Seconded, even if it’s just to make us more aware of how some of this can be avoided - esp the doors and washing the car.
Paint blistering issue update
- Thread starter seventen
- Start date
OK I've just spoken to Beaconsfield Workshop again.
If you are worried about the panel blistering issue on your Emira - they will provide an free inspection for you. I've confirmed they will do this for you. When the blistering starts it can initially be very difficult to spot yourself but the workshop can usually find it.
You can ring them on 01494-675211.
I've no connection to Beaconsfield Workshop just a former (and future
) customer of theirs and I'm found them to be very helpful. I'm sure other body shops and dealerships can do the same just that Beaconsfield have done 100s of Emiras now and know exactly what to look for.
It may be something you wish to consider when your factory warranty is nearing it's end.
Also, please make sure the car is clean for them just as a courtesy.
If you are worried about the panel blistering issue on your Emira - they will provide an free inspection for you. I've confirmed they will do this for you. When the blistering starts it can initially be very difficult to spot yourself but the workshop can usually find it.
You can ring them on 01494-675211.
I've no connection to Beaconsfield Workshop just a former (and future
) customer of theirs and I'm found them to be very helpful. I'm sure other body shops and dealerships can do the same just that Beaconsfield have done 100s of Emiras now and know exactly what to look for.It may be something you wish to consider when your factory warranty is nearing it's end.
Also, please make sure the car is clean for them just as a courtesy.
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I think the focus on water pooling behind the door panels might be a red herring.
The Emira uses SMC composite panels. These don’t behave like steel skins where trapped water causes corrosion from the inside.
Paint blistering on SMC is more commonly related to substrate or coating issues — for example microscopic voids, incomplete cure, or trapped volatiles inside the panel or primer layer. When the car heats up in sunlight or even a warm garage, any moisture or residual volatiles in those micro-voids can expand and lift the paint film locally.
A humid environment might aggravate the issue, but the root cause traces back to manufacturing or surface prep rather than water physically sitting inside the door cavity.
The Emira uses SMC composite panels. These don’t behave like steel skins where trapped water causes corrosion from the inside.
Paint blistering on SMC is more commonly related to substrate or coating issues — for example microscopic voids, incomplete cure, or trapped volatiles inside the panel or primer layer. When the car heats up in sunlight or even a warm garage, any moisture or residual volatiles in those micro-voids can expand and lift the paint film locally.
A humid environment might aggravate the issue, but the root cause traces back to manufacturing or surface prep rather than water physically sitting inside the door cavity.
This makes sense, but shockingly 3 years into this, no one has been able to confirm this. I think this is why almost everyone wants to see a dissected door (specifically the back of the outer door skin) to either validate this composite/manufacturing root cause theory or something else.
Agreed. Since it's presumably a bonded door assembly, I'm curious if the bubble areas correspond to points where glue is applied to the backside. Water doesn't seem a likely cause.
You can browse the reports of the issue just on this forum and answer this question.
For some doors it does - for many doors it doesn't. It also doesn't correspond to the position of blisters found on the quarter panels.
We have a composites expert on this forum in Steve Tillett. He made several comments about the bubbling issue earlier in the thread. I think his explanation is the likely culprit.
This might be silly, but has any one questioned if paint color may be a contributing factor for blistering? My '24 is plain white and I have not noticed any paint issues (yet). I also don't remember seeing any photos of white cars with blisters. I assume that different paint colors have different chemical compositions.
I do not think so. Looking at past posts, most of the original colours have had blistering issues. It appears to be a panel issue rather than a paint issue. Just a shame that after 3 years, Lotus have not got to the bottom of the root cause!
Great. Having an expert who understands composite construction and methods is an excellent move forward. Steve, apart from redirecting me/us to your earlier comments, what can we do to help and support any further research into this problem?
Well, I can see it's a different process to ours and I don't pretend to know everything about it. I understand they use a mix of fillers, fibres and resin and compress this into a two sided metal tool. Not a process we would use because the tooling is very expensive and the resulting moulding would not have long enough fibres to create the structure we require. But then they are trying to flip the mould around quickly, without much manual labour.
I can see that the majority of problems are coming from the doors and this does not surprise me. When you create a feature like the door handle depression, you are asking for trouble with resin flow. I am guessing that they inject in the substrate and if it flows around that handle, the air can get islanded as the flows meet each other. Then as it's trapped, the compression stage happens and these bubbles compress. It is then cured quickly before the tool is opened and those bubbles are trapped in the cured moulding. After time and with heat and cool cycles those bubbles find their way to the surface.
This is perhaps why the answer has taken so long to solve. The large tooling costs and the inability with this type of tooling to suddenly change materials, could be why it is taking so long to solve.
Again. This is just a guess based on the trials and tribulations that we have had flowing resins through two sided tools whilst trying at the same time to have them air free.
This is why anything made of composites that is mission critical is usually very expensive pre preg, because 100% guaranteeing composites without air is hard. Which is why you don't often see it on the body panels of shopping wagons.
Thank you so much, Steve. Would it be fair to say the problem relates to insufficient curing time? Could it be that air and other moisture enhanced chemicals which would normally be expelled during a lengthy curing time are still entrapped, with painting taking place under these conditions?
If so, do you think this explains why, with heat from the sun, for example, applied to the external face of doors and other panels, blisters are forming as the entrapped moisture (possibly not rain related) try’s it’s hardest to escape towards the source of heat. A thought that many are concluding.
Has anyone had bubbling form on the inside of panels?
There was a time, in fact a considerable time, when Lotus was scrambling to obtain parts to keep up with orders. I’m simply speculating here, based on several assumptions, that during this shortfall, shortcuts (eg shortened curing times) were made in order to keep up or catch up on orders or demand.
Your thoughts are welcome, Steve, along with any others.
Depending on the answers, hanging on to damaged or rejected doors, might be prudent.
I don't think it will be curing time and almost certainly not moisture. Simply the air in a two sided tool has nowhere to go once the resin flow has jumped over the bubble and left it behind.
if that bubble is then squashed and cured under pressure, as it heats up and expands, then cools and contracts, it will show eventually. Maybe the styrene or catalyst gases in those bubbles will accentuate the progress of them towards the surface but I've never seen a bubble pop out of any of the panels that we make for Caterham and to some degree voiding will always be present in those mouldings too.
Thank you Steve. It seems heat applied to the external side of the panel, for some owners, months to years after delivery, seems to be drawing out whatever remains in the composite panel. Some, probably a considerable number, have had the paint repaired only to have the problem raise its ugly head again.
Would you consider it in anyway beneficial to strip the paint back to bare composite (assuming a spare-rejected door or panel is available) and heat treat that panel/door for lord knows how long, to rid it of any remaining gases (air etc)? And only then undertaking a repaint using top quality products.
To add to see Steve's comment (and apologies, this turned into a long post once I got going):
1. If you go down to a microscopic level, you will find micro-voids/airpockets in every SMC panel. For those who like detail, this is because resin flow fronts can meet and trap micro air pockets, fibre bundles have tiny interstitial spaces between them, and curing can create micro spaces (cure kinetics, gas release).
2. However, in high-quality automotive SMC, total void content should be very low (<1% by volume). Most of these voids will be too deep in the laminate or too small to impact surface integrity. So, the existence of micro-voids alone is not abnormal or automatically problematic.
3. In SMC, there are two reasons why micro-voids located near the surface might cause a problem with the surface coating (the paint!):
Gas expansion - trapped air, styrene vapour, volatiles. This does not require moisture, just a micro-void near the surface and heat to cause expansion.
Moisture-driven expansion - incomplete cure, poor storage before paint, or vapour ingress. Note, I don't think this is related to water pooling inside the doors. The physics is totally different. SMC does not act like a sponge, and water inside the door isn't going to find a way through the inner panels to the back of the surface coating and then cause tiny random blisters.
4. Lastly, it's important to understand the concept of Adhesion Margin in the exciting world of coating engineering! You can have voids in the SMC, and have gas or moisture expansion, but never see a problem if the manufacturer has built in sufficient adhesion margin to tolerate the internal pressure. Adhesion margin is the safety buffer between the actual bond strength of the coating system and the stresses trying to break that bond. All cars have these stresses, and manufacturers try to make sure they have a sufficient adhesion margin in the coating system.
5. SMC surface adhesion strength is influenced by many factors, which makes composite paint systems extremely sensitive to process control. My gut tells me that this is the issue— either at Lotus or its panel supplier, or both. For example:
Here ends the sermon!
1. If you go down to a microscopic level, you will find micro-voids/airpockets in every SMC panel. For those who like detail, this is because resin flow fronts can meet and trap micro air pockets, fibre bundles have tiny interstitial spaces between them, and curing can create micro spaces (cure kinetics, gas release).
2. However, in high-quality automotive SMC, total void content should be very low (<1% by volume). Most of these voids will be too deep in the laminate or too small to impact surface integrity. So, the existence of micro-voids alone is not abnormal or automatically problematic.
3. In SMC, there are two reasons why micro-voids located near the surface might cause a problem with the surface coating (the paint!):
Gas expansion - trapped air, styrene vapour, volatiles. This does not require moisture, just a micro-void near the surface and heat to cause expansion.
Moisture-driven expansion - incomplete cure, poor storage before paint, or vapour ingress. Note, I don't think this is related to water pooling inside the doors. The physics is totally different. SMC does not act like a sponge, and water inside the door isn't going to find a way through the inner panels to the back of the surface coating and then cause tiny random blisters.
4. Lastly, it's important to understand the concept of Adhesion Margin in the exciting world of coating engineering! You can have voids in the SMC, and have gas or moisture expansion, but never see a problem if the manufacturer has built in sufficient adhesion margin to tolerate the internal pressure. Adhesion margin is the safety buffer between the actual bond strength of the coating system and the stresses trying to break that bond. All cars have these stresses, and manufacturers try to make sure they have a sufficient adhesion margin in the coating system.
5. SMC surface adhesion strength is influenced by many factors, which makes composite paint systems extremely sensitive to process control. My gut tells me that this is the issue— either at Lotus or its panel supplier, or both. For example:
- Surface chemistry – Is the primer system fully compatible with the resin system? Has mould release been completely removed?
- Surface topography – Is the surface prepared to the correct micro-roughness, without being over-sanded or polished smooth?
- Substrate cure and coating cure – Was the SMC fully cured? Were correct flash and bake cycles achieved between primer and topcoat layers?
- Paint system integrity – Correct bake temperature, film thickness control, and avoidance of solvent entrapment.
Here ends the sermon!
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Lotus UK have been building composite body cars for decades, they even build half the panels on the Emira. They are very experienced with composites and have dealt with many of the issues over the years.
What are the chances that a company with this knowledge would not know exactly what the problem is, especially with having access to the failed panels?
Technically there's no reason that Lotus don't make all the panels on the Emira. For non-technical reasons they don't.
There may be non-technical reasons why they can't disclose what the issue is or step in and fix the issue.
What are the chances that a company with this knowledge would not know exactly what the problem is, especially with having access to the failed panels?
Technically there's no reason that Lotus don't make all the panels on the Emira. For non-technical reasons they don't.
There may be non-technical reasons why they can't disclose what the issue is or step in and fix the issue.
For those in the UK concerned about this, especially those about to run out of warranty* I'll mention again that you can get your car inspected. The issue can be difficult to see before the blisters start appearing but a bodyshop with experience of this issue can spot it.
See this post https://www.emiraforum.com/threads/paint-blistering-issue-update.6632/post-196770
*It may be that we do have longer warranty for this issue than the 3/5 year paint one, yet to be determined.
See this post https://www.emiraforum.com/threads/paint-blistering-issue-update.6632/post-196770
*It may be that we do have longer warranty for this issue than the 3/5 year paint one, yet to be determined.
Such the tease. Surely there's a way you can directionally steer us to a "possible" "non-technical reason" for why this hasn't been resolved. Come on, throw us poor old dogs a bone.
What are Geely, Lotus and every other entity associated with the manufacture of the Emira hoping to achieve?
Supplying a faulty panel to replace an already faulty panel is not going to reduce their liability down the track.
To quote Geoff ‘It may be that we do have longer warranty for this issue than the 3/5 year paint one, yet to be determined’.
Amen to that.
As a matter of interest. When the paint ‘bubbles’ are burst and the surface examined, is there a hole, or crater indicating escape of any substance. Would the formation of a bubble not involve heat (sun for example) and a substance that expands when heated even mildly. Is there discernible evidence that such a reaction took place below the painted surface?
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