hi all, I know this has little to do with french cars, but if anyone can give me a few pointers i would appreciate it.
I need to do a large amount of spraying this weekend if possible. The vehicle is essentialy outside. I was hoping to build a cocoon around the areas i am working on, to prevent dust etc.. the vehicle is too big to get indoors...
Its cold and wet today (probably will be on the weekend)
I was thinking of using a heater to bring the temp up, but this could increase humidity... should I run a de humidifier alongside?
I am spraying cellulose, and have a suitable gas cartridge mask, but would i be better breathing air from outside and not using the mask? its going to be a very saturated atmosphere in there.?
I am doing 2 coats of primer and as many colour coats as i can.
its a solid colour, so no need for laquer...?
thanks
John
advice , paint spraying
Moderator: RichardW
If you're using solid colour cellulose there's no need for a clear lacquer coat. You get some of the shine straight from the gun (75% thinners on the last coat) and the rest from soapy water and wet'n'dry paper (P1200) then a lot of cutting compound and elbow grease- that's the great thing about cellulose, even if it is flattish you can eventually get a showroom shine with nothing much more than hard work!
But...unless you have to spray it, I'd avoid doing it at this time of the year. There's a lot of moisture in the air and this can lead to the paint layers not adhering to each other and eventual lifting. If you must do it try and do it on a dry sunny day with low humidity, because if you're outdoors a heater or dehumidifier won't make any difference at all. If you can build some sort of shelter it'll help!
Heat won't benefit you much as cellulose dries by solvent evapouration- it's other great benefit for home sprayers is that it flashes touch dry really quickly, so as long as it's not windy you shouldn't get too much in the way of dust or bugs in the finish, again, you can polish it out when the paint has hardened.
I once sprayed a car in the garden in October, and the paint chipped very easily and the only reason I can think of is that it was done in damp air......ever since I've always done it on hot but not humid summer days, use a water seperator in your airline as well- running the compressor a lot builds up water in the tank, after a long session it's amazing how much comes out of the drain valve, and if it's sucking in humid damp air ther'll be pints of the stuff! A seperator will stop it getting as far as the gun.
The cartridge mask will be fine, so long as you use the correct cartridge-i.e. one rated for paint vapours, etc. You only really need forced air if you're using an isocyanate two-pack....nasty to breathe.....
Best of luck...it's great when the paint finally goes on!!Makes all the hard work worthwhile 8)
But...unless you have to spray it, I'd avoid doing it at this time of the year. There's a lot of moisture in the air and this can lead to the paint layers not adhering to each other and eventual lifting. If you must do it try and do it on a dry sunny day with low humidity, because if you're outdoors a heater or dehumidifier won't make any difference at all. If you can build some sort of shelter it'll help!
Heat won't benefit you much as cellulose dries by solvent evapouration- it's other great benefit for home sprayers is that it flashes touch dry really quickly, so as long as it's not windy you shouldn't get too much in the way of dust or bugs in the finish, again, you can polish it out when the paint has hardened.
I once sprayed a car in the garden in October, and the paint chipped very easily and the only reason I can think of is that it was done in damp air......ever since I've always done it on hot but not humid summer days, use a water seperator in your airline as well- running the compressor a lot builds up water in the tank, after a long session it's amazing how much comes out of the drain valve, and if it's sucking in humid damp air ther'll be pints of the stuff! A seperator will stop it getting as far as the gun.
The cartridge mask will be fine, so long as you use the correct cartridge-i.e. one rated for paint vapours, etc. You only really need forced air if you're using an isocyanate two-pack....nasty to breathe.....
Best of luck...it's great when the paint finally goes on!!Makes all the hard work worthwhile 8)
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jgra1
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BX many thanks..
yeah I used to work in a classic garage when i was a kid, and learnt about compound and 'flatting'
, amazing ..!
the paint that is on the vehicle is sooo bad i cannot get anything from it, car paint, brushed on, and probably one coat! if you can flat the brush marks, the paint has gone..
this was supposed to be a quick cheap repspray, nothing fancy
I have got 3 litres of paint for £17 which isnt bad..
I was thinking to use DIY dust sheets, tape them together to make a huge dust sheet to go under around and above the van, on a wooden frame, to give some protection to each side as I paint it.
The farm its on it very dusty.
Weather wise, here in Sussex Sunday looks to be dry and warm, wind 10mph, probably the last chance I am going to get
intersting about water collection, i will need to look at compressor to see about that..
J
yeah I used to work in a classic garage when i was a kid, and learnt about compound and 'flatting'
, amazing ..!the paint that is on the vehicle is sooo bad i cannot get anything from it, car paint, brushed on, and probably one coat! if you can flat the brush marks, the paint has gone..
this was supposed to be a quick cheap repspray, nothing fancy
I have got 3 litres of paint for £17 which isnt bad..I was thinking to use DIY dust sheets, tape them together to make a huge dust sheet to go under around and above the van, on a wooden frame, to give some protection to each side as I paint it.
The farm its on it very dusty.
Weather wise, here in Sussex Sunday looks to be dry and warm, wind 10mph, probably the last chance I am going to get
intersting about water collection, i will need to look at compressor to see about that..
J
Have a good read of this; he's a bit of a perfectionist but there's a lot of good stuff in there.
http://www.thebugshop.org/bsfqpnt.htm
It is possible but not easy to get a decent job on a wet day.
First thing before you get too excited is to make certain the paint you're about to use is compatable with the stuff already on there, if not it'll blister when you hit it. Best test is to wet a small patch using the thinners for the paint you're about to use. If it's compatable it should just soften the paint a little. If incompatable it will bubble like paint stripper, then flatten but leave an uneven surface (just like the paint will if you put on an incompatable paint.)
Be careful using heaters as they usually have a heat source such as an element that glows and can cause an explosion, this is why paint shops use "heat lamps" to heat and dehydrate.
Ordinary thinners will go milky if used in damp/humid conditions; the thinner needs to have what is known as a "retarder" thinner added to the mix. This tends to slow down the drying and prevent the milkyness, however, this throws up its own set of problems by leaving the job more vulnerable to insects and dust (and small children and inquisitive wives) getting attached to it before it sets properly. If painted in really wet conditions and all precautions aren't observed, you may also fine that whenever the car gets into very wet consitions, that the entire painted surface will become covered in pin head sized 'water blisters' that are made of water trapped beneath the surface, rising each time the car gets wet for any period of time. If an attempt is made to get rid of them, they become like small chips in the paint....as I say, long involved job; best read the link for a mopre thorough explanation.
Alan S
http://www.thebugshop.org/bsfqpnt.htm
It is possible but not easy to get a decent job on a wet day.
First thing before you get too excited is to make certain the paint you're about to use is compatable with the stuff already on there, if not it'll blister when you hit it. Best test is to wet a small patch using the thinners for the paint you're about to use. If it's compatable it should just soften the paint a little. If incompatable it will bubble like paint stripper, then flatten but leave an uneven surface (just like the paint will if you put on an incompatable paint.)
Be careful using heaters as they usually have a heat source such as an element that glows and can cause an explosion, this is why paint shops use "heat lamps" to heat and dehydrate.
Ordinary thinners will go milky if used in damp/humid conditions; the thinner needs to have what is known as a "retarder" thinner added to the mix. This tends to slow down the drying and prevent the milkyness, however, this throws up its own set of problems by leaving the job more vulnerable to insects and dust (and small children and inquisitive wives) getting attached to it before it sets properly. If painted in really wet conditions and all precautions aren't observed, you may also fine that whenever the car gets into very wet consitions, that the entire painted surface will become covered in pin head sized 'water blisters' that are made of water trapped beneath the surface, rising each time the car gets wet for any period of time. If an attempt is made to get rid of them, they become like small chips in the paint....as I say, long involved job; best read the link for a mopre thorough explanation.
Alan S
RIP Sept 19th 2008.
She said "Put the cat out" She didn't mention it was on fire!!
She said "Put the cat out" She didn't mention it was on fire!!
Well it certainly hasn't been good spraying weather today.... 
Rain falling from the sky by the bucketload...and we still have a hosepipe ban!! A good point there from Alan about compatability- have you gone back to bare metal, or are you going over an existing finish?
I have the problem on the Triumph that it has good paint in a lot of areas, but there is cellulose and also acrylic on there.I'm going to do it all in Cellulose, but going by past experience I'm going to leave it alone and not go back to steel unless I have to, and just put a quick isolator coat over it. It'll only need a litre and it's only around £15 a litre anyway.
The only problem with isolator, however, is that it sucks moisture out of the air like a sponge......you have to get the primer over it in less than an hour in good conditions, let alone damp!!
All of which means that I'm going to leave spraying the Triumph until next year- it's a bit piebald at the moment but better that than the paint falling off....
Rain falling from the sky by the bucketload...and we still have a hosepipe ban!! A good point there from Alan about compatability- have you gone back to bare metal, or are you going over an existing finish?I have the problem on the Triumph that it has good paint in a lot of areas, but there is cellulose and also acrylic on there.I'm going to do it all in Cellulose, but going by past experience I'm going to leave it alone and not go back to steel unless I have to, and just put a quick isolator coat over it. It'll only need a litre and it's only around £15 a litre anyway.
The only problem with isolator, however, is that it sucks moisture out of the air like a sponge......you have to get the primer over it in less than an hour in good conditions, let alone damp!!
All of which means that I'm going to leave spraying the Triumph until next year- it's a bit piebald at the moment but better that than the paint falling off....
Many years ago I resprayed my Triumph Stag with cellulose without problems. i'm sure it had acrylic paint on it as many neglected rust chips had spread under the paint like spiders legs and took loads of work to grind out.
I was advised by an experienced sprayer that there was no point in removing the original paint and to test a bit and see what happened - and had no problems at all.
Also used cellulose on a F reg Triumph 1300 again without problems. Think it dried quicker than the car went.
I was advised by an experienced sprayer that there was no point in removing the original paint and to test a bit and see what happened - and had no problems at all.
Also used cellulose on a F reg Triumph 1300 again without problems. Think it dried quicker than the car went.
jeremy
Sometimes you might get away with it on original finishes, but on something that's been repainted particularly in a pretty average DIY job, the chances of getting away with it are about on par with winning the lottery.
Acrylic over nitro cellulouse lacquer is no problem, reverse can be an entirely opposite proposition.
Alan S
Acrylic over nitro cellulouse lacquer is no problem, reverse can be an entirely opposite proposition.
Alan S
RIP Sept 19th 2008.
She said "Put the cat out" She didn't mention it was on fire!!
She said "Put the cat out" She didn't mention it was on fire!!
the main compatability problem is when the car has had a cheapo blowover at some time in the past with one of those oil based truck body paints- the sort used by the 'we respray your car for £400' type places.
Today's a good painting day.....
This'll be what we in the UK refer to as an 'anti-bloom' thinner.Ordinary thinners will go milky if used in damp/humid conditions; the thinner needs to have what is known as a "retarder" thinner added to the mix.
Today's a good painting day.....
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jgra1
- (Donor 2021)
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thanks all...
well, i spent 6 hours with friend trying to remove the brush painted 7year old unprimered paint that is the main problem with the van...
what hard work..
I tried many things, have ended up with an orbital sander running 40-60 (too begin with) grit, it still takes ages to remove the brush marks and get to a lower paint level..
there are at most four colours underneath.. The van was, I believe, painted grey. There seems to be a light blue and a light green popping up.. It is much smoother now but resembles an artic camouflage!
I still have both front doors and all of the front to do... just to get close too spraying an isolater and then primer.... still sunny tomorrow
If you want a top class smooth finish you will have to put on loads of primer surfacer - then leave it for some time (like a week or 2) to dry.
I expect where you have rubbed it down and rubbed out blemishes the surface is now not very even, and with golss on all the variations of thickness will show through - like all the old VW motor caravans that have rippled sides (or Reliant Scimitars for that matter) You will find that with care you can spray primer filler almost continuously and the thing to do is to build up the surface with it - so spray more on the uneven bits.
When you have finished it will be laden with solvent which will take ages to come out (remember you have used more solvent than paint) and if its in a garage it will smell for a long time. The secret really is to weather it but the primer will is porous and will absorb moisture which makes things more difficult.
When you rub it down with wet and dry wrap the paper round a piece of wood about a foot long. This syops the paper following the contours in the paint and means that the high bits are rubbed off - aiding levelling.
You will also find that the wet and dry sticks in the soft paint even when wet - and the secret here is to get some old fashioned hard soap like Sunlight and wipe that on the paper as you go. This lubricates the process and helps get a good result.
I expect where you have rubbed it down and rubbed out blemishes the surface is now not very even, and with golss on all the variations of thickness will show through - like all the old VW motor caravans that have rippled sides (or Reliant Scimitars for that matter) You will find that with care you can spray primer filler almost continuously and the thing to do is to build up the surface with it - so spray more on the uneven bits.
When you have finished it will be laden with solvent which will take ages to come out (remember you have used more solvent than paint) and if its in a garage it will smell for a long time. The secret really is to weather it but the primer will is porous and will absorb moisture which makes things more difficult.
When you rub it down with wet and dry wrap the paper round a piece of wood about a foot long. This syops the paper following the contours in the paint and means that the high bits are rubbed off - aiding levelling.
You will also find that the wet and dry sticks in the soft paint even when wet - and the secret here is to get some old fashioned hard soap like Sunlight and wipe that on the paper as you go. This lubricates the process and helps get a good result.
jeremy
There's a product on the market out here (so no doubts same stuff but possibly different name) called "one shot". This is a spray putty and primer all in one.
If you want to use it as a spray putty you use a higher % paint to thinners and to use as a primer you dilute it accordingly.
If you've used an orbital sander, it would pay to blow a coat of one shot over as a putty, sand by hand and then throw a wet coat of it over as primer before you paint.
It gives a good base to put the top coat over and will improve the overall finish particularly after the paint shrinks as a simple primer will tend to leave fairly deep swirl marks left by the orbital through the top coat.
Alan S
If you want to use it as a spray putty you use a higher % paint to thinners and to use as a primer you dilute it accordingly.
If you've used an orbital sander, it would pay to blow a coat of one shot over as a putty, sand by hand and then throw a wet coat of it over as primer before you paint.
It gives a good base to put the top coat over and will improve the overall finish particularly after the paint shrinks as a simple primer will tend to leave fairly deep swirl marks left by the orbital through the top coat.
Alan S
RIP Sept 19th 2008.
She said "Put the cat out" She didn't mention it was on fire!!
She said "Put the cat out" She didn't mention it was on fire!!
-
jgra1
- (Donor 2021)
- Posts: 4625
- Joined: 27 Nov 2005, 19:07
- Location: Kent / Susssex
- My Cars: 2010 C5 X7 2.0 hdi 160 exc auto
MG TF 135
Boxer II 2.2 camper conversion
BMW R1200RT
BMW K1300 R
Honda V F R 800 5thG / MT500 Armstrong - x 39
well all, this has become a saving winter coat now, not a high class finish...
The main problem with the van was the brush paint added before I got it... It has taken 2 days and 2 people too get something that resembles flat again. In places it has come up well, in others maybe more time needed..
anyway, on arriving at van sunday morning, some of the bare metal has already started surface rusting.. I made a (wrong?) desision to try and cover this prepared bit of van (65%) with isolator and a coat of primer ...
there wasnt time to add any colour , so now , in a dry but open barn in fairly damp wather, what have i done >.... will the paint blister once its on the (second) coat of primer?
The main problem with the van was the brush paint added before I got it... It has taken 2 days and 2 people too get something that resembles flat again. In places it has come up well, in others maybe more time needed..
anyway, on arriving at van sunday morning, some of the bare metal has already started surface rusting.. I made a (wrong?) desision to try and cover this prepared bit of van (65%) with isolator and a coat of primer ...
there wasnt time to add any colour
, so now , in a dry but open barn in fairly damp wather, what have i done >.... will the paint blister once its on the (second) coat of primer?Despite dire warnings of the consequences the fact is that many cars are driven for a long time with just primer on and then satisfactorily gloss painted.
You'll find very few people follow the instructions to the letter - and still produce satisfactory results. With some care and common sense you'll probably be OK.
Letting the primer harden well is advantageous. When I did my Stag I mopped it a week or so after I put the top coat on and iot looked great - only for it all to sink over the next couple of months. it really does take a time for the solvent to come out. If however the primer had gone really hard - make sure you rough it up with some wet and dry before the next coat (being careful not to sand the edges too much.)
You'll find very few people follow the instructions to the letter - and still produce satisfactory results. With some care and common sense you'll probably be OK.
Letting the primer harden well is advantageous. When I did my Stag I mopped it a week or so after I put the top coat on and iot looked great - only for it all to sink over the next couple of months. it really does take a time for the solvent to come out. If however the primer had gone really hard - make sure you rough it up with some wet and dry before the next coat (being careful not to sand the edges too much.)
jeremy