Dealing with recurring hairline cracks

[markjg123]

sounds like solid brick. I’d gouge it out and fill it with this :
https://www.halfords.com/motoring/paints-and-body-repair/fillers-and-preparation/davids-isopon-p38-easy-sand-250ml-711663.html?istCompanyId=b8708c57-7a02-4cf6-b2c0-dc36b54a327e&istFeedId=367c5610-f937-4c81-8609-f84582324cd6&istItemId=xxpmqw&istBid=t&_$ja=tsidcid:14882035628|agid:126020935177|tidla-329100326289|crid:550463621677|nw:u|rnd:10044943866939411236|dvc:m|adpmtloc:9045402&gclid=EAIaIQobChMI1ez1t9CW9QIVGKd3Ch0pjQRyEAQYAyABEgKqk_D_BwE

Do you mean gouge out all of the plaster down to the brick along the full length of the crack? Then fill with car body filler, sand back flush and paint over with the emulsion?

 

[markjg123]

Might the radiator have been put back on too soon after the wall was skimmed?

This is a possibility. I can't recall when the radiator was put on that wall. It wasn't always on that wall.

 

[Harry Bloomfield]

This is a possibility. I can't recall when the radiator was put on that wall. It wasn't always on that wall.

I meant the heat turned back on and drying the plaster out too quickly.

 

[Deleted member 292770]

Do you mean gouge out all of the plaster down to the brick along the full length of the crack? Then fill with car body filler, sand back flush and paint over with the emulsion?

gouge back to whatever backing plaster there is . ie cement , lime . hoover all the dust out and fill , sand and paint.
the filler shrinks as it dries so fill flush first , sand lightly and repeat the process. make sure the radaiator is off as it dries within minutes.

 

[markjg123]

I meant the heat turned back on and drying the plaster out too quickly.

In that case no, as the radiator was hung there long after the plastering was done.

 

[markjg123]

gouge back to whatever backing plaster there is . ie cement , lime . hoover all the dust out and fill , sand and paint.
the filler shrinks as it dries so fill flush first , sand lightly and repeat the process. make sure the radaiator is off as it dries within minutes.

OK thanks for the advice. Does the car filler take a coat of emulsion without any primer? Does it look different to the painted plaster in certain lighting or from certain angles?

 

[opps]

gouge back to whatever backing plaster there is . ie cement , lime . hoover all the dust out and fill , sand and paint.
the filler shrinks as it dries so fill flush first , sand lightly and repeat the process. make sure the radaiator is off as it dries within minutes.

I use a lot of two pack filler. I have never noticed it shrink... and whilst not wanting to be a pedant, it doesn't dry, it cures.

Strangely, the Halfords product description says that it has a self mixing nozzle?

 

[Deleted member 292770]

OK thanks for the advice. Does the car filler take a coat of emulsion without any primer? Does it look different to the painted plaster in certain lighting or from certain angles?

i’ve not primered it buy you could . should look uniform if you paint the whole wall

 

[opps]

When faced with minor reoccurring cracks. I rake out, brush in neat PVA. Let that dry. Then gun in Toupret Fibacryl. I flush fill with that, wait for it to shrink back and then fill with Toupret Redlite. Once that has dried, I sand it back and paint (two coats of emulsion).

It works well in over 90% of cracks that I deal with. If there is ongoing movement it will fail but may only present a very fine hairline crack, one which might be hidden by lining paper.