Mixing MR MDF and Standard MDF paint difference?

[Chems]

I have a commission piece of work I'm doing and for one part of the MDF build I want to bend a bit of 6mm or 4mm if I can get it MDF around a small curve in a the design. Only the front face will be visible so no cut edges to worry about but will I be able to see the difference of the standard 4mm MDF as opposed to the rest of the MR-MDF I will be using?

I ask mainly because I only want a tiny piece and to get a small bit of 3mm MR MDF I will end up buying a lot more than I need where as I have 3mm MDF in the shop ready to go. Inless any forum members want to donate some to the cause?

 

[RobertMP]

I used some std MDF making test pieces for my kitchen refresh which was MR MDF. There is a difference at the primer stage because the std stuff needs a bit more messing about for good edges. Once the top coat is on I could see no difference.

 

[Chems]

Thanks for that robert, should be ok then. Going to be priming this time with PVA glue mixed with water 5/1 parts for the fluffy edges.

 

[BradNaylor]

There should be no discernable difference between the finish on standard MDF and that on MR MDF.

I regularly mix them on projects - frequently using standard MDF for door panels and backs where no edges are visible.

It is only on edges that the difference is plain to see.

Cheers
Brad

 

[JonnyD]

Thanks for that robert, should be ok then. Going to be priming this time with PVA glue mixed with water 5/1 parts for the fluffy edges.

I have never found the need to prime the edges with anything other than primer. If you sand well up to 240grit a few extra coats of primer is all you should need with the edges sanded well between coats.

Jon

 

[imaginarynumber]

I agree with JohnnyD.

Just use Dulux Trade acrylic. I sand first with 180 silicon carbide (Nuetral Abrasives being one of the better brands- now available from Selco- amongst others).

I prefer painting the MR as there is less grain swell and the egdes are much crisper- ie less chipping on the chamfers. The waterbased primers to tend to take (very slightly) longer to dry.

MR does vary alot from maker to maker- some use different resins in the faces. This means that the end grains varies with the inner being a different density to the outer.

 

[Richard Findley]

Hi mate,

As with most of the replys you've got, in my experience the face shouldn't show any difference. I think the key is to make sure you've got good quality MDF. I had some slatwall panels made up for me for a job and they used some cheapo rubbish wich is very tough to get a good quality finish on :evil: :evil:

Richard

 

[yo_chuci]

can i ask how your are gonna paint it...
is it brush/roller or are you spraying...
i keep looking for a HVLP spray gun to use with my compressor but can't find one that isn't a fortune (and i aint gonna use it loads so don't want to spend loads for something that'll sit in a box)
i've seen the elec ones at aldi etc but wondered if anyone had found a good gun for a compressor...

sorry for the hijack thread

 

[joiner_sim]

I'm going to be painting up the fitted wardrobes I'm currently doing.... A little worried now about the fluffy edges that might appear on the ends!!!! :roll: