Wood Thickness...UK based...?

[ArcadeAddict77]

I am looking around at various cabinet plans and most quote their dimensions in fractions of an inch. Fair enough I say, being very new to woodwork I pull out my ruler and start converting inches to cm as all the wood suppliers quote sizes in mm.

So it turns out the typical sizes people seem to be using are 5/8" and 3/4".

I make these 16mm and 19mm respectively.

The standard sizes available from say B&Q or Wickes are 6, 9, 12, 18, 25mm.

So I am starting to panic. I have the UAII designs printed out so I have some hope of making this thing, but it appears I cannot buy the right thickness of MDF.

Can anyone say what they have used / done to resolve this? Or perhaps a supplier which is able to source 16mm and/or 19mm 4' x 8' MDF sheets?

Hopefully this is just a panic attack and the answer will present itself when I come back to rational state of mind. 

Thank you for any assistance in advance!

[Octo]

If 18mm is what's readily available, use it and tweak the plans a little. It's only 1mm difference, so it won't be noticeable for the most part. Your side panels will be the same, and the horizontal pieces just need to be 2mm wider.

[Blanka]

It's just a panic attack.
Use 18mm for the 3/4 and 15 mm for the 5/8 panels. They are about the same. The European sheets are a tad thicker than advertised, and the US ones a tad thinner than advertised, so it's roughly the same. And not to forget that glue and moist/heat working can give more difference than this.
Even the sheet sizes are like foot-measurements here. 1220x2440 is very similar to 4x8 feet.

[ArcadeAddict77]

Thank you both for your swift replies. The 18mm is readily available, I may have to hunt for the 15mm; but your quite right 1mm is no difference.

I was worrying about the t-molding, but with such little difference in thickness it won't be noticable on the final product.

Thanks again! 

[Octo]

Yep, 3/4" T-molding on an 18mm panel will overhang about 2 hundredths of an inch. I'd bet most people accidentally cut their slot this far away, so not to worry.

[ArcadeAddict77]

For completeness:

I have just found a couple of products which Travis Perkins can supply, although I guess most local stores may not hold them in stock.

MDF STANDARD 15X2440X1220MM (856420) - £17.22 + VAT (Sales Tax)
   
MDF MOISTURE RESISTANT 15X2440X1220MM (862663) - £22.00 + VAT (Sales Tax)

Does anyone believe there is any benefit in paying extra for the moisture resistant option? Considering I will be coating the MDF with a PVC glue / water mixture, priming and then painting?

[Rusty Shackelford]

I asked this same question a few months ago when looking for wood. Use 18mm MDF for 3/4. You can live with the small tmoulding over hang or trim it with a very sharp knife/chisel.

A good tip for converting inches into mm is to type it in words into google i.e.
3/4 inch into millimeters. Alot of time saved with the ruler!

A tip if buying from Wickes: the bigger the sheet the cheaper the price!

[Octo]

The moisture resistant MDF will still swell if drenched, but it reduces back to near its original size. I would say the only part that will come in contact with constant moisture is the CP, due to drinks and sweaty hands, and that can be covered with a cheap sheet of 1/8" plexi. If it's the base you're worried about getting wet, I'd put levelers on each corner, to hold it above any possible flooding. If you get enough water in your house to get above the levelers, then you have bigger problems than a moist cab.