Priming parts before assembly - good or bad idea?

I'd just make sure to scrape any primer off the insertion tabs or mating surfaces of plastic before gluing it... it should work fine then.. for small areas like cockpits I prime before assembly, the rest of the plane gets primed as a unit.

I never paint any parts while still on the sprue trees.
I also never prime anything unless it is necessary.

I do both—before and after—depending on the build sequence. I always prime, if for no other reason than to help find surface glitches.

Stay flexible—do what works for you. Don't do what doesn't work more than once.

Priming metal parts is important for topcoat adhesion. Some people suggest a primecoat if you have light and dark parts (as in kitbash or conversion parts) or if you plan on preshading before doing your final coat. I don't see a need to prime the plastic because of fear the top coat won't stick. If I prime I usally do it after I do the build (interiors are done as I build).   Greg

Triarius wrote:

Don't do what doesn't work more than once.

DOH!

So that's the secret!

jwb wrote:

Triarius wrote: Don't do what doesn't work more than once. DOH! So that's the secret!

Oh DRAT!!! I hate it when I blow it like that!
Okay, guys, now we have to kill him—or worse, initiate him into the MAPFMSOB…

Tom, my son paints (enamel) most of his parts while still on the sprue. That way he doesn't have to mess with tweezers or painted fingers. We don't primer the parts, just the car body gets that coat of paint usually. He brush paints as I do so we try to avoid getting paint onto the glueing surfaces. But if we do, a quick scrap with a razor blade cleans it up. Once my son cuts the parts from the sprue and cleans them up, he touches up the little missed spots of paint.

I paint after cutting from the sprue.

Whatever works... 

I think this all boils down to personal preference...Years ago when the market only had "tube glue" you used to get a horrid mess when gluing parts where the mating surfaces were painted...not to mention the mess it could make of your kit if you used to much glue.

I now have Ambroid Proweld, CA ( in various forumlas ), and have just the other day picked up Tamiya Thin Cement ( comes in a clear glass bottle with small built in brush ) though I have yet to use it as I'm restocking my diminished supplies ( since returning to the hobby ) before jumping into a kit.

A kit I had done about 3 years ago ( my one and only kit in ohh about 10 years ) I did things a little differently than how I was "taught" to do them.

I placed the parts in a sink with some Dawn and let them soak for a few minutes before rinsing and letting them dry overnight. After the parts dried over night I then "primed" everything using FLOQUIL model RR "white" primer from a spray can ( All the parts on this kit were molded in a "light gray", while not as bad as red or some other colors parts used to come molded in. ). Now in the past I had never really bothered to take these steps, I believe it helped as things went a little smoother than I ever remember them going.

I then "pre-painted" all of the parts while still on the sprue trees before doing any sub-assembly or further construction. ( This I have always done, but I may try something different with my next kit. )

Which method is best? Which ever one is best for you and gets you the results that you desire. I know one of the fellas that worked at the hobby shop recommended I "wash and prime" all my parts before final painting, as it would give the "color-coats" something to adhere too..So I tried it and will never go back.