to continue with the hot air guns and scrapers for a week, as suggested in the previous post, I think we would have been able to remove all the paint but other things seemed more pressing at the time.

[Ynot]

Hmmm...

 

The Hirebase guy seemed very sure that with the right grade of sandpaper belts to start and finish the job the machine should definitely be man enough for the job - maybe you had the same issue as we did years ago and had the wrong belt to start with...? Any idea what grade you were using?

 

At the end of the day, if the man says it will do the job after explaining what's what, and it doesn't, then there's a case for refund of the hire fees...

 

IF it does work, then it'll be the easiest option for us - worth a try I suppose, but your comments taken under advisement. :)

[Hilary Watts]

We had a selection of abrasive sheets and started with the coarsest grade available (something like 40-60 grit sandpaper or possibly coarser)) but the sander still didn't really 'bite' into the surface of the paint in the same way that it did with my floorboards at home where you had to keep moving the thing around to avoid digging a hole. On the painted stage it simply tended to polish the top surface rather than cut through it.