paint on cast iron down pipe

[calvert]

Ive just painted a cast iron down pipe using Wickes universal primer followed by Farrow &Ball eggshel. 2 days later thers are lots of little vertical cracks in the paint. Any ideas please?

 

[oldgreymouse]

First off, what was the original finish on the downpipe, these were usually painted black, sometimes white, and a few years ago, a 'bitumastic' paint was used a lot. This had a slight Tar smell and hung around for days.

If you have painted the downpipe then I am guessing you will now want to paint it again so all I would do, as it will have had a couple of days to dry off, is to use a good 100 grit paper and rub the whole pipe down again, I actually use an 80 grit sanding mesh to sand a metal downpipe, but if this is a one off job, then good quality sandpaper will do.

After cutting the existing paint back, blow out the dust from the wall mounting brackets or pipe joints, I use an old bike pump to do this, then wash the pipe down with warm water and sugar soap, allow to dry out, coffee break!!

I would then apply a coat of zinnzer 'Cover stain' which is good to cover any trace of the old bitumastic paint, or problem under paints, I add a second coat as this paint, although spirit based, dries in about an hour. If you are using Farrow & Ball, are you using their exterior eggshell? if so, do use an undercoat, then the f & b. Sorry this advice is suggesting 4 coats of paint, but if you want the job to look nice for a couple of years!!!!!

 

[joe-90]

You should have just redid it with bitumen paint.

 

[calvert]

Thanks for the reply. I never expected bitumen paint. The down pipe is only about 20 years old at a guess. That explaines why the previous 2 colours were flaking off in big lumps!