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Primer for the tips

RV7Ron

Well Known Member
Ok guys, I have searched the forums and cant seem to find this specific information. I would guess its out there somewhere, but bare with me as I probably ask questions that have already been answered in the vast database of VAF.

I am working on my emp tips right now. My installation strategy of choice is to rivet the tips and then glass/blend the seams into the alum with the West System. My question is on the topic of priming them (I plan to use the SW paint system). Of course, there are two materials in play here that I need to account for...the aluminum and the fiberglass tips.

Questions:

1. Do I use Alumiprep & Wash Primer on the alum (no alodine), followed by anti-corrosion epoxy primer and lastly epoxy sanding primer? Can I skip the wash primer step?
2. Is it ok if I spray all of the above on both the alum and the fiberglass or do I need to carefully mask this to keep it seperate?

I suspect I am overanalyzing this, I have read a couple of excellent writeups on installing the tips (specifically Bob Collins & Dan Checkoway) but they seem to just present this step as being understood or I totally missed it.
 
anyone? bumping this to see if anyone has any input...maybe everybody was too busy at work today? :)
 
primers

you will be ok to use an epoxy primer(sealer) to protect any aluminum and then spray on any primer surfacer (2k) to fill in bodywork and sand scratches. i don't know what products sw makes(i dont trust it by experience yrs ago.). i would suggest and use dplf from ppg first and then surfacer.

just my 2cnts, cobra1.
1 clean
2 alum prep
3 epoxy prime (no need to mask glass)cover all for good adhesion
4. surfacer
 
Epoxy

Ron,
The emp tips are gelcoated so really don't need a high build primer/surfacer the way the cowlings do. You probably will need a little glazing putty or other good sandable filler to fix a few scratches, voids, etc...

Once they're good and smooth and mounted to the emp then I would do NOTHING until you're ready to paint the airplane.

If you're ready to do final paint THEN is the time to prime and paint the entire emp at once. Modern epoxies (such as PPG DPLP, etc..) are designed to be used as wet on wet sealers. This means that you shoot the epoxy, then let it flash for approx 30 minutes and then shoot your top coats. all in one session.

If you let DP cure, you'll need to wait several days before you sand it (which must be done), then when its top coated you're only getting a mechanical bond (good, but not as good as wet on wet).
 
Also

Ron,
I just noticed your comment about using West to fair the seams. I did something like this on my '9 and wished I hadn't. I think you get a much better looking result to NOT try and fair the tips into the emp. You're going very dissimilar materials with the glass and aluminum so its really hard to make them blend together nicely. I think the best look is to just rivet them to the emp and let the aluminum LOOK like aluminum. You end up with a really nice crisp transition at the seam, plus no filler!

Your mileage may (will!) vary.

Good Luck
 
What do you guys think of riveting them on then running a small bead of proseal in the seam? Wouldn't look as nice as glass/filler but it wouldn't
crack or move around.



I'm going to be on this task soon as I waited too long to order my wings, should give me somthing to do. If there is a way to make the seam go
away, im game.
 
thanks guys

I did something like this on my '9 and wished I hadn't.

I looked at dozens and dozens of tail feathers at OSH this year. Two observations: 1. the vast majority had some kind of fairing design like mine to eliminate the rivets and seam. 2. I only seen a couple that had cracks and from my observation, it looked like they hadnt glassed the seam. For me I like the look of the blended tips...maybe its that deep, dark, secret love I have for the clean lines and aerodynamicly smooth composite airframes I guess!...there I said it! :)

I do appreciate the feedback though, although I am too far in now to change the process even if I wanted to. Who knows, I may live to regret doing it this way but thats ok I'll accept that possiblity...it is experimental after all and purely a cosmetic issue. If and when I build another one, I'm sure my prior experience will weigh heavily on maybe doing some stuff differently. I understand this first build is going to be a learning experience, thats what makes it so fun.
 
Yup

I know the too far in to change feeling. :D

Let me know what you think in a few years when you build your second one. :eek:
 
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