Prime before dimple?

Anyone have any issues of priming the parts before dimpling? Wondering if anyone has done it and the result of priming first. Paint stays on? scratches?

Thank in advance

I have been priming before dimpling on my RV-7. Here's why: Those dimples will absolutely eat a scotchbrite pad!

My first priming session, I dimpled before priming, and I burned through seveal scotchbrite pads on the back side of the dimples. So, I decided to try it without, and I haven't had any issues with the dimpling, or parts fitting together. Priming prep-work is SO much faster without working around and in all the dimples, and extends your scotchbrite pad life by a good margin.

The only downside, if you are not using a good primer, you have to be pretty careful when you dimple, so you don't scratch up your new primer moving the parts around to dimple. I am using AKZO and this stuff is tough as nails, and very hard to scratch, so it makes working with parts really easy after priming.

The actual process of dimpling hasn't changed for me. I do have to ream an occasional hole every now and then, where the primer has collected in the hole, but its only happened less than a dozen times overall. The dimple die still sets a very nice and clean dimple, and the dimpled parts still fit together nice and tight. AKZO will withstand being dimpled and not flake off as well.

I'll do my whole plane like this from now on You can check my build log in my signature if you'd like to see photos of it. I have a whole category on priming alone....just did a few parts tonight actually.

I've tried both ways and either will work. If you have poor primer surface adhesion, or your film thickness is too great, the primer may lift at the dimple. With a good primer (even a good single pack zinc rich etch rattle can) and good surface prep this will not be a problem. For my large fuselage sheets I had to edge finish and prime everything before the winter, so I did, and later match drilled and dimpled with good success. The mistake I made was pre-fabricating and priming many of the small angle components. For the RV-7 a lot of these simply don't seem to fit or require small adjustments later on. Thus you are better off priming these in small batches with a good etch rattle can later.
Tom.

Whatever floats your boat...

I Prime After everything is done. So After dimpling. Yes it's a bit more prep work but I can tell better f the dimples are good with light reflection. After priming that is no longt possible. Thus for now I prime after dimpling. Just on mans opinion.

My process is de-burr edges and holes,scuff with a scotchbright pad, wipe off the dust, dimple, then clean with acetone and prime. I'm only using a rattle can self etching primer and have had no problems with flaking or having it come off unless I scratch it pretty good. I still feel like an airplane building rookie, but it has worked out well so far.

I'm dimpling after priming. Like Cubed Root, I find that dimples really eat a Scotchbrite pad. It's also a little tougher to make sure the oxidation is removed from each dimple.

Using Stewart Systems EkoPoxy with very good results.

Fred

Scuff before, prime after.

Yeah the eat a scotchbrite pad, but I scuffed, cleaned, dimpled, cleaned and primed. Just a little different order and the dimples can be easily scuffed and primed.

YMMV

Process

BillL said:

Yeah the eat a scotchbrite pad, but I scuffed, cleaned, dimpled, cleaned and primed. Just a little different order and the dimples can be easily scuffed and primed.

YMMV

Click to expand...

That's how I do it with a slight variation.
Wipe with lacquer thinner, scuff, dimple, wash (Bon Ami and grey scotchbrite) prime.