Preparing wing skin surface for self etch primer.

[Guest]

I'm going to spray the inside and outside surface of the wing skins with this "Tempo aviation self etch primer." The instructions on the rattle can only say surface must be clean. I E mailed the manufacture and thay would not reply. I have heard that I should scuff up the surface with red scotch brite, then clean with 409 house hold cleaner, then tac rag. Does anybody have a better idea or some input on this matter? Thanks Lyle

Wings
-8

[captain_john]

Well, I don't know what kind of product 409 is. Sure, I have heard of it... but I don't know what it is. I would be concerned about residues.

A simpe wash with a mild detergent and a fine (grey) scotchbrite pad is my MO. I then wipe it dry and use DuPont's 3900 or 3990 cleaner. You could also substitute laquer thinner without a problem.

This leaves a clean, oil free surface which also has been "profiled" for a coating to adhere to.

My two...

CJ

[cjensen]

here's my .02 and modus operandi:

i, too, use self etching primer in a rattle can (NAPA 7220). i scotchbrite, then wipe with a dry rag to remove larger particles, then i clean with a 50/50 mix of solvent and 99% pure isopropyl alcohol (in a spray bottle), then i wash with pure isopropyl (99%) alcohol (also in a spray bottle). this leaves the surface clean and very dry. it works great, and i have had great results with the primer.

[jim_geo]

I'm using the Sherwin Williams self etch primer. I scuff with gray Scotch Bright then wash, wipe with MEK. The process works good for me but I'm not totally sold on the primer.

[tshort]

I really like AKZO.
A little PITA with the prep / alodine, etc., but the end product is indestructible. Everything else I tried (SW, SEM, etc) scraped off really easily or could be wiped with MEK.
I recently converted Bill Murrish to AKZO and he is very happy with the results!

Thomas
-8 wings

[jim_geo]

I've done the aluma prep and alondine with zinc chromate on the HS and really like the results. For me it just comes down to not wanting to deal with all the chemical hassle. The zinc chromate also seems to resist MEK really well. I found that out while trying to clean up some over spray.

[mustang]

I always finish off any cleaning job with silicone and wax remover before priming any bare metal. This stiff will take off wax so if there are any finger prints or oily residue that you missed, it cleans it all.

I will definitely be using this stuff before painting the quickbuild components. (they are soaked in WD-40) If you have oil residue in the rivets, then you can pour gunwash laquer thinner onto the area and then blow it out with compressed air, taking the oil with it. The gunwash is the cheap and dirty solvent that eats just about everything, but for the price it is very effective. I would still use the wax remover after the gunwash however and once again blow it out of the rivet depressions.

Cheers, Pete

[mkast]

There's a product called 3812S made by Du Pont. It's fast dry enamel reducer, read the can instructions, it covers using it as a cleaning prep.
Removes just about anything, oil, grease, scotchbrite dust, Sharpie marks, ink, lite rust (on ferrous metals). I'd suggest using cotton shop towels, paper doesn't work well.

[Dan A]

lyle,
Do not! I repeat, DO NOT USE 409 cleaner on aluminum as it is caustic and will ruin your skins. As for the rattle cans of tempo, That is up to you. I would use a higher quality primer as noted in other posts.
Good luck,
Dan N742DA

[Lyle]

Thanks Guys for all of your input. For all of the internal parts, (smaller parts) I have been using the Aluma Prep, Alodine and the AKZO Epoxy primer. I have seen the pro's use it. I think it is the best way to go. But to do a good job with the Aluma Prep and Alodine, I feel you have to submerge the parts in the solution. (in a container) For the skins that is not to practical since it would take two real large containers. So for me anyway I think the self etch primer for the skins is the way to go. Yes I found out that I did not like the Tempo primer. I have been scuffing it up with gray scotch brite then lacquer thinner to clean. Then I use DPX 171 self etch primer by PPG works well. I'm sure that some of the other ideas will work just as good.

[jim_geo]

I completely get using small containers for aluma prep and alodining. When it came time to assemble some aileron hinges I decided since they hang out there in the weather it may be nice to do a very good job of surface protection. I have pretty much bagged doing much more than scotch bright and Napa Auto gray self etch primer on any of the larger parts, and at that's usually only where two or more parts join. Spars and ribs excepted, They get primer. As you can see difference in color between the aluma prep and the alodine (in the second picture) being able to completely submerge the part, even for less than two minutes, really changes the parts nicely.