Plane or sand MDF alcove shelves

greensalad

Long story short, I ordered some alcove shelves. I measured my alcoves, submitted the measurements and received some beautiful alcove shelves made exactly to my measurements… that don’t fit. I didn’t include any tolerance as I assumed they would do that for me (like every other fitted item I’ve bought where you submit exact space measurements and leave them to provide you a product that fits…)

Oh well, lesson learnt. Check if they will include a tolerance/ease for fitting first before assuming. Either way I now need to remove the merest of millimetres from these alcove shelves so I can fit them in.

My question is, do these need to be planes or could I sand? They are 38mm thick veneered MDF. I think I can sand, but am concerned about ruining the veneer. OH thinks they have to be planed down, but that means making another tool purchase and my understanding of hand planes is they need to be fine tuned and sharpened and all first… plus we already own an orbital sander.

So WWYD? Stick some masking tape on the edge of the veneer and sand away a few mm? Or invest in a plane, spend time sharpening and sanding it to make it perfect and then use that?

MikeJXE

You would be better off with a good router to take off a few mill or maybe a belt sander might do it 

DanDare999

How do you plan to reduce their size?

Cut to the smallest dimension across the alcove or scribe to fit?

greensalad

DanDare999 said:

How do you plan to reduce their size?

Cut to the smallest dimension across the alcove or scribe to fit?

Just sand or plane down the edges to remove the required mm. No scribing because the backs are already wide enough as the alcove tapers a few mm, it’s about 750 at the front and as much as 755 at the back. The shelves are exactly 750. So I only need to lose enough mms to slide them in. I was going to just take off a little on each side, concentrating on the front half of the sides, and keep sliding them in to check until they fit.

Norman_Castle

Hand planes take experience to sharpen and use properly. A poorly sharpened plane won't give the result you want.

However you do this cutting through the veneer with a sharp knife should help avoid damaging the veneer you want to keep.

DanDare999

greensalad said:

DanDare999 said:

How do you plan to reduce their size?

Cut to the smallest dimension across the alcove or scribe to fit?

Just sand or plane down the edges to remove the required mm. No scribing because the backs are already wide enough as the alcove tapers a few mm, it’s about 750 at the front and as much as 755 at the back. The shelves are exactly 750. So I only need to lose enough mms to slide them in. I was going to just take off a little on each side, concentrating on the front half of the sides, and keep sliding them in to check until they fit.

If you're not scribing then why?

How do you intend to deal with any gaps?

MikeJXE

As the reveal is tapered and depending on how many you have how about scoring the plaster work and digging a trench for them to slide in ? All you need to do then is filler for a perfect finish 

Bendy_House

Mike has two good ideas - use the safest tool, a belt sander, or set the shelf in to the wall, assuming it's plaster skim, for example.

For the first, I just tried a Facebook Marketplace for belt sanders, and there's a barely-used Bosch not too far away for £40, and probably haggleable on that. If you don't already have one, they are great tools. Used carefully, and with the shelf held securely so it cannot shudder, this would remove the required mm or so very easily.

For the latter idea, if you scribe and dig out a slot in the wall, then place a strip of masking tape on the top-end of the shelf before positioning it, fill in the slot over it, sand when dry (masking tape protects the shelf), and if you then gently run a sharp knife flat against the filled wall on to the masking strip on the shelf, you'll be able to peel away the visible masking tape neatly, leaving a hidden strip buried under the filler. That make sense?

If belting, obviously belt backwards away from the front edge in case you burst the veneer forward.

greensalad

DanDare999 said:

greensalad said:

DanDare999 said:

How do you plan to reduce their size?

Cut to the smallest dimension across the alcove or scribe to fit?

Just sand or plane down the edges to remove the required mm. No scribing because the backs are already wide enough as the alcove tapers a few mm, it’s about 750 at the front and as much as 755 at the back. The shelves are exactly 750. So I only need to lose enough mms to slide them in. I was going to just take off a little on each side, concentrating on the front half of the sides, and keep sliding them in to check until they fit.

I was going to just take off a little on each side
 If you're not scribing then why?

Because they don't fit?

DanDare999 said:

How do you intend to deal with any gaps?

Not look too closely

greensalad

MikeJXE said:

As the reveal is tapered and depending on how many you have how about scoring the plaster work and digging a trench for them to slide in ? All you need to do then is filler for a perfect finish 

I did consider that, but I need to attach the sliders to the wall so I'm a bit concerned about carving it out and it looking terrible. I think I'd rather reduce the width at the fronts instead.

greensalad

Bendy_House said:

Mike has two good ideas - use the safest tool, a belt sander, or set the shelf in to the wall, assuming it's plaster skim, for example.

For the first, I just tried a Facebook Marketplace for belt sanders, and there's a barely-used Bosch not too far away for £40, and probably haggleable on that. If you don't already have one, they are great tools. Used carefully, and with the shelf held securely so it cannot shudder, this would remove the required mm or so very easily.

For the latter idea, if you scribe and dig out a slot in the wall, then place a strip of masking tape on the top-end of the shelf before positioning it, fill in the slot over it, sand when dry (masking tape protects the shelf), and if you then gently run a sharp knife flat against the filled wall on to the masking strip on the shelf, you'll be able to peel away the visible masking tape neatly, leaving a hidden strip buried under the filler. That make sense?

If belting, obviously belt backwards away from the front edge in case you burst the veneer forward.

Thank's I've bitten the bullet and ordered a belt sander on a Black Friday deal. I had a look at secondhand, but at the moment I have no car so going to collect anything is impossible. So I've bought a cheapie Einhell one. My snobbery about high quality tools has tempered a bit recently, as I've had some good wins with cheap tools for one-off jobs. I'm still happy to spend a bit more on something that I know will get a tonne of use, but for a job like this a £35 cheap tool will probably get me there fine. What grit sandpaper should I be using on MDF? I'll do it outside obviously and wear a mask.