Author Topic: Stripping paint off the 6.9  (Read 350 times)

Max-NL

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Stripping paint off the 6.9
« on: 09 December 2018, 03:03 PM »
Wanted to share this picture with you guys. We're currently stripping the paint off the 6.9 for a bare metal respray. The choice of method is with a heat gun and a razor, less dusty and strainfull than sanding. Except for the roof which we're going to sand. This is because if we're going to use the heatgun there we should remove the headliner and sounddeadening. Windshield and rear window will be removed. Front doors are going to be replaced with better ones which will be stripped completely. Rear doors are good so we're going to strip them completely.

1971 350SL
1975 280S
1975 450SEL 6.9 #140

rumb

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Re: Stripping paint off the 6.9
« Reply #1 on: 09 December 2018, 04:01 PM »
That is a very interesting way to strip the paint, I have not heard of before. I think I will have to give it a try.
'68 250S, '77 6.9 euro, '91 300SE, '98 SL500 '14 CLS550

ptashek

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Re: Stripping paint off the 6.9
« Reply #2 on: 10 December 2018, 07:17 AM »
I personally wouldn't use a heat gun. There's a real risk the panels will warp when cooling down. Even sandblasting can cause that and it generates less thermal stress than a heat gun would.

Have you considered chemical stripping?

Full chassis stripped to bare metal, inside and out isn't a prohibitive cost all things considered (~1500EUR with VAT). Check entlackerhelden.de, they've done my chassis during the restoration. Well worth it.
1993 "Pearl Blue" W124 280TE
1979 "Icon Gold" W116 450SE (history, resto)
1977 "Milan Brown" W116 350SE (parted out)

Max-NL

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Re: Stripping paint off the 6.9
« Reply #3 on: 10 December 2018, 07:44 AM »
The guy who owns the shop (classic cars restoration shop) where the 6.9 is stored advised us to use this method, as he has done it multiple times even on cars way more expensive than the 6.9 and never had issues. You don't heat the metal to a high temperature, just enough so that you can put the razor between the paint and metal layers. After that you just keep it warm to keep the paint flexible. I'd say that the metal is warmer after a full day in the sun in the summer than what I'm putting it through. And we've done it before with the 350SL, which is in primer now and doesn't have any warpage.

The problem with chemical stripping is that a) Unless you know a guy who knows a guy the store bought strippers aren't strong enough and b) you need to thoroughly wash it after your done which isn't great when you have no windows or doors.

We're not going to strip it completely. It's just going to a exterior bare metal respray. After this one is done (hopefully spring 2019) we're going to do my dad's '71 350SL and then his '75 280S. Both of which we shall do the same as the 6.9 (welding and bare metal exterior respray).
1971 350SL
1975 280S
1975 450SEL 6.9 #140

oversize

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Re: Stripping paint off the 6.9
« Reply #4 on: 10 December 2018, 03:36 PM »
Every process has its pitfalls. I prefer Soda blasting however not many people offer the service, it can be slow ($) and won’t remove body filler. It can also accelerate oxidation if not washed off properly.

Sand or bead blasting is thorough and quicker, but it can damage surfaces and remove small particles of metal which will rust in hard to reach crevices if not thoroughly cleaned out.
1979 6.9 #5541 (Red Bull)
1978 6.9 #4248 (Skye)
1979 6.9 #3686 (Moby Dick)
1978 6.9 #1776 (Dora)
1977 450SEL #7010 white -P
1975 450SEL #8414 gold -P

marku

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Re: Stripping paint off the 6.9
« Reply #5 on: 11 December 2018, 09:55 AM »
Took mine back to bare metal first using PQR15 cellulose stripper which got a lot off but wouldn't touch a primer used in a respray. Then used one of those paint stripping scratch free discs on an angle grinder. Worked really well and gave a very good finish for respray.
450SE silver green/bamboo velour/green vinyl roof
Mercedes Viano Ambiente 2.2CDI LWB

Justin280s

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Re: Stripping paint off the 6.9
« Reply #6 on: 11 December 2018, 01:18 PM »
I'm a spraypainter and still have not decided  how to strip mine.  It's sure is the worst part of a respray.  If they were painted in a 2pack finish, I would paint strip it.  Unfortunately acrylic  paint just makes a runny mess when this method is used.

UTn_boy

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Re: Stripping paint off the 6.9
« Reply #7 on: 11 December 2018, 09:39 PM »
I'm a spraypainter and still have not decided  how to strip mine.  It's sure is the worst part of a respray.  If they were painted in a 2pack finish, I would paint strip it.  Unfortunately acrylic  paint just makes a runny mess when this method is used.

Most, if not all, W116 cars that had metallic paint were base coat/clear coat from new.  All of the solid colors were a single stage enamel. 
1966 250se coupe`, black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3, papyrus white/dark red leather
1973 300sel 4.5, silver blue metallic/blue leather
1976 280s astral silver/blue MB Tex
1978 450sel 6.9 Euro, Anthr/velour

marku

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Re: Stripping paint off the 6.9
« Reply #8 on: 13 December 2018, 09:12 AM »
I did opt to respray with cellulose although I have seen some really great 2 pack finishes. That cellulose was original and I know nothing about acrylic finishes was the deciding factor. Since then I have used acrylic on another vehicle with very good results.
450SE silver green/bamboo velour/green vinyl roof
Mercedes Viano Ambiente 2.2CDI LWB