Mixing Paint Types

[skinner2k3 3]

Morning

 

Having plated the sunroof hole with a sheet of ally (years ago) I finally got round to keying it up and acid etch priming it with a view to painting it.

 

I had a can of “color matched” black paint in the garage which I stupidly thought would cover it. Got about 2 ¾ layers on before it ran out!

 

My Question is can I mix aerosol paints?

 

I don’t intend on paying another £11 for a pathetic little 300ml can of “matched” paint which doesn’t match, so I may just get a can of off the shelf Peugeot black or even gloss black.

 

Should that be ok or will the different paints react?

 

Cheers

[wardy18 33 1 Cars]

all spray can paints are solvent based and so shouldnt react - but dont quote me on this!!

[skinner2k3 3]

I was thinking along those lines also. Guessing as long as I give the first application plenty of time for the solvents to evaporate and the paint to cure fingers crossed I will be ok.

 

I think to be sure I will find a scrap bit and do a test. Dont want to have to strip the roof if they react!

[Stu 18]

It depends on the base mate, cellulose can only go on top of cellulose, 2 pack can go on top of anything (more or less) barring synthetics i think.

 

I daresay if its come from an aerosol it'll be 2 pack.

[toddydal 1]

if i was you i would just put 1 -2 dryish coats on 1st and then build up to a coulple of wet coats to finnish,if you hammer wet coats on at the start i would say it will probly react

[Paintguy 0]

I daresay if its come from an aerosol it'll be 2 pack.

Doubtful mate, there are very few companies making 2 pack aerosols

 

I'd agree with toddydal's advice, but I'll try and explain to give you a better idea why:

 

It's not so much the different paints that react with each other, but more the solvents that are used to thin them down. Since rattle can paint is so thin, it has a high solvent content which makes it more likely to attack the underlying paint. By putting on a few 'dry' coats, you seal the underlying surface to some extent, helping to prevent this damaging solvent attack.

 

By 'dry' coats, we mean light coats, best sprayed slightly further away than normal. This gives the solvent more time to evaporate on its way to the panel.

[toddydal 1]

nicely put paintguy,just out of intrest do you prefer sata or devilbiss guns

[Paintguy 0]

Believe it or not, my favourite gun ever is an Iwata W400 and I'm hunting around for a PPS adapter so that I can use mine at work.

 

For base we use a GTI-W, which is a nice gun, but I prefered the SATA 2000 digi that I used to use (even though the guage isn't designed for a left-hander like me!)

 

For clear we have a GTI (transtech), but I'd rather use my trusty W400.

 

How about you?

[skinner2k3 3]

Doubtful mate, there are very few companies making 2 pack aerosols

 

I'd agree with toddydal's advice, but I'll try and explain to give you a better idea why:

 

It's not so much the different paints that react with each other, but more the solvents that are used to thin them down. Since rattle can paint is so thin, it has a high solvent content which makes it more likely to attack the underlying paint. By putting on a few 'dry' coats, you seal the underlying surface to some extent, helping to prevent this damaging solvent attack.

 

By 'dry' coats, we mean light coats, best sprayed slightly further away than normal. This gives the solvent more time to evaporate on its way to the panel.

 

Thank you both for this good advice.

 

I will do what you have suggested.

 

Thanks again.

[toddydal 1]

ive used devilbiss for years, then i got a sata 2000 given free so i put my divilbiss away and used the sata for a while then one day i got my devilbiss back out and couldnt believe the finnish i got with it so i put the sata gun away. next thing we get water base in so i now use the sata for basecoat ,,,i only ever used my devilbiss for clearcoat but because the clears are uhs it wouldnt go thru my devilbiss gun and i said im not buying a new gun to put the new clear on so i ended up with 3 brand new devilbiss gti pros for free after conning the 3 paint factors we use.i sold one on ebay,got 1 still in the box unopened and use the other for clear only.

[Tom Fenton 1,542]

SO then guys, are these DeVilbiss and SATA guns really worth the money over and above the cheapos? I've done a reasonable amount of spraying stuff now, using a cheapo Machine Mart gun, the ones as above have always seemed expensive to me, but do they really produce that much of a better finish? And why is this, what do they do that is superior to a cheapo one? I normally use a cheapy cheap Clarke one, I did buy a more expensive Sealey "Gold" gun but couldn't get on with it for some reason.

[toddydal 1]

its not the gun it the person behind it i say,my brother bought a mini and it was brush painted with some s*ity black paint,i stripped it back to bare metal and done all the repairs and said to him get a compressor and il spray it for you,well he came up with a little 25lr one which wouldnt run my devilbiss gun because the air just died so i bought one of the little mini sprayguns for 10£ the ones that a egg cup hold more paint in and fair enough i had to fill the pot a few times but the job turned out unbelieveable so i would say its not the price of the gun its who uses it.thats why i got my guns for free because thers no way i would pay £300 for a spray gun

Edited April 16, 2008 by toddydal

[Paintguy 0]

Well we seem to have wandered a fair way off topic here, but the OP's question has been answered, so I'm sure we're safe

 

I'd agree with what's been said above Tom. It's the same with anything really; the best tools in the world won't help if the guy using them hasn't got a clue, yet a decent operator can do a good job with even the cheapest of kit. But put a quality tool in the hands of someone that knows what they're doing, and they'll be able to turn out top class results every time.

 

And that's what you gain with the likes of DeVillbis, SATA and Iwata's more expensive guns - consistency. Our guns are on the go 24 hours a day at the moment, with little more than a rinse out between jobs, and I know they'll produce the same finish on the first car of the shift, as they will on the 20th. Reliability also comes into it when you're getting through that much work, and again, that is something you can count on with high end kit.

 

Then of course there's efficiency. The best guns may transfer 20% or more paint onto the panel than a cheapo (in fact guns for professional use have transfer efficiency standards to meet), which as well as being kinder to the environment (less overspray going up the chimney), also reduces costs, as less paint is needed for each job since wastage is lower. With the number of jobs a top painter can get through, these savings all add up, so a better gun will pay for itself in no time.

 

Having said all that, there's no way I'd spend that sort of money on a gun for my own personal use. A blue ebay special, kept scrupulously clean, would do me just fine for the odd job at home.

[projectpug 0]

Paintguy hit the nail on the head with regards to reliability over long periods of time and repetitive use. I used DA sanders in work a cheap one lasts me a month but a recent professional one which cost me about 4 times the cheapy has already lasted 6 months so im already in profit. Also the fact that the more expensive one is more powerful and operates easier due to different bearings inside it. We also used The GTi range of devilbiss and find them excellent and they are about 3 years old now and touchwood fine

[Tom Fenton 1,542]

Interesting stuff, I worked as a sprayer for 6 months at a place that manufactured loader and digger attachments for compact tractors, so I'd say I'm at least half decent with a spray gun, I guess I'll stick to my cheapo one as I can and do get a reasonably good finish on stuff with it.

[Paintguy 0]

As the saying goes then Tom - "if it ain't broke, don't fix it"

 

You've got the know-how, so spending a fortune on a gun isn't going to make a vast improvement over what you have

[Tom Fenton 1,542]

Indeed, just wondered really as sometimes these things can be a night-and-day difference. Obviously in this case not so!

 

This link is a bonnet and wing I painted using Celly in the garage, not the best picture, but not so bad paint in my opinion!

 

http://i12.photobucket.com/albums/a221/tom...05/IMG_0093.jpg

[toddydal 1]

i do agree with paintguy about the better build quality of the guns,weve got prepers using cheap primer guns and i would say they go through 4-6 guns a year,but the better guns seem to go on and on for ever,i had my old devilbiss gti gun for over 10yrs and i never even put a service kit in it in all that time,but i have to say i am impressed with the new gti pro,to be honest ive never heard of the spray gun paintguy uses but its like i say a good pro can use anything,its like the old saying a good pro never blames his tools it the person behind using the tool(or somthing like that)

[cheapthrills 0]

interesting stuff, just for a slight change of tack again.

paintguy, you mentioned using a pps adaptor, presume you mean the 3m system. i looked into it recently and it seems to be a great setup. how do you find it? any drawbacks?

i'm only doing occasional bits of spraying but thought it might be handy to get a kit

Edited April 18, 2008 by cheapthrills

[toddydal 1]

yes i think he means the 3m system,weve had it for a while,are you useing the depenser type or the other type with the hard pot with the strainer that comes out to clean,you know what i mean the 1rst type we had it had 2 depensers on the wall with cups in one and strainers in the other,we found this type expensive as we were using s*it loads of them and our formans tight so wer on the other type now,you still have to clean the pot but you just clean the strainer and use again plus you just mix your paint straight into the pot so it also saves on mixing cups

[Paintguy 0]

Yes, I do indeed mean the 3M Paint Preparation System

 

I didn't even know that there were 2 types - we use the one with disposable lids and liners. Yet we get through loads of them, but clean up is so much quicker, and makes for a tidier paintroom IMO. I like it because we can also save any bits of unused paint for doing little jobs like mirror backs or bumper blow ins. I'll have a look out for the type you are using though, as our place is always trying to cut down costs (as am I really, as our productivity bonus takes costs into account, so spending less = more money in my pocket )

 

Cheapthrills - As said, the main disadvantage of the system is the extra cost. To be honest, if you're only doing the odd job then the time you'll save on cleaning up your paint pots etc isn't really going to outweigh the extra expenditure.

[toddydal 1]

i dont know if its new or not but we found it better for us and cheaper,we all have 2 each one for water and one for clear,you still have to clean the pot so i suppose its just the same as a normal pot but saves on strainers and mixing cups,,,how much are the disposable one nowadays are they alot cheaper

[Paintguy 0]

how much are the disposable one nowadays are they alot cheaper

Not exactly sure, but they work out at less than a quid per job.

 

btw, link to Iwata W400. A bit of an underdog compared to SATA and DeVilbiss, but highly rated by those I know that have used them When I went over to the Lechler training facility, their painter was using one too (with a SATA 200 for base). Not bad to say he had a cupboard full of the latest guns to chose from!

 

Have you found the 'pro to be a step up from the GTI? I've looked at them, but the two types of (clearcoat) air caps confuse me, and I can't seem to find any info on the differences between them.

[toddydal 1]

i know what you mean,my base guns got t1 air cap and the clear gun has t2 and i cant think what the other clear cap is but when we got the base guns the guy who gave them to us said it was all a con so that you buy 2 guns he said he uses base guns for clear with the t1 cap,i think i might swap caps about and see if ther is much difference,i will try and con one of them iwata guns off a rep,because we have 3 scemes i use them all against each other by saying il just use your sceme if you give me free guns or paint or jackets or remote controll helicopters etc etc it works every time

Edited April 19, 2008 by toddydal

[Paintguy 0]

Oh yes, got to love the freebies. I've got a wardrobe full of jackets, fleeces and t shirts from various companies

 

Talking of swapping caps, we have a guy at work that alleges to be an experienced painter, but I really do have my doubts after seeing his work. The first week he started, he came to me saying that he just couldn't get his clear to go on properly. Turns out he'd put the #115 (water base) air cap onto the clearcoat gun Even I'd struggle a bit with that