27 replies to this topic

[phils sprite]

hi everyone

ive recently just respayed my bonnet i sanded it down with 600 untill i was happy with the results then i filler primed the stone chips and sanded again with a block i then applied sevral coats of halfords white primer waited untill this dried and then i rubbed down with 1500 grit to get rid of orange peel i then sprayed my colour (halfords rover electric blue from a rattle can) did many coats and was amazed with the results i was about to apply my laquer a week later only to find lots of little bubbles surfacing from the paint!!!! was ver angry and i sanded it down again to reveal spots of white primer and bare metal in places i then reapplyed the white primer and a few hours later i came back to it to find the primer was all cracked and it just carrys on cracking every time you spray it!!!!! any ideas what this is!?? and any ideas on how to rectify the problem!??

many thanks for any help phil. :'(

[Retro_10s]

sounds like the first time you applied your colour you hadn't degreased the panel properly, blistering is caused by Poor adhesion between the top coat and primer -probabnly moisture between them. The only certain way to eliminat it is to start all over agian.

Also what temperature did you spray at?... if it's too cold the paint will crack.

Have you got any pictures of the bonnet we could see?

[phils sprite]

oh right but i did use a strong solvent degreaser before any spraying?

yea the bonnet was sprayed in the cold i have no where thats warm to spray and the cars gotta be on the road by march!

we also found that the paint dosent crack if you cover it with the yellow acrilic primer what do you suggest i do nitromors the bonnet and start again or cover with yellow primer and respray?

this is a poor pic but its all ive got at the moment.

cheers for the help! phil.

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[koss]

this is a poor pic but its all ive got at the moment.

cheers for the help! phil.
[/quote]

Is there any filler or stopper under that bit on the first picture?
I had a similar problem applying primer over stopper.

[phils sprite]

whats stopper???

erm i cant remember for sure but we found that if you spray it with the yellow filler acrylic primer then it dosent crack

cheers for any halp again phil

[Retro_10s]

don't use high build primer to hide cracking. You mention the use of nitromors: are you sure you got rid of all the residue if you used it?... The easy way round this problem mate it to go down to bare metal on the affected patch and a few inches around it, and build up the primer again making sure you complete every stage of prep faultlessly.

[koss]

whats stopper???

erm i cant remember for sure but we found that if you spray it with the yellow filler acrylic primer then it dosent crack

cheers for any halp again phil

Its like fine filler cellulose putty for filling small scratches etc

[phils sprite]

hey guys thanks for the help well this weekend i sprayed the whole bonnet with filler primer the yellow stuff! hehe a 50:50 mix with thinners it now looks like this! ill have to wait till next weekend to spray it but so far so good. hehe

all the best guys phil

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[rozzer!]

hey guys thanks for the help well this weekend i sprayed the whole bonnet with filler primer the yellow stuff! hehe a 50:50 mix with thinners it now looks like this! ill have to wait till next weekend to spray it but so far so good. hehe

all the best guys phil

looks sealed well enough now. dry flat it with 320 grit before you primer it. allow to dry. dry flat it agaoin. degrease. if there are any break thrrough's dust a little primer over the area, leave for a few minutes and then start applying colour coats, in even passes. allow to dry between coats and tack off with a tack rag. this removes any debris from the paint. after the final layer of colour, alllow 15 minutes to dry, give a final tack off and apply the clear coat.

[phils sprite]

hey guys thanks for the help well this weekend i sprayed the whole bonnet with filler primer the yellow stuff! hehe a 50:50 mix with thinners it now looks like this! ill have to wait till next weekend to spray it but so far so good. hehe

all the best guys phil

looks sealed well enough now. dry flat it with 320 grit before you primer it. allow to dry. dry flat it agaoin. degrease. if there are any break thrrough's dust a little primer over the area, leave for a few minutes and then start applying colour coats, in even passes. allow to dry between coats and tack off with a tack rag. this removes any debris from the paint. after the final layer of colour, alllow 15 minutes to dry, give a final tack off and apply the clear coat.

oh my god!! im so so so so lost sorry to say i barley understood those technical terms! hehe

whats a tack rag? 320 grit!!! ive been using 1200- 1500!!?? whats flatting?? only mist with primer!? dont i cover it in primer? do i then have to sand the primer down?? tack off in between every single coat? dry flating whats this? how long do i leave it in between coats?

many thanks for any help im really relying on you guys! thanks again phil.

Edited by phils sprite, 30 January 2007 - 11:36 PM.

[phils sprite]

sorry also wanted to ask about roller painting. as i have to paint the boot, rear half of the car, both doors, offside apanel,bonet wings and scuttle what would you suggest to be the best painting method for doing this lot? i already have a spray gun, air brush and a compessor but ive heard about rolller painting would this be the better option for an absoloute novice?? if so how on earth do i go about it?? would love it if someone could make me a step by step guide to print out so i can take it into the garage with me!!!


thanks so much you guys are ledgens!

[Retro_10s]

Ok we'll take this 1 step at a time

whats a tack rag?

A tack rag is a piece of 'tacky' cloth, you use this to after prepping your panel to get rid of the last flittle bits of dust that you cna't wipe off, it ensures a dust free surface for paint to adhere to. You simply wipe it over the panel...

320 grit!!! ive been using 1200- 1500!!??

As you know, Wet and dry come in differnt grades.... the higher the number.. the finer the grade. 320-800grit is for keying a surface ready for paint, 1200-1500 are for finishing a paint job which leads to....

Flatting

Flatting is where you use a Fine grade (1200) sheet of wet and dry to 'flat' out any mior imperfections before polishing you freshly painted panel up. flatting back ensures a flat consistent surface of paint, making polishing a dream!

Only mist with primer!? dont i cover it in primer?

The panel should be covered in primer,.. about 2-3 coats would do, then 'Flat' it back with 600-800 grit. This gives the Top coats (colour coats) a good surface to adhere to.

Dry flatting, what's this?

This is where you use 'wet and dry' paper withough a lubricant. Generally I wet sand paint with warm water, the water stops dust going everywhere and acts as a nice lubricant, stopping scratches.

how long do i leave it in between coats?

whatever the manufacturer specifies on the back of the paint can mate

As for roller painting, read my project thread in the painting section to answer all questions.


CooperShaz has written a step by step 'how-to' spray your car guide, it's a sticky thread at the top of the painting section. read it and learn.

[phils sprite]

thanks retro 10's your a diamond!!!!

well ive bought a gloss mini roller from diy shop and im gona give it ago! also bought an electric buffer so paint should be looking good soon!!!

thanks again for all your help! phil.

[Retro_10s]

careful with the electric buffer, they can burn through the paint easily. I do all mine by hand.

[Gr4h4m]

I found that some of the paint says on the back re-coat within 7-10 mins and fully dry in 40 mins. if you leave it longer than the 7-10 mins between coats it will wrinkle... the only way back is to use nitromoors to get everything off and start again, This can happen if you have left it some time and the flat it down the next coat reacts and causes the wrinkles.... I presume it because the paint hasn't gone off all of the way to the metal and when you flat it back you expose the paint underneath????