Outer heater box refinishing
 

Anybody have any luck refinishing the fiberglass outer heater box? I media blasted it with 60 grit aluminum oxide at a distance to prevent fiber breakout, and clear coated it with Duplicolor matte clear (with UV protection), and the whole thing fish-eyed. I sanded that down with 220, then maroon scotch-brite (about 320-400), compressed air, tack clothed it, and got the same result. Its almost like the clear is not compatible with fiberglass.

Re: Outer heater box refinishing
 

I painted mine satin black and then coated it with a compatible clear coat.

But if you want that original look I wonder if a clear engine enamel might work.

Re: Outer heater box refinishing
 

Ideally i would like original finish, but at this point I'm open to all ideas. What brand of black satin did you use? I assume that adhered good?

Re: Outer heater box refinishing
 

Sanded down to 400 then cleared with activated automotive clear. Gloss was in the gun from a spray being done, so that is what was used. You can get a spray can of 2k clear for about $30 last I saw.
Edit- Post #285 in my build thread has a pic.

Re: Outer heater box refinishing
 

I had used just good ol Krylon satin on my box after just scuffing it with a red scotch brite.

Re: Outer heater box refinishing
 

I wet sand using fine sandpaper then, clear coat. Both came out real nice.
I washed the heck out of them with soap and water inside and out. Rinsed them real good with water then wet sand, freshened up the outside surface, got every nuke and cranny. Kind of like prepping paint before applying a clear coat. When done, wet sanding wash with soap and water very little soap.And then rinse real good. Make sure there very dry, I at the time had them in the very hot sun for awhile dry them good, clear coated with a automotive clear pain. I applied
a few coat as soon as the direction said, you can reapply. They look new.I was very happy with them.
Never apply paint right away after sanding , give the surface a good time to deactivate any gasses that made have been created from the standing, basically, make sure the surface is fully cured before applying the clear coat. I would what San what you have there right down to the surface. Make sure it's all off and in pretty much follow my directions.I mentioned. That how I did it.
Good luck
NGN
Nick

Re: Outer heater box refinishing
 

I'm definitely no expert, if it crinkles and alligators I sand it off and try something else until I am happy.

For my 68, I had a couple of holes in my heater box that I had to repair with epoxy filler anyway. So an original finish or look was already out of the question, it needed to be painted. I used Duplicolor satin black engine enamel followed by their engine clear coat.

I think if I had a nice heater box like yours with no damage I would try a couple different enamel clear coats to see how it reacts. It's funny how the ceramic enamels differ from regular paint in how it lays down and dries.

I would also follow Nick's advice above, particularly the rinsing and cleaning. It is amazing what gets left behind.

Re: Outer heater box refinishing
 

Over the years there have been several threads posted regarding the restoration of these fiberglass housings. I thought I had saved a step by step walk through by forum member F.A.A.benny but I can't seem to find it. He mentioned getting great results polishing the bare housing with a specific fiberglass polish called Rolite. Sometimes he would clear coat them after that and sometimes not since some people don't want them to be too shiny. Here's a thread with some good information. You could also search the forum for posts by F.A.A.benny, you may have better luck finding his restoration thread than I did. Good luck, I too like 'em when they look original an unpainted.

Re: Outer heater box refinishing
 

Thanks all for your input. For surface prep, i followed Nicks directions. Sanded the junk off with 220, then dry sand scotch brite, wet sand scotch brite, wet sand 600, double wash with TSP, triple rinse (drying in between) and let it sit out by the window for the last 2 days. The good news is it looks really good bare. Bad news is I tried again with the same Duplicolor 1K matte clear, and got the same results UGH!!!!

Im not going to lie, those boxes with the matte black look really nice, so tempting, but i think my next step is to try Dagnabbitt's suggestion and try an enamel.

If that doesn't work, i might just leave it bare, after the 600 wet sand, it looked real nice. Wish me luck!

Re: Outer heater box refinishing
 

I used this on one:
https://www.amazon.com/dp/B0082LJMC6?th=1
SprayMax 2K Glamour High Gloss Clear Coat

It is just like a 2 part automotive clear coat. There is a button on the bottom of the can that gets pressed to release the hardener into the can.

Re: Outer heater box refinishing
 

Here it is in a matte clear. https://www.amazon.com/USC-Spraymax-...xtaddt-20&th=1 It is not "just like a 2 part automotive clear coat" It is an automotive clear coat. The only negative to using this paint is what is not used will harden in the can about 24-48 hours. That time can be extended a bit by storing in the fridge.

Edit- I would suspect you are getting the results from the Duplicolor are from it being primarily oil based. The 2k Spraymax is polyurethane. Much different, plus it has a catalyst to cure. Enamel may work. But the 2k is known to work. Did you look at the results on my box?
I know i quoted Jason Banks but most of this is to help the OP. Just clarifying.

Re: Outer heater box refinishing
 

After six years they still look the same.

Re: Outer heater box refinishing
 

Tony, did you clear it after polishing it 3 times with Rolite? Any "upkeep" polishing required during the six years?

Re: Outer heater box refinishing
 

No clear. I polished the original finish because it was still a good one. That picture shows one side polished, the other hadn't been done yet.

If the case' material is the same throughout, in other terms never had an exterior finish coat? then seems to me you can blast or whatever, then polish to heart's content where original appearance is desirable.

That polish brought the original appearance back, and lasts. I've only dusted it since.

FWW, my engine bay was sprayed black nothing sacred. I was able to remove the paint from the case with lacquer thinner and a nylon brush, rinsing often to prevent damage. That said, only about 5% of the surface had paint, though it was a couple of coats:metal:.

Re: Outer heater box refinishing
 

If wet sanding with 600 grit looked really nice, how about trying car wax on a small area on the bottom?

Re: Outer heater box refinishing
 

I restored the housing I used to install factory ac in my truck by doing this:

1. I lightly sanded it with a fine sandpaper
2. I cleaned it
3. I lightly "dusted" it with napa Chassis Black paint (a satin like paint)
3. I clear coated it.

I think it looks pretty good as it is not just all black. As you can see it is nearly like the original heater box.

Re: Outer heater box refinishing
 

Just to clarify, you say you did 3 coats, and let sit over night. Did you not wipe off excess until morning, letting it sit? Or wiped off dry each coat?

Re: Outer heater box refinishing
 

So i found some matte clear enamel, and after sanding i can happily say it finally layed down smooth! Because the box is bare, the first coat soaked right in, like painting a sponge. I put 2 more coats on, and it looked marginally better. I was thinking i would need 6-8 coats to give it the amount of "depth" of clear i thought it needed. After coat 3 i started scuffing it with scotchbrite, and it sharpened right up! Nice circular pattern and it looks nice.

I did order some Rolite, and plan on trying that. My only beef with the clear is its quite light still. Very light to medium gray. The Rolite looks to darken up the case quite a bit. A few shades darker like the original and possibly matte clear over that.

Re: Outer heater box refinishing
 

Note that if you polish the matte clear it will be gloss. Defeating the purpose of the matte.

Re: Outer heater box refinishing
 

Sorry, i should clarify, i just sprayed a small area to test. The plan is to sand that back down to bare, and then apply the Rolite. I'm looking for a darker finish closer to factory, I like how Tony's came out.

Attached image is just the clear and how it looks after 3 coats scuffed up with some scotch brite. I used Duplicolor clear coat matte acrylic enamel.

Re: Outer heater box refinishing
 

I painted mine with Dupli Color Cast grey engine paint. Been probably 6 years and holding up good.

Re: Outer heater box refinishing
 

I admire you all for trying to keep the the heater boxes looking original. I removed my heater-only box in 1998 when I added a Vintage Air system. Still have the box, blower motor, and squirrel cage, and a fairly new heater core.

Sometimes I think it would have been a lot simpler to retain the factory heater and simply install an under-dash A/C system. But that's never gonna happen. In fact, I'm replacing the antique V/A unit with an Old Air system.

Don't know what the heater parts are worth, but I should probably take photos and list it all in the For Sale section.

Moderators: Kill that last sentence If I've violated a rule.

Re: Outer heater box refinishing
 

1970Tex, did you check your compressor for water or oil?

Re: Outer heater box refinishing
 

So heater box is finally back in. Rolite for the win! 3 coats is what i went with. Mine doesn't quite look as good as Tony's, i was hoping for a darker finish, but I'm somewhat happy with how it turned out. I don't know if i over sanded, but my fiberglass looks quite course. There is no mistaking it from one of those newer made in Taiwan boxes, it looks clearly original, which is what i was going for. But dang, those satin black ones still look really sweet!

Re: Outer heater box refinishing
 

Looks good. Given the new paint on the FW and fan housing, be sure your grounding lead is contacting bare metal. Especially that sheet metal screw to the firewall. My lead worked for a year and then out of the blue, quit. I waisted most of a day because I failed to check the basics first. Turned out the screw lost continuity to the FW even though it was still tight. Also, that hole in the fan housing is for a vent tube on a AC truck. There isn't much water in the area but I'd address in some way.