Dealing with rough edges and cavities in plywood

[Tim Brennan]

I am cutting some circles of 18mm birch plywood using a router and then rounding one edge with a 6mm radius. Router bits are from the festoon set and have hardly been used if not new. The plywood has some rough surfaces and cavities, so I am applying some wood filler and then sanding it down. The trouble is that the filling takes 20 minutes and I have another 18 to make. I thought of the spray on filler but I don't have a spray booth. I am assuming this is happening because the plywood is not the furniture grade stuff - I paid £30 for a 8x4 sheet. I don't really want to spend much more than that.

See photos below for details.

Is there a better method that takes less time?

 

[woodbutcherbower]

Hi mate,

What you’re experiencing is 100% to be expected from a £30 sheet of shuttering-grade ply. ‘Proper’ 18mm birch is well north of £100 a sheet. The only thing I’d suggest to speed up the process is to use a faster-setting filler. The one you picture is water-based and will take forever to set. Your best option is to ditch it and use a 2-pack (filler + catalyst hardener) which will be rock-hard and ready to sand in 20 minutes. If the ply’s being stained or left it’s natural colour, use this;
https://www.amazon.co.uk/Everbuild-...Grams/dp/B00ADZJEQI/ref=mp_s_a_1_2?keywords=2+part+wood+filler&qid=1703405971&sr=8-2

If it’s going to be painted, use this;
https://www.screwfix.com/p/ronseal-high-performance-wood-filler-white-550g/45077

Hope you get fixed up.
Kevin

 

[Tim Brennan]

Thanks Kevin for the tips.

I was thinking last night that I might try some different router techniques to see if I can improve the finish as well. So far I have done lowered the bit in 6mm deep increments. But what I haven't tried is machining a circle with a 1mm larger radius and then taking the last 1mm off in the final pass.

I also just saw a video on YouTube that said climb cuts can be cleaner than push cuts. Something else to try.

 

[kevinculle]

As the old saying goes, time is money...or in this case the money you don't want to spend on quality materials becomes the time you must spend working around the defects that come with that "bargain" price.  In the end the result will be less than satisfying.

 

[bobtskutter]

I use low quality materials all the time - it's what I can get hold of!
The Ronseal 2 part wood filler is good and sets very quick, but it doesn't take varnish or stain very well.  It prefers to keep it's own colour (it does come in a Tan colour as well).
I use Bona Mix and Fill plus sanding dust to fill in voids on edges.  It's water based, takes ages to dry but sands well and takes what ever colour the sanding dust was.  If you try and use PVA + dust make sure you use plastic scrapers, PVA discolours if it contacts metal.

I've made several cabinets and shelve units out of OSB for the spare bedroom in my house.  I use the Bona mix and fill on the edges.  I apply it with an old credit card wearing rubber gloves then use my gloved hand to rub it into the edge.  The stuff sets in 24hrs which suits my hobby / part time wood working.

My new years resolution is going to be "find a better source of material".

Bob