Finishing my MDF project plan

[Onefortheroad]

Hi,

I have a standing desk unit built with basic MDF, and I am looking to treat it to finish. The unit has a lot of exposed edges.

What I have done so far from reading is sanded down the edges and used PVA lightly diluted with part Water over the edges and joints only. I have yet to sand down the PVA edges, but what grit paper should I use?

My next step planned was to run a couple of coats of light coloured Danish Oil over it all. Lastly, i was going to apply a one coat clear gloss varnish over it for desired protective finish.

Does this sound okay?

What would you recommend Ronseal diamond hard varnish or Ronseal quick drying varnish?

Thank you very much in advance.

 

[foxhole]

Danish oil alone would protect it and provide a resistant surface, though now you have pva on it this may prevent the oil being absorbed in those areas leaving a patchy appearance.

 

[Deleted member 174758]

I have yet to sand down the PVA edges, but what grit paper should I use?

Starting with about 120 grit work up through the grits to about 240 or better 320. The finer grit won't have as much raised grain as lower grits when you apply the finish.

My next step planned was to run a couple of coats of light coloured Danish Oil over it all. Lastly, i was going to apply a one coat clear gloss varnish over it for desired protective finish.

If you are going to coat with a clear finish then I wouldn't use PVA at all. Any "overshoot" onto the flat surfaces will will telegraph through as a watermark (or that's what it can look like). Instead apply diluted sanding sealer (which is actually bleached blond shellac diluted in meths) to the edges, leave to dry, then cut back any raised grain with fine frit paper. If necessary you may need to repeat this process. I wouldn't bother with the Danish Oil. It may end up coming out blotchy on MDF (at least that's been my experience). If all you are trying to do is darken the colour that can be done more cheaply with some French polish, available in various shades. I'm also wary of applying a water-based top coat, such as Diamond Glaze, over an oil finish

What would you recommend Ronseal diamond hard varnish or Ronseal quick drying varnish?

I think that either would do

 

[Onefortheroad]

Thanks for replies.

Shame I posted too late though after applying pva. It seems that yes pva and oil don't go for the reason that it appears shiney like gloss. Luckily though I was very careful with the pva only onto the edges.

Anyways, I have two coats of the danish oil applied now and it's looking we'll. my only downfall is the colour, I picked cider which actually looked light in the example but its in fact tuned out quite dark and oaky. Too late now though as its applied. Lesson learned for future, pick a lighter colour.

 

[Onefortheroad]

What would you recommend Ronseal diamond hard varnish or Ronseal quick drying varnish?

I think that either would do

I have a problem.

After applying my oil coats, I applied two light coats of "Ronseal Diamond Hard Varnish" Satin finish - I have allowed for plenty drying time and it's been a couple of days now and it seems that the surface looks dry but isn't perfectly dry. It's still slightly sticky. For example; If I touch the surface using clean hands and apply slight pressure, sticky residue is noticeable on the hand.

Is there anything I can do? Please!!!

Thanks

 

[Deleted member 174758]

What would you recommend Ronseal diamond hard varnish or Ronseal quick drying varnish?

I think that either would do

I have a problem.

After applying my oil coats, I applied two light coats of "Ronseal Diamond Hard Varnish" Satin finish - I have allowed for plenty drying time and it's been a couple of days now and it seems that the surface looks dry but isn't perfectly dry.

First off, was the oil coating thoroughly dried? Was the finish new, not something that had been sitting on the shelf for 5 years? As I wrote in my last response I'm not keen on mixing finishes and in your quote you've missed out part of my original advice on this, namely:

I'm also wary of applying a water-based top coat, such as Diamond Glaze, over an oil finish

So I took a look at the manufacturer's web site and the back of the can says the same, "PREPARATION: Ensure all surfaces are free from wax, grease and oil by wiping with a cloth dampened with white spirit.". the manufacturer also states that brushes can be washed-out in water, indicating that this is a water-bourne finish.

So I suspect that the two finishes have reacted with each other, water over oil. Have you talked to the manufacturer's technical department about this problem? They may be able to suggest something

My feeling is that you may well have to strip the lot off (i.e. scrape, sand. white spirits) then seal the surfaces with a clear sanding sealer (check carefully, this must be a dewaxed blond shellac dissolved in methylated spirits/denatured alchohol, a sort of French polish) to seal the oil in before refinishing the surface. French polish can often be used to provide a clear/nearly clear barrier coat between different incompatible finishes and at this juncture it may be your only "Get Out of Jail" card