Chemical dipping

[jongant]

I am just learning an expensive lesson. My 1965 FHC was repainted 3 years and 20,000 miles ago. Those miles are both wet and dry. Against the caution of my paint shop, I had the tailgate and the bonnet chemically dip stripped and then electrophoretic primered.

Paint was duly applied and all was good for a long while.

After a year, I noticed a few dents around the rim of the tailgate and thought it was golf balls or similar. I also started to notice that the seams were bulging a bit and put it down to age although the edges seams were absolutely flat when I started the repaint. The tailgate had survived 40 years and 150,000 miles up to that point.

Months further on, I can tell you that the rear door no fits flush to the body and visible lumps and bumps are growing by the week. Furthermore I notice that the rear lower edges of the bonnet, where the bonnet wraps round the round bar are starting to grow.

All of these instances are despite copious quantities of wax oil.

Clearly I have no proof that the dipping process is at fault, but I would advise anyone who is considering this process, to think very carefully about components that have seams or joints that can trap agressive chemicals. I thought this process would get into places that nothing had got before. Perversely I was right, trouble is it finds it difficult to get out and keeps working.

I am now working on another door that has been cleaned up by a much better process in the right hands.

[MarkE]

I've seen this sorry sight a few times now on cars that have had an expensive dip and e-coat preparation. I guess that a few years ago it sounded like the best way to preserve your car for years and years to come.

The saving grace is that you didn't have the main body done, and at least the bonnet and tailgate can be unpicked, de-rusted in the normal manner, and put back together without ripping the car to bits.

When I stripped mine, using a paint stripper to start with, I was lucky to have the guy who was going to paint it drop in just when I started. He insisted that I didn't use the stripper within an inch or so of any seam, and the best practise was to mask out the seams to ensure that nothing contaminated them. I have also seen cars which start to peel paint from the seams, as the stripper has seeped in and waited, sometimes for a few years, to react with the paint.

All in all, an expensive addition to the restoration bill!

[Tony]

Do you ever get the feeling , you can not do right for doing wrong. For every plus their is a minus. Maybe we try to hard with our obsession with rust?

I hate rust, rot , damp, weeds and any thing else that attacks my little world of being right. Then again if things did not decay there would be an awful lot of debris about and the world would not go around.

[SteveG]

Mark,

Is there to your knowledge a 'best' way of stripping a car? I have some small rust areas in one floorpan and gearbox tunnel, as well as needing the paint removed. Having heard horror stories about dipping shells I am thinking of having the tub soda blasted before having the usual e-coat applied. I am now doubting this as there seem to be pros and cons with whichever method is chosen. Any advice would be most welcome.

[MarkE]

Steve, Soda blasting won't help you as it is not abrasive. It will remove the paint but won't touch the rust. It polishes glass and chrome, and brings old aluminium castings and rubber bits up like new!

The only way to sort out rust as far as I can see is to cut it out if rotten, or remove it from the bare metal with an orbital sanding machine or an abrasive media blaster (sand blaster in general terms).

Some restoration bodyshops will do local blasting for you, using a small nozzle / low pressure system, but I would only use a specialist who knows what he's doing. Many cars have been ruined by careless blasting which heats and distorts panels.

[SteveG]

Mark, Thanks very much for your help, I'll have a chat to some specialists for the paint as can't stand the thought of having to remove it all by hand! As for the remaining small amount of rot I'll cut it out and take it back to solid metal for the repair.

It's a bit of a minefield with so many restoration services, what you think will speed up a process could end up causing many more hours of work in the long run.

[MarkE]

If you're stripping all the paint from the car then using a paint stripper on the outer panels is fine...just don't go too near the flanges around the roof (the gutters), the window / door apertures and the tailgate / bulkhead areas. It's really the inner bits like the floors, inner door areas and bulkhead which have the complex seams / joins that a stripper can seep into, and it?s probably best to sand those down.

I found that using paint stripper was the least messy operation (especially compared to an orbital sander) and it will also 'melt' skims of filler quite well.

I took my time doing the work, and it was probably a year from when I started stripping the bodyshell to when it went into the bodyshop. If you paint the bare metal with phosphoric acid (I used 'Jenolite') then the body can stay in bare metal for years (in a dry garage) without any rust getting hold.

Here it is after about 9 months...looks odd, but it's well preserved, with very little work required to be done by the bodyshop in order to remove the coating.

[vipergts]

Don't

[daverawle]

A hot-air gun on warm strips the paint quickly once some heat builds up in the panel. It's quite therapeutic seeing it coming off in long strips. Takes a few days to strip the entire outer surface safely, just need to wear a mask. The underside probably would still need to be media blasted but less chance of causing problems there.


Dave

[jongant]

New-secondhand door all painted and looking lovely.

Took the opportunity to cut up old door in sections so we can all see whats what.

Clearly its not absolutely clear to see thye rate of degradation.

But draw from it what you will.

Anyhow.........no more chemicals for me!!

[Dave K]

I worked on the maints in a paint plant in Coventry for a few years that carried out electrophoretic dipping for Aston Martin, London taxis, NATO cabs, and body shells for the MG owners club. If the process is done properly the e coat should be drawn inside the box cavities of every component of the vehicle. The shell starts the process with a good wash in demin water, then onto the alkali wash, demin water, phosphate wash, demin water and then finally into the e coat where magnets are applied to pull the paint into every cavity of the car. Normally any item that can be removed is, like doors and bonnets etc, and they go through on their own. I have had every component of my car through the process except the body and the engine block, gearbox. I can't fault the process and with all the pre washes all traces of any acids should be thoroughly removed. Having said that all the cars that go through are brand new and have never been acid dipped.

I took most of the paint off myself by good old fashioned means and elbow grease and then had the seams media blasted; even then the idiot put too much pressure on the boot skin and pushed it back against the support frame meaning I had to re skin it.

Dave