Lotus Elan

Body restoration

PostPost by: lotuselanman » Sat Dec 18, 2010 9:29 pm

Hi,
Next year I hope to commence restoring the body on our +2.
As usual it has cracks, stars, and in general does not look good.
Is there a good book on the topic or where can I read up on restoration processes.
Thanks,
Les.
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PostPost by: nebogipfel » Sat Dec 18, 2010 10:07 pm

Les,

This has been discussed on the forum and I suggest this thread may be useful.

PS My paint is now 6 years on and I'm still happy with it (touch wood :lol: :lol: )

PPS I can't remember dropping the 2004 from my name but it's still me :wink:

elan-archive-f16/paint-primer-for-fibreglass-t12358.html


If you want the Wilkins book discussed in the above thread it is long out of print but there are copies around and it is available here ..

http://www.lotus-books.com/additions.html
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PostPost by: reb53 » Sun Dec 19, 2010 5:23 am

"PS My paint is now 6 years on and I'm still happy with it (touch wood "

Mine is 20 years old and I have yet to have a new crack appear.
I did it myself and did what the Wilkins book said, so I guess you can't get a much better recommendation.

Ralph.
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PostPost by: desprit dan » Sun Dec 19, 2010 9:25 am

Hey john, I notice from the "old" thread that you are using a gravity feed gun, I have thought some time now, that using a conventional suction feed gun, my problem with the polyester, is that I have to thin it to get it out, and that thinning is affecting the curing process.

I will also add that (as I'm sure you are aware), much of the micro blistering in paint doesn't come from within, but is water in the paint from the compressor, and that a huge effort is needed to stop water reaching the gun.
When you see blistering on horizontal panels, it makes me think that there was water in the gun handle bubbling up, and the change in gun angle allows it through; what are your thoughts on this?
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PostPost by: nebogipfel » Sun Dec 19, 2010 9:48 am

reb53 wrote:Mine is 20 years old and I have yet to have a new crack appear.
I did it myself and did what the Wilkins book said, so I guess you can't get a much better recommendation.

Ralph.


That's impressive for any paint job :wink:
------------------------------------------------------------------------------------------------------------------
Les,

I just thought I'd add a bit about repairing the actual 'glass. This method is basically Miles Wilkins with a few thoughts of my own.

The best results are achieved by stripping the shell back to bare glass. Various methods of blasting fiberglass have been discussed on the forum but I cannot comment. I did my shell the old fashioned mechanical way by hand and machine as in the Wilkins book. Others may well comment on experiences with blasting.

Note: I recommend that before you strip your shell you either make photographs or detailed drawing of the size and extent of any problems because they are a bugger to see after the shell is stripped!

1. All areas of major damage should be ground back deeply into the fiberglass and feathered out beyond the extent of the problem. New standard weight matting should be laid in to restore the strength and approximate level. If you can repair from both sides do so although it's not always possible.

Repairs on the outer surface only can be just as strong but you need to ensure you grind deeply into the laminate.

2. Fine gel cracks and small cracks can be ground back until the glass matting is exposed (through the gel coat) and then repaired with a couple of layers of fine surfacing tissue (fine fiberglass matting). Make sure you grind the gel away well beyond the area of damage.

Note: On my own shell I took the precaution of adding extra matting to the inside of the shell (when I had access) to high stress areas where cracks typically appear. On a +2 the area near the pod pivot points is a good example. I added some under my wheel arches to try to lessen the effect of stone impacts.

Final shaping can be done with a good quality polyester body filler. There are no magic products, FWIW I have used U-Pol products for many years and find them reliable.

The last stage recommended by Wilkins (and used by me) is to spray the whole repaired and well sanded shell with a polyester spray filler. I used and am happy with U-Pol "Reface" Ideally you need a gravity fed spray gun with a large nozzle to spray it successfully and I foud in good conditions you need to move quickly because it will cure in the gun! :shock:

I have cut and paste the painting section from the old thread so it's all in one place .........

FWIW I can tell you the method I used:-

1.Repair the shell ready for paint and key the surface DRY with
production paper (p180 grade)

2.Apply spray filler as per instructions and again flat DRY with
production paper (p180)

3.Apply first 2K primer coats and again I flatted dry (p180) but at
this stage you could use water and p240 "wet or dry" paper
You could skip this stage but it gives you more chance of getting
everything flat and smooth

4.Final 2K primer coats flatted wet with P600-800

5.Colour coats flatted wet with p1500 and soapy water and then final
polish with an electric mop to restore the shine

Allow as much drying time as you can.

I have never known 2K primer to react with or indeed flake off filler
and therefore presumably spray filler

Poor adhesion is usually caused by inadequately keying the substrate
but 2K products generally have good adhesion properties.

On the spray filler and primer coats a "guide coat" (light dusted coat
of colour) greatly assists in seeing the highs and lows when you are
flatting

The method I used was based on Miles Wilkins repair and painting
techniques and my own instinct and experience

I am no authority on painting fiberglass (I paint tin cars) so it was
very much a voyage of discovery but I was very pleased with the result
and one (now 6) year on it still looks good.

I will just add my two mantras again :lol: Keep everything as dry as possible (including your air supply to the spray gun) in this I depart from Miles Wilkins. Never flat glass or filler wet

and .......allow as much drying time as you can for every stage of the process, I don't mean hours, I mean days. If you are in a hurry, don't do it.
Last edited by nebogipfel on Sun Dec 19, 2010 10:45 am, edited 1 time in total.
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PostPost by: nebogipfel » Sun Dec 19, 2010 9:58 am

desprit dan wrote:Hey john, I notice from the "old" thread that you are using a gravity feed gun, I have thought some time now, that using a conventional suction feed gun, my problem with the polyester, is that I have to thin it to get it out, and that thinning is affecting the curing process.

I will also add that (as I'm sure you are aware), much of the micro blistering in paint doesn't come from within, but is water in the paint from the compressor, and that a huge effort is needed to stop water reaching the gun.
When you see blistering on horizontal panels, it makes me think that there was water in the gun handle bubbling up, and the change in gun angle allows it through; what are your thoughts on this?


Dan, That's a relief, you have explained the mystery. Thinning the polyester is the reason it didn't cure properly.

It must not be thinned. I used the recommended gravity feed gun with a 2.0 nozzle wacked the pressure up and went for it. It is a bugger to spray and I would recommend not doing it on a hot day because it cures very fast. I would also suggest not trying to do too big an area in one hit. I did mine as front of shell, back of shell, doors, and then bonnet and boot. That made it a bit easier.

Yes, the air supply should be as dry as possible.

I can't see water collecting in a conventional suction feed gun, I'll have to think about that one :)
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PostPost by: Craig Elliott » Sun Dec 19, 2010 11:01 am

Just to add to the above, a few observations that I've picked up in discussion with others that have in-depth experience of doing re-sprays etc. Apols if these are lessons in sucking eggs!

- whilst soda blasting is a good way of getting paint off quickly it is still quite aggressive so care is needed (this was feedback from a restoration that was discussed quite a lot on this forum a couple of years ago)
- one way of sorting gel cracks and other damage is to grind them out and repair them before stripping the rest of the paint off the car. There is a big risk that if you strip all of the paint off before you do repairs that you will miss cracks etc and these will quickly show up following the re-spray.
- there are a number of causes of blistering (statement of the obvious I know...) remember that glass fibre can act like a wick and draw moisture from the underside of the surface (e.g. wheel arches) so using a good sealant under the arches is a good idea. Similarly making sure the shell of the car is absolutely dry before painting is essential. I had very bad blistering on the bootlid of my car so I stripped it and left it by a radiator for a week or so before re-painting. The blisters haven't come back after three years but remember after 10-15 years + you're asking a lot for paint to be blister free. It's more difficult to get the shell dry if you're doing a diy paint job but the judicial use of electric heaters (esp ones that direct heat like they use in boat yards) can help. Be very careful if you have the option of using a paint oven - if you get the shell too hot it will sag and deform. Gas or paraffin heaters are not a good idea as they will raise the humidity in the area you are heating - the idea is to warm the car up in as dry an environment as possible to get the water out of the body.
- Other causes can be water in the paint as mentioned above, and if a fibreglass panel is new they can be caused by poor removal of the releasing agent.
- Time is all - be patient, accept that it will take a long time and don't rush!

C
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PostPost by: desprit dan » Sun Dec 19, 2010 11:28 am

As a matter of course when painting, I leave the fitting loose where it joins the spray gun, you can see and indeed feel water escaping there, (you could argue that it is already too late at that point) some people have a small water trap screwed directly to the spray gun, this works by gravity, i.e the water is collected at the bottom, but if the gun is turned on it's side, any water collected can get out, into the paint; on fibreglass and non fibreglass cars, most of the micro blister I have seen is on the bonnet, roof, or bootlid, there must be a reason for this.
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PostPost by: nebogipfel » Sun Dec 19, 2010 11:45 am

Craig Elliott wrote:Just to add to the above, a few observations that I've picked up in discussion with others that have in-depth experience of doing re-sprays etc. Apols if these are lessons in sucking eggs!

- whilst soda blasting is a good way of getting paint off quickly it is still quite aggressive so care is needed (this was feedback from a restoration that was discussed quite a lot on this forum a couple of years ago)
- one way of sorting gel cracks and other damage is to grind them out and repair them before stripping the rest of the paint off the car. There is a big risk that if you strip all of the paint off before you do repairs that you will miss cracks etc and these will quickly show up following the re-spray.
- there are a number of causes of blistering (statement of the obvious I know...) remember that glass fibre can act like a wick and draw moisture from the underside of the surface (e.g. wheel arches) so using a good sealant under the arches is a good idea. Similarly making sure the shell of the car is absolutely dry before painting is essential. I had very bad blistering on the bootlid of my car so I stripped it and left it by a radiator for a week or so before re-painting. The blisters haven't come back after three years but remember after 10-15 years + you're asking a lot for paint to be blister free. It's more difficult to get the shell dry if you're doing a diy paint job but the judicial use of electric heaters (esp ones that direct heat like they use in boat yards) can help. Be very careful if you have the option of using a paint oven - if you get the shell too hot it will sag and deform. Gas or paraffin heaters are not a good idea as they will raise the humidity in the area you are heating - the idea is to warm the car up in as dry an environment as possible to get the water out of the body.
- Other causes can be water in the paint as mentioned above, and if a fibreglass panel is new they can be caused by poor removal of the releasing agent.
- Time is all - be patient, accept that it will take a long time and don't rush!

C


Good points Craig, Doing the repairs before stripping is a another good way of not missing them :wink:

FWIW I used U-Pol Stone Chip on the underside of my car in the wheel arches to add an extra layer of protection. (I have no connection with U-Pol ...honest) Don't be tempted to use cheapo stone chip, it's useless.

There is no escaping the fact that painting fiberglass is NOT easy. A steel body shell is a pretty stable substrate under paint but glass is a very different animal. On hot sunny days I can still smell fiberglass sometimes when I'm sitting in my car ....and that's 6 years on.

All together now ..........Keep it dry ........Keep it dry..... Take your time........Take your time :!: :!: :lol:

PS. It is worth adding that since Miles Wilkins wrote his book paints have improved. Modern 2K primers offer high build, good adhesion and when fully cured excellent "hold out" and resistance to shrinkage. Likewise 2K top coats and laquers offer a very durable, naturally shiny final finish. FWIW I wouldn't recommend cellulose primers and paints when doing a full respray on a fiberglass shell.
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PostPost by: Craig Elliott » Sun Dec 19, 2010 1:05 pm

... on some cars, by the time you've finished doing the repairs, there probably won't be that much left to strip... a good way of doing this in a staged way :D ?

I suspect the reason that the roof bonnet and bootlid are often badly affected by micro (and not so micro) blistering is that these are the high points on the car and condensation forms there. Over time this wicks up through the glass etc etc...

I'd also suggest that leaving a car out in frosty weather isn't a good plan - any damp will freeze with bad consequences for the paint.

The one advantage of cellulose paint is that i've found it's relatively easy to use (less noxious for a start) and also quite forgiving if you go wrong - assuming you're not using a metallic finish. But I suspect it's horses for courses and the paint you choose will also depend on the type(s) of paint already on the car...

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PostPost by: nebogipfel » Sun Dec 19, 2010 1:11 pm

Craig Elliott wrote:... on some cars, by the time you've finished doing the repairs, there probably won't be that much left to strip... a good way of doing this in a staged way :D ?

I suspect the reason that the roof bonnet and bootlid are often badly affected by micro (and not so micro) blistering is that these are the high points on the car and condensation forms there. Over time this wicks up through the glass etc etc...

I'd also suggest that leaving a car out in frosty weather isn't a good plan - any damp will freeze with bad consequences for the paint.

C


There are nearly as many theories as blisters and no getting away from the fact that they are always a worry.

Despite the best of efforts they still happen sometimes.
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PostPost by: Craig Elliott » Sun Dec 19, 2010 1:12 pm

Oh yes, one more thing, allow plenty of time, don't rush and be patient!
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PostPost by: nebogipfel » Sun Dec 19, 2010 4:18 pm

Craig Elliott wrote:Oh yes, one more thing, allow plenty of time, don't rush and be patient!



Hadn't thought of that .... :lol: :lol:

---------------------------------------------------------------------------------------------------
You're right about cellulose, I used to love using it back in the day (and still do when I can get away with it)

The two big problems with it over a fiberglass substrate is it takes ages to dry fully and as a result the relatively huge solvent content has a long time to do it's worst. I have seen a celly finish still sinking months after it was applied!
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PostPost by: AussieJohn » Sun Dec 19, 2010 4:52 pm

I did a massive repair on my tvr griffith and left the hand rubbed filler 3 months to go off; then had a bodyshop spray a good coat of polyester spray filler which was left for a month before sanding. The paintwork looked good but now after 4 years I am getting a few heavy sinkage marks. Any clues as to what went wrong? [ painted by the bodyshop; I dont know whether they undercoated after the spray filler or coloured straight on top].
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PostPost by: nebogipfel » Sun Dec 19, 2010 5:45 pm

AussieJohn wrote:I did a massive repair on my tvr griffith and left the hand rubbed filler 3 months to go off; then had a bodyshop spray a good coat of polyester spray filler which was left for a month before sanding. The paintwork looked good but now after 4 years I am getting a few heavy sinkage marks. Any clues as to what went wrong? [ painted by the bodyshop; I dont know whether they undercoated after the spray filler or coloured straight on top].


Very difficult to give you a definitive answer .....things which could give problems include:

Was the repair done with fiberglass matting followed by a thin skim of filler because big wodges of filler will often shrink?

Was it kept dry while the filler cured (and the spray filler)? 3 months is a bit of an overkill! by the way :)

If the area adjacent to the repair was the original paint finish, the paint can react differently on the filler area and the old paintwork

Without knowing what primer and top coat was used it's difficult to make any useful comment.

It is also possible that the different substrates are being affected by temperature particularly if you live somewhere subject to high temperatures.

Sorry, as I say it's a tricky one.
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