Micro blisters ggrrrr

[Burton4130]

ill get some pictures soon for inspection

[Elanintheforest]

A feature of the Carcoon and Air Chamber is that you can drive a wet car in, zip it up and put the fans on, and it will be perfectly dry withing a few hours. I can't see that this would create microblisters, and as you say, the humidity is considerably reduced in that environment, minimising the risk of microblisters forming through wicking up from the underside.

It sounds much more likely that damp was introduced into the primer / paint when the car was re-painted.

Mark

[Andy8421]

When it reaches steady state, the air inside and outside the carcoon will have the same relative humidity - so the car will end up just as damp (or dry) inside the carcoon as it would be outside.

[Grizzly]

Mark, The Carcoons we had originally were quite old so didn't have dehumidifiers and if you drove a car in wet you would get quite heavy condensation on the inside, since then we have fitted the dehumidifiers and i'd agree in that set up you can put a car in how ever you want with good results.

[denicholls2]

With that much paint that's all of different provenance on the car, I think it might be a bit unfair to place blame on the Carcoon. What you've got is an entire ecosystem gone awry.

The basic problem of Fiberglass is that it in addition to being slipperier than steel, it has deeper and broader pores to hold any moisture that is present pre-painting (or through osmosis) and use it to "boil off" paint layers put above it. But your car has both physical and chemical opportunities going on at each of many layers.

This is one reason it is generally recommended not to respray fiberglass bodies. Not that the average car has had this advice followed, of course, but you have an extreme example, and gravity is likely also in play with this much paint.

My 2-part Lagoon Blue car has a few but large (quarter-sized) blisters. But painted outdoors in Washington State, which is a rain forest. What I can say is that aside from the abrasive destruction I've added, it has been stable and spider-free for the decade I've owned it. Unfortunately, it's still a stable bad paint job, with cat prints to boot.

[Burton4130]

When it reaches steady state, the air inside and outside the carcoon will have the same relative humidity - so the car will end up just as damp (or dry) inside the carcoon as it would be outside.

I thought I would carry out a practical test this evening, so I went into the garage, which was freezing, unzipped the carcoon vent flap and stuck my hand inside... Definitely, 100% milder in the bag! Honestly.

[alan.barker]

I have had 2 cars with micro blisters, a 1973 +2S130 and a 1976 TVR 3000M.
So they were repainted as follows:
Both cars were rubbed down dry, left in a heated spray booth for several hours at LESS than 30? to dry completly.
Also between different coats left several days/ weeks to dry .
The Lotus Elan +2S130 i kept for 7 years after painting before selling and no micro blisters came back
The TVR 3000M has just been done a few weeks ago and the painting procedure took 10 Weeks. Drying in paint Booth at below 30? between coats. Time will tell if the micro blisters come back.
I know many people have different ideas how they Garage their Cars. My OWN PERSONAL CHOICE is never ever put a Cover. I am lucky to have a 80 sq mtrs garage under my House and it's dry but i still use my Anti Humidity Machine now and then to be sure it's dry.
I prefer just before i take my Cars for a run to rinse off the Dust outside in the Garden than use a Cover.
I know someone will now say i've got it all wrong there are some special perfect Covers but they're not for my Cars
Alan

[Mick6186]

The liquid in the micro blisters must be caused by condensation trapped in the bodyshell being drawn out by the conditions the car is stored in.If a cold car is put into a warm environment/carcoon then any moisture in the substrate will condense out and be trapped beneath the paint. Think of a cold glass of beer. Paint must be waterproof otherwise metal cars would rust in a week.
Mick

[cobraboy]

My car had a back to gel coat respray by the top guy at the time. About 7 years later I took it out one spring and it had micro blistered over winter. Bonnet, boot lid, and tops of doors are affected.
They rise up and go down depending on temps and humidity.
I remember when it was in bare gel I noticed the gel coat had millions of tiny bubbles in it, when its in the gel what can you do ? I live with it.

[alan.barker]

I would think dry soda blast then tissue and resin all the Car.
Alan

[Grizzly]

With that much paint that's all of different provenance on the car, I think it might be a bit unfair to place blame on the Carcoon. What you've got is an entire ecosystem gone awry.

I agree, not all carcoons are the same..... some are no better than a car cover but others pull moisture out better than any other type of cover. From my experience a cheap plastic car cover will do more damage to a GRP car than just leaving it open to the elements.

[Grizzly]

I have had 2 cars with micro blisters, a 1973 +2S130 and a 1976 TVR 3000M.
So they were repainted as follows:
Both cars were rubbed down dry, left in a heated spray booth for several hours at LESS than 30? to dry completly.
Also between different coats left several days/ weeks to dry .
The Lotus Elan +2S130 i kept for 7 years after painting before selling and no micro blisters came back
The TVR 3000M has just been done a few weeks ago and the painting procedure took 10 Weeks. Drying in paint Booth at below 30? between coats. Time will tell if the micro blisters come back.
I know many people have different ideas how they Garage their Cars. My OWN PERSONAL CHOICE is never ever put a Cover. I am lucky to have a 80 sq mtrs garage under my House and it's dry but i still use my Anti Humidity Machine now and then to be sure it's dry.
I prefer just before i take my Cars for a run to rinse off the Dust outside in the Garden than use a Cover.
I know someone will now say i've got it all wrong there are some special perfect Covers but they're not for my Cars
Alan

Thats more or less how i do it too, under no circumstances ever bake an old hand laid GRP shell or you will rapidly find all the trapped air bubbles in the resin.

Mick6186, It depends what paint you are talking about....... Many Primers are recommended against use with GRP as they are Porous and will absorb moisture, the problem then is the top coat gloss isn't porous so you get a layer of paint holding moisture which then freezes, expands creating a bubble, then gets filled with more moisture and the cycle repeats. GRP (especially old hand laid GRP) will have bubbles in the resin, over time heat from the sun will expand the trapped air/vapors in them causing small cracks (this is more becomes more of a problem was the Resin gets old and brittle), this then causes a capillary action which starts the process...... You don't get the same blistering on a modern injection formed GRP panel, the better quality hand laid panels are similar but your never going to get it perfect by hand.

GRP is great stuff, some one once told me way back when that you need to treat GRP in the same way as if you were trying to paint a sponge technically GRP isn't supposed to be Porous but in reality it is.

[alan.barker]

The "Option 1 " method to tissue all the car seems to work. I haven't seen any bad reports about them. But it's not cheap.
Alan

[gus]

I would never walnut shell or soda blast a +2. The work required to fix that destruction would probably cost more than a new shell.

Any widespread blistering is improper painting/prep. Even really good body men do not always know how to handle fiberglass

The car originally had gray epoxy primer that was probably good at keeping moisture out.

I think impatience is the cause of many bodywork ills.

[10kph]

A few years ago I asked MIck at Boss motors who previously worked at Lotus in the 70s as to why they used clear gelcoat and early cars and other makes used coloured gelcoats. He replied, so you can see the bubbles,scrape them out and fill.
As mentioned above, Epoxy primer is the answer to seal the surface when applied at the correct temperature then it can be levelled with filler or surfaced with 2K primer before flatting