reasons flaking paint on steel beam indoors and solution?

Question

reasons flaking paint on steel beam indoors and solution?

Answer 1

If you put an alkyd over a galvanized surface you will have problems.



The zinc from the galvanization process reacts poorly with the alkyd resins resulting in saponification (a slick soap like layer) that results in poor adhesion. Prime with an acrylic primer first, then use your preferred topcoat, or as other answerers have correctly stated use a DTM and accomplish both tasks in one.



Cheers!

Answer 2

1

Answer 3

Flaking could be caused by:

1. Wrong paint originally used.

2. Beam wrongly prepared before painting.

3. Damp.

4. Age.

5. Excessive heat applied over time.

6. Chemical reaction with something that's come into contact with the paint.

7. Something I haven't thought of.



Remove flaking paint with a wire brush and/or sandpaper. If steel beam is bare steel, apply primer to prevent rusting and re-paint with suitable paint. If steel beam is rusty, remove rust before applying primer. If beam is already nicely painted or coated underneath the flaking paint, just clean and then paint on top of that surface.



Edit: I specified red oxide primer in my answer before, but it sounds like this might not always be suitable or appropriate. Sorry about that.

Answer 4

If there is a glossy paint under the peeling paint, then the prep did not include roughing up the surface of a previous gloss finish. If the paint is peeling down to the bare steel, then the steel may not have been properly primed before the paint was applied.



Solution. Mechanical removal of loose paint. Sanding, scraping, and sand blasting are all options for removing loose paint. Sand or sandblast to a rougher finish any gloss finish on remaining paint. Apply primer to any bare metal surfaces or painted areas where there are scratches down to the metal. Finish with two coats of paint compatible with the type of primer you use. As a rule, I prefer an oil based paint for any difficult to adhere situation.

Answer 5

You do not say what kind of paint. if it is emulsion, it will not ' key ' to metal.



If painting steel anywhere, it needs to be primed with a proper metal primer. Ordinary primer as used on wood will not 'key' to the metal.



Strip off the paint, then rub down well with a ' wet and dry ' paper ( as used by car body painters ) then apply a special metal / zinc based primer bought from your local trade supplier. Undercoat then enamel.



Trade store would give advice. Good Luck !

Answer 6

My guess is that the paint is of the wrong type.the bond may be compromised and will not expand or contract with the metal beam,there are paints that you can buy for the purpose,you will have to scrape down the beam.However internal metal beams are usually box section units that can be plastered over such as cat nic then be painted,with conventional finishes.

Answer 7

Poor surface preparation. Beams should be stripped of all old paint, rust, grease or oil, etc and then primed and painted.

Answer 8

Bad prep and wrong paint.Use oil based primer after you clean and prep it and paint with DTM direct to metal paint.

Answer 9

musician is spot on with his remark below. get the correct metal primer and then the paint. hammerite do a very good wide variety.