I'm assuming you're new to the game. Blappers are outrageous fun cos of the awesome amount of melee damage they can churn out from their secondaries. They're actually quite complex to build cos of experimenting with different methods of mitigation as you progress. I stumbled on it by virtue of the fact that I chose an Elec/Nrg when I was a noob myself and realised the secondaries are much more impressive in dealing damage. Also, with IOs, you can actually build quite an efficient Blapper these days.
My suggestion to you is to go make one, have fun dealing with your weaknesses and maximising your strengths. Once you get an idea of how it works better, re-roll if you want to, or respec. I wouldn't bother with Boxing, Kick, Power Thrust (except for KB purposes), and I wouldn't even bother slotting them. Your aim is how to conserve end yet maximise recharge on bread-and-butter attacks like Energy Punch and Bonesmasher. And please do 3-slot BU and Aim for recharge at least!
For single-target secondaries, you can consider Elec and Nrg (I have both and I think Elec actually gives a better Blapper-slant, Thunderstrike comes ealier than Total Focus and has a aoe/kb aspect). For primaries, I'd go with personal preference. I'm still enjoying leveling my Sonic/Elec, whereas my 50 Elec/Nrg has been respec'd to focus more on the AOEs (team-oriented farming).
And yes, do post on the blaster forum, this section's more for 'accomplished' guides. =P