Rolling & Laying Off

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Hi, I am looking for help please. I am trying to paint my steel narrowboat with Dulux Trade exterior gloss. I have been using a 6" mohair roller, then laying off with a dry 4" bristle brush. The finish is coming up like sandpaper. I have noticed that when I roll the paint on it is full of air bubbles, which I then lay off with the brush. I think this may be causing the rough finish. I am not expecting perfection using domestic paint, but feel I should be able to get a better finish than I am at the moment. Any guidance would be much appreciated.

Suffolkman
 
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As a fellow narrowboater I felt I had to chip in on this one!

What prep have you done before applying the paint? It sounds like the surface might be contaminated with something (polish perhaps?). To achieve any decent kind of finish any previous paint would need to be well rubbed down and degreased/cleaned with a spirit wipe as a minimum otherwise any subsequent application will suffer.

Can't say for sure obviously but that would be my suspicion. An interesting choice of paint too! Hope you can improve on the results.
 
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Prep work is the key to getting a good and lasting finish, give a good sand, remove any rust then prime any bare metal then undercoat. Give a light sand in between coats.
 
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Prep work is the key to getting a good and lasting finish, give a good sand, remove any rust then prime any bare metal then undercoat. Give a light sand in between coats.


Thank you for both your replies, I prepared the existing paint with an orbital sander, the finish was still whole, though faded. I did not use a spirit wipe, to my knowledge the paint has never been polished. I was wondering if I should use a different roller, or possibly thin the paint before rolling. I am sure I am not the first narrowboater to have tried a domestic paint, rather than a marine type.

Badger
 
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I don't think your technique is the problem here I roll then lay off all the time with gloss.

What primer/undercoat did you use?
 
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I did not thin the paint, but am thinking of trying it next. The undercoat was a dark grey Dulux to match the gloss. I was also thinking of trying a foam roller, but was wondering if that might put in more bubbles. ??
 
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If your using dark grey u/c then i presume your glossing a black or very dark colour. These colours are the most difficult to gain a decent finish on because they show every single spec of dust. Also are you painting outside in an area easily contaminated?, this will mean dirt/dust is continuously getting into your paint film.
You may well be over rolling the paint, this can cause bubbling as does surface chemical contamination, did you de-grease first or as your going along? The nap of the roller can also cause bubbles. Thinning paint can also allieviate bubbling.

But why are you using weather shield? Specifically marine/boat paints are way better and are not affected by the VOC changes, the weathershield will not stand up to a wet/humid application for long,it does not contain the same quality resins and pigments and will be a far less tougher finish so can't help but feel your wasting your time anyway.
 
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If your using dark grey u/c then i presume your glossing a black or very dark colour. These colours are the most difficult to gain a decent finish on because they show every single spec of dust. Also are you painting outside in an area easily contaminated?, this will mean dirt/dust is continuously getting into your paint film.
You may well be over rolling the paint, this can cause bubbling as does surface chemical contamination, did you de-grease first or as your going along? The nap of the roller can also cause bubbles. Thinning paint can also allieviate bubbling.

But why are you using weather shield? Specifically marine/boat paints are way better and are not affected by the VOC changes, the weathershield will not stand up to a wet/humid application for long,it does not contain the same quality resins and pigments and will be a far less tougher finish so can't help but feel your wasting your time anyway.

Thank you for your comprehensive reply. Yes it is a dk blue finish, and I am painting outside. I realise I will not be able to achieve perfection. I am trying to cut costs I suppose, marine paints are so expensive. It is just the superstructure of the narrowboat I am doing, nothing under the waterline...really it is just an experiment. Interesting your comment on thinning the paint can cause bubbling. What type of roller would you recomend, and what cleaning (degreasing agent ) would you recomend..
Many thanks.
 
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Think you miss read my post, thinning the paint can help prevent bubbling but will mean extra coats.

I'm certain though that your bubbling is being caused by the roller, i dont use rollers for gloss but apparantly you you need to use a high density foam roller , i know that mohair will encourage bubbling, ideally you need one person applying with the roller whilst a second person lays off behind them.

Degrease with meths or brush cleaner.

There's a reason why marine paints are expensive!
 
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