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damunk

painting over paint? engine bay respray

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damunk

engine bay respray with rattle cans

 

do you have to take every bit of the paint off and get it down to bare metal?

 

because an orbital sander would be hard work to take the paint off.

 

i think of only using a wire wheel with a drill but seems drastic .

 

 

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steveo3002

no , the factory paint will be way more protection so dont strip it off unless peeling /flaking

 

use a red scotch pad to scrub at the old paint to provide a key , you need to work at it until its all dull paying extra attention to corners and creases and anywhere that see's more wear ..the pads can be used with warm soapy water or panel wipe 

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damunk

yeah ive just bought some red scotch pads and an etch primer for the rust parts.

 

one question steve, there are parts where the paint has peeled because of rust. do i sand this part down, use a filler to get it level with the factory paint, then sand it like you said to key it in then spray etch primer on the whole thing.  before putting on the main coats.

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steveo3002

yeah sand it until its clean metal , try and get any pits clean with a dremel /wire wheel , go through the grades of paper and make sure its finished with 180 or 240 , just etch the bare metal , no need to etch the sound original paint 

 

and yes if its pitted badly then use filler ..but as i said preferably over 100% clean metal  or the rust will be back ...bilt hamber deox gel works well if you use enough 

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damunk

any harm in etch priming the whole thing grey including factory paint?  I just thought it would be a easier way to check for any defects when shining a light on it all.

making sure it's all smooth looking

 

 

 

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steveo3002

i guess not , its fast drying anyway so i doubt it will help you , its meant for bare metal

 

the way a painter checks the surface is to wipe it down with panel wipe and catch the surface in the light at the right angle , shows up any defects 

 

you could also go over it with this just before painting ..helps the paint bond 

 

https://www.ebay.co.uk/itm/UPol-Grip-4-1K-Universal-Adhesion-Promoter-450ml-Aerosol-Can-clear-GRIP-AL/323234033081?epid=547503408&hash=item4b423fedb9:g:Nr0AAOSw4J5a57B9

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damunk

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damunk

you know that bilt hamber gel you use. 

 

1)do you still need to sand any rust off if your going to use that gel? from youtube vids seem you just apply it and it takes away the rust to bare metal

 

2) also is a must to shrinkwrap any part you have applied it too?

 

 

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steveo3002

yeah clean it up first otherwise it would take more gel

 

put a thick layer on and cover it , once its turned black its used up , rinse it off and do it again until theres no rust pits , will take several goes over a few days to clean it up well

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damunk

seems like you can't get it from local shops. looks like an ebay job :( will have to wit till next week now

 

seen this from tool station https://www.toolstation.com/shop/Painting+%26+Decorating/d150/Metal+Paints+%26+Primers/sd3152/Rustins+Rust+Remover/p20340

Edited by damunk

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Buxton

I did mine, looked really good i just thourally cleaned and degreased it, scotch pads are great as said, get some good quality clear on top, cheap stuff fades after a while.

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damunk

guys, do you have to spray on the underside of the chassis beams?

hard to get to those underneath parts and the parts that are near the subframe.

 

those parts dont get seen anyway when engine is in

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steveo3002

dont have to paint anything you dont want to ...personally id try and do as much as possible 

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damunk

bilt hamber was pretty good. on the chasis leg it took three times though to get ride of the rust. I've got 99% off, Just a few dots (pits). Might just etch prime over those.

 

Ive also used it on the engine mount covers. My question is, shall I take the engine mount covers for powder coating or just use 2K paint finished with a 2K clear coat?

 

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steveo3002

up to you both work fine...personal choice 

 

although once damaged powder coat is harder to touch up /redo 

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damunk

because it's powder coating is thicker?

 

i've bought some steel body filler so after i take off the rust with the gell, again will etch prime to prevent rust return. roughen it back up with sand paper and use the filler to get it smooth.  finish off with painting

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steveo3002

harder because its melted on powder ...vs a repair with a paint brush on painted jobs

 

fill onto bare metal or epoxy primer only....NOT OVER ETCH

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damunk

aah bugger, etched it now.

 

i will sand it rough, i did read quite a few  posts from forums that you can do it either way aslong as you roughen the surface.

https://www.hotrodders.com/forum/can-you-put-filler-over-self-etching-primer-safely-121000.html

 

the etch primer protects rust from returning. it would defeat the object using the filler first because the filler is prone to moisture.

 

it seems it's one of those topics that is hotly debated for and against, i did think about it hard before choose to etch the the clean steel the rust was removed from.

 

 

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steveo3002

etch takes on moisture too

 

the only primer that doesnt is epoxy

 

much like your link says 

Edited by steveo3002

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damunk

steve, as i have etch primed the  rust partrs as the etch has chemicals which will stop rust from returning or growing if there were any pits left. and u suggest no filler on top of that.

 

can i now put some expoxy primer over the  etch primer where i want to put the filler to give it a smooth finish. theres only 4  of  30mm patches that i want to fill

 

 

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steveo3002

proper answer no 

 

if you want to do it right thinners it off and epoxy it 

 

 

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damunk

So what is the etch primer used for then? obsiuly bought the wrong stuff

Bought two cans for nowt

 

 

ill sand it back off the where rust was no problem . that aint a big deal then epoxy primer like you said

 

but can i leave the odd parts where it was over the normal paint. it was a proper thing coat lol

Edited by damunk

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steveo3002

etch is used to help further coats of primer adhere to the steel , it contains acid and etches/bites into the steel so that it sticks

 

its not the wrong stuff , just isnt used under filler - for etch you would fill any defects onto clean bare steel , then etch any bare metal spots then on with high build primer 

 

or 

 

epoxy primer is more modern and better performing - you can coat the whole project to seal it first then fill over it , or fill the dents then epoxy over the whole thing  

 

both are acceptable ways to do a nice job...you just need to follow the correct steps , if youre able to use epoxy then do so its much better and doesnt soak up the moisture at all 

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damunk

I have now been told dont need the filler. the dimples and rough texture left by rust remover apparently will smoothen off after a couple of coats of high build primer or top coats.

 

might just fill it with the etch paint and sand it smooth. we talking 0.1 -  0.3mm 

 

so bought a tin of filler for no reason 

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