Respraying question

[iandromiskin]

I've stripped the bonnet on my green saloon and just decided to spray the one half that was sanded in primer to protect it from oxidisation etc and noticed that there are some metal scratches showing through the paint. So the question is what can I do ? Is it just a case of the more layers of primer (3) and colour (3-4) are applied that these will gradually be covered up or do I need some sort of thin layer of body filler or paint primer stuff before hand to hide these blemishs ?????




Its hard to make out, but there are little stratch marks and tiny pin hole depressions here.


Noticably scratches.

[Dean]

I'm guessing too coarse a wet and dry was used to prep the surface. They look like 'prep' marks.

Wait until the paint has gone hard, use 1200 or 1500 wet and dry after they have soaked in a bowl of warm water for a few minutes.

Gently using the paper resting on the section between base of little finger and wrist (this is the flattest part of your hand) and a bit locked between your finger to stop it sticking to the bonnet. Rub the scratched area until the prep marks have gone, they may be in the metal, so may take sometime. They will go eventually.... you sometimes get this when abrasive pads on an angle grinder have been used to strip the paint off quickly.

Wipe with a sponge to get rid of the waste, clean with panel wipe and spray small rubbed area with primer.

[ASL642]

I would suggest you spray with spray filler (yellow) It fills any tiny imperfections in the metal. No good for really big scratches/ grooves, but should cover those scratches. Available from anywhere that sells the paint.

[iandromiskin]

I think the previous owner went a bit crazy with a machine sander as there are a lot of similar marks on the front of the bonnet. Lots of wet and dry sanding ahead so

[jonathon]

Trouble is with celly primer is that it will always sink, might look great in the winter, them when summer comes and a bit of heat they will simply re appear.
An excellent product is an epoxy filler primer, this is a direct to steel paint and needs to be sprayed with a 0.2-0.3 gun tip as its increadibly thick. A few coats of this will be enough to fill the marks and give a good coverage over them.
Ideally guide coat this, and flat with a 240 disc then apply high build primer, and prep as normal for top coat.
This works wonders too over filler where there may be pin holes or slight undulations that can be almost impossible to flat out. A coat of this and hey presto the perfect finish ready for primer and top coat.

[bmcecosse]

Is it available to the amateur Jono - in rattle cans - or just for gun use - by professionals ?

[chickenjohn]

You could try sanding the affected area down to the primer, then applying 1K stopper. (Don't use cellulose knifing stopper). Sand this down and feather the edges of the repair, re- prime (5 coats), the sand again and the marks should have gone.

If you still have problems, you may have to go all the way back to bare metal in those areas and use very thin skims of filler.

I have found that cellulose shrinkage problems are avoided by then etch priming over filler and bare metal areas before priming. This avoids any shrinkage.

[chickenjohn]

By the way these types of prep problems can be avoided by applying a dust coat of black to the primer and sanding this off.Any low areas. scratches etc will be revealed as dark marks and these can be filled with stopper etc as above....

[jonathon]

BM, the filler primer I mention is not for home use as it containc the dreaded Cyanide. However there are two other products which will do the job and are safe for home use.
Firstly is a rattle can 1K high build primer made by UPOL and known as HIGH AL. this is a high build primer.
The other is high build celly primer made by HMG in grey or white. Its mixed 1 to 1 with thinner and is air drying available in 1L and 5L tins for gun use.

Both products are available to use with the appropriate fume mask.

[bmcecosse]

Useful information! Thanks.

[iandromiskin]

Just bought some of the UPOL 1K primer in a rattle can so we'll see how I get on with that.