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Do I Need Primer For Respray?


agent_zed

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Hi,

the 2b needs a bit of love again so just planning what i'll need. In the past when i've resprayed various panels i used the etch primer that i already had (i sprayed the original mild steel panels with it) and then top coat.

 

This seems to have worked ok, i.e. the paint has never flaked off, but the problem i do get is that if any plastic sheeting touches the car and gets wet it's has some kind of reaction and goes white and the paint softens and takes up creases from the plastic. Still don't know why but as long as i don't put a sheet over it then it's fine.

 

So long story to get to the question... should i use a normal primer over the existing paint? or can i just flat it back to a decent surface and spray the topcoat straight on again without bothering with a primer?

 

I am guessing you'll say use a primer but thought i'd check as it has been a while since i last sprayed.

 

 

 

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Guest chris brown

You tended to answer your own question. Yes priming would be best then use a good 2 pack paint. If using metallic then you will need a laquer from the same paint manufacturer to be sure of the best finish.

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Thanks guys, yeah i guess i did answer it myself a bit :crazy: half forgotten what i did last time so just needed a bit of a prod in the right direction.

 

i won't touch 2k, i don't have the breathing kit that i would be happy with. I use a chemical P2 respirator with celly which seems to do the job as i can't even smell anything when spraying so must be working. Wouldn't 2K need a barrier primer also? don't think it will go straight over celly will it? or it that the other way round.

 

It's only a flat colour so no laquer required.

 

Think i'll go the primer route to be sure.

 

Going to go for a little change this time i think though and spray the front arches black. The rest of the car is yellow. I did consider doing the nose cone black too but i think i won't as i have to sort my lights as the chrome is gone so i'll spray them black too.

 

Hopeing to go to Stoneleigh so have a date to aim for to get everything spruced up. :)

Edited by agent_zed
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Next question.... Should i use anti-bloom thinners?

 

In the past i've just used standard thinners. Could this be the problem with the white marks/reaction to water and plastic?

 

Or perhaps just premium thinners?

 

any thoughts?

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  • 3 weeks later...

Anti bloom thinners is so cheap why wouldnt you?

Primer is always a must if you want a good quality job that will last. Look at plasticizer to give durability on flexable surfaces. A decent DeBliss or similar will put the paint on effortlessly. Air needs to be nice and dry and I like to spray at 30psi, yes its slower than 60/70psi but gives a flatter finish and needs less flatting and mopping. Its also more forgiving for a novice because it lays the paint down more slowly.

 

You can get paint that dries under UV lights for a faster turn around and saves oven backing. You can do many things but it all comes down to whether you want a quality job or just a passable job.

 

 

Dont confuse primer and etch primer. Etch primer is for galvanized and plated material and alloys. Its also extremely toxic and I wear full BA when I spray etch primer. It contains cyanide not to mention other carconagens. It has to be sprayed in controlled environments too with fume scrubbers to prevent next doors plants from dropping dead, not to mention their kids. 8 years ago a scrubber failure lead to a body shop where my friend works being fined and the resulting loss of plans life in the gardens for quite some distance had to be paid for buy them too. So blatantly flouting the rules could see you getting a good slap on the wrist. Standard primer is all you need to overpaint.

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yeah i went for anti-bloom as i don't see the weather getting much better for a while so might have to spray in less than perfect conditions.

 

So i definitely used activated etch primer but it wasn't the deadly kind. I think we are getting confused in terminology though as there is 2 pack expoxy primers which are nasty things with cyanide and 2 pack activated etch cellulose primers.

 

'

https://www.phoenix-paints.co.uk/etch-primer 2 Pack Etch Primers

As the name suggests 2 Pack Etch Primers (or 2 Part Etch Primers)are supplied in two parts - the Primer and an Activated thinners. It is the activated thinners that contains the acid and thus causes the reaction in the primer.

2 Pack Etch Primers should not be confused with Two Pack Epoxy Paints. Whilst the terminology of 2 part (or pack) means the same, the two products are as different as chalk and cheese. Two Pack Epoxy Paints are very hazardous and should only be handled in the proper environment, 2 Part Etch Primers are essentially no more dangerous than their single pack cousins.

The disadvantage of 2 Pack Etch Primers is the fact that you have to mix the two parts together.'

 

I used a cellulose etch primer on all my panels from the mild steel to the grp and after 10 years it's held up pretty well. It's the top coat that doesn't seem to hold up so well but not from flaking off but by having the weird reaction as mentioned above.

 

This time around i will be using decent thinners so perhaps that has been my problem in the past and if i put a normal primer on perhaps that will stop any reaction with the etch primer if that is doing something.

 

Getting a good finish out of the gun i've generally been ok at and only need a bit of polishing to get it nice enough for my needs. Oh and having to flat out all the flys :) I tend to stick a bit more thinners in for the last coat as i've seen people saying to do that and it seems to work for me.

 

I might try using my gravity fed gun this time as it's smaller so perhaps i can use lower pressure on that. Otherwise it will be my bigger gun but that always seems to need a lot of psi or it just won't spray properly even though i think it is a 1.2 nozzle if i am remembering my numbers correctly.

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