I am faced with masking filling and sanding plater/filler between oak beams that have shrink
Its proving a monumental task, esp. the sanding
Mt orbital sander tears the masking tape and its prone to grind the ends off the sheet of abrasive if it gets too close to a wall.
I bought a 'palm' sander from Wickes for £15 his morning,. It lasted 20 mins before the sanding pad fell off and the Velcro underneath got buggered. I took it back and got a refund.
I like it too, rake out the hole, fill it once relatively roughly as deep as it takes in one go, give it an hour or two, tamp it down firmly by thumb, give it another hour or two, then re-fill it level with a filling knife, 24 hours to properly dry, minimal sanding and never had the cracks open up again.
Don't sand and don't mask. Hack off any unevenness before filling, fill deep and scrape the filler back flush with the existing good surface, then fill it smooth with a second coat once the first coat is firm enough. Ordinary Polyfilla or one-coat plaster works fine for me - if the edges open up after a while use decorator's caulk, which will allow a bit of movement. And cut the edge in properly with a bit of brush skill, ferchrissakes.
precisely. It's way easier than overfilling then sanding back. Most people fail at it because they don't listen to the one golden rule: don't let even 1 grain of sand remain above the level surface. Do that and it's /the/ way to fill.
any plaster/filler works as long as it doesn't slump.
If I were doing it I would sand the open areas with my posh Mirka RoS (light and easy to use overhead and very effective dust collection), then do the edges either with my multimaster (the oscillating action - is rotary rather than orbital - so it will sand right up to an edge without hitting against it all the time like an orbital does).
Alternatively I would use my Mirka hand sand block with vacuum extraction:
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With an Abranet sanding sheet and a vacuum hook up there is very little dust which is nice when sanding overhead.
Rather than worry about sanding right up to the edge, I would be inclined to caulk the final interface between ceiling and beam, so that you have something flexible at the join. You can tool that with a fugi type tool. The acrylic caulk will take a few days to dry out fully if you use a heavy bead - but it shrinks back slightly as it does which leaves a quite need slightly concave finish.
If you look at:
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The interface between tile and ply suspended ceiling is caulked and then painted along with the ceiling - it makes for a neat (IMHO) finish at the join.
The problem is that that implies you can stop the filler a fixed distance from the edge. In fact I am using massive amounts of caulk - on
7th tube so far - to do what can be done that way, but this part of the L shaped house features the 90 degree bend and the green oak was exposed to rain longer because the roof was tricky to make in that part because of the bend so the final shrinkage was far greater. Even the longitudinal shrinkage of the main verticals is enough to cause cracking.
Across the 12" width of the central 12" square oak beams the shrinkage is about an INCH
16 years on, its finally reached equilibrium and its time to sort it all out.
I have tried about 6 different techniques so far, and this is the first one that actually works, but am simply physically incapable of doing the sanding by hand. At lest more than a half beam in a day, and there's 48 half beams in the ine room alone..
I have got it down a lot by being better at filling, but there is an irreducible residue of sanding needed.
Are there multitools that don't need velcro pads?
I suspect that plaster dust and velcro are anathema
As other have mentioned try and get the filler as close as possible to the final finish without having to sand down afterwards. Possibly don't try to get the finish in one go - fill to below the surface, key this surface before it sets and then a final thinner filler layer.
What I've found useful to get a flat surface for filling over distances of 12 inches is a taping knife which has a long blade and can be run over the existing wall and the plaster to ensure one is flush with the other
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Toolsatan also do them in stainless steel and to 12 inches.
Plenty of cheaper/larger versions available on ebay
I was thinking more of filling up to the edge, but not bothering to try sanding right to the edge. Then just covering the edge of the filler with (tooled) caulk.
Any hand sanding would need to be very quick and minimal obviously given the scale of the job. Those proper sanding pads with handels etc make it much easier. Also the ones that can be mounted on a pole make it much easier - i.e. you can stand ont he ground and use full arm moevments etc.
Working overhead even with a lightish tool like a multimaster will still get tiring.
The only other option I can think of for sanding right to an edge that can also achieve a good finish, is a linear action sander. These aree far less common than orbital or RoS machines. Festool do one:
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There are some punched backing pads that allow for extraction through the pad. I have not seen any with clamps to hold the paper.
Generally I have not had difficulty with the velcro type unless you allow the pad to overheat (too much pressure usually - not that difficult to do with such a small pad). Then they lose their ability to retain the paper.
Axminster do some "interface" pads which are basically thin double sided velcro sheets designed to sit between pad and paper. The idea being if you knacker the velcro, you don't need to replace the more expensive pad on the machine - just the interface pad. (they also have some thicker spongy versions designed for curved surfaces)
IME dust does not seem to cause it a problem... having said that, not all velcro backing pads are made equal.
In you airplane hobby have you ever come across Humbrol Maskol which is a liquid applied mask that dries to a thin rubbery finish and later is peeled off. Using it in quantity would be prohibitively expensive but perhaps someone on here knows of something similar available that is more economical, Copydex perhaps. More expensive than tape but if it saves muscle pain.
Applying tape is in fact the quickest part of what I am doing. Then the caulking is second, painting is minutes per bay. Filling and sanding are hours per bay.
That's what I want to throw money at to get the time down
So far it seems that there are lots of suggestions but not many to actually achieve what I want.
I think you should be able to reduce the sanding time, and make it hand-sanding rather than hoisting a machine over your head.
That probably comes at the expense of slower, more careful filling, and time between two layers of filler, but as you've plenty of bays to do, you probably have no need to actually waste time between layers, just work your way round and then back to the start.
I may have missed it in this thread but Bill Wright suggested recently
"Wrap a bit of sandpaper round a multitool blade and secure with a dab of superglue. Makes a detail sanding finger that will reach into places other sanding solutions can't reach!"
I've not had cause to try it yet so please look North if it brings the ceiling down :)
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