# Can I flat primer on wheels with scotchbrite?



## Franzpan (Mar 2, 2009)

Today I finally managed to get primer on my wheels. Next up is the task of flatting back.

They are 10 spoke wheels so pretty awkward, can a scotchbrite pad be used to flat the primer at all? As they would be easier in and around the spokes.

Any tips would be appreciated :thumb:


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## Sutty 90 (Aug 24, 2014)

Yes and no. Ideally you would be better using flatting paper for the best results as you will get a smoother and more uniform finish. If your struggling to get it in to tight areas try wrapping some paper around a flat rigid object, I've used metal rulers or mixing sticks in the past to good effect on tight spoked wheels. Obviously by its nature the scotch is abrasive and can be used to smooth things off but I would only use it as a last resort in areas that you really can't get into properly.

Sutty.


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## steveo3002 (Jan 30, 2006)

yeah it would work but use sandpaper where you can as the scotchpad wont flat it as such


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## Scoobycarl (Aug 13, 2011)

A foam backed pad like norton 600 or 800 grit would be ideal but you would probably have to buy a box of them so wouldnt be practical mate ? What primer did you use 2k or 1k ?


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## Franzpan (Mar 2, 2009)

Thanks guys, the bodywork section never disappoints :thumb:

I'm using Upol 2k primer. 3:1 with 10% thinners as I'm using a mini spray gun with quite a small tip.

I'll have a look at those foam pads. Don't mind buying a box too much as they'll always find a job in my Garage


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## Sutty 90 (Aug 24, 2014)

Norton foam pads are great for flatting primer by hand. Couldn't tell you how much they are but they are on a long roll in a box. Can't stand the feel of the foam backing though lol 

Sutty.


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## Scoobycarl (Aug 13, 2011)

Think there £25 a box but theres loads in there and are great wet not as effective dry unless the textures knocked off primer first


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## Franzpan (Mar 2, 2009)

Found them for £22 from refinish systems Ltd. I'll give them another bash with normal paper and see how it goes, if not I'll order a box tomorrow.

Is it better to wet sand the primer than dry?


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## Franzpan (Mar 2, 2009)

Wow just tried wet sanding and what a difference it makes! Sands so much easier and the paper doesn't gum up at all. It also makes the paper more flexible for the corners of the spokes. Wet sanding seems to remove the paint quicker than dry? Is this right? I was using 400 but think I'll need to get 600 or maybe 800


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## Sutty 90 (Aug 24, 2014)

Yeah wet sanding is a lot quicker than dry, the water keeps the paper from clogging up and keeps it sharper for longer. If your planning on painting straight over the primer with no more repair work id personally just go straight in with 400s to take the top off and then 800s to refine. Don't forget to use some sort of guide coat inbetween.

Sutty.


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## Scoobycarl (Aug 13, 2011)

As above bang on what id suggest mate


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## Franzpan (Mar 2, 2009)

Thanks for all the help guys.

Went and got paint this morning. Was going to get base and clear but the paint shop recommended direct gloss so I got that to see how it goes. Do you think this will be ok?

Any tips on applying it would be great!


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## Sutty 90 (Aug 24, 2014)

Direct gloss will be perfectly fine mate. The difference is more down to personal choice than anything. 

When applying the paint do it in two coats. First one a nice light dust coat and for the second a heavier wet coat. Allow the paint to dry between coats, the use of a heat gun will speed up the drying process alot quicker. If your struggling getting into the tighter areas give those bits one or two extra dust coats, how many you feel is necessary, to build up colour and then wet coat as usual.

Sutty.


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## Tintin (Sep 3, 2006)

Don't want to hijack Franzpan's thread, but what brand of direct gloss would you recommend Sutty? Or are all the big name brands OK? Thinking of doing some spot repairs on my project.


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## Franzpan (Mar 2, 2009)

Thanks Sutty :thumb:

Would a couple of wet coats sit ok? I'd like an extra bit of thickness so I can flat and polish the face.


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## Sutty 90 (Aug 24, 2014)

In all honesty I've not used direct gloss for a good few years now, I've been using water based clear over base systems on solid colours rather than solvent 2k. Last solvent system I used was Nexa Auto Colour by PPG. I would recommend any of the big brand paint schemes direct gloss, these can usually be found in your local auto factors or even pop into a local bodyshop to buy. In my experience with direct gloss the finish is more in the application than the product itself. I'm sure someone with more relevant direct gloss experience chip in to advise you further.

Sutty.


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## Sutty 90 (Aug 24, 2014)

Franzpan said:


> Thanks Sutty :thumb:
> 
> Would a couple of wet coats sit ok? I'd like an extra bit of thickness so I can flat and polish the face.


In all honesty id recommend practising getting a good finish first and then getting the second coat on nice. By getting a nice even wet finish and allowing it to dry in a controlled envirenvironment you can allow the paint to flow out and almost self level. It will remove the need to flat and polish.

I wouldn't personally flat and polish wheels. There's too much risk of flatting through due to the many sharp edges and small working area. You will be surprised with what you can get away on wheels due to them being nice and low down once fitted.

By putting more coats on you run the risk of trapping solvent in & the whole thing not drying properly unless thourghly dry between coats.

For me id be practising getting a good finish on the second coat to a level your happy with and leave it at that.

Sutty


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## Franzpan (Mar 2, 2009)

Got the paint on two of the wheels tonight. Its not perfect and will need to be re done but I've learnt so much that its been worth while.

Unfortunately I had to use the wheels as a Guinea pig as I had nothing else to practise on. The first wheel is a tad orange peely but I realised on the second one that by applying a wetter coat it evens out much better. The second wheels is perfectly acceptable orange peel wise however I did get a run which I'm blaming on the light. Painting with a tripod light is no good. Too many shadows and once a bit of paint goes on then the light bounces off it everywhere. Daylight painting only from now on.

My biggest problem is little spots in the paint though. All over both wheels. They're like little bubbles. I'm putting this down to water or oil in the paint. My own fault as I was only using a little water trap at the gun. I have a bigger wall mount moisture trap at the farm so I'll get that for next time.

Also my regulator at the gun is rubbish!!! When the compressor kicks in and the pressure rises the regulators pressure rises too! Stupid eBay special. Buy cheap buy twice springs to mind.

I'm also struggling to understand how to set the airflow knob on the gun. Sometimes while I'm spraying the pressure will just cut out all together and I have to open the air flow a bit more to cure it. However it does this again and again?


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## Aaran (Sep 18, 2007)

you need a full size water trap and regulator on your compressor before your on gun regulator. you need to set the reg off the tank just below what psi your compressor kicks in.

your getting the pressure variance at the gun reg due to the fluctuations from the tank, a reg in line will sort that out and also fix your water issue assuming it is water.

tomorrow morning go pop one of these bubbles with a pin and see what comes out. if its water then thats your problem, it could also be water from the wetsanding. if i wet flat anything its either forced dryed for a few hours of left in the warm until the next day. 95% of primers are porous (bar epoxy)

a good tip to save on hours of sanding is to key all the wheel (or sand blast it with mega fine grade shot) and then use an epoxy primer (something like maxmayer) which will seal exposed alloy and primer the wheel and subject to no crap you can catch its re-coat window and go right over it with direct gloss, you wont have to sand a thing.

over thin your 2k gloss paint, i always shoot it with 15-20% thinners in my ppg or maxmayer direct gloss and it makes the world of difference to how it lays down and flows out(ie: next to no orange peel) just give it extra time between coats to allow for the thinners to flash out. 2 full wet coats will suffice


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## rich9 (Jan 28, 2014)

Those gun "regulators" are not really regulating pressure they just a choke valve. You need a proper filter-regulator on the wall.

Your stop-start issue may be due to blocked hole in cup lid. Paint splashes in the hole now and again.


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## Franzpan (Mar 2, 2009)

Thanks for the advice guys :thumb:

Its round two tonight! Got the wheels sanded back smooth again last night so I'm ready to try again. Got a decent filter to attach at the wall and I'll dial the regulator on the compressor down to just above the pressure I want. I'm also going to thin the paint this time as I didn't do that previously.


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## Franzpan (Mar 2, 2009)

This will hopefully do the trick


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## Guest (Apr 16, 2015)

Folk have come up with many different designs to remove water from the airline...loads on the internet.I used some copper tube with "drops" before the filter/regulator and its worked well.


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## Franzpan (Mar 2, 2009)

That looks good. Once I get my compressor properly plumbed in around the workshop I'll do something like that.

Had another go tonight. Thinned the paint to 20% and it laid down real nice with minimal orange peel. However I'm still getting moisture spots in the paint. The new filter doesn't seem to be working. The inside of the glass wasn't even damp after use whereas the little filter at the gun was full of little beads of water.

The big filter was about 5 metres from the compressor and then another 10m of hose to the gun. I take it these air filters are pretty much plug and play? I didn't get any instructions with it lol.


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## Franzpan (Mar 2, 2009)

Finally getting good results on the wheels :thumb:

Got the air issues sorted, it will be a while before I can get my air line plumbed in so atm I have 10m of hose coming out of the compressor and coiled up in a bucket which I fill with cold water each time before painting. The hose is clear and you can see all the little water droplets condensing before the filter and then after the filter the hose is completely dry. I'm no longer getting the little moisture bubbles in the paint.

I had a few issues with silicone contaminants but I just upped the panel wipe regime which cleared this up.

I'm thinning the paint to 20% which lets it lay down nice and flat, I'm only getting the odd bit of orange peel where I haven't applied enough paint. Its a fine balance between applying enough and getting runs though 

Will get a few pics when I'm home from work.


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