Post by Brian M on Jan 31, 2009 22:58:14 GMT
From: OliverShaw1 Sent: 02/05/2005 13:39
Trying again; last attempt had a typing/editing glitch where I omitted the crucial word "not" !!
--------------------------------------------------------------------------------
Although I have never painted a caravan I have had good results with both yachts and cars. Some of the techniques are no doubt very similar.
Brush or spray?
I suspect that the most important consideration is what you personally are used to. Both require a degree of skill to achieve a really good surface, and personally I find that I can achieve a far better finish with a top quality brush than with a DIY aerosol spray can. The old tradition of coachpainting, aprocryphically used by the great motor body builders (building bodies for Rolls Royce, and others of like calibre) was to use multiple layers of lacquer, applied by brush.
What follows is specifically in the context of brush painting, since I do not have the expertise to offer any advice about spray.
Use the very best quality brush that you can obtain. Some experts like a mixture of natural and synthetic bristles, and some like bristles with split tips. I have recently been using Hamilton Perfection Gold and the top-of-the-range Harris (can't remember the model name) reasonably successfully, both from my local B&Q.
Expect to pay around £20 for a good 2-/12 " to 3" brush; this may seem a lot, but it is only a small fraction of the total cost of materials plus the value of your time, and it is well worth the expense.
Materials
It is worth using a specialist paint for the job, emphatically not ordinary household paint. There are a number of vehicle paints formulated for brush application. Note that they may need the use of thinners or flow agents, depending upon temperature and area to be painted and drying conditions, and if thinners or flow agents are needed that will usually mean their own dedicated products unless they actually say otherwise.
Alternatively, although I have in fact always used vehicle paint on vehicles and yacht paint on boats, I am fairly sure that a good yacht paint would do the job equally well. You might have a different choice of type of paint there, and a different but slightly restricted choice of colours. Of the yacht paints, two-part polyurethane (e.g. International's Perfection range) is by far the hardest and longest-lasting, but it is so hard that fairing-in repairs after stone chips or other superficial damage is very difficult. However both one-part polyurethane and conventional yacht paints will also do a very fine job, and personally I now tend to use conventional rather than polyurethane paints.
Be aware that the fumes from 2-part polyurethane are carcinogenic; if you decide to use it, read and follow the health and safety instructions provided with the product or on the data sheets.
Both vehicle paints and yacht paints will give a much higher gloss than domestic paints, and can be expected to last significantly longer.
Techniques
The basic technique is to apply the paint by brushing horizontally, then go over it with much lighter vertical strokes, and finish by laying it off with very light horizontal strokes. Keep a wet edge at all times.
Some people have reported excellent results working in teams of two; one person applying the paint by roller and the second following immediately behind and laying it off by brush. I have not tried this myself, but it seems a good idea, provided you take adequate steps to ensure that the roller does not either encroach on neighbouring areas or spray off droplets in all directions; if you are doing one panel at a time (as I suggest) you might want to mask up the 'van first.
Two other tips, both from International Paints' excellent instructions: 1 - never paint straight from the can, but decant the amount you expect to use into a paint kettle and then seal up the can; this minimises contamination of the paint. 2 - when you reseal an opened can of paint, put a couple of teaspoonfuls of thinners into the can before closing the lid; this will help to prevent a skin forming on the paint.
The two biggest problems both arise from the size of the job. Few people can get their caravans inside a building, so if you are having to work outside you need to by fairly choosy about the weather. Obviously you need a dry day, but also one with minimal wind, avoiding either extreme of temperature (too cold and the paint won't flow out properly, so it leaves brush marks; too hot and it dries so quickly that you cannot maintain a wet edge), and if possible a day when there are not too many insects flying around (they seem to have a death wish, committing suicide in your new wet paint).
Check the allowable temperature range for applying your paint before you start; it should be stated on the tin or on a data sheet, and not all paints have identical temperature ranges. Make absolutely sure that you are well within this range; if not, don't be tempted, wait for a more suitable day.
It is imperative to maintain a wet edge, otherwise you will get the paint "pulling" when you try to join up to a part you painted a few minutes before. To some extent the design of a Safari helps here, because you can make use of the beadings to split the van into manageable sized panels, and do just one panel at a time. However it may be necessary to use a flow agent or retarding thinner to help the paint maintain a wet edge, particularly in warmer conditions. At least some paint manufacturers maintain technical help lines, and certainly I have found International's help line to be excellent. Phone numbers for these should be on the tin.
Hope this is helpful,
Oliver
Reply
Recommend Delete Message 5 of 6 in Discussion
From: OliverShaw1 Sent: 02/05/2005 14:19
Two further thoughts:
Compatability
If the paint is original I don't expect you to have any problems with aplying any new vehicle paint, but if the 'van has already been repainted at some times it is possible that your proposed new paint may react adversely with the paint already there. If it does so, the result is likely to be blistering, and it may all have to come off again. So if in doubt try a little on a small (and if possible inconspicuous) area first.
If there is a compatability problem it may be possible to use a barrier coat of an appropriate product.
I have only very occasionally met this problem, essentially when applying either cellulose paints or Hammerite over what appeared to be domestic paints, or when applying two-part polyurethane over an unknown substrate. I suspect that International's Universal Clear Primer might be a suitable barrier coat for applying 2-part poly, but it is most important to check with their technical help line if you want to use this route.
Preparation
And of course 98% of the work lies in the preparation before you even start applying the paint ... ...
This means repairing any damage, removing any loose paint, priming any bare metal, then building up and sanding down to achieve a perfectly flat surface.
It is the sanding that is the real killer. I was brought up in the tradition of doing it by hand, using wet-or-dry paper used wet (with a drop of washing up liquid in the water to help lubricate), but when I bought another boat last autumn I cheated by using an orbital power sander; the first time I had ever tried this on a previously painted surface, because it cannot be used wet, but I was very pleased with the result. Very much less physical work for me, although so much dust is created that you need to take plenty of time to first brush it and then wash it off the job, and then let the dust in the atmosphere settle and then wash down the job again - if necessary more than once.
Worth experimenting with different grades of paper in your power sander, not only different grits but different materials. And the effect of a given grit size (the number of the paper) seems to depend on the material; with my sander I ended up using Piranha papers (by Black & Decker), at 100-grit for heavy-duty sanding and 150-grit for finer sanding (including sanding down the undercoat), then finishing up with 240-grit wet-or-dry used wet before the first top coat and about 400-grit wet-or-dry between top coats.
When the surface is finally prepared, it is worth going over it with a rag dampened in the appropriate paint thinner - and if this becomes visibly stained with sanding dust then do it again, repeatedly if necessary, until all sign of sanding dust is removed. Let the surface dry off before you apply the paint.
Then immediately before applying the paint go over it with a Tack-Rag, to remove any dust that may have settled since you wiped it down with thinners ... ...
Oliver
Reply
Recommend Delete Message 6 of 6 in Discussion
From: nimueandme Sent: 04/05/2005 00:52
hi, we have never painted a caravan but we did paint the landrover, we used car paint and a lot of thinners, we did it with two thin coats and the result was amazing,as Oliver says you get a really good gloss and hard finish with these kinds of paint , we learned from our mistakes painting our previous land rover with household paint for metal that it does not go onto a large surface easily as you get brush marks ect so it is worth going for the right kind of paint.It is difficult to say how much paint you would need, we were advised by shop and had enough left over to paint 6 more landrovers, but as we had the colour mixed for us we had to keep it.Any way good luck with painting
nimueandme
Gloria and Dennis
Trying again; last attempt had a typing/editing glitch where I omitted the crucial word "not" !!
--------------------------------------------------------------------------------
Although I have never painted a caravan I have had good results with both yachts and cars. Some of the techniques are no doubt very similar.
Brush or spray?
I suspect that the most important consideration is what you personally are used to. Both require a degree of skill to achieve a really good surface, and personally I find that I can achieve a far better finish with a top quality brush than with a DIY aerosol spray can. The old tradition of coachpainting, aprocryphically used by the great motor body builders (building bodies for Rolls Royce, and others of like calibre) was to use multiple layers of lacquer, applied by brush.
What follows is specifically in the context of brush painting, since I do not have the expertise to offer any advice about spray.
Use the very best quality brush that you can obtain. Some experts like a mixture of natural and synthetic bristles, and some like bristles with split tips. I have recently been using Hamilton Perfection Gold and the top-of-the-range Harris (can't remember the model name) reasonably successfully, both from my local B&Q.
Expect to pay around £20 for a good 2-/12 " to 3" brush; this may seem a lot, but it is only a small fraction of the total cost of materials plus the value of your time, and it is well worth the expense.
Materials
It is worth using a specialist paint for the job, emphatically not ordinary household paint. There are a number of vehicle paints formulated for brush application. Note that they may need the use of thinners or flow agents, depending upon temperature and area to be painted and drying conditions, and if thinners or flow agents are needed that will usually mean their own dedicated products unless they actually say otherwise.
Alternatively, although I have in fact always used vehicle paint on vehicles and yacht paint on boats, I am fairly sure that a good yacht paint would do the job equally well. You might have a different choice of type of paint there, and a different but slightly restricted choice of colours. Of the yacht paints, two-part polyurethane (e.g. International's Perfection range) is by far the hardest and longest-lasting, but it is so hard that fairing-in repairs after stone chips or other superficial damage is very difficult. However both one-part polyurethane and conventional yacht paints will also do a very fine job, and personally I now tend to use conventional rather than polyurethane paints.
Be aware that the fumes from 2-part polyurethane are carcinogenic; if you decide to use it, read and follow the health and safety instructions provided with the product or on the data sheets.
Both vehicle paints and yacht paints will give a much higher gloss than domestic paints, and can be expected to last significantly longer.
Techniques
The basic technique is to apply the paint by brushing horizontally, then go over it with much lighter vertical strokes, and finish by laying it off with very light horizontal strokes. Keep a wet edge at all times.
Some people have reported excellent results working in teams of two; one person applying the paint by roller and the second following immediately behind and laying it off by brush. I have not tried this myself, but it seems a good idea, provided you take adequate steps to ensure that the roller does not either encroach on neighbouring areas or spray off droplets in all directions; if you are doing one panel at a time (as I suggest) you might want to mask up the 'van first.
Two other tips, both from International Paints' excellent instructions: 1 - never paint straight from the can, but decant the amount you expect to use into a paint kettle and then seal up the can; this minimises contamination of the paint. 2 - when you reseal an opened can of paint, put a couple of teaspoonfuls of thinners into the can before closing the lid; this will help to prevent a skin forming on the paint.
The two biggest problems both arise from the size of the job. Few people can get their caravans inside a building, so if you are having to work outside you need to by fairly choosy about the weather. Obviously you need a dry day, but also one with minimal wind, avoiding either extreme of temperature (too cold and the paint won't flow out properly, so it leaves brush marks; too hot and it dries so quickly that you cannot maintain a wet edge), and if possible a day when there are not too many insects flying around (they seem to have a death wish, committing suicide in your new wet paint).
Check the allowable temperature range for applying your paint before you start; it should be stated on the tin or on a data sheet, and not all paints have identical temperature ranges. Make absolutely sure that you are well within this range; if not, don't be tempted, wait for a more suitable day.
It is imperative to maintain a wet edge, otherwise you will get the paint "pulling" when you try to join up to a part you painted a few minutes before. To some extent the design of a Safari helps here, because you can make use of the beadings to split the van into manageable sized panels, and do just one panel at a time. However it may be necessary to use a flow agent or retarding thinner to help the paint maintain a wet edge, particularly in warmer conditions. At least some paint manufacturers maintain technical help lines, and certainly I have found International's help line to be excellent. Phone numbers for these should be on the tin.
Hope this is helpful,
Oliver
Reply
Recommend Delete Message 5 of 6 in Discussion
From: OliverShaw1 Sent: 02/05/2005 14:19
Two further thoughts:
Compatability
If the paint is original I don't expect you to have any problems with aplying any new vehicle paint, but if the 'van has already been repainted at some times it is possible that your proposed new paint may react adversely with the paint already there. If it does so, the result is likely to be blistering, and it may all have to come off again. So if in doubt try a little on a small (and if possible inconspicuous) area first.
If there is a compatability problem it may be possible to use a barrier coat of an appropriate product.
I have only very occasionally met this problem, essentially when applying either cellulose paints or Hammerite over what appeared to be domestic paints, or when applying two-part polyurethane over an unknown substrate. I suspect that International's Universal Clear Primer might be a suitable barrier coat for applying 2-part poly, but it is most important to check with their technical help line if you want to use this route.
Preparation
And of course 98% of the work lies in the preparation before you even start applying the paint ... ...
This means repairing any damage, removing any loose paint, priming any bare metal, then building up and sanding down to achieve a perfectly flat surface.
It is the sanding that is the real killer. I was brought up in the tradition of doing it by hand, using wet-or-dry paper used wet (with a drop of washing up liquid in the water to help lubricate), but when I bought another boat last autumn I cheated by using an orbital power sander; the first time I had ever tried this on a previously painted surface, because it cannot be used wet, but I was very pleased with the result. Very much less physical work for me, although so much dust is created that you need to take plenty of time to first brush it and then wash it off the job, and then let the dust in the atmosphere settle and then wash down the job again - if necessary more than once.
Worth experimenting with different grades of paper in your power sander, not only different grits but different materials. And the effect of a given grit size (the number of the paper) seems to depend on the material; with my sander I ended up using Piranha papers (by Black & Decker), at 100-grit for heavy-duty sanding and 150-grit for finer sanding (including sanding down the undercoat), then finishing up with 240-grit wet-or-dry used wet before the first top coat and about 400-grit wet-or-dry between top coats.
When the surface is finally prepared, it is worth going over it with a rag dampened in the appropriate paint thinner - and if this becomes visibly stained with sanding dust then do it again, repeatedly if necessary, until all sign of sanding dust is removed. Let the surface dry off before you apply the paint.
Then immediately before applying the paint go over it with a Tack-Rag, to remove any dust that may have settled since you wiped it down with thinners ... ...
Oliver
Reply
Recommend Delete Message 6 of 6 in Discussion
From: nimueandme Sent: 04/05/2005 00:52
hi, we have never painted a caravan but we did paint the landrover, we used car paint and a lot of thinners, we did it with two thin coats and the result was amazing,as Oliver says you get a really good gloss and hard finish with these kinds of paint , we learned from our mistakes painting our previous land rover with household paint for metal that it does not go onto a large surface easily as you get brush marks ect so it is worth going for the right kind of paint.It is difficult to say how much paint you would need, we were advised by shop and had enough left over to paint 6 more landrovers, but as we had the colour mixed for us we had to keep it.Any way good luck with painting
nimueandme
Gloria and Dennis