Paint and caulk questions

[doddmoore]

SO, after talking with you all here and on the FB page I have decided I am going to paint my aluminum panels gray where they face the engine bay. I'm not going with Powder coating for many reasons, none of which matter right now. John mentioned I should think about the caulk I was going to use and would it stick to the paint. Fellas, I make cookies for a living so the adhesive properties of certain caulk to varying substrates is NOT in my wheelhouse.
Stats:
I am going to use Sharkhide on the inside of the panels that don't face the engine compartment.
I would like a gray color to help show oil and such.
I know the F panels as well as the footbox panels will need to be painted on the engine side. The rest that are under carpet will get treated but not painted most likely.

What say you?

[Gumball]

I used body seam sealer by 3M on my panels, instead of caulk. It's designed to be painted over, where as silicone is not very paint friendly. I didn't paint my panels, but don't like to use silicone around my shop, as it can contaminate other surfaces that are awaiting paint.

[KDubU]

I used black silicone and painted my aluminum black. It worked fine no problem, just don’t apply to much.

[phileas_fogg]

I used clear GE silicone caulk between panels (like the manual suggests) and for small gaps at the corner intersections, and 3M Dynatron Seam Sealer (https://smile.amazon.com/gp/product/B005RNFBMC/ref=oh_aui_search_detailpage?ie=UTF8&psc=1) for larger gaps like at the lower inside edge of the right side foot box where it meets the 4" tube. On those larger gaps I also fabricated small angled filler panels out of aluminum to give the caulk some structure to which to adhere.

Whatever the sealant, use painter's tape to keep the stuff from getting all over. Before the sealant cures, lift the painter's tape to get a defined edge.


John

[Mark Reynolds]

Bigger issue is getting the paint to stick to the aluminum. That requires a special surface prep or at least some self etching primer made for aluminum. If you want a silver gray color then after drilling and fitting all panels and discarding the ones you don't use and skipping the dash recommend taking to a local metal finisher and have them type 2 anodized with minimum etch. Then they will be corrrosion proof and you will not need to apply sharkhide to the other side.
Recommend Bostik adhesive for final installation.
https://www.breezeautomotive.com/shop/bostik-1100-urethane-adhesive-sealant-gray/

[Avalanche325]

As Mark mentions, paint and aluminum don't mix without special primers.
There is really no need to do anything to any panel that you don't see. Sharkhide is expensive and not overly fun to apply. I polished my engine bay panels and Sharkhided them. I didn't do anything to the other panels.
You really shouldn't see any of the sealant. More is not better.

[phileas_fogg]

My process for painting panels is to sand with 80 or 100 grit (whatever is on hand), wipe with acetone, and then I use Pre-Kote (http://www.aircraftspruce.com/catalog/cspages/prekotesurface.php?clickkey=7243). A couple of coats of Rustoleum Hammer Tone in the color / temperature I want, and I'm done. To prep all your aluminum panels, you'll need at least a gallon of Pre-Kote.


John