Advice sought: resurfacing an old workbench.

[isaac3d2]

I'm thinking of resurfacing my old wooden workbench with a sheet of 25mm plywood. The existing surface is neither flat or smooth. I can try to flatten it a bit but I doubt I'd ever get it as flat as the ply. Obviously I want to avoid bounce when I use a chisel and mallet, so the contact between ply and old bench should be good.
Any suggestions?

 

[Bingy man]

I’m thinking that some type of acrylic adhesive ,something that will fill any voids between the top of your bench at the bottom of the ply . It’s the high spots you will have to remove prior. Can’t think of a particular product at this point though..

 

[Ttrees]

Plywood is expensive, and not very flat either.

 

[Phil Pascoe]

Polyurethane foam?

 

[Jameshow]

Polymer sealant? Ebt etc.

 

[AJB Temple]

I think ply is hopeless for a workbench top. When chopping out mortices etc it is inevitable that the bench top will be impacted. Most ply has a very thin top surface and you will have chunks out of it in no time if you do any amount of work. bench tops need to be tough. What is your current bench top made of?

 

[isaac3d2]

@Ttrees: I have some spare 25mm ply left from another job, so the cost is not a factor in this case. As for flatness, it's a lot flatter than my current bench top
@ ABJ Temple: I won't be chopping directly on the ply surface, I'll always use a sacrificial piece. I don't chop that many mortices.
I'm not sure what timber the bench is made of but it appears to be a softwood such as Douglas Fir, which of course, is not that soft.

 

[AJB Temple]

Mortices / half laps / dovetails / box joints / tenons. Ply will be knackered quickly but if it's essentially free then sacrifice it! I would lip the edge as ply splinters are a real devil.

 

[isaac3d2]

Hmmm...
I have already edged the plywood with some beech I had left over. Perhaps the best thing to do would be to not glue the plywood down to the bench but just use it as a removable bench top when I need a flat surface. For making joints, I'll just have to live with what I have until I can afford a new bench...

 

[--Tom--]

If the current top is softwood, shouldn’t be too hard to at least get it flat, the ply like you say can be lain on top when needed for layout/assembly.
If you put it on a wonky top I don’t think you’ll have a satisfactory workbench for doing joinery on

 

[Ttrees]

Indeed ply offcuts make great sacrificial tops though.
What I didn't do well in pointing out is the fact that if you think ply is flat,
then that could likely be why you doubt you could get your bench top as flat as it.

Not having something what's actually flat to begin with, and as long as the work,
is a recipe for a fight with a hand plane.

If you have 2 lengths of fairly rigid parallel in width timbers,
you can compare them against each other, and the reason I mention parallel is,
so you can flip one over to double the error, should one bowed timber be mating with the
other
Get the angle poise lamp and check if you can see light.

David Charlesworth's old youtubes would explain all that...
as in his definition of a straight edge, and the use of it thereafter,
checking where the work is pivoting from, tolerances to aim for,
plus reliable honest planing methodology to get you there.

The angle poise lamp makes things easier than pivoting to see light under a benchtop,
and shim or plane accordingly.

All the best
Tom

 

[Orraloon]

Without seeing the benchtop its a bit hard to say but generally its best to get the existing surface flat as a starting point. Other option is remove the top and perhaps use 2 layers of ply as a replacement. Other sheet goods would do so depends what you have. MDF is usually very flat and particle board flooring is another one. A bouncy benchtop will drive you nuts.
Regards
John

 

[J Bodger]

There’s a Paul Sellers video on YouTube about making a bench from ply. He cuts it into strips and glues them together. He also deals with getting it flat.

I had a problem planing beech because my beech bench top had developed a hollow. It took quite a bit of planing to get it flat. Planing your top should be easier than beech.

Two options there - but your bench top must be flat for accurate work.

 

[pe2dave]

Would one of these 'self levelling compounds' be any good on timber?

 

[Cooper]

In the old days of the ilea when I was a woodwork teacher our benches were about 30 years old and needed to be resurfaced. The technicians came and reversed the tops so the underside was revealed. There were fixing points that had to be plugged but with new vice jaws the benches were as good as new!!
Obviously I have no idea how your bench is constructed so my thoughts are possibly irrelevant?

 

[Phil Pascoe]

Would one of these 'self levelling compounds' be any good on timber?

No. They're not much good on floors, either.

 

[TigersFan]

Could you temporarily screw a straight board to each side and make up a router sledge. You should be able to get a lovely flat surface and keep the parts for future maintenance.

 

[BrianatBisley]

I know this will sound crazy, but what about a layer of some really cheap particle board? Just replace it when it gets too banged up to use. I have a workbench made of solid maple. It is great but does require flattening from time to time. Glue, paint, epoxy and chisels all take their toll. I cut most ply on sawhorses. They are so scarred that they barely stand. You can see light through the cross pieces. They are a consumable. In a way, a workbench top is the same.

 

[Ttrees]

Not many scratches or any other damage on Frank Klausz's bench.

 

[Orraloon]

Could you temporarily screw a straight board to each side and make up a router sledge. You should be able to get a lovely flat surface and keep the parts for future maintenance.

That would be a very good way to do it and a top layer of ply would only be required if the existing top has got too thin to be viable.
Regards
John