Any paint / spraying gurus ?

[Arfa Daily]

I'm looking at the possibility of making some seating booths to go into our burger joint. My construction material of choice is always MDF, as it's easily cut and shaped. I will need to get a highly durable gloss finish on the exposed bits, so was thinking that some kind of spray-gunned finish would be in order. So I'm guessing that first, I'm going to need to get a couple of good coats of some kind of primer / undercoat on to seal the MDF, and then give this a flatting down with a finishing sander so that I have a nice sealed and smooth surface to get a top coat on.

The question is, what to use as a top coat ? I was thinking that maybe some kind of car paint would get a good finish, maybe topped off with one of the clear-coats that get used on cars to create a hard durable finish. Any experts got any thoughts on this ? What would be needed as the undercoat etc ?

Arfa

[Tim Watts]

On Saturday 26 January 2013 14:56 Arfa Daily wrote in uk.d-i-y:

Regarding the car paint idea - I'm wondering how that would stand up to teh necessary cleaning? At least if its modern car paint and not cellulose based.

I have a friend who makes bespoke kitchens (too expensive for me!). He has the carcasses sprayed with primer and undercoat, then the top coat is applied by brush after installation.

Would something like Rustins Bar Top be compatible with another underlying paint? And would it be clear enough. It is claimed to be damn tough but it's not normally applied over paint.

[Ericp]

Dont think paint will do much service with bodies sliding in and out of the thing. You will be continually painting it.

Some sort of hard finish sheeting like formica would be my bet.

[polygonum]

Some car body shops have a sideline doing this sort of work. IMHO the preparation, choice of paints, understanding of technique, etc. is too great an effort for one job.

I can give a sort-of recommendation - that is a company whose computer systems I used to support! They are based in Milton Keynes and do some very fancy in situ work.

non-auto work does not seem to be on the site - wondering if they trade under another name for that? Would be same contact details.

[Steve Firth]

"Arfa Daily" wrote: [snip]

May I put in a word for WBP at this point? It's stronger than MDF and has the advantage to my mind that you can get good paint finishes on it.

Made several internal boat fittings in WBP ply that was saturated in epoxy before getting a final coat. This lets you get a mirror finish, if you want and the epoxy is a good substrate for a range of paints. It's not cheap, but I had several people admire the finish.

I used two-pack polyurethane top coats, mostly bought from international paints. This can be sprayed but needs protective equipment including air masks. The polyurethane paint can cause severe allergic responses, dermatitis and respiratory problems. It's safe to apply by brush, but I found the best finishes were obtained using foam brushes. No brush marks and about as good a finish as spraying.

MDF and paint to me is always a bit of a headache. Some primer doesn't stick because of release coats on the MDF surface. Although I've never had a problem with acrylic primer.

Acrylic car top coat would seem to be a good choice, it works well with acrylic primer and it sprays well in my experience. As you say a clear top coat would improve durability. I'd be tempted to use a two pack polyurethane varnish applied with a foam brush.

[tony sayer]

Not to certain but there is a type of Car paint, Two pack or part IIRC that is rather dangerous to use if your DIY'ing whereas the olde cellulose is much simpler and less iffy.

If you have a few to do compressor and spray gun, it'll always come in handy of course;!)...

I used to use one for car spraying many years ago, and got rather decent finishes after a bit of practice..

[John Rumm]

You could spray it with an acrylic paint - use it as undercoat as well (I am assuming you want a fairly bold saturated colour here). For a really durable finish, perhaps a coat of West Systems epoxy rollered on?

[Steve Firth]

John Rumm wrote: [snip]

A good idea, but bear in mind that epoxy darkens in sunlight will rapidly progress through brown to treacle. Epoxy should always be finished with a two-pack polyurethane paint or varnish which will prevent UV from reaching the epoxy beneath.

[The Natural Philosopher]

Right. The answer to this is to bite the bullet and wander down a car spray booth.

A modern 2-pack is what you want, but its dangerous to spray except with masks, in a booth.

Now if you spray whatever they say as primer and do the hard work of rubbing down, it wont be TOO expensive.

But it wont be cheap.

[John Rumm]

IIRC West Systems do one designed for boat finishing that stays nice and clear...

[Windmill]

I've noticed that. Presumably the UV also weakens the epoxy?

[Steve Firth]

That would be an ecumenical question.

I've not yet experienced any failures on the stuff I've epoxied. Nor have I seen any evidence of weakening and failure of the epoxy. But I always UV proof the job.

[Dave Plowman (News)]

Most modern car paints are water based and require baking in an oven. You can still get two pack and cellulose, though.

I had the old Rover resprayed several years ago (plain black) and that was is water based. Which seems to be lasting very well.

[polygonum]

Most modern car paints, including those used in re-finish, are indeed water-based. However, a full oven bake is not always required. The evidence for this is in the number of "driveway repairs" of various types now available.

[Andy Dingley]

Formica! Go 1960s, find some Practical Householder back issues and let you= rself go. Looks good, looks retro, not hard to do. With modern tools (Evost= ik Timebond, not 528, and a router for trimming, it's even easier to do it)= .

Also look at Valchromat, rather than plain MDF. It's MDF, with extra resin= and pre-coloured. Edges rout cleanly and you can finish it with just a va= rnish (wax for ddomestics, but commercially I'd PU it with a gel varnish). = It's just that bit tougher against edge knocks than standard MDF.

[Dave Plowman (News)]

It would take several days to dry without the oven. And keeping it dust free on the drive might prove difficult?

Don't think aerosols use water based stuff.

Cellulose is still the easiest stuff to use at home with a decent spray set. But is pretty expensive.

[polygonum]

They keep it sufficiently wind, rain and dust free by assembling a tent-like structure around the vehicle. Not sure exactly what they do regards heating, etc. Hot air? IR?

[John Rumm]

Some that I have seen erect a small (6" square) radiant panel close to the finished repair and bake it that way.

[Tim Lamb]

In message , Arfa Daily writes

There are a few basics concerning moisture and oil droplets in your compressed air source which I have long forgotten. Cellulose was a bit unforgiving if used on a humid day without air drying tackle.

Water based stuff must be a totally different ball game:-)

[Adam Aglionby]

Valchromat looks fascinating, for areas that aren`t getting directly sat on , car wrapping films, long way from the Fablon sticky back plastics of old.

Cheers Adam