Body , Panel Fit, Flat, Gap, Prep and paint ..

[CHANGES 1,224]

Body ,  panel fit ,flat, gap, prep and paint.   

 Part 1

 Introduction  

Before undertaking any restoration, partial or complete, you need to ask all the relevant questions..   The main one is what do you or the customer expect from the finished result..  The next one is, how is going to be achieved.

In this thread we will run through what was undertaken to achieve the specified body restoration requested by this customer..

  The subject is 1982 Esprit turbo ‘G’ car.  The customer’s request was to achieve a flat panel finish with all matching gaps, along with spot on panel alignment..   The paint finish should be flat with as much depth as possible.   The focus was on emulating a hand finished show or promo car.

Analysing the project

 The first consideration is a 38 year old GRP body with all the usual defects.  These vary from gel crack, to flaking paint and micro blister, with some previous repair work etc etc..  However the biggest problem is the panel deviation..  Over the years GRP will move and distort. You can see this in most of the examples out there.. When they left the factory as new, the panel alignment and shape would have been much more consistent than what old father time has left us with now.. This is just the nature of the beast … The challenge is to not only return a 38 year old example to as new, but also move it onto the next level only found in show/ promo versions..

   An inspection of subject Esprit did not show any horror stories, just what we expect to see..  Although several coats of paint in some areas, I felt sure there was no hidden nasties.. When I explained everything involved and the time span needed to complete the requested finish the customer said proceed..   

 

The starting point.    

 

First we check and asses all panel fitting and contours. This will mean removing the panels and then refitting with new seals etc, shimming and adjusting to the best possible fit . By using a long flexible steel ruler as a plain gauge and straight edge, you can easily expose all the areas of concern.  These can be marked up showing all the high and low spots.  The aperture fitting is always testing,   Gaps will end up going in every direction, so finding the mean position is all we can do.   Once happy it’s the best it can be, we can start the graft .

The following pictures show how the contours of the roof and tailgate have sunk and bowed.    

 

 

Stripping off all the paint exposing faults in the gel finish was next. Any obvious gel crack areas were immediately addressed by removing said gel coat in that area at same time.  This is a selfless task that has to be done to get the best results.  It is very important to establish a solid and structured base to work from for this type of finish… Straight forward repaints will only require rubbing back to provides a stable substrate to prime and paint over.. However we will be building the base layers using GRP and various polyesters and carbon fillers, to reshape the panel profile.  If we were to do this over just a sanded paint layer, there is a possibility chemical/solvent reactions can soften the original paint making it unpredictable..  Unfortunately if dodgy paint layer is left, initially everything would seem fine and only some time later (months/ years) you can get wobbles in your flat finish or sinkage / mapping around repair build blend points ..  This happens because the original paints eventually dries back, contracting and pulling on the surface .. On straight colours, if clear coat layer has enough depth, you may get away with another flat and polish , but you are usually stuffed with metallic finishes as the metallic in the base coat will shift and show fault .

The next stage will be to address the areas pictured above , to achieve the desired shapes and gaps.. 

TBC..       

 

 

 

 

 

[Fridge 977]

Can't wait!

[CHANGES 1,224]

Part 2       

Generating shape and profile of roof and tailgate. 

As the previous pictures show the top of the tailgate profile has sunk significantly and the body line is now inconsistent. This same problem was on the main roof area but not as obvious in photo’s . Unfortunately the curse of this type of restoration is even the slightest waver will be seen in the reflection spoiling the whole effect.  Any deformity on the roof area will jump out at you because of its location to the eye line ..   Looking at any panel head it on will disguise faults. But create an angle of view below 45 degrees and things start to appear..  When a paint finish has an orange peel effect , below this angle you start to see it clearly.   However an orange peel effect can also take your focus away from general panel deformation, this is why some restorers never fully colour flat.   You can test this analogy on any car finish, you may be surprised what you start to see..  Using a straight line in any reflection or strip lights as I do, will also help your eye focus on the actual surface profile as well as paint finish quality. 

In the following pic of roof section it is hard to see the fault , but it has sunk around 1mm by the yellow X,  also in the foreground you can pic out when air pockets under the original gel coat have been exposed on the capping rail. (0256)

These sort of dips and hollows are all over the roof panel and only visible with this method or in final finish. So extra attention to detail here pays dividends later ..

  The roof and the tailgate roof extension should have a natural slight curved shape from side to side and front to rear.  This slight dome effect is what gives the panel a certain rigidity.   On the next pic you can just make out the curve , also a small dip in the center between the two red dots..   (0261Li)

           

This all may seem very petty to most. In the above pic you get the impression there is not much wrong with any of the above, even though previous views have shown how far out things actually are.   Photo’s , especially without gloss finish will disguise the true shape .

So correcting these faults requires generating a fresh surface skin , lifting all the sunken points and sculpting the optimum profile. This is a very long messy and quite intensive process to get spot on . It requires constant building and flatting until desired shape it achieved ..    On these roof area’s , mainly due to the amount of building up needed, especially on the tailgate, we used a carbon fiber filler ..  This provided the volume, rigidity without the weight..    Following pic shows things progressing with additional application of carbon fillers needed on the tail gate .  (0290)

    

A lot of the initial work can be done with air sanders, Orbital and flat bed, but as the shape forms you will need to use all hand blocks and planes etc, with guide coats .      The next pic shows the roof now starting to get the true shape , with matching profile across the shut line with tailgate ..  A final skim over with 180 grit on DA (orbital sander) to ensure all traces guide coat paint is removed .  (292)

 

Next step is to apply a glaze filler , This is a fine grain , quite fluid filler , which we use to eradicate all the finer defects .  It will also provide a substrate that can be worked to a high degree of finish. With this application we can now start to hone the final shape .. When applying and sanding we also level up the height of the roof to the capping rails.  They should be in the same plain and match up leaving the appropriate gap for the finishing trim to be attached ..  Whilst doing this it is necessary to insert a shim the same thickness as the finishing trim under the capping rail to insure correct height is maintained when finally fitted up .    ...  (293)

 

It should also be noted , that between each filling process, sufficient curing times should be allowed.  Although these are activator hardened in less than 30 min , in can be several hours before full cure has occurred. This will vary on temperature and accuracy of ratio on mixing.. Working the surface after just 30 min is common practice , but the best and more accurate results are achieved by allowing more time .. ( These will also vary with different products and application )

TBC 

[Lotusfab 3,210]

Nice work Dave, can’t wait to see the car!

[eeyoreish 890]

Great work! I just hope your ruler hasn't got a kink in it 🤔

[drdoom 418]

Dave, I'm working on a body shell stripped first via media blast ( ground walnut shell and garnet, I believe ) and in several places the gelcoat was taken off. Once I've sanded down the remainder of the thing, removing the last of the primers going just down to the gelcoat, should I have it sprayed with an epoxy sealer before laying on other finishes? 

 

[CHANGES 1,224]

2 hours ago, eeyoreish said:

Great work! I just hope your ruler hasn't got a kink in it 🤔

Only where it is supposed to have . 

2 hours ago, drdoom said:

Dave, I'm working on a body shell stripped first via media blast ( ground walnut shell and garnet, I believe ) and in several places the gelcoat was taken off. Once I've sanded down the remainder of the thing, removing the last of the primers going just down to the gelcoat, should I have it sprayed with an epoxy sealer before laying on other finishes? 

 

A lot will depend on quality of what you are looking at .. Area's where gel coat has de-laminated will be of concern .. Aggressive sanding of exposed GRP surface with 40 grit to key in primary repair.  Then apply layer of resin with cloth or mat as you would to any damage repair area. ( I will be covering this type of repair a bit later in the thread ) ..  As long as your gel coat or substrate is sound and crack free you can start working the finish..    Unfortunately media blasting can disguise gel crack , so you need to go searching..  Areas where it lifted during blasting will have been bad spots.. Its ones you can not see that come back to bite you.  In situations like that I would orbital sand each panel one at a time down to a circa 300 grit..  This will be quite smooth . Then apply a thin stain coat by hand , wiping over the panel  allowing it to soak down into any cracks ..  Then stain should not put much colour on the panel but will highlight all  the cracks .. you can then grind  them out and carry out resin build repair as previously stated.  .. ( don't over apply stain if cellulose based )  .    Spraying an epoxy coat all over will only bury what is there already ..  Unless you apply a tissue or similar layer within this , any cracks will eventually work their way up .   If you are looking to do similar to what is in this thread,  then only local repairs will be needed.  You will see as the thread progresses, we use polyester coat to seal everything down once required form is achieved ..   These are also far more resistant to cracking..    

[CHANGES 1,224]

Part 3       

Generating shape and profile continued

Following the glaze coat is the next stage of flatting,  all by hand now..  Air tools can be a bit aggressive , leaving marks that will need filling again , so although its labour intensive by hand it can work out quicker..  Another reason for hand flatting is feel/ sound. It is not easy to explain but you can feel and hear how the surface is flatting out .. When it becomes uniform it has a different feel and sound to the stokes ( My therapist said what you are now thinking ). At this stage seeing the very slight deviations will be difficult even with a straight edge . Using a guide coat will help show up the odd spots etc , but I find by just wiping a hand over the surface you can pick out any low spots and defects.  ..   The next pic shows the roof really starting to form out now , with just a small build adjacent to the capping rail to bring into line (329)

The next two pics show how the profiles of the roof and tailgate harmonize. The first shows the smooth progressive flow from one to the other which we had lost with the sunken tailgate (330)     

The second shows the consistent shape starting to form side to side, with the tailgate matching the roof line perfect (331)

We can now start to progress down the tailgate length … As with most, the shape has sunk , the following pic’s will show what with have to start with and work from.. (280) (282) (283) (284)

 

With the top front section being level where we have already formed,  the back transom area is not far out , but as pic;s show the center substantially dips down over the length ,,  This was the same on both sides.    The next stage is to carry out the same process of build and flat to bring in line and match to the quarter panel profile ..  It is also important to note that on the 'G' cars there is a stabilizing strut that need to be fitted to the inside of the quarter panel before finalizing shape.  With out this the panel can flex and any shape will become inconsistent.

TBC  

[drdoom 418]

Is creating a stain for the reveal of gel cracks a matter of adding black paint to thinner? 

[CHANGES 1,224]

3 hours ago, drdoom said:

Is creating a stain for the reveal of gel cracks a matter of adding black paint to thinner? 

Basically yes.  You will need to play with the ratio,  but you will soon work out what gives the best results..  Go to a spot you know there is gel crack and practice your application on that area ..   find a method that works best for you ..     

[Rolls 208]

You could also wipe with wax and grease remover for the crack reveal. You will have to look a little harder but it does work..

Regarding the epoxy comment. I would be cautious using epoxy pre-repair. Resin doesn’t adhere particularly well to it.

I admire your contour work Dave. I found my lotus body to be particularly challenging.

[drdoom 418]

Thanks, Roland, I've observed adhesion issues with contact cement over epoxy repair of the cockpit rear bulkhead finisher panel, now mindful of this. I may regret having done some work on the shell in epoxy/cloth if unable to reliably lay on fillers needed to finish. 

[CHANGES 1,224]

Part 4      

Generating shape and profile continued

Establishing a level down the sides of the tailgate is far more straight forward than the previous sections..  What does need to be considered is any minor distortion down the backbone on the quarter panel itself at the same time ..  (298)

On this Esprit they were very good, however I have seen some quite out of shape when stored or used with the support rib that was previously mentioned, being incorrectly fitted or not fitted at all  …  We will still needed to work the overall surface finish of the quarter panel , but at this stage we are just establishing a level across the joint to finalise the tailgate form.  (340) 

 What we have not mentioned up to now is the gapping.. The main reason for this is the tailgate aperture to panel fit was not that bad on this one .   A bit wobbly in parts but fairly square …. It is very common to see them tight on two diagonal corners and loose on the apposing  Also very poor aesthetically around the hinge points.  Not a lot you can do with that except re-shape the tailgate to custom fit ..  In this case we just needed to build the edges of the tailgate with small amount of filler to bring the gap to a parallel tight 7mm..   It was decided the final gapping will be 6mm , but at this stage we are using the 7mm gap gauge to allow for the polly ,primer, and colour coat etc ..  This can build up each surface which will close the gap to the desired ..  Failure to just follow this principal will result in gaps being tighter than requested, or compromising the Polly coat isolator.        (342)

Whilst establishing the uniform shape, some areas on the quarter panels threw up a mismatch which would have looked wrong if corrected within the tailgate form .. It is important to follow the natural flow and curves of the body,  This is what  makes it look all balanced when finished.. If you short cut, just to make individual area levels match, then you can loose the effect. It is important to maintain an overall focus as you progress. By doing this you will find you attention will natural flow from one area to the next, blending the form as you go .. (346) (338)

Even on areas which seem fine I will coat with a glaze filler, this will help refine the shape and provide good adhesive qualities .  (377)

The natural progression now takes us into the transom ..  This unfortunately only fitted where it touched and was full of lots of minor annoying faults ..  (388)

 

Also, must remember to sweep up yet another bucket of dust 

TBC

 

 

 

 

[Jacques 959]

Excellent thread!

Thanks.

Jacques

[CHANGES 1,224]

Part 5     

Generating shape and profile continued.

There was enough room in most of the fixing holes to get a reasonable position, but to get the best mean result I had to slightly slot a couple ..  This still left a lot of basic miss matching which needed working with the fillers again to level out..

  

You will note on the last pic that a piece of molding trim is taped in place next to the transom panel .. This is to ensure that the body line blends perfectly when completed rather than just random butting up ..  This is just one of those tiny details that easily gets overlooked and will be noticeable when on finished body ..

The next two pictures show the typical poor edge fit.. They may not stand out so prominent in the pic’s but in reality were quite bad 

 

Once the high / low spots are identified, it just a case of more filling and flatting..  I am afraid to generate the desired finish there is no easy way around it . Just fill flat and graft..

You will note on the later pics that we have also moved into the rear quarter panels now.  As previously stated , its a natural progression following the flow of the lines ..   However  there was an aerial hole put through the O/S rear quarter which had to be addressed  .  I will cover how that was removed in the next section , along with other seam cracks / air voids and adjacent gel cracks .  But to finalize the shape of the transom , once again a coat of glaze filler was used.  With one final flat we generated a smooth transition from transom to back deck and quarter panel .

TBC 

 

  

[LOTUSMAN33 1,470]

Great job and unbelievable attention to detail, looking so good now 👍🏻
Dave  

[CHANGES 1,224]

Part 5     

Hunting out and Repairing seam joints etc.

As mentioned in last post an aerial hole had been drilled through the rear quarter panel .  When this was done no load plate was fitted inside so gel stress cracks spread out from the hole ..  I quite often see cars that have had the holes filled in and they sink back and spoil the appearance of nice paint jobs. This is all because they glass the inside and then use filler on the outside. Too eradicate properly you need to grind back a reasonable area though the gel coat , tapering down to the base of the hole, before applying GRP repair patch to the outside.

As you can see from next pic a repair section had been fitted to this car in its past . It was a nice repair but had some micro blister in the paint above it ..  this may have just been a prep issue , but we will refinish the whole area again.. Once this section was down to gel coat lots of little spots of concern availed themselves.  These will all get individual attention before the complete panel is addressed.

  

An area that always come up is the ‘B’ post seam adjacent to the door latch. Other than a small crack been evident on close inspection, they won’t look bad .. But these area’s always crack due to the way they were initially finished . When the two halves of the mold were joined , they were glassed up on the inside and in most cases air voids got trapped in the joint area. Over time these expose a weakness and unless you go digging and fix properly they will just keep cracking,  

 

When fully exposed with all little crevices opened out, first apply small GRP repair patchs to the base of the exposed area. This is to fill and build without allowing any air pockets to get trapped again. Then apply final overlap GRP repair patch.   If require you can also run a fresh patch of GRP on the inside . 

 

 

You will find as in this case that some of the mounting holes for the door catch will get filled out . So prior to doing this sort of repair a couple of reference photo’s and dimensional drawing will save the guess work when re drilling .

Next we will start prepping for the quarter to door alignment.

TBC   

 

[CHANGES 1,224]

Part 6     

Matching quarters and doors

Once we have flatted an filled out the ‘B’ post area , we can start to build out for the gapping. First we need to re- fit the door and find the best position to minimise the amount of filling needed. 

So as we progress along the rear quarters, we can start to level match into the doors.

After establishing the best position for the door, we need to find the discrepancies. This is back to the old faithful straight edge.. 

 On the above pic you will note we have a close match on the top face,  which unfortunately didn't correspond with the seam swage area .( pic below) .   The swage line is where the body mold goes and this has to line up perfect with the door mold swage line. So as a result we need to use the swage line as the default height setting .  As a result the door had to be reset and we then needed to fill out the top edge  .

   When we move down the outer face of the panels , we start to see them drift away from each other …  Not by much significant enough to look off with flat panel and gapped finish. In the next 2 pic’s  you can just make out the misalignment . The door drifts away on the upper section and the rear quarter on the lower area .

On the above pic’s you can also see how the door gap has little consistency and is quite wide.  We do suffer with wind noise when we drive these Esprit. A lot of this comes from panel fit and gapping..  I have noticed a massive improvement when this has been addressed .. 

To complete this task we must first fill the door gap. This is done by applying  a roll of GRP to the gap then filling straight across the two panels with quality filler.  

 

Then using long flatbed sander by hand we can start to form a consistent level across the two panels .  At the same time you have to match this into what we have previously done along the rear half of quarter panel. Done correct this should providing a smooth flow along the whole panel and into the door.

You may notice a wooden block between the top of the door and ‘B’ post. This is used to jam the door in the required position prior to fill over . Without this the door can move in and out slightly on the door seal . So this give us a more stable platform to work from  

Next up is door to front wing.

TBC  

[Lotusfab 3,210]

The car must be amazing now its done!

[RichardJGC 381]

11 hours ago, Lotusfab said:

The car must be amazing now its done!

Still very much a work in progress 🙂

[LOTUSMAN33 1,470]

I wondered who the lucky owner was, you should have an absolutely stunning Turbo when you are back on the road Richard, this post made me look at my gaps and alignment with a straight edge and can see similar discrepancies which I’ve never paid attention to before. Can’t wait to see the end result especially as I’m thinking about paint as well.

Dave  

[CarBuff 200]

35 minutes ago, LOTUSMAN33 said:

this post made me look at my gaps and alignment with a straight edge and can see similar discrepancies

We can't expect our hand-made glassfibre Lotus cars to be as good as the commercial below.

 

Heck, I'm sure our '88 passes the Tennis Ball Test. 🙂

 

 

[CHANGES 1,224]

14 hours ago, CarBuff said:

We can't expect our hand-made glassfibre Lotus cars to be as good as the commercial below.

 

Heck, I'm sure our '88 passes the Tennis Ball Test. 🙂

 

 

Well maybe all we needed was 'some' Balls to try .. !!!  

[Lotusfab 3,210]

Dave, what fillers are you using please. The green one looks like Dolphin glaze?

[Lotusfab 3,210]

P38 Isopon?