Repairing Deep scratches on bumper

MSG2004

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Hello

In the rain today reversed into a narrow alley, the drivers side bumper aught the wall edge. several scratches on metallic black bumper, one about 1mm deep and a chip on rear wheel arch about 4mm sq. The good thing is its on the side of the bumper and looks like dirt.

I do not want to have it repaired professionally as the damage is not that great or easily seen.

Any good touch up paints/tips please.

I intend to go to halfords within 2 weeks and get paint, light sand scratches and touch over. The damage is 99% to the plastic bumper near the drivers rear passenger door.

TIA
 

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1mm is quite deep and it might be better to fill the marks with P38 and lightly sand off, with the aerosols you can loose the spraying on the rear end on the corner, always after filling give it a light sand using a block and all high spots will be seen, when flat it would need two coats plus the top clear
 

White230CE

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I've just practised re-spraying my plastic lower sills with an aerosol.

Firstly, I would suggest getting your paint from MB, not Halfords. Halfords does not stock the full range, and even their customised paint-mixing service produces irregular matches.

I didn't bother filling scratches in because it was the lower sill and most were on the underside anyway, but the outcome showed me that filling is necessary if painting somewhere which can be seen.

I found the spread and coverage from an aerosol to be limited, and can produce a somewhat patchy effect. While the outcome wasn't bad in the end, I think with more paint and sanding between layers, I would have achieved pretty good uniformity, but I didn't want to spend any more money or time. With the MB aerosol, be prepared for the expense - you do not get much paint for your money. Also, do not use the aerosol to the last drop. Towards the end, pressure declines, and your spray pattern will deteriorate as a result.

If you are spraying a metallic colour, do not sand the last coat, because that will disrupt/dull the metal flecks and give you a bad finish. Just use a tack rag to wipe off residual dust/overspray before spraying your clear coat. The clear coat should go on betweeen 12-24 hours after the last coat. Then, rub down the clear coat if necessary, with 1200-1500 grit. I did not on mine as it seemed ok; I just used a cutting polish.

Enjoy!
 

rob the painter

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Any automotive paint supplier in your area can produce an aerosol to the exact shade for a similar price to Halfords. If you have a Morelli or Hex Holdings branch (or similar) they should be able to give you everything you need.
 
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MSG2004

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Thank you both!!
I'm pretty lazy when it comes to things like this.
However, this w203 was ought last year, 07 plate. I have decided to touch up, but when I have he car washed, that is when it may make me rethink and fill in the groves/etc.
I was hoping for a easy solution :(
Cheers
 

White230CE

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Any automotive paint supplier in your area can produce an aerosol to the exact shade for a similar price to Halfords. If you have a Morelli or Hex Holdings branch (or similar) they should be able to give you everything you need.

Rob, do you know if Eurocolour do paint matches, and if so, are they any good?

Thanks
 
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MSG2004

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BTW. just checked out the 'p38' - states that it's for metal only - most of the scratches are on the plastic bumper.

Any plastic repair kits lease?
 
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MSG2004

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Xtractorfan

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P38 will be absolutely fine on bumpers, Tho' if you are a perfectionist then you will go for the plastic filler, I think P40 is actually fibre glass.. and never allow basecoat to sit more than 1/2 an hour without lacquering otherwise the lacquer wont stick, and the basecoat will absorb moisture from the air..
With plastic repairs you have to flat down first and remove all the little grainy bits on the edge of the scrape otherwise they will move around when you rub down the hardened filler..
 

rob the painter

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Rob, do you know if Eurocolour do paint matches, and if so, are they any good?

Thanks

Sorry, I don't know. We don't have them in my neck of the woods. As a point of interest, a good quality independant bodyshop should be able to blow-in a bumper corner for around £80 (cash) and you'll never know. Beware of some people offering smart repairs for half that price though, i've seen some so bad you will have wished you did it with an aerosol yourself.
 

Xtractorfan

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Eurocolour as far as I know are using a cheaper brand of paint , basically mixing different paint brands together.. so the match will not be good...
 

White230CE

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and never allow basecoat to sit more than 1/2 an hour without lacquering otherwise the lacquer wont stick, and the basecoat will absorb moisture from the air..

Hi XtractorFan. There seem to be so many conflicting views on when to put the lacquer on, ranging from your advice, to the 12-24 hours I was advised. I was told that if the lacquer goes on too soon, the basecoat does not cure properly, and/or the lacquer can 'pickle' the basecoat. Are you able to separate myth from science please? :confused:

Many thanks! :D
 

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The base coats as used in aerosols are an acrylic, this is why they do not react on any surface, no matter what they were painted with.

All paints shrink as they dry, there is a difference to being touch dry and surface only dried, this shrinking effect also applies to a scratch or scored line, if the under surface was not perfect, it will shrink or pull back from the sides of the line or scratch, and this being the case it must be flatted again and another coat put on. the drying time for this can be up to several hours but in the sun its much faster or with a heat lamp.

On surfaces where the is no damage, or danger of the paint sinking or shrinking, the top coat can be applied with ½ hour and a good bond will result.

Paint that has sagged or run, leave it 24 hours and it will have shrunk down to a minimal, and it will quickly sand off.

You would have to be very heavy handed to trap any solvents in the paint coats, it is so thin, it will run before that will happen.

Any mistakes do nothing other than leaving it to dry, rub down and start agian
 

Xtractorfan

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I think the confusion over the drying times arises because of the introduction of waterbased paints, now with waterbase it is sensible to leave as long as possible to dry, to ensure that the paint is fully dried before applying the basecoat, but with solvent based paint, as malcolm has said they are so thin that they dry very quickly.. basically solvent based paints should never be left for more than 1/2 an hour before lacquering.. I bet you have seen lacquer peeling away from a repainted panel, this is mainly caused by leaving the basecoat too long before lacquering..
As for the other problem, pitting, this is caused by moisture being absorbed by the basecoat.. polyester / acrylic.. then being trapped by the lacquer when it hardens, moisture then swells and evaporates with the heat and causes pitting or
micro blistering.... there is also lacquer popping which is caused by too much heat.. if the basecoat isnt dried properly, or is dried too quickly, the top coat dries and skins over, trapping solvents, then when you lacquer, and again force dry the lacquer, the trapped solvent boils and pitts the lacquer

So basically one coat, ten minutes, second coat, ten minutes, third coat, check that all is covered and uniform, wait 20 mins and then lacquer, wait ten mins and second coat of lacquer. Now if the air temp is below 12deg then use a heater to gentlly heat the panel, if using a blow heater, switch it off whilst painting , and let the paint flash off before starting the heater up again.. you can check the dryness of your paint coats by touching the masking tape beside the repair, but remember that on ocassions, if you have no heat, that metal will be colder and wont dry as quick as the paint on the tape..
 

White230CE

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Thanks XtractorFan and Malcolm. Soundly reasoned advice as always. :D

One question please: What do you mean by 'let the paint flash off'? I don't understand 'flash'.

Thanks
 
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"Flash off" is surface dry so that it will not run,,so just touch dry but not all of the thinning agents have evaporated, so still soft if touched hard
 

White230CE

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Well, I've had to bite the bullet and paint a part of the offside rear panel that is exposed to view. It was either keep the original, which had some dents in the chrome strip, or use the donor's which had a scrape. Because I didn't want to buy and fit a new chrome strip, I chose the donor's.

It had taken a scrape at the top just where it meets the edge of the door. Luckily, the chrome strip wasn't damaged, but the plastic itself was scraped. Filled, painted and lacquered as per latest advice. Very pleased with the outcome. The colour match isn't exact, but overall very acceptable for a partial re-spray with aerosols. I prefer this slight mis-match to a dented chrome strip. :lol:

Thanks again.
 

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Pleased that you have done it. The 124 bumpers from new had a matting agent of 10%, and a flexi agent of 20% the trouble is you cannot blend these products as they were a 2 pack top coat. With metallic the air pressure, they angle of the gun, all play a part of the overall colour.

The little things on these cars like the strips under the headlamps that rust are easy to take out and do a good job with.

Anyway so pleased that you have done it
 

White230CE

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The little things on these cars like the strips under the headlamps that rust are easy to take out and do a good job with.

Anyway so pleased that you have done it

Thanks Malcolm.

As it happens, when I took off the front wings, those strips had to come off, so I took the opportunity to repaint them. Waiting for MB to get me the little plastic washer jet tripod that inserts behind the strip (they broke when I removed them to paint) so I can put both strips back on!
 

symonc1

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£60 repair..... easy.... send me a pic it ant gonna be more than £60
 

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