Bubbling Paintwork
Discussion
Help, your advice please.
In November, a cold month, I bought a nice shiny kit car. In June, a hot month, I'm horrified to see dozens of paint bubbles appearing. Clearly, the hot air is making something; probably air pockets expand and cause these. The car is the usual fiberglass shell originally supplied in grey gelcoat finish but I've no idea what's gone on since.
Is there a trade secret to the problem or I'm I facing a respray and bankruptcy. All advice greatly received.
In November, a cold month, I bought a nice shiny kit car. In June, a hot month, I'm horrified to see dozens of paint bubbles appearing. Clearly, the hot air is making something; probably air pockets expand and cause these. The car is the usual fiberglass shell originally supplied in grey gelcoat finish but I've no idea what's gone on since.
Is there a trade secret to the problem or I'm I facing a respray and bankruptcy. All advice greatly received.
wag said:
Help, your advice please.
In November, a cold month, I bought a nice shiny kit car. In June, a hot month, I'm horrified to see dozens of paint bubbles appearing. Clearly, the hot air is making something; probably air pockets expand and cause these. The car is the usual fiberglass shell originally supplied in grey gelcoat finish but I've no idea what's gone on since.
Is there a trade secret to the problem or I'm I facing a respray and bankruptcy. All advice greatly received.
Soundsl like a crap paint job, with possibly moisture/dirt under the paint.
Time to get it sorted properly, I'm afraid.
I've been doing a lot of extensive research into composite bodies, If the blisters are from the gel coat it's due to micro fractues from expanding air bubbles in the gel coat itself, these are remedied by letting the car see all the heat possible in our summer weather, then in the winter all the gel coat needs to be exposed, then a good self etching primer is applied to cover and seal exposed parts i.e. blistered gel coat.
If it's the paint, then it is possible that the primer/paint was put on in the winter. The gel coat would have been keyed using say wet 600grade paper, then primered with a good quality self etching primer and finally after much elbow grease it would have received the top paint or laquer coat. In any of these stages if the primer, paint or laquer was applied on a slightly damp car then the relevant layer will start to lift, crack or blister (moisture, humidity BAD!).
If a standard primer was used, then here is another problem, epoxy self etching primer is a flexible substrate which will physically bond to a plastic or resin providing a good strong base for the following coat of... etc. if this code of practice is not followed then problems will occur, generally when the paint is most stressed- in the heat of summer!
I'm afraid there are two choices, let the summer do the damage then repair these areas or again let the summer to the damage then take it back to the gel coat and get the job done properly.
I have drawn these conclusions from 20 years of experience, normally these problems arise from the addition of body kits onto cars and the owner wonders why his paint is falling of after putting it through the car wash!
Did I mention about the self etching primer?
This is just a summary of possiblilties, and the preparation needed to spray a vehicle, I have found that some of the new series on the Discovery channel can help demonstrate the work required to do a decent spray job. I would estimate at least £1000 for a professional job on a body inside and out using 2pk aclrylic from say glasurit or vibra.
Series names- hot rod series, orange county choppers, classic car restoration just to name a few.
>> Edited by dangerrous on Tuesday 22 June 15:00
If it's the paint, then it is possible that the primer/paint was put on in the winter. The gel coat would have been keyed using say wet 600grade paper, then primered with a good quality self etching primer and finally after much elbow grease it would have received the top paint or laquer coat. In any of these stages if the primer, paint or laquer was applied on a slightly damp car then the relevant layer will start to lift, crack or blister (moisture, humidity BAD!).
If a standard primer was used, then here is another problem, epoxy self etching primer is a flexible substrate which will physically bond to a plastic or resin providing a good strong base for the following coat of... etc. if this code of practice is not followed then problems will occur, generally when the paint is most stressed- in the heat of summer!
I'm afraid there are two choices, let the summer do the damage then repair these areas or again let the summer to the damage then take it back to the gel coat and get the job done properly.
I have drawn these conclusions from 20 years of experience, normally these problems arise from the addition of body kits onto cars and the owner wonders why his paint is falling of after putting it through the car wash!
Did I mention about the self etching primer?
This is just a summary of possiblilties, and the preparation needed to spray a vehicle, I have found that some of the new series on the Discovery channel can help demonstrate the work required to do a decent spray job. I would estimate at least £1000 for a professional job on a body inside and out using 2pk aclrylic from say glasurit or vibra.
Series names- hot rod series, orange county choppers, classic car restoration just to name a few.
>> Edited by dangerrous on Tuesday 22 June 15:00
When I had my JBA Falcon sprayed the guy put it in his paint booth/oven for 4 hours before he touched it. He said it would cause any moisture and air bubbles in the gel to burst. As it happened the JBA had quality mouldings and nothing happened but this guy has obviously been bitten in the past.
Steve
Steve
steve_D said:
When I had my JBA Falcon sprayed the guy put it in his paint booth/oven for 4 hours before he touched it. He said it would cause any moisture and air bubbles in the gel to burst. As it happened the JBA had quality mouldings and nothing happened but this guy has obviously been bitten in the past.
Steve
It's a good policy. I went around mine attacking the gelcoat with a hairdrier for 2 days - found all kinds of horrible trouble.
Wag, gelcoat bubbles normally apppear near moulding returns where the laminator has missed wetting out the first GRP layer into the gelcoat, these normally leave big bubbles from 5-20mm...does this sound familiar?
From what you say it sound like the bubbles are smaller and more random - I'd guess trapped moisture in the paint itself.
John S.
I had the same thing occur on a new door fitted to my tin top. The cause was contamination in the spraying gear (a friend with many years bodywork experience suggested silicon contamination). Two other cars painted at the same shop around the same time were similarly affected. Door had to be removed, stripped and repainted, luckily not at my cost.
........leave big bubbles from 5-20mm...does this sound familiar?
Thanks John. All this advice sounds spot on, I just wish I'd known about the potential problems when I looked at the car. There are a few big bubbles of this size in the middle of the bonnet so I guess the problem relates to a bit of everything that has been suggested.
Incidentally, what would happen if I tried to stick a sharp needle in to release the air? Cracks?
Thanks John. All this advice sounds spot on, I just wish I'd known about the potential problems when I looked at the car. There are a few big bubbles of this size in the middle of the bonnet so I guess the problem relates to a bit of everything that has been suggested.
Incidentally, what would happen if I tried to stick a sharp needle in to release the air? Cracks?
Wag,
Bubbles in the middle of a panel are IMHO, totally unacceptable. Time you named and shamed the manufacturer? I'd speak to the company direct, even if someone else built it.
Without sounding like a doom-monger, pinholing the bubble won't help the situation much - ultimately, the bubble has to have the gelcoat removed and the void filled. I found that polyester resin mixed with colliodal silica (which works as a thickener) was the best thing to fill these holes with. If a bodyshop suggests using ordinary polyester car bodyfiller/stopper then they don't know what they're doing - walk away!
The bubbles form between the gelcoat and the grp so if you punctured the bubble it may well sink into the hole in summer weather leaving a depression, and if left over winter possibly water could enter and expand when frozen causing gel cracks.
If you are keen to use a pin, then at the very least I'd suggest beg/stealing/borrowing a modelling mini-drill bit (say 0.5mm) used in a Dremel or similar. Good toolshops sell Microbox 20 pc. drill sets from 0.3-1.6mm at around £10. Reason being, the gelcoat over a bubble is very thin (approx. 0.5-1mm) and unsupported because of the bubble void, if it's cold when you use a pin the gelcoat will bend into the hole depression which may well crack it.
Best of luck,
John S.
>> Edited by cinqster on Sunday 27th June 00:57
Bubbles in the middle of a panel are IMHO, totally unacceptable. Time you named and shamed the manufacturer? I'd speak to the company direct, even if someone else built it.
Without sounding like a doom-monger, pinholing the bubble won't help the situation much - ultimately, the bubble has to have the gelcoat removed and the void filled. I found that polyester resin mixed with colliodal silica (which works as a thickener) was the best thing to fill these holes with. If a bodyshop suggests using ordinary polyester car bodyfiller/stopper then they don't know what they're doing - walk away!
The bubbles form between the gelcoat and the grp so if you punctured the bubble it may well sink into the hole in summer weather leaving a depression, and if left over winter possibly water could enter and expand when frozen causing gel cracks.
If you are keen to use a pin, then at the very least I'd suggest beg/stealing/borrowing a modelling mini-drill bit (say 0.5mm) used in a Dremel or similar. Good toolshops sell Microbox 20 pc. drill sets from 0.3-1.6mm at around £10. Reason being, the gelcoat over a bubble is very thin (approx. 0.5-1mm) and unsupported because of the bubble void, if it's cold when you use a pin the gelcoat will bend into the hole depression which may well crack it.
Best of luck,
John S.
>> Edited by cinqster on Sunday 27th June 00:57
Please note that polyester filler i.e. Plastic pudding is an acceptable filler for gel coat imperfections/repair. Infact it is used to repair moulds in the grp industry.
Ref: Competition car Composites by Simon McBeath
Fibreglass and composite materials by Forbes Aird
An excellent read for an indepth understanding in the composite industry
Dangerrous.
Ps it is very rare for a grp shell to be free of any imperfections (flash lines etc), although a coloured gel coat is always available it is advisable to paint the shell in an appropriate protective shield, the use of epoxy gelcoats has minimised gel coat vulnerabilities but it's still the only barrier between the atmosphere and the composite below
NEVER EVER USE CHEAP UNBRANDED MATERIALS, TOP MANUFACTURERS HAVE INVESTED HEAVILY IN GUARANTEEING YOUR PRIDE AND JOY CONTINUES TO LOOK LIKE IT HAS JUST COME OUT OF THE PAINT SHOP!!!!!!!!!
ultraviolet anyone?- the most effective natural way to breakdown plastics and basic paint pigments etc.
the sun's light spectrum is a fascinating study, it's power is not just limited to the production of solar energy
>> Edited by dangerrous on Sunday 27th June 08:59
Ref: Competition car Composites by Simon McBeath
Fibreglass and composite materials by Forbes Aird
An excellent read for an indepth understanding in the composite industry
Dangerrous.
Ps it is very rare for a grp shell to be free of any imperfections (flash lines etc), although a coloured gel coat is always available it is advisable to paint the shell in an appropriate protective shield, the use of epoxy gelcoats has minimised gel coat vulnerabilities but it's still the only barrier between the atmosphere and the composite below
NEVER EVER USE CHEAP UNBRANDED MATERIALS, TOP MANUFACTURERS HAVE INVESTED HEAVILY IN GUARANTEEING YOUR PRIDE AND JOY CONTINUES TO LOOK LIKE IT HAS JUST COME OUT OF THE PAINT SHOP!!!!!!!!!
ultraviolet anyone?- the most effective natural way to breakdown plastics and basic paint pigments etc.
the sun's light spectrum is a fascinating study, it's power is not just limited to the production of solar energy
>> Edited by dangerrous on Sunday 27th June 08:59
dangerrous said:
Please note that polyester filler i.e. Plastic pudding is an acceptable filler for gel coat imperfections/repair. Infact it is used to repair moulds in the grp industry.
Ref: Competition car Composites by Simon McBeath
Fibreglass and composite materials by Forbes Aird
>> Edited by dangerrous on Sunday 27th June 08:59
I know it's commonly used in the GRP industry (rarely on boats BTW) but I still wouldn't use it. Ever tried blending/fairing plod into GRP by sanding - the attrition rates aren't even the same.
John S.
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