Enquire

Interested in:

Alternative Methods

Alternative paint removal methods and why we don’t use them.

If you would like to know more about the various materials and terms used in the blasting world, take a look at the the pdf entitled 'Real technical stuff for the car restorer' in the downloads section.

Some people actually try to use bead blasting for paint removal, using glass bead. Unlike angular particles in plastic media, glass bead is harder and spherical and therefore needs to be propelled at the surface fairly hard to remove paint, it has no cutting edge, it relies on impact. This creates two problems - kinetic energy, which produces heat, which can cause distortion – and peening, a ‘hammering’ of the metal which can actually move the surface around (in microscopic terms) and even trap particles of debris and corrosion in the surface you want to clean. On chunky things the peening is not a problem but embedding dirtin the surface is counterproductive.
 

Chemical dipping has enjoyed some success in recent years, but it has also had its fair share of problems.

The process has to break down all the layers of paint, filler, underseal etc, but it also removes all the seam sealer, allowing capillary action to draw the aggressive chemicals into the seams of the shell.

If you know anything about soldering, prepare a solder joint in copper pipework and put the flux into the joint, warm it up, now try and get the flux out without taking the joint apart! You will never get rid of it. So when all those rust eating chemicals are in the seams and box sections of your car, how do you get it out?

Now chemicals that eat corrosion don't necessarily remove paint and rubbery seam sealer and underseal. But something in the process does remove them and it also removes all the lead loading in the panels, (upmarket body filler). Not much attacks lead - except heat ….. above 327degrees C.  You figure it out.

So it is true that the chemical dipping gets to places that we can't get to with our blasting processes - like the box sections, and it is also true that there may be some blast media residues left in the bodyshell, box sections or sills and the like. Whilst our dry media residues may be a nuisance, most of it will vibrate and shake out of the shell on the trip home and a quick hoover should do the rest, …… whereas the wet chemical residues are there to stay.

“Ah, but you get distortion in the panels when you use blasting”, I hear someone say.

True, it is a risk. But it is a risk in almost any process: at least you can see it and deal with it; unlike the chemical residues that are lurking in the seams that you can't get to.

We had a shell brought to us after it had been chemically dipped because the restorer was not happy with the finished result, the shell was not completely clean and there were corrosion run marks and surface corrosion in many areas, especially around the underfloor box sections, seams and overlaps. We took pictures of the car before we cleaned it by our methods.

By a quirk of fate, the owner became very ill and we had to store the car for nearly 8 months. During that time we observed the chemicals literally eating their way out of the body shell. For example, around the wheel arches, a little brown bubble would appear, which then exuded a brownish black liquid forming a little blob on the surface. This eventually dried up to leave a very corroded spot with a hole in the middle.

As this was coming from the inside out, what is it going to do to your new paint job? All over the shell was much the same where there were overlapped panels and spot welded joints, particularly in the boot and the underside of the car. The poor old painter gets it in the neck every time; when a blister appears in the paint, one automatically assume it is poor paintwork, but in truth the painter has probably done a perfectly good job on what appeared to be sound metal. He can't possibly be responsible for something that is eating its way out of the car. We hear about these problems from trade customers quite a lot.

So when deciding which method to use, have a good read on the forum pages to see how other people are getting on with various processes, and then make your mind up.

Soda blasting is also used, and does a good job generally, but it also has a residual problem, the Bicarbonate of Soda with a Ph of 7.5 (slightly alkaline) becomes something much more aggressive with a Ph of 9.5 when the temperature increases. So on a nice hot day your paint will be quietly pickling away at the seams and overlaps.   Soda blasting will remove paint, but not corrosion.

Cryogenic ice blasting is too slow, and very noisy.

Shot blasting or steel grit blasting is far too aggressive and will almost certainly cause damage to panels.

Sand blasting. Though the common name for blasting tiny particles at a surface to remove the coating is still 'sand blasting' using sand is illegal, because it releases respiratory damaging silica into the atmosphere, so the term should actually be grit blasting. There are good operators around who can strip the paint and underseal and remove corrosion all in one process by grit blasting, but we would recommend that you have a look at some work they have done, or talk to a previous customer before entrusting your precious classic car to them. operators with that skill are few and far between, and once it is all distorted and bent and rough to the touch there is no going back. We often hear of owners/restorers who presented a really good shell to a blasting contractor for blasting, they used coarse media, and the car was wrecked.

One of our customers is a Porsche restoration specialist.  He recently brought his 172nd car to us in 19 years trading. He hates the fact that he has to do a 1000 mile round trip to us from the West Country with every car, and although he has tried other companies and processes, (because time is money), he admits he keeps coming back because he gets the results he wants from us. Have a look at the link to his web site below, he mentions us lower down the page.

Testimonials – http://www.rogerbrayrestoration.com/restoration.htm