Help choosing durable finish for MDF

[hobbyst]

Hello All,
Firstly I wanted to say thank you all for all the info and advice. I'm new to woodworking but so far I found this forum the most useful source of information by far. <O:p<O:p

I'm gearing up to make some bookshelves for my study out of E0 MDF. The finish I'm after is semi gloss (not the really glossy mirror finish) in white. At first I thought about 2 pack polyurethane (like kitchen cabinet makers use. At some stage I'm also going to re-paint my kitchen in white, so I thought I would use the same product for everything) but
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1. it's been very difficult to find out which 2 pack polyu is used by cabinetmakers<O:p</O:p
2. I read on your forum that 2 pack ply is highly toxic and very dangerous. I've got little children and even though they are not allowed in the garage, the word toxic makes me uneasy.
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I've used Cabot's polyurethane with hardener for my floors and I'm going to use the same product for clear finish on plywood as it's durable and the finish is really nice but I'm at the loss as to what to use in white. Any word of advice? Would be much appreciated.
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BTW, I'm going to get a spay gun (I'm thinking itawa gravity W101 - good quality, easy clean up, small for my small projects and the price is reasonable)
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I spent days reading about epoxys, polyurethanes, autopaints, boatpaints and I'm really confused now.
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I would really appreciate some advice.
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cheers<O:p</O:p
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Magda<O:p</O:p

[Master Splinter]

If you are coating the MDF all over in a film-forming finish like poly, there's no reason to go to the expense of an E0 MDF - it's not like formaldehyde is a particularly nasty chemical, it's produced by your body and some people naturally exhale more formaldehyde in their breath than OHAS guidelines permit in the air anyway. It's also released by plants.

The industrial polys are generally something from Mirotone or similar not-found-in-hardware-store brands.

Unless specified otherwise by the manufacturer, these industrial two pack polys should only be sprayed in a proper spray booth with forced air breathing equipment and all-over suit (ie not just a simple filter mask).

Once set, poly - like epoxy and other finishes - is basically harmless. It's the isocyanates in the uncured resin that are the problem, but once cured they are no longer bioavailable.

Probably the easiest poly finish is Minwax wipe on poly. Doesn't require you to learn how to put on an even spray coat.

If you are dead keen on a spray finish, car paints can work well without needing as much equipment as poly.

[hobbyst]

Thank you so much for the info. I won't be using 2 pack poly after all. I don't want my kitchen to outlive me but I'm keen on spray painting though. I found some Higard Clear Lacquer from HiChem. It comes in a range of gloss levels. I'll give them a call tomorrow to see what they recommend for using as a white base coat.
I looked at the wipe on poly and this brand has heaps of really interesting products. Thank you for this.
Much appreciate your help.
cheers
Magda

[GSRocket]

Lightly sand the waxy factory finish off the MDF and coat with thinned out epoxy resin.
Boat builders will frown on thinning epoxy but for MDF it really works.
After it's dried, another sand.
I then wipe on with a rag another coat or two of epoxy with no thinners.
For big areas use a foam roller and then wipe.
This finish is quite attractive left as it is, if you want a dark walnut finish,
but you can paint it with what ever you want.
The MDF will be very hard, waterproof and durable,
I will go as far as saying that it will look as good if not better than many "professional" finishes.

[Cliff Rogers]

Our kitchen was done with something called 'acid etch' & it is applied by spray like a car paint.

I didn't do it, the cabinet maker didn't even do it, he sent it to a place in Cairns to be done.

[Vernonv]

Our kitchen was done with something called 'acid etch' & it is applied by spray like a car paint.

That could have been an etch primer he was referring to (often used when painting bare non-ferrous metal) and then coated with "normal" paints ... I'm not aware of any acid etch paints per se (but then again maybe I've just never seen them).

[Cliff Rogers]

I'll have to ask.

[Vernonv]

Actually after a bit more searching I found some "acid cure 2 pack" paint. Looking at this brochure, it could be a likely candidate.

[Cliff Rogers]

Acid cure, acid etch.... maybe I spilled beer on where I wrote it down.

[hobbyst]

Vernonv, thank you for the brochure. I had a look at it and it looks exactly like what I was after.
I also spoke to HiChem helpdesk and they recommended MDF sealer followed by 2 pack Iso-free finish. But the finish only comes in one gloss level (I assume 'outstanding gloss' means very glossy...). Has anyone used these product before and if so were they any good?
cheers
Magda

[Vernonv]

HiChem have a "universal flattening base" that they say can be used with their iso-free 2 pack (plus others paint types) ... see here.

[hobbyst]

Thanks for this. After days of reading brochures on their products, I still missed this one...
cheers
M