MDF finish on workbench

[Andrew1]

Hi i am looking for some advice on varnishing MDF that is part of a workbench.
The workbench/ tool station is constructed of CLS timber, with shelving and side panels in 12mm MDF. Shelving is under supported, so no issues with structural integrity.
The top will be 18mm ply and the CLS is also being clad in 3mm ply, to give an improved finish.

My issue is that i am looking to put a protective coat on the MDF, retaining as near to original colour as possible, as well as sealing the ply cloaking the CLS and also the same finish on the 18mm ply top. As i will dragging tools in and out of shelves and cupboards need something hard wwearing

I want to go for a hard wearing, but pleasing finish, and hence thought varnish would be best solution.

My questions are-
Can i used thinned varnish to seal, i assume has to be oil based poly
If sealers are normally waterbased, wont that cause an issue
Any better suggestions on how to finish off, but dont want coloured/ painted finish.

Appreciate all thoughts

 

[ScaredyCat]

For what it's worth, I used water based floor varnish as the finish for my wife's desk which has 18mm ply with a walnut trimmed edge. There wasn't much (I can't see much) colour change at all, but the surface is lovely. It feels strangely soft to the touch but is pretty hard (if that makes sense). It did it over a period of 2 weeks, about 10 coats in all. I like it enough to be building a work surface for myself using the same method.

.

 

[Andrew1]

Hi, thanks for coming back. I have also used waterbased varnish as i build radio controlled boats from scratch and the finish is fine. The issue is more whether it will cause problems with the MDF using water based polyurethane, but thanks for response

 

[ScaredyCat]

MDF Sealer then https://www.toolstation.com/shop/p87589. Sand (denib) after sealing then apply varnish or whatever over that. The sealer is really watery but when it tries it seals nicely.

 

[Andrew1]

Hi, thanks for that, assume either water based or oil based varnish ok after sealing

 

[worn thumbs]

I normally use sanding sealer and the first coat will almost disappear.A quick flat down and a second coat and you should be set.

 

[Andrew1]

Thanks worn thumbs, waterbased or oil varnish.

 

[worn thumbs]

Meths based!Its the only type of sanding sealer I buy.

 

[Andrew1]

Hi meant varnish

 

[grafter]

I used to finish MDF workbenches/work tables with oil based poly diluted down with white spirit and left to really soak in, then wipe the excess and apply 3/4 coats. This has for me worked great and I have a bench top/work tables that's stood up to alot of abuse.

Recently I've bought a CNC MFT made from MDF and I applied liberon superior danish oil and because it's thin in soaked in well again wiped the excess off after 20mins or so and a 320 grit between coats and layered 3/4 coats and it's worked out really well.

Personally I would avoid a water based finish on MDF.

 

[Andrew1]

Thanks Grafter, oil based poly it is