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Reasons for Paint Bubbling on Exterior Door?


(DavidJ) #1

Hello, not sure if this is the right place for troubleshooting, but wondering if anyone could offer me some advice?

I dropped in on an old customer yesterday, and during our conversation they mentioned blistering on their front door I’d painted earlier in the year. They were good about it, and despite it wanted me to quote for their bedrooms, but it’s still something I need to remedy to maintain their confidence.

This door is not in direct sunlight, and strangely the bubbling is only present on the lower half of the door. I’ve often thought it should be due to not dusting off properly before painting, hence the paint doesn’t stick, but I’m pretty diligent about this.

I used F&B water-based undercoat underneath Dulux tinted gloss. I know this probably isn’t ideal, but the customer’s wife changed her mind halfway through and bought the paint fait accomplit…

I’m thinking cut out the blisters, sand/dust, maybe Zinsser, level with 2-pack if necessary, then repaint the whole door…

If I sound uncertain, it’s because I am a relatively young decorator (5 years) and work on my own, so don’t have many people to bounce ideas off.

Grateful for any pointers, especially how to avoid in future.

As a last point, I have had blistering on black paint in direct sun before, but my guess is this combination is just asking for trouble? I prepped the bejesus out of that one too…


(Andy Crichton) #2

Hi David, thanks for posting your question. Bubbles in recent paintwork, all been there, aren’t great are they!

Personally I would carefully cut out the bubbles first and check why they let go. If you look at the back of the paint chip, is it dusty? Or is there a knot where the paint bubbled? Or any other surface defect? Maybe the original paint let go and took the new paint with it?.

You may not have any joy being detective, moisture and heat don’t go well and you cant see them, but you ant to try to get to the bottom of it so as to avoid a repeat.

I wouldnt try and make good the damaged paint, rather take it back to bare in complete sections and start again. Use a microporous paint system, look at Sikkens and finish with AZ or super shiny XD. Don’t mix and match paints either. F&B undercoat is designed apparently for F&B hybrid topcoats, so who knows if they are compatible with Dulux oil? gloss.

Good luck. If you have any photos they can be posted from the Quick Reply section if they are online in Picassa or Flickr or other service. To attach photos on your computer reply using the “Quote” option and there are 3 attachment buttons at the bottom you can use. The max is 2MB per photo but any size will fit.


(DavidJ) #3

[quote]Quote from Andy Crichton on November 30, 2012, 01:30
Hi David, thanks for posting your question. Bubbles in recent paintwork, all been there, aren’t great are they!

Personally I would carefully cut out the bubbles first and check why they let go. If you look at the back of the paint chip, is it dusty? Or is there a knot where the paint bubbled? Or any other surface defect? Maybe the original paint let go and took the new paint with it?.

You may not have any joy being detective, moisture and heat don’t go well and you cant see them, but you ant to try to get to the bottom of it so as to avoid a repeat.

I wouldnt try and make good the damaged paint, rather take it back to bare in complete sections and start again. Use a microporous paint system, look at Sikkens and finish with AZ or super shiny XD. Don’t mix and match paints either. F&B undercoat is designed apparently for F&B hybrid topcoats, so who knows if they are compatible with Dulux oil? gloss.

Good luck. If you have any photos they can be posted from the Quick Reply section if they are online in Picassa or Flickr or other service. To attach photos on your computer reply using the “Quote” option and there are 3 attachment buttons at the bottom you can use. The max is 2MB per photo but any size will fit.[/quote]

Andy thanks for your advice. I understand it makes sense to just treat discrete sections rather than the whole door, but I have a couple of queries as to how to go about it neatly:

  1. How to strip back the paint to bare? I don’t normally do this, but when I do I use a heat gun, if possible. Never used Nitromors, but understand it is messy. I’m guessing a heat gun would be neatest.

  2. If I go back to my customer and say “well, I’ve done some research and it could be x, y or z, but anyway it might be best to proceed with matching paints this time and I hear Sikkens is great stuff”.
    Two problems: a) I’ll have to get the paint colour-matched (their garage door is in the same colour) and being Eeyore about it, surely it would be best to repaint the whole door rather than risk a slight colour mismatch?
    b) Cost. Again - and I’m genuinely curious here - would you bill the customer for replacement paint (since they supplied it in the first place), pay for it yourself (ouch) or offer 50/50? ** since typing this I’ve seen that the Sikkens paint is only £15/litre - I’d assumed much worse! - so I guess that’s not too much to eat.

I’ve kind of answered my own questions here, but I’m still interested in whether to strip and repaint the whole door if I’m using different paint. I guess I could buy the matched paint and paint up a piece of scrap wood and see how closely it matches…

Thanks again for your help Andy, it’s good to have a brain to pick.


(DavidJ) #4

File was too big…


(Andy Crichton) #5

hi David

a heat gun, as in hot air gun, is safer and easier to control than a naked flame, but that depends on where you are burning off and windy conditions, as you may disturb the good paint adjacent. Matt Evans uses an infra red stripper that is more controlled.

Chemical Stripper - Nitromors is one of those products you want to disappear off the market forever.

If the paint is still soft, you may be able to get a carbide scraper and get it off. Then good sanding with a detail sander.

If stripper needed, better an eco friendly stripper. I will ask Russ Pike nicely and hopefully he will explain about Fluxaf products for stripping paint.

I am not suggesting you only re-paint the repairs! Repair the defective areas and repaint the whole door per the spec of the paint you decide on.

Unless the client has wilfully damaged your door, or you are working to someone else’s spec, or it is a materials failure, I would say the correct thing to do is to repair and leave it looking sheeny shiny and don’t leave an invoice for the client. Just say you have dealt with it, you are all square and any problems give me a call.

If you think it is a materials failure, you can always ask a rep to take a look. But this is where using one company undercoat and another’s top coat leaves you with no leg to stand on. Which is where experience and confidence in your specs comes into play when specifying a system. Being a painter is not always easy is it!!!

But a front door failure isn’t the end of the world for you, and solve it right and the client will rightly remember you went out on a limb to help them, without any drama.


(DavidJ) #6

Hi Andy, right that makes more sense, just take the damaged parts back to bare but do actually repaint the whole door (durr). I think I’m spending far too much time on my own and getting a bit neurotic… I doubt the paint will still be soft as I put it on a year ago. Don’t have a detail sander, but one is on my list for 2013. Heat gun it is then.

You are right, client hasn’t really done anything wrong and I think a materials failure is highly unlikely. On the plus side, the Sikkens really isn’t that dear and it will give me experience with something other than Dulux. Let’s hope I don’t have to repaint their garage door to match!

And no, being a painter isn’t always easy! But these are nice customers (clients) and are also those with the messy wallpaper/bonding problem. I’m still mulling over your advice on that one…