734 Primer is Evic’s latest development in 2K polyurethane pigmented primer for MDF substrates. In short, 734 delivers faster, easier, and higher quality finishing.
“Black-lines” are almost eliminated by this primer - outstanding sharp edge coverage is combined with excellent resistance to sand throughs, significantly reducing the number of repaints. This primer even resists sand throughs when using a hand held orbital or wide belt sander with a little care.
Sanding is easier – excellent flow and levelling is coupled with just the right amount of powdering. Less time and effort is required to produce a smooth surface ready for top coating. The right balance between ease of sanding and preventing rub-throughs has been struck, which in turn reduces nuisance sanding dust.
MDF fibres don’t tend to “fluff up” – this makes sanding routes and pockets easier, as less work is required to achieve a smooth finish. Pre-sanding the route (or edge) gives an even better result.
Gloss retention is excellent – the gloss hold out is superior to other primers, giving a higher quality of finishing, which may bring you in more business.
Technical Notes from the Field
734 is different to other primers. You will get the best results using your normal topcoat setup. e.g. a 1.4mm gravity (or 1.5mm suction) gun, 45 psi at the gun, 6 psi at the pressure pot (if using). This product also works very well with air assisted airless topcoat setups (as used by spray robots).
734 performs at its best when applied at only a moderately high film build – trust us on this one. Polyester users should take note of this – don’t spray 734 like it’s a polyester (it isn’t!).
We recommend that you spray A and B mixed ready for use (though a few users add 5% solvent). There is the option of 730B hardener (fast), or 732B (medium-slow), for varied weather conditions.
Pre-sanding MDF edges with 240 grade paper “seals” them, giving an even better result.
This primer works best when finish sanded with 400 grit paper for an excellent gloss finish.
Using a topcoat setup, 730A or 732A users should be able to learn to spray 734 fairly easily. However, if you are block stacking panels to spray edges, we recommend a flash off time of five minutes between coats. This may be slightly longer than usual, but the final result is much superior.
Polyester users (such as 750A, 766A, or 1560A) should really take note of the warning about excessive film builds. And if you are new to polyurethane primers, you will enjoy a much longer potlife of several hours, a dramatically more pleasant odour, fast tack-off times and overspray that doesn’t stay wet for a long time. The typical “cloud” of polyester sanding dust will also be greatly diminished.
