Paint ????

[Hugh GilhespieParticipant @hughgilhespie56163]

Hi All,

 

My first and dearly beloved beam engine passed it’s trial run on compressed air on Sunday. Amazingly it actually works. Just needs a bit of leak sealing and lots of TLC to finish it. So, I am about to take my first faltering steps into the very confusing world of spray painting. I have nice, clean and oil free compressed air, a small but decent spray gun but no idea about what sort of paints to use! I have ordered some Trimite two-pack etch primer, as recommended by Christopher Vine in ‘How (not) to paint a locomotive’ because that seems to be a universal requirement for painting bits of metal but after that????

 

Can anyone recommend what paint to use? The bits I will be painting are aluminium and steel and not very big although I do have a Worden kit that I want to paint as well. Ideally what I want is stuff that gives a perfect result when applied by an idiot! Failing that at least as idiot proof as possible – Not too concerned about any specific paint properties like solvent resistance or temperature stability, just want a reasonable finish without having to take out a second mortgage. I do want to spray paint though as it’s on my list of things I should have a go at and try to learn how to do.

 

All suggestions gratefully received.

 

PS – Also feeling proud cos I made a whole post without metioning how good/crap Myfords are and sans the slightest sniff of G code.

 

 

[Hugh GilhespieParticipant @hughgilhespie56163]

[JasonBModerator @jasonb]

I’ve used Phoenix paints on my last few models, Craftmaster also gets good comments for both brushing & spraying.

 

Jason

[mgjParticipant @mgj]

Dear old Blackfriars gloss enamel produces a very hard wearing finish. Very good paint, doesn’t mind a bit of heat, and brushes out very smoothly..

 

If I were spraying, which I shall be shortly, I’d use car 2 pack. Mixed properly its of thee right viscosity, sprays beautifully, dries quickly and is diamond hard. As long as you just go for a wet film. Leave it 5 and recoat, its difficult to get a run, and you get a briliant shine without polishing. Lechler stockists will match a colour, (I expect the others will too) if you have used some other paint for brushing. 2 pack can be used as a one pack for touching in. Just atkes a bit longer to set.

 

Do it outside on a warm dry day, and then take it in to set. Wear a mask.

 

Without doubt the best and easiest to spray but a touch pricey. But then you gets what you pay for, and the special “thinners” and other additives which are common to all mixes can be stored for a long time. Clean with gunwash grade cellulose thinners of course. Never used these sexy base coats, but then on both (ali) racing cars and model aircraft one wanted to keep the weight down – still managed ot stick and not peel off

Edited By mgj on 23/05/2011 17:28:12

[KWILParticipant @kwil]

Do not forget to get the Primers right, aluminium requires an etching primer to give good adhesion.

[Ramon WilsonParticipant @ramonwilson3]

Hi Hugh,

Congrats on the progress, bet you are well pleased.

 

If I recall, your engine – well certainly the parts to be painted – are mainly ali or bronze so Kwil is right about using an etch primer to get the initial adhesion. Sounds like you are already ahead on that with ordering the ‘Trimite’ but the thing to be sure of is that the next layer(s) which should ideally be a conventional primer is compatible. A ‘cellulose’ primer may attack it so do a test piece before putting anything on the model.

Experience gained over many finishes – and quite a few disasters among them – leads to stressing that – a test piece will save much heartache and regret.

 

Acrylic paint gives a very hard and smooth surface but again beware of putting this over a cellulose based primer. This can, not neccessarily will, lead to all over, minute, cracking of the acrylic as the cellulose is flexible and the acrylic not. (This takes about a fortnight or so to develop and it’s a bit of a gut wrencher – certainly been there)

The standard car aerosol primer is still cellulose based but it’s very unlikely you will find standard grey primer in a tin now.

 

Using primer to create a smooth surface on which to apply the top coat is much better than coat after coat of top coat. If the substrate is right just a couple of thin coats is all that should be required to achieve a depth of colour.

 

Best advice is to keep to the same type of product throughout the varying layers if possible. Personally I wouldn’t use enamels as this can be difficult to spray without runs – certainly likely if you are new to spraying.

 

A lot of other factors come into play too – size of spray gun for object to be painted, viscosity of paint relative to the pressure used and the speed of drying of the paint used.

 

If the gun is too large then the work could be flooded with paint, too small and the layers thin and the temptation to put on too much in order to build the finish. Viscosity should be about that of milk for a cellulose type of finish. Orange peel type of finish denotes paint too thick or insufficient pressure. Pressure depends on type of gun etc. but nominally around 20/25 psi. Keep the gun moving and not too close, about 8-10″ with a small ‘touch up’ type of gun. Too far away and the paint will exhibit a sandpaper type surface as the paint is drying before it hits the surface

 

Above all do that test piece – not just to test compatibility but to get ‘your hand in’. You do need to practice to acquire the technique – for the subject in hand

 

Oh yes masking. If you need to mask anything off I would recommend Tamiya masking tape which you can get from most model shops that sell plastic models. It has a much lower tack than conventional tape and is much thinner. It comes in varying narrow widths in neat dispensers but it’s cheaper and far more versatile if you buy the 40mm wide (no dispenser) as this can be cut with a scalpel to suit all sorts of shapes.

If the finish is cellulose let the paint dry well before peeling the tape off ‘back on itself’ and not at 90 degrees to the surface. That will help minimise any lifting of the paint. I can’t comment on other finishes as I have not used them for spraying – Phoenix – two pack, enamels or the new water based finishes.

Any one else have any experience using the water based products?

 

Hope that helps some Hugh

 

 

Regards – Ramon

 

Edited By Ramon Wilson on 23/05/2011 20:43:51

[Can ManParticipant @canman]

Also be very careful when spraying 2-pack coatings. They contain isocyanates which can be carcenogenic! The traditional simple dust masks do not offer full protection and you should really consider a proper solvent resist mask.

[mgjParticipant @mgj]

Almost all non ferrous requires an etch primer I think, but then if you speak to the paint kings they will also say that most metals require first a hot caustic degrease, then shot or suitable blasting and then another degrease before anything is applied. That is of course a cousel of perfection, and it is surprising to learn that paint will adhere very well in the absence of a lot of these treatments..

 

If the metal surface is good and well degreased and the paint chosen correctly you don’t NEED an etch prime, or indeed any primer depending on the durability required and future use.

 

See comments about racing components.

 

However, for our purposes a good degrease followed by an etch prime and prime is a good idea, but I have seen some try to etch prime as if it is a primer, and paint it “wet”. It isn’t a primer in the conventional sense – its a chemical surface treatment, and one really wants no more than a mist, just enough to discolour the (well degreased) surface. Then you apply the proper primer, not just when its touch dry, but generally some hours after that, to allow the etch to do its bit, etch prime being an acid. It should be noted that etch primes performance is often badly degraded by grease spots/finger prints etc, so a good degrease is a very very good idea.

 

The OP mentioned spraying – Sealey do a very nice gravity fed touch up gun with fan spread control for about £25. you can mix up very small quantities(20-50cc) of 2 pack using a hypodermic syringe (sans needle), and cover a sane area with it, without wasting paint. And its very easy to clean too.

 

 

[adyParticipant @ady]

I read an article in a ME back issue today.

vol 203 no.4366

p708. Empire building.(Empire of India)

 

Even to a complete newby it was pretty obvious that doing a really decent paint job takes a highly skilled approach with a huge amount of preparation and dedication.

 

It actually made me realise I won’t be going THERE anytime soon.

 

The depth of knowledge skill and experience required to achieve a properly completed show standard piece is a bit of an eye opener.

[Ramon WilsonParticipant @ramonwilson3]

Quite agree here mgj as there are some ‘grey’ (non etch) primers that adhere extremely well.

A while back over this way the ‘grapevine’ said a certain Pound Shop was selling tins of conventional grey primer for just that. A friend tried some and it’s adherence to brass sheet was exceptional.

 

The potential for disappointment though, without using an etch primer on ali or brass, is always there. It may (or may not) take some time for the paint to peel or flake but when it does it’s not what one wants to see or have to renovate whether it’s that flat side of a tender or a complex frame of a stationary engine.

 

For me, as I see it , by using one you are at least trying to minimise that potential.

 

Degreasing is as you say essential, along with a slightly abraded surface if at all possible.

 

Can Man’s advice about personal protection when spaying two packs is sound advice too. When I used to apply the two pack clear coat to model aircraft I used a carbon filled mask which I then covered over with two tea towels tied as per cowboy facemasks and head covered up with another for just a little bit more protection. Not exactly as defined by Health and Safety but needs must and “Owt is better than n’owt in’t crisis”.

 

My spray booth was a wooden frame work surrounded by garden fleece which stopped any direct breeze but allowed movement of air. Despite staying ‘up wind’ and being as quick as possible I could still feel it. Oh yes – tip for the unwary – if you wear glasses and you spray in an enclosed area change them out for old ones particularly if you’re using two pack – no, please, don’t ask

 

Regards – Ramon

 

[DMBParticipant @dmb]

Hi all,

I have seen the most fantastic finish on a large model aircraft. It looked exhibition quality – perfect! The owner said he warmed the paint before application, making it much more runny. I think he said it was ordinary Humbrol brushed on, but I`m not sure.

[mgjParticipant @mgj]

John I can agree. I did my TE with ordinary brushed Japlac and there not a brushmark on it. The only trouble with the long drying paints is dust, and in that what you wear when you are painting. Your suggestion of warming both paint and object is very good. Using a quality enamel you should NOT expect to get brushmarks.

 

Contrary to what many would say, an exhibition grade finish isn’t actually that difficult, provided one pays attention to detail and is thoroughgoing about preparation. It can be a bit of a longwinded process in the preparation, but difficult – no. Its pretty mechanistic. You just do what you have to do, and it will work, especialy with high grade modern paints. With 2 pack its dead simple, because you get such a superb and durable finish straight off the gun, and you don’t have to worry about viscosity, because it will be right if mixed properly.

 

One of the tricks is masking off. Finding a decent edge masking tape is not so easy. The commercially available DIY rolls are fine for attaching newspaper, but I found it tolerable useless for doing a paint over paint edge. Specialist auto paint suppliers do stock special tape for that which will stretch and flex to accomodate curves. The ordinary Tamiya stuff from model shops is pretty good too – thin enough not to leave a lumpy edge, and won’t allow bleed under, and peels off very cleanly and easily too. Available in 10mm and 6mm wide. So I did edges with that, and then used ordinary for all the “filling”.

 

Going on from Ramon’s point – most of these paints will adhere very well so long as there is a good mechanical key and a non greasy surface, but I only stated that to make apoint. Here weight is not a problem so it makes sense to etch prime. I would disagree slightly in that from what I learned from the paint specialists in DQA, the degreased and abraded surface is far far more important than almost anything else.

 

As for 2 pack – sure its unpleasant stuff, but we are not professionals and we are not using it continuously indoors. Like you Ramon, I mixed it in a well ventilated place, and wore a mask, and stood downwind and sprayed out of doors.

 

Edited By mgj on 24/05/2011 12:38:56

[KWILParticipant @kwil]

There is a very useful UPOL 8 acid etch primer sold by Halfords in a spray can.(usual disclaimer)

[Hugh GilhespieParticipant @hughgilhespie56163]

Hi All, Thanks for all the helpful comments. I have pretty much decided to use cellulose paint for my spraying attempts. Three reasons, firstly the 2k type car paints with isocyanate hardeners do sound pretty nasty. Lovely results I’m sure but I already have asthma and COPD so probably not the best idea to start breathing in those particular fumes. Secondly I have read that cellulose paints are a bit more forgiving for the inexpert sprayer – and that is definitely me. Finally they are relatively inexpensive. The only problem seems to be that although there are any number of colours available, they are all car colours. I haven’t yet found an on-line supplier with a good old-fashioned colour chart. Failing that I will have to try and spot cars with the colours I want then specify make and model rather than ‘a nice darkish green’.

> >

I also couldn’t resist putting a video of the dearly beloved beam engine on You Tube. For any one interested, the link is

>

http://www.youtube.com/watch?v=gRhHejzFmnA

>

Thanks again, Hugh

[Martin CottrellParticipant @martincottrell21329]

Hi Hugh,

 

That’s a very sweet running engine you’ve built there! Just a word of advise on preparation of your engine frames, I would advise just smoothing any sharp edges around the outsides and also around the cut-outs as sharp edges do not take paint well.

 

Regards, Martin.

[Ramon WilsonParticipant @ramonwilson3]

Hi again,

I find discussing painting techniques most interesting as it is a subject dear to heart. I first tried to ‘put a finish’ on a model aircraft just as I joined the army. It will probably make you smile mgj when I say it was confiscated because and I quote “When your boots are like this you can ‘ave it back. Courtesy of fierce Corporal Hammond. It disappeared to be handed back on Passing Out day. (I did find it well hidden in a cupboard and worked on it in secret for a while but it was too nerve racking in case ‘he’ came in and you didn’t mess with ‘Hammy’. Ha ha, happy days.

 

Since then I have painted a lot but my experience is basically limited to model aircraft and the odd model boat and mainly with cellulose based products. I have never, for instance had to paint largish sheet metal areas and have had little experience of spraying other materials other than what has been mentioned.

 

However, anyone remember ‘Brushing Belco’ ? This cellulose paint was supposed to be brushable but any solvent based paint remelts the previous layer and it’s extremely difficult to brush. Despite it’s title Belco suffered the same way. Someone, not sure who, showed me a technique with ‘Belco’ and that was to get it on as quickly as possible trying not to brush it out as this would – still will – lift the previous coat. Once a sufficiently thick layer had been obtained the tip was to take a very fine haired brush and loading it with neat thinner gently drag the thinner quickly across the area holding the brush near flat to the surface. The thinner would dissolve the layer and spread out the resultant surface near as smooth as spraying and high gloss. Too much thinner or to slow strokes normally meant a restart.

 

When first answering Hugh’s querie I did mention brush painting but upon rereading it decided that was not replying to the question so deleted it. I had mentioned warming the paint as you state John and mgj. Standing the paint on a radiator just before use or in a bowl of reasonably warm, not actually hot, water will improve the flow considerably but the real need for brush painting successfully is a really good and suitable brush. That does not neccessarily mean expensive but it does mean good quality. For model applications I have found the flat synthetic bristles artists brush far easier to apply a smooth coat than the conventional round brush found in most model shops. If you need really good brushes for this kind of application you can’t do much better than these –

thoroughly recommend them but only as a satisfied customer so usual disclaimer

 

My early attempts then were mainly brush painted enamels and based on many coats of colour on a thin substrate of dope and talcum powder. I knew of the technique of talc substrate but not the way to go about it. Lots of colour means lots of waiting for paint (enamel) to dry before being able to rub it down. It wasn’t until I took up flying aerobatic models competitively the weight factor really came into play and the technique of getting the substrate as flawless as possible leaving the (heavy) colour to be applied as thinly as possible began to become the norm. The accepted way to achieve this was to apply a light dust coat of silver over the dope and talc ‘primed’ areas. Silver shows up every single flaw which can be filled and then rubbed down again. This can and was repeated until the surface was ready for colour.

 

I’m reluctant to put a pic of model aircraft on here but as it’s relevant to the topic I guess no one will mind too much

This is a ‘Gieseke Nobler’ model that was built around the mid nineties. It is covered in conventional Japanese tissue and painted with ordinary car cellulose which was readily available at the time and sealed with two pack clear coat. The masking took far longer than the actual painting. Yes its all masked and sprayed, lettering as well. The wingspan is 50 something inches maybe 52 certainly no more

Total all up weight as pictured was 42 ounces. That’s reasonable for the size of model and the amount of paint! (The 42 on the nose is coincidental – that refers to the engine)

 

Masking on models is definitely done with finer tape than conventional DIY stuff. As you say Tamiya is about the best – that’s readily available at a model shop. If anyone happens on any tan coloured BETTO masking tape that’s even better – I’d like to know if you do as I haven’t seen any for a while now.

 

As an addition to mgj’s advice cut the tape thats going to mask the edge of the paint line as narrow as will take the masking ‘blanket’ eg newspaper or, even better, aluminium kitchen foil. This way the removal stresses on the paint below is kept to a minimum.

 

Heres another pic of the above model masked up for the red lines. It’s in my ‘spray booth’ which is temporarily tacked on to the workshop.

 

The masking tape visible is stuck to the narrow masking tape beneath. Time to mask this far

Edited By Ramon Wilson on 24/05/2011

[Ramon WilsonParticipant @ramonwilson3]

 

Oop’s looks as if I have

The masking tape visible is stuck to the narrow masking tape beneath. Time to mask this far outweighed the time to paint the areas – hours to minutes! and this is something else to be considered. It’s easy to treat masking as a pain to be got over as quickly as possible to get on with the painting. Time taken to mask should be considered as the part of the painting process, painting itself is secondary for a good result.

 

Sorry about this – I guess you can tell – I love painting and the results it can give. Hope I haven’t gone on too much.

 

Regards for now – Ramon

[mgjParticipant @mgj]

Hugh – cellulose are excellent – provided you get the viscosity (thinning) right.

 

That depends on how fast you move the gun and how far the gun is from the subject – to a point. A bit of practise, but you want to spray a WET FILM. Too dry and it loooks sort of dry and won’t melt to a good shiny surface. Too much and it will run. Also don’t be in too much of a huury to get the paint on, and don’t dwell. Put a film on, let it go off and then put the next film on (start off, run on, run off) and build it up like that so it doesn’t slump.

 

And with cellulose don’t do it when its damp or it can bloom which is a pain.

 

Personally I don’t like spraying cellulose, but then I have got used to 2 pack which is so much easier. but I did do one racer with it, and it came up like glass. Can you still buy cellulose like that? I am not sure i’d agre about cellulose being easier. I can understand your concerns about health, but easier? Still give it a go. You can, done right, get a very good finish out of a can in fact.

 

Colluurs – they are all car colours but most suppliers can match a colou, and there is a huge range, going back to the year dot.. Halfords certainly can, and on the spot. At a price but one or two of their touch up bottles would certainly do a model.

[mgjParticipant @mgj]

Hugh – cellulose are excellent – provided you get the viscosity (thinning) right.

 

That depends on how fast you move the gun and how far the gun is from the subject – to a point. A bit of practise, but you want to spray a WET FILM. Too dry and it loooks sort of dry and won’t melt to a good shiny surface. Too much and it will run. Also don’t be in too much of a huury to get the paint on, and don’t dwell. Put a film on, let it go off and then put the next film on (start off, run on, run off) and build it up like that so it doesn’t slump.

 

And with cellulose don’t do it when its damp or it can bloom which is a pain.

 

Personally I don’t like spraying cellulose, but then I have got used to 2 pack which is so much easier. but I did do one racer with it, and it came up like glass. Can you still buy cellulose like that? I am not sure i’d agre about cellulose being easier. I can understand your concerns about health, but easier? Still give it a go. You can, done right, get a very good finish out of a can in fact.

 

Colluurs – they are all car colours but most suppliers can match a colou, and there is a huge range, going back to the year dot.. Halfords certainly can, and on the spot. At a price but one or two of their touch up bottles would certainly do a model.

[Ramon WilsonParticipant @ramonwilson3]

Hugh, mgj,

 

Cellulose paints other than aerosols are difficult to obtain these days.Tthey are now also relatively expensive compared to what they used to be. My last contact with a car finish supplier where I bought all my cellulose was about three years ago. They could still supply cellulose but only to – “vintage car restorers” – I guess that would be registered VCRs. When I explained my use would be modelling they agreed that providing I would sign to say I was not using this paint for standard car repairs they would sell me some. I never followed that up as I used some stock paint for the model in hand and the company – Morelli’s – has now closed. Morelli’s was a nation wide concern so whether they have gone completely or it’s just the Norwich branch I don’t know.

 

Hugh small amounts of cellulose paint will be difficult to find however all may not be lost. There is a model company called White Ensign. They produce a range of paints called ‘Colour Coats’. They are not cellulose as far as I know but they can be thinned with cellulose and sprayed. A friend of mine uses this paint regularly and does exactly that. It may be worth a look on WE’s website.

 

Regards – Ramon

[lesley hackettParticipant @lesleyhackett50196]

I found a supplier of small paint tins that people might find usefull 30 ml 50ml and 100 ml

**LINK**

lesley

[Author]

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