Priming advice....e gads
Posted: Wed Sep 05, 2007 10:32 pm
My plan: acetone - distilled water rince and light application of SherwinWilliamBGP 988 self etching primer. Gonna be a QG. This sound OK?
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Priming advice....e gads
https://www.rivetbangers.com/forums/viewtopic.php?f=27&t=2289
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Posted: Wed Sep 05, 2007 10:59 pm
First, welcome to RB! Second, I'm guessing by your user ID that you are from California...if so, I would go for more protection. If you're in one of the interior states, I'd say you're gonna be fine. I'm in Illinois, and used NAPA 7220 (same thing as SW988), and I think I've gone overboard. I've really lightened up on the primer at this point.
Posted: Wed Sep 05, 2007 11:45 pm
Ahh...the good old primer wars.
The thing is, there hasn't been any extensive scientific study on how well spray can primers hold up to the elements over a period of time. I have heard of people leaving their parts outside with GBP988 for years in harsh conditions without even the hint of corrosion.
What you need to know are the facts. Spray can primers are meant to be topcoated, as they are not a sealer. They prep a surface for a top coat to be applied. With that being said, the wash primer that Van's uses on QB's isn't a sealer either!
In the end, it comes down to the environment the plane will be located at. Are you going to keep your bird in a hangar in the middle of the desert (aka no primer!) or tied down next to the pacific (aka full alodine, epoxy primer)?
Since there is a 50% chance my plane will be hangared near salt water, I primed everything with AKZO two part epoxy primer. My prep involves roughing the surface up with a maroon scotch-brite pad, acid etching with AlumiPrep, cleaning the surface with acetone, then priming with AKZO.
Also, something to think about, is so in a few year you discover some light corrosion. You can always have Corrosion-X sprayed inside to inhibit it. You gotta remember there are 1,000's of spam cans flying around with NO PRIMER AT ALL. Best thing to do is go to the local airport and look at an older plane that is in for maintenance. Look at how much corrosion is inside.
Lastly, if you do go the spray can route, here is the prep I would go for:
1) clean all parts with acetone. This is so the oils on the surface don't get embedded into the piece by step 2. (This step is optional...when I use GBP, I don't do this).
2) Rough up the surface with a scotch-brite pad. Wear gloves to keep oil off.
3) Clean all parts with acetone again to get rid of any oil and mostly dust
4) Spray away.
Good luck with your project and I hope I didn't overload you with information. Feel free to email me at mike@rvplane.com with any questions. Also, welcome to RivetBangers!
The thing is, there hasn't been any extensive scientific study on how well spray can primers hold up to the elements over a period of time. I have heard of people leaving their parts outside with GBP988 for years in harsh conditions without even the hint of corrosion.
What you need to know are the facts. Spray can primers are meant to be topcoated, as they are not a sealer. They prep a surface for a top coat to be applied. With that being said, the wash primer that Van's uses on QB's isn't a sealer either!
In the end, it comes down to the environment the plane will be located at. Are you going to keep your bird in a hangar in the middle of the desert (aka no primer!) or tied down next to the pacific (aka full alodine, epoxy primer)?
Since there is a 50% chance my plane will be hangared near salt water, I primed everything with AKZO two part epoxy primer. My prep involves roughing the surface up with a maroon scotch-brite pad, acid etching with AlumiPrep, cleaning the surface with acetone, then priming with AKZO.
Also, something to think about, is so in a few year you discover some light corrosion. You can always have Corrosion-X sprayed inside to inhibit it. You gotta remember there are 1,000's of spam cans flying around with NO PRIMER AT ALL. Best thing to do is go to the local airport and look at an older plane that is in for maintenance. Look at how much corrosion is inside.
Lastly, if you do go the spray can route, here is the prep I would go for:
1) clean all parts with acetone. This is so the oils on the surface don't get embedded into the piece by step 2. (This step is optional...when I use GBP, I don't do this).
2) Rough up the surface with a scotch-brite pad. Wear gloves to keep oil off.
3) Clean all parts with acetone again to get rid of any oil and mostly dust
4) Spray away.
Good luck with your project and I hope I didn't overload you with information. Feel free to email me at mike@rvplane.com with any questions. Also, welcome to RivetBangers!
Posted: Thu Sep 06, 2007 10:23 am
Welcome to the group! 
Posted: Thu Sep 06, 2007 1:26 pm
Welcome to the world of building. The advice above is good for sure. Talk to some local builders as well, they will all have a different opinion, but it will give you a feel for what direction builders are going in your part of the world. There are certainly environments that don't need much priming at all, then there are those that may really need it if you park outside and plan to keep your plane for a very long time.
Posted: Thu Sep 06, 2007 10:41 pm
Actually most of California is arid. Low humidity, and very little rainfall. Unless you live right on the coast. Whereabouts are you CalKid?
Posted: Fri Sep 07, 2007 3:36 pm
Chad, do you remember me whining about the humidity while setting up the tent at OSH? It's dry as heck out here! 
Despite him being on the wrong coast, Mike's got a lot of good info there.
Recently I was talking to a local builder who said he had some minor adhesion issues with his rattle can primer, but he also admitted he didn't scuff up the parts prior to spraying. So like Mike said, scuff, clean then prime, even if using rattle-can self-etching primer.
One more thing... I wouldn't bother with the distilled water rinse. Just wipe the parts down with acetone (after you've scuffed them), and you should be fine.
Welcome!
Despite him being on the wrong coast, Mike's got a lot of good info there.
Recently I was talking to a local builder who said he had some minor adhesion issues with his rattle can primer, but he also admitted he didn't scuff up the parts prior to spraying. So like Mike said, scuff, clean then prime, even if using rattle-can self-etching primer.One more thing... I wouldn't bother with the distilled water rinse. Just wipe the parts down with acetone (after you've scuffed them), and you should be fine.
Welcome!
Posted: Fri Sep 07, 2007 5:09 pm
I do recall that...I don't think that was the only time, however...RV7Factory wrote:Chad, do you remember me whining about the humidity while setting up the tent at OSH?
It's finally somewhat dry here too!!
Temps are much better today as well! 
Posted: Fri Sep 07, 2007 7:07 pm
Wrong coast? Last time I looked at a map, I was on the right coast.RV7Factory wrote:Despite him being on the wrong coast...
Posted: Sat Sep 08, 2007 1:19 am
Don't confuse me with the facts!bullojm1 wrote:Wrong coast? Last time I looked at a map, I was on the right coast.RV7Factory wrote:Despite him being on the wrong coast...