Help repairing plywood

nightrider1470 · 14 Feb 2013 at 10:47

I bought a 10x5ft of plywood to use as a projector screen,.wanted MDF but they didnt have in that size. Any way after priming it, I have noticed some areas are showing some type of blister marks, see pic.

Wondering how to best get rid of them? Sanding and polyfilla maybe?

PhillyDee · 14 Feb 2013 at 10:51

You will probably have to remove the bubbles, sanding them will push the layer in, and acheive nothing. Best bet is to remove the bubbles by cutting round them, fill them in, and then smooth it over. You will end up with a different finish though, as wood has a grain, and filler does not.

cjgardens · 14 Feb 2013 at 10:52

Have you got it wet.

Think that's all you can do sand amd then fill and sand it again.

Or buy new

nightrider1470 · 14 Feb 2013 at 10:55

Ok thanks!!

Am wondering for a extra perfects finish if I could have the plywood plastered?

Its currently been coated once with dulux difficult sufice primer and was when I noticed these marks. I plan to paint with 2-3 coats of Matt grey paint once its flat, I hope!!

So I should take a stanley knife and actually cut the blister marks out, cutting around them, then fill and sand?

LOAM · 14 Feb 2013 at 10:57

I would say its probably the wrong type of ply to be honest. You really need WBP (Weather and Boil Proof) as its external grade / waterproof and generally a better grade. To fix that you will need to remove the effected laminated layers, give it a good sand and then fill it with a decent 2pack wood filler. It then needs painting.

But truth be told its more hassle than its worth, just buy a new piece.

cjgardens · 14 Feb 2013 at 10:58

What are you using it for. If you plaster it then move it it's going to crack

nightrider1470 · 14 Feb 2013 at 11:45

Its wall mounted on my wall and is to be used as a projector screen so a flat clear finish is vital.

Could I not chicken wire the wood then plaster maybe?

I will cut the areas out and polyfilla it and see what it looks like

Mercenary Keyboard Warrior · 14 Feb 2013 at 11:52

Is it easy to take back down?

And if you push the "bubbles" will they flex in easily?

Assuming both yes then I would drill a tiny hole into each buble, inject some wood glue and place a heavy weight on each one that pushes the bubbles down.

You will then have a tiny hole to fill rather than a great big area.

What about covering the board with a quality projector screen material though. If you literally stick the projector material to your board you get the best of both worlds, the projector material and the true shape of a hard flat surface.

robfosters · 14 Feb 2013 at 12:04

I would sand down using very coarse paper till they have gone, then fill using something called sanding sealer, It's what modelers use to get an ultra smooth finish on model boats.

http://www.cornwallmodelboats.co.uk/acatalog/fillers.html

Hostile-17 · 14 Feb 2013 at 12:40

picture indicates the board has got wet, try removing the blisters and filling would be my bet, or get a new peice if budget allows

Maccapacca · 14 Feb 2013 at 12:43

Scrape the bubbles out then fill with a decent timber filler but as above is it really worth it? you'll have a board with even grain then a line down it of smooth filler.

Odd choice for a projector background with the grain.

nightrider1470 · 14 Feb 2013 at 15:11

Ok av been thinking!

The wood really isnt up to scratch to use for a projector screen and as people have mentioned its going to be more hassle than its worth!

Can I get someone to screw/nail plasterboard's to the plywood then plaster for a nice clean finish?

Nightglow · 14 Feb 2013 at 15:16

What the other side like?

Can't you turn the sheet over.

I myself wouldn't have used plywood, too grainy.

nightrider1470 · 14 Feb 2013 at 15:20

No! other side is worse mate. Its on the wall now so wondering if I can plasterboard it then get a mate to skim it for like £40

Just not sure if this can be done?

Nightglow · 14 Feb 2013 at 15:31

nightrider1470 said:
No! other side is worse mate.

Sound like shuttering ply or Chinese ply, you plaster that, it will only bubble again or delaminate with wet plaster.

Work out cheaper looking for a local timber merchant who stocks 10'x5' 3mm or 4mm mdf, you can also get oversized MDF boards up 12'x6'

malfunkshun · 14 Feb 2013 at 15:33

frame and cloth over it?

nightrider1470 · 14 Feb 2013 at 15:45

Nightglow said:
Sound like shuttering ply or Chinese ply, you plaster that, it will only bubble again or delaminate with wet plaster.

Work out cheaper looking for a local timber merchant who stocks 10'x5' 3mm or 4mm mdf, you can also get oversized MDF boards up 12'x6'

Am not saying plaster over the plywood mate!

Am asking can I nail or screw "plasterboard's" to it....... then have it skimmed?

Plywood>>>>>>Plasterboards>>>>>>>>>Plaster!

I would have to rent a van again to get such a large piece of wood again or pay high delivery prices!, + not got the tools to cut it

I think to cloth it, I would need to pull it off the wall to get the cloth behind which seems a nightmare!

Nightglow · 14 Feb 2013 at 15:56

I certainly wouldn't waste £40 covering it with plasterboard & skim it.
Even the best plasterer will not achieve 100% finish,you still see surface marks, plus I reckon that ply even cover with plaster board will still bubble when skim, as it will pick up some moisture from the plaster.

nightrider1470 · 14 Feb 2013 at 15:59

I will try to patch it up and see how it looks

People are telling me to sand the areas and others say cut a chunk out then fill? which one?

PhillyDee · 14 Feb 2013 at 16:01

Try sanding it first, if not, remove and fill.

I would go with the stapling of fabric to it.

Help repairing plywood

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