Filler/undercoat where am I going wrong ?

[sonic]

As some of you know I am spending this year fixing my faff , main thing that I keep having to redo is my body work on the bolt on parts (skirts/spats/blocks)

The car came with them fitted , but the finish was pants , so decided to redo them

Results , the cracked spat , looks good for a week before all the cracks appear again

The side skirt , looks good for a week the filler marks appear again

Spoiler blocks , were very shit , have ended up sanding right down and filling the gt-4 insert bit , but still getting a shit finish with the undercoat , keeps shrinking

I have tried , normal undercoat , no joy , high build , no joy , and etch , no joy , everytime I work on them , they are sanded to oblivion , left to dry , panel wiped , left to dry , light coats , left to dry , it just seams this friggin car has it in for me , it's not like I haven't sprayed anything before , I sprayed my c/s bumper twice when I had it to match the 2 cars it was on , and got a really good finish both times

Any tips ? Pwease

[carlasumm]

Have you tried plasticote bit more rubbery so stretches with the heat causing parts to swell and contract

[Trebor4460]

Etch prime..2pack base and 2pack clear.. But use the right breathing mmask;)

[princy]

Is it the spats you're having trouble with?

[sonic]

Just plastic parts in general , I know HOT weather is not ideal , so I am not doing stuff in the midday sun , plus that would make me a fat sweaty bloke

Will admit , just sanded down the etched spoiler block , and a couple of well directed high build primer hits has started to get a nicer look , I opwont touch it tommorow see if it all shrinks and cracks again

[Akuma77]

canbrush american formulated paints what i used on my engine bay plastics

http://www.ebay.co.uk/sch/i.html?_trksid=p2050601.m570.l1311.R3.TR5.TRC1.A0.H0.Xcanbrush+&_nkw=canbrush+spray+paint&_sacat=0&_from=R40

[sonic]

Silly thing is , my wide arches (1st one ) looks bob on , if I can't get it right , I may just vinyl wrap the bastard

[arizona]

any useful tips on this thread?

http://www.celica-club.co.uk/forum/index.php?/topic/163986-sports-m-scoop-issue/

[Bazzagt4]

Hi fellow fenlander,

I had problems when doing my wheel inserts so took the part to Ketts down Weasenham lane way and the owner was very helpful and solved my problems straight away with a special can of pre undercoat, worked a treat, why not drop down and see the miserable old git, he is very helpful, but very miserable.

Good luck and keep faffing

Ps, look after my lovely wheels won't you, no not the bloody gold ones.

Regards

The other fenland tubby.

[princy]

Etch primer is a waste of time on anything but bare metal so that's out.

Ideally you want to get rid of all traces of existing paint or use a bar coat/isolator coat. Then a plastic plastic primer as an adhesion promoter, then high build primer, then your top coat with a flex additive unless they're rigid plastic in which case you can get away without the flex although I always tend to put half the recommended amount on steel anyway as it helps the paint stand up to stone chips a little better, although you won't be able to put any flex in if you're using rattle cans.

Hope you can make sense of that mate

[dazzy]

Are you using a good quality filler? Is it in date as they have a shelf life?

[sonic]

Hi fellow fenlander,

I had problems when doing my wheel inserts so took the part to Ketts down Weasenham lane way and the owner was very helpful and solved my problems straight away with a special can of pre undercoat, worked a treat, why not drop down and see the miserable old git, he is very helpful, but very miserable.

Good luck and keep faffing

Ps, look after my lovely wheels won't you, no not the bloody gold ones.

Regards

The other fenland tubby.

Last time I see mick from Ketts he was in tesco , my brother in laws girlfriend had been pissing around so I picked her up , dumped her in his trolley and he just walked off with her without battering an eyelid

And 'nice' wheel number one sits on the drivers seat ready , going to cut the spending down on the car till end of October , got bens birthday and my naples trip in the next 8 weeks so they are priotriy , but still have the other 3 arches , and wheels to do so once no vis here , and the front spacers have been bought and fitted the other 3 should be ready for you

Reading the gen7 scoop thread , I think a lot of my probs is the heat and to much to soon

[Bazzagt4]

Sounds like you have it all sussed bud,

Just remember if you need a hand with anything then just shout, I also have many tools if you need anything ;-)

Regards

Baz

[sonic]

Well update time , concentrating on the spoiler blocks , well actually just the one , winning the war on any reaction , but even thou I sand it to oblivion so it's baby but smooth , as soon as I add a little paint , the gt-four logo appears in the paint again , at this rate it will of cost me more in paint than new blocks would of cost

[Trebor4460]

used etch prime on my front splitter and rear valance and it did a great job, a month or so down the line and no chips or cracks.. o yeh and it did say on the can suitable for GRP and most plastics, and yep i know it was developed for bare metals but it works well on fibre and plastics too, better imo than your run of the mill primer.

[princy]

http://auto-paint.co.uk/carpaint/index.php?act=viewProd&productId=228

[sonic]

http://auto-paint.co.uk/carpaint/index.php?act=viewProd&productId=228

I shall give it a try , failing that , I shall wrap the bastards

[Auto-boy]

How are you sanding it down? Are you using an orbital sander which is always best? If not, and you are sanding by hand, always use a sanding block or else your fingers will influence the finish. (you probably already know all that).

I've painted a lot of cars over the years, and each car is different from the last car. Part of the problem here is that the filler has very different properties to the fiberglass and so you will often see the imperfections when you paint it due to the different surfaces etc. I would fill the logo's with fiberglass because then you are sticking to the same materials. If you want to go extreme, cut the GT4 logo out, fill the gap with fibreglass and mesh and flatten if off.

If you wrap them, the logo may still show through as wrap is extremely thin. I wrapped a mini a few months ago and I couldn't believe that all the shopping trolley dings still showed through the wrap.

Edited August 9, 2014 by Auto-boy

[Insanity-74]

As mentioned previously etch primer is a waste of time on plastic. One thing to consider is that when painting over filler, it has a different surface to the surrounding plastic so despite still being able to see the GT4 words in the raiser block it could just be where the paint changes colour?

Body filler has a nasty habit so shrinking anyway, you should use a putty glaze over the filler to help remove minor imperfections and hide any shrinkage, let it dry for a good few hours before doing any further prep, leaving it overnight helps. Once the filler is dry I try to leave it for at least a week before I start sanding it down, the it's just a case of high build primer, leave it to dry, rub it down, more high build primer........it took me about ten coats of high build primer to get things looking right on the front bumper.

Try to avoid anything marked as easy sand.

Also again as mentioned, use a sanding block, I use a thing from B&Q made for sanding ceilings, it's basically a long sanding block with a clamp at each end to hold the sand paper down. I find that electrical sanding devices can be a bit harsh for thins like this and it's too easy to go too far with them, just a it bucket of water and a lot of wet n dry. Although maybe use an orbital sander on the first couple of coats to make life easier and quicker...then go onto doing it by hand.

You can try heating it in the oven between coats, on a very low heat for a few mins can help, just don't melt the blocks

As for the cracked spats, get yourself to Maplins, find the glue section and purchase some plastic weld, I think bondloc do it? You could also use it to fill the GT4 letters on the raiser blocks, drill a series of holes each side of the crack, small ones only a couple of mm, then get some alloy wire mesh, halfords sell it for about three quid in a4 sized pieces. Use that on the back of the crack, then using small zip ties to nit the two halves of the crack together along with the plastic weld glue making sure the glue finds it's way into the drilled holes, behind the zip ties and into the mesh, let it dry overnight.....for two days is best, then use more of the plastic weld to fill the front of the crack, again leave it overnight, it should be more than strong enough, sand off the front of the zip ties leaving the backs in place......make sure the connection of the zip tie is on the front so when you sant it away the back is as smooth and flat as possible....look on my project thread for pictures on how I did it. Then sand it down and use filler as normal.

If you are more patient, go on amazon, look for this stuff

http://www.amazon.co.uk/gp/product/B009EU5ZMK/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1#productDetails

It is excellent, very strong, dries rock hard so it can be sanded.

[Auto-boy]

As mentioned previously etch primer is a waste of time on plastic. One thing to consider is that when painting over filler, it has a different surface to the surrounding plastic so despite still being able to see the GT4 words in the raiser block it could just be where the paint changes colour?

Body filler has a nasty habit so shrinking anyway, you should use a putty glaze over the filler to help remove minor imperfections and hide any shrinkage, let it dry for a good few hours before doing any further prep, leaving it overnight helps. Once the filler is dry I try to leave it for at least a week before I start sanding it down, the it's just a case of high build primer, leave it to dry, rub it down, more high build primer........it took me about ten coats of high build primer to get things looking right on the front bumper.

Try to avoid anything marked as easy sand.

Also again as mentioned, use a sanding block, I use a thing from B&Q made for sanding ceilings, it's basically a long sanding block with a clamp at each end to hold the sand paper down. I find that electrical sanding devices can be a bit harsh for thins like this and it's too easy to go too far with them, just a it bucket of water and a lot of wet n dry. Although maybe use an orbital sander on the first couple of coats to make life easier and quicker...then go onto doing it by hand.

You can try heating it in the oven between coats, on a very low heat for a few mins can help, just don't melt the blocks

As for the cracked spats, get yourself to Maplins, find the glue section and purchase some plastic weld, I think bondloc do it? You could also use it to fill the GT4 letters on the raiser blocks, drill a series of holes each side of the crack, small ones only a couple of mm, then get some alloy wire mesh, halfords sell it for about three quid in a4 sized pieces. Use that on the back of the crack, then using small zip ties to nit the two halves of the crack together along with the plastic weld glue making sure the glue finds it's way into the drilled holes, behind the zip ties and into the mesh, let it dry overnight.....for two days is best, then use more of the plastic weld to fill the front of the crack, again leave it overnight, it should be more than strong enough, sand off the front of the zip ties leaving the backs in place......make sure the connection of the zip tie is on the front so when you sant it away the back is as smooth and flat as possible....look on my project thread for pictures on how I did it. Then sand it down and use filler as normal.

If you are more patient, go on amazon, look for this stuff

http://www.amazon.co.uk/gp/product/B009EU5ZMK/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1#productDetails

It is excellent, very strong, dries rock hard so it can be sanded.

Absolutely fantastic advice this!