Can I use caulk on a metal garage door?

[phatboy]

Hi,

I a re-painting a Henderson galvanised garage door from the mid 80s.

The paint was generally pretty loose, so after 12 hours scraping and a few spots of Nitromorse, it's basically completely bare and rust free.

Where the main metal sheet meets the vertical end pieces, there is some gaps. Can I prime the door (Zinsser Bulls Eye 1-2-3 seems the best bet), and then use ordinary caulk to fill these gaps?

Then for top-coating in Anthracite, I am going to use car paint (It's £20 vs £75 for Dulux MetalShield!), mixed to be rollable.

If anyone has any recommendations on anything I've written please do tell, I've never dealt with painting metal before!

Thanks
Tim

 

[Burnerman]

I'd consider using a silicone rather than caulk, purely for weather resistance and the ability to absorb some movement......if you actually need any filler at all?
Choose a primer suitable for galvanised surfaces before you top coat.
John

 

[Nige F]

Fair play to you phatboy I just leave random shaped patches where it flakes and slap u/c + gloss on As to car paint I'm not sure because it's changed so much since it was cellulose - But you may find that an agriculture supplier has brushable "plant/tractor enamel"- worth a look - small roller for the panels and a 1inch brush for the deep grooves. Apply the silicone After it's finished - paint don't like sticking to it.

 

[Burnerman]

Aye - anything but brushing cellulose or Hammerite The coach enamel could well be the answer.
John

 

[phatboy]

Thanks all,

I thought of car paint as it's obviously suitable for metals. Still unsure why it's a fraction of the cost of MetalShield!

Probably don'y really need caulk, but if it would work hiding the warping of the panel between rivets, and take only 10 minutes, I'd have done it! I'll get the silicone specialist to do it if I feel the need afterwards!

Zinsser Bullseye seems to be recommended around and about, so I'll try and get the dark tint of that as I am going so dark with the topcoat!

Thanks all!

 

[darkan9el]

I wouldn't use caulk on a metal door, maybe exterior frame sealant or a car panel glue. I painted my door with 3 coats of Crown Trade Undercoat and a top coat of Crown Trade Gloss. That was 4 years ago and still looks good today, I also have a south facing front.

 

[Blagard]

I would not use silicone at all as Nige F pointed out one issue paint does not like sticking to it, in fact some paints will react to it going wrinkly when painted over. So once you have the silicone on, any redecoration could present problems. For small gaps maybe a paintable mastic would be suitable although a caulk suitable for exterior use should be OK after any priming.

 

[opps]

Personally, I'd use zinc plumbate primer on the galvanised finish. The undercoat and gloss as normal.

I would advise against using caulk, I am not sure that it will be able to deal with the big temperature changes. I definitely would not recommend silicone, as pointed out, the paint won't adhere to it.

Try one of silicone free "silicone type" sealants, such as Puraflex 40 or Sikaflex or CT1. You may need to spot prime the sealants with waterbased undercoat, if you don't, the oil based gloss may stay tacky for weeks (literally).

 

[Tigercubrider]

Why do you need caulk at all?
I had a Henderson, any gaps are tiny and paint would fill any voids.

 

[phatboy]

Hi all,

So, the door repaint is complete! In the end I spoke to a local car paint shop, who were able to make me a better product for less cost!

I have used Selemix 10% gloss (So pretty matt), in Anthracite (RAL7016). It is 4 parts paint, 1 part hardener so is completely set and weatherproof in 2.5 hours, and 'hard dry' in 16 hours. It also goes straight onto bare galvanised steel, and requires 1 coat.

I nearly got away with 1 coat too, but the first part of the door I hadn't quite got the rhythm yet and so some of the 'dips' didn't quite get filled so I had to re-coat it.

As the colour change was so extreme, I also used a brush to push paint under the vertical edge pieces, so it looks good from all angles and completely hid the old white.

Full set of pictures, including new handle below!



All in all, pretty pleased with it, and just need to full and sand the frame before painting to match.