Sharpening

[Baldhead]

First off

I don't want arguments, bitching, biting, fighting etc. etc.

This is a genuine question and I would appreciate genuine answers only.

I have some lapping film which I bought some time ago from Workshop Heaven, which should be stuck onto float glass, however float glass is extremely expensive, so I am thinking of using Perspex instead. Has anyone tried this? will Perspex be flat enough? is there an alternative I could use?

As I will be using water as a lubricant I think MDF is out of the question or will it be ok if the water is just on the surface?

TIA

Baldhead

 

[Graham Orm]

I use conti board, not had a problem, it's pretty much sealed and is as flat as is needed I reckon. (An old kitchen cupboard shelf). Where are you buying your glass? Should be about £10 per sq metre for 4mm clear. Recommend 6mm laminated or better still 6mm toughened which you will have to order and wait for. (All glass is float these days). To take the sharp edges off try emery cloth.

What about a large tile? Most places will sell you just one and you can take a straight edge to find a nice flat one.

 

[Spindle]

Hi

The issue with perspex will be it's flexibility - it will adopt the profile of whatever substrate you use, if you already have a flat substrate in mind, (tile, granite off cut etc.), why not use just that?

Regards Mick

 

[Peter Sefton]

I would stay with float glass, you may be lucky enough to pick some up for free. Avoid anything that will take up water or oil and swell.


Mod edit:-- Please read forum Rules section 8.

 

[marcus]

Do you have a glaziers near by, they would quite possilby give you an-offcut for nothing, or for pennies anyway.

 

[Graham Orm]

Where are you BH? I've got 3 pieces of 6mm toughened about 800 w x 250 deep from an old TV stand. They can't be cut because they're toughened but will be ideal if you have the space. If you want to come for them you can have the lot (Stockport).

 

[Harbo]

Give it a go - I've used Perspex stuck to a chunk of old kitchen Worktop to lap plane soles?

Rod

 

[Steve Maskery]

I don't see the point really. Glass performs better, you can pick up a piece of glass for next to nothing and Perspex is quite expensive. Or have you got a load of Perspex lying around just waiting to be used?

 

[Baldhead]

Thanks for the replays guys.

I have a piece of Perspex which I was going to put on top of a piece of hardboard which in turn would be glued to 3/4 ply, I have enquired at the local glaziers but they were about as helpful as......well let's just say they weren't very helpful.

Graham thanks for the offer but I live in Northumberland, I have been watching eBay for TV tables etc etc but locally they are selling for stupid prices!

Thanks again

Baldhead

 

[Cottonwood]

A sheet of perspex will get manged up in no time with grit particles. Plus its soft and bendy so will rely on whatever you rest it on for a support.
If I was to use the scare sharp method, I would get a piece of granite worktop from a kitchen fitter.

Recommend 6mm laminated or better still 6mm toughened which you will have to order and wait for. (All glass is float these days).

Toughened glass is NOT flat, the way it is manufactured means that it goes bendy-even though the bends are slight-but enough to ruin the notion of flatness, which is after all the whole point of the scare sharp method...

 

[Graham Orm]

A sheet of perspex will get manged up in no time with grit particles. Plus its soft and bendy so will rely on whatever you rest it on for a support.
If I was to use the scare sharp method, I would get a piece of granite worktop from a kitchen fitter.

Recommend 6mm laminated or better still 6mm toughened which you will have to order and wait for. (All glass is float these days).

Toughened glass is NOT flat, the way it is manufactured means that it goes bendy-even though the bends are slight-but enough to ruin the notion of flatness, which is after all the whole point of the scare sharp method...

Fair comment, I wasn't aware of that but it makes sense as it goes through a heat treatment process to toughen it.

 

[Steve Maskery]

+1 for granite. You should be able to get a piece from where a sink was cut out.
If there is a fireplace place near you, they have lots of scraps of marble from the bit that was cut out for the fire itself. I'm not certain of its flatness, but I would think it was worth a go.
Pity your glazier was not very helpful
S

 

[Cheshirechappie]

If all else fails, perhaps you could laminate up a sort of 'chopping board' from strips of hardwood offcut, planed as flat as you need on both sides. Then put a piece of perspex on top of it, perhaps held in place by pins tapped into the wood around the edges of the perspex, so it doesn't slide around but can be lifted off for cleaning. You may have to check for flatness occasionally, but if it's laminated with the grain alternating in direction, it should stay pretty flat anyway. You also have the luxury of being able to make it the exact size you need, too.

Come to think of it, even softwood would do. It won't deflect enough to deleteriously affect sharpening, and has the advantage of being something you can just do without having to spend time, effort and car fuel tracking down materials.

 

[Jacob]

A bit of MFC worktop will do. Your wet n dry will stick to it enough if you just wet it thoroughly with white spirit. Helps if you keep it flat between boards when not in use. Paper backed is best and also cheapest say 30p a sheet. So called "lapping" film is way beyond the needs of a woodworker.
Scary sharp is good for when you want to flatten something but is hopeless as a routine sharpening method as it is just too fiddly - if you are working hard you need to sharpen quickly and frequently

 

[david123]

Got a piece of 4 cm float glass from our local glazier he even beveled the edges for me. He wouldn't take any money for it as I had used him in the past, and of course would use him again if I needed any. worth an ask.

 

[Phil Pascoe]

A few years ago a crowd of us were doing a fused glass course, and we got quite friendly with the staff of a glaziers who supplied our dichroics and such. We asked for offcuts of float to practice on and we were refused... yes...you've got it... health and safety.

 

[Dangermouse]

Go to your nearest stone mason and ask for some offcuts, I got a bit of polished dead flat granite, 24" x 8" x 4" for £5.00

 

[Cottonwood]

I suspect if you make up a lanimmated base, it will soak up water (lube from from the scary method) and then it will mang up the lanimations and make the surface uneven.....
Yes, I'd get a 40 mm or thereabouts thick piece of granite, put rubber underneath to stop it sliding about.

A sheet of perspex will get manged up in no time with grit particles. Plus its soft and bendy so will rely on whatever you rest it on for a support.
If I was to use the scare sharp method, I would get a piece of granite worktop from a kitchen fitter.
I suspect if you make up a lanimmated wooden base, it will soak up water (lube from from the scary method) and then it will eventually mang up the lanimations and make the surface uneven.....
I'd get a 40 mm or thereabouts thick piece of granite worktop or a tomb stone, put rubber feet underneath to stop it sliding about.

Recommend 6mm laminated or better still 6mm toughened which you will have to order and wait for. (All glass is float these days).

Toughened glass is NOT flat, the way it is manufactured means that it goes bendy-even though the bends are slight-but enough to ruin the notion of flatness, which is after all the whole point of the scare sharp method...

Fair comment, I wasn't aware of that but it makes sense as it goes through a heat treatment process to toughen it.

I wasnt trying to be awkward, but wouldnt want anyone to think toughened glass was the ideal. The other weakness with toughened glass is (paradoxically) it is actually quite fragile. If you tap it on the edge, even slightly-BANG and your sheet has gone...LOL

 

[powertools]

I use a polished granite worktop saver from Sainsburys £14 I think I also use it to sand small bits of wood on.

 

[AndyT]

Use a mirror - you can see that it is flat - if it wasn't you'd get a fairground. style distortion. I got mine out of a skip from a department store that was being refitted.