Hot Rod Forum banner

Problem with soft paint

4K views 4 replies 2 participants last post by  electrophotic 
#1 ·
I have a ‘soft paint’ problem on my car (an MGB) which was re-sprayed 6 months ago at a local sports/performance car restoration specialist. This was a full bare-metal re-spray. Even the lightest touch (with fingers or clothing) will leave permanent scratches on the paint surface. I complained about this, and the other day the proprietor of the restorers visited me to see the car, and brought with him the paint retailer and a technician from the paint manufacturer. The technician carried out a hardness test on the paint and confirmed that the paint job was too soft and unacceptable, and would require all or some of the applied paint to be removed and the job re-done.

The products used were:

  1. Lechler R-EC epoxy primer + Lechler 29370 hardener (2:1) + Lechler 00516 thinner as required.
  2. Lechler TI primer + Lechler HS hardener (5:1) + Lechler 00740 thinner as required.
  3. Lechler BSB basecoat + Lechler 00741 thinner (10%).
  4. Lechler Macrofan HS clearcoat + Lechler HS hardener (2:1) + Lechler 00741 thinner (10%).
The paint technician said that there had been insufficient thinner added to the basecoat – he thought it should have been 20%, and said that this is what they (the manufacturers) recommend. I’m surprised that such a small difference could be responsible for what now appears to be a very soft paint surface. He has advised that both the clearcoat and basecoat should be removed before re-spraying.

Later, using a razor blade, I peeled off a couple of square inches of paint. The clearcoat came away with all the basecoat attached, leaving the primers attached to the car. The primers appeared to be fully cured and wouldn’t mark by fingernail. The basecoat layer didn’t seem to be soft – it scratched off the clearcoat as black dust. The remaining layer of clearcoat is very soft, and will mark easily.

Approximate paint thicknesses are:
Primers – 200 microns
Basecoat – 25 microns
Clearcoat – 90 microns

I’ve looked at the Lechler data sheet for BSB basecoat and it recommends a mixing ratio of 1000 parts BSB to 600-800 parts 00741 thinner.

Could the basecoat be responsible for the paint softness?
(Attached photo shows scratches left by artists' small watercolour brush)
 

Attachments

See less See more
1
#2 ·
I have never heard of the paint brand you are referring to (different country I am assuming), however, for the clear to remain that soft, I would suspect the activator/hardener for the clear coat was either mixed at the wrong ratio, the wrong kind was used, or was left out all together. If the paint company recommends to remove it and re-do it, then that is exactly what you should expect the painter to do, regardless of the cause.

Kelly
 
#3 ·
Kelly, I'm in England, and Lechler are an established Europe-based paint manufacturer who seem to have a good reputation over here.


The painter knows he has to rectify the problem, but is waiting for Lechler to confirm in writing what the problem is and what rectification work is necessary. He says he doesn't know what has caused the paint to remain soft, and that my car was painted in the same way as all his other customers' cars (typically Ferrari, Aston Martin, etc).
 
#4 ·
At least it seems tha5t things will get repaired and that is a good thing. I was thinking after I posted, and it could have been a mixing error, but it also could be a bad product. Not saying everything at the paint company is bad, but occasionally for whatever reason, there are some bad batches of products that come around. The activator could have been old, or not sealed properly, etc. It could be a lot fo things, but if you get a definite answer let us know for future reference. Good luck with it.

Kelly
 
#5 ·
Thanks, Kelly. I think faulty product can be ruled out - this was discussed when the guys were here looking at the car. The paint retailer has a high turnover of the products used on my car and he said there had been no complaints from any other customers. The painter is sure he did all the mixing right, although I know that mistakes can happen (especially if interrupted when mixing stuff).


I didn't mention in my original post that this is the second time this car has suffered a defective re-spray. I took it off the road in July 2012, stripped it down ready to go into the paint shop, and it was returned to me a few weeks later looking like new ... except the paint was soft. This was a different paint shop, different products, different paint system (solid black gloss - no clearcoat). It turned out that their painter was the proprietor's son with only a little experience (their top paintwork guy had just retired before my car went into the shop), also they mixed Pro-Spray paint with FSL (cheapo) hardener which the Pro-Spray tech man said was a no-no. I wouldn't let them have the car back to have another go, and it took nearly 2 years to get a refund out of them (threats of legal action and pressure from Trading Standards).
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top