|628 forum posts|
As part of my ongoing restoration of a Wilfin lathe I'm trying to get a nice smooth finish on all painted parts.
First part to be painted was the drip tray which the process was
Bend bent parts back to shape
Weld up crack on rim, grind smooth
Flap disc entire surface
Body filler entire surface (the tray looked like a moonscape of little pits)
Flap disc entire surface smooth
Screwfix basics red oxide primer, 2 coats, sand between coats
Machinery enamel. BS 00 A 09 Mid Gray, Gloss
Paint, sand, paint again (and a few more times trying to get a flat finish)
Now the issue is, if I paint thinly I get brush strokes left in the paint surface, if I paint thick the brush marks level out but I get left with splotches where some paint is obviously thicker than other parts.
I looked at my mini lathe and they have done a pretty good job of getting a perfectly flat finish with some no doubt cheap labour. Can anyone see the part of my process that is giving me such uneven fninishes?
|229 forum posts|
Edited By AdrianR on 13/04/2019 10:29:27
|Mike Poole||13/04/2019 10:31:12|
1968 forum posts
A good quality brush is a help and working at a temperature that is not too hot or cold, thinning the paint may help but a small amount can make quite a big difference.
|Adrian 2||13/04/2019 10:43:39|
|68 forum posts|
I am not familiar with the paint you are using Adrian. If you are intending to use your lathe when completed , oil and suds can soften and lift paint particularly new paintwork.
After all your hard work and care will you be able to live with this if it happened?
|Speedy Builder5||13/04/2019 11:01:10|
|1778 forum posts|
Owatrol oil contains a de-oxidant (Some cobalt based salt) and is slow drying. It can be used on its own as a rust "killer" or added up to 50% with undercoats and 5% with topcoats. It will slow down the drying process when mixed with Oil based paints but improve flow properties. Besides metal, can be used on wood (useful if the wood is very thin) to protect and harden the surface. A friend turns up lamp shades on his wood lathe which are very thin and translucent, paints with Owatrol to stop them cracking when dry.
|Mike Crossfield||13/04/2019 11:21:16|
|187 forum posts|
Your preparation sounds good, though you don’t say how you rub down between coats. For the very best finish I use 400 or 600 grit wet and dry paper and soapy water between coats to remove minor imperfections and brush marks. Use a cork or rubber backing block where feasible. As has been already said, a really good pure bristle brush of the right size makes a big difference if you’re applying by hand, and a slow drying paint will make it easy to keep a wet edge and allow brush marks to flow out. I’m a big fan of Tractol paint, which is capable of excellent results when hand applied, and is tough as old boots. Even better if you have spraying facilities.
|vintage engineer||13/04/2019 11:50:37|
132 forum posts
You need a Purdy or Hamilton paint brush, they should cost you £30-£40 but will last you a lifetime. Try putting the paint on with a small roller and take it off with a brush.
|628 forum posts|
My current brush is a Synthetic Harris Trade Fine Tip 2" or 2 1/4". Its the second cheapest screwfix sold (I thought avoiding the truly cheapest might give me an edge). I was thinking that some bristles on a stick are some bristles on a stick no matter how cheap. Will have a look around for the more expensive brushes.
Think my sandpaper was 320 grit, was sanding dry but with all the paint immediately clogging my paper I was considering using water to see if that helped, will do so in the future.
Called the drip tray a functional if not nice looking job, it may well be the soonest thing that needs repainting anyway because of wear in use. Next job will be the legs which I will try a better job on.
|Mike Crossfield||13/04/2019 13:14:30|
|187 forum posts|
Definitely invest in a better brush. I use Hamilton Perfection Pure Bristle. Less than a tenner on eBay for a 2 inch, or you can get a set of 4 different sizes for about £25.
|David Standing 1||13/04/2019 13:48:19|
|1222 forum posts|
Remember if making a comparison that you are brush painting, and the manufacturers spray paint.
|David Standing 1||13/04/2019 13:52:55|
|1222 forum posts|
I do not like synthetic brushes, they flick paint, and do not flow as well as real bristle.
Also, if your paper is immediately clogging with paint, the paint is too soft/hasn't fully gone off.
When you say sandpaper, do you really mean sandpaper? Sandpaper will fall apart if wet, only wet and dry will work wet.
I spent years working in bodyshops, so do have a bit of background in paint prep and finishing.
|4418 forum posts|
Also, a trained painter with all the right gear and plenty of practice! A paint booth might even use electrostatic attraction to attract paint on to the object. Aerosol paint droplets are pulled on to the surface in the same way a rubber balloon rubbed on a woollen jumper sticks to a ceiling. Done properly the finish is far more consistent than anything done with a brush.
Given Rainbow hasn't got professional kit and experience, his approach looks very suitable to me. Good brushes and the right paint etc. make the job easier, but as painting is skilled work he might just need more practice.
I'm hopeless at painting: I can do a good job provided I concentrate, but painting is so boring! After ten minutes I make mistakes, half-an-hour later I'm seriously considering spraying the paint by exploding a firework in the can. After an hour with a brush I don't care what the paint looks like at all...
|Simon Birt||13/04/2019 15:08:40|
|7 forum posts|
This is a subject dear to my heart, in fact I have just posted a video on You Tube in which I bang on about paint finishes and how it is not hard to get a decent one.
Over the years I heave done a fair bit of of painting and the contributors are correct when they say it is a skill that needs practice , that said it also needs an understanding of the process and the right kit.
What really taught me about painting was owning and maintaining a narrow boat, which over a few years I have repainted in sections. Exactly the same techniques can be used painting models machine tools etc.
I will dig out some photos and post them here, if there any interest then I can perhaps write a short guide to the process.
Just a couple of points in the meantime: Synthetic enamels generally should not be thinned for brush painting, if you do under no circumstances use white spirit, it will cause the paint to loose shine. The other golden rule is use good quality brushes. For large projects I use Purdy Monarch Elite and small stuff British made Sable brushes. Both expensive but will last for years if treated well.
|Phil H1||13/04/2019 16:21:05|
|171 forum posts|
I had to do the same to a Myford Super 7 drip tray and cabinet (minus the welding) because of age and rust.
The brushed red oxide primer instructions (oil based from Halfords) said that any paint could be applied over the top. So I tried some Halfords cellulose, grey spray primer. I had to apply several primer coats and use very fine wet and dry inbetween coats before the red oxide brush marks underneath 'blended in' to a reasonable level.
The final stage was to take a Myford belt guard to an automotive paint blenders for a match. They matched the gloss grey paint and gave me several large, rattle spray cans of the mixed paint (it wasn't too expensive at the time).
I have no idea what they did differently to the usual gloss spray paint that you buy but it was definitely cellulose and went on far better than any spray paint that I have used before. It gave a beautiful gloss finish and one large rattle can covered the entire cabinet and drip tray.
I now have plenty to do the lathe belt guards and tailstock if I ever need it.
Might that work for you instead of wrestling with the brushes.?
|larry phelan 1||13/04/2019 17:51:37|
|438 forum posts|
If you intend to use your lathe,rather than just look at it,you might save yourself a great deal of trouble.
The drip tray on my lathe was finished in a nice shade of dark blue as new. In no time flat,between cutting oil and swarf there was very little left of the paint finish. I touched it up a few times,but then gave it up as a waste of time. Strange to say,it has not rusted,so I leave it alone and just get on with the job.
Machines are there to be used,not admired.,so if the paintwork on my lathe is not the"correct" shade,so what ?,the machine still works.
1184 forum posts
I've found that the paint flattens and brush-strokes level out over a period of some weeks and what you might have considered a bit ho-hum initially looks much better.
|Phil H1||13/04/2019 19:11:01|
|171 forum posts|
You are right of course i.e., use don't admire - but I repainted my lathe drip tray and cabinet about 8 years ago and it still looks immaculate. The odd scratch of course but it was well worth the effort. In my case, the lathe and cabinet had been stored in a cold damp garage from 1975 to when I took it. So the cabinet really did need attention.
|229 forum posts|
Re brushes, I have heard bristle for oil and synthetic for water.
I also dampen synthetic with water, and dampen bristle with white spirit before starting.
Another thing to improve bristle brushes is to use fabric softener after washing them out with soapy water and dry overnight wrapped in kitchen roll.That is after cleaning them with white spirit of course.
15538 forum posts
I'd say that your are not going to get a top finish painting onto something sanded with a flap wheel, Work through the grits with the paper wrapped around a block, you will probably have to second or third fill and block it out each time to see the imperfections.
A better primer with more solids would also help and as was mentioned above allow the paint to fully harden before any sanding, solvent based particularly gloss may be touch dry fairly quickly but will take a long time to be hard enough to sand.
This will give you an idea of what I do on a model where I want some cast texture to remain, bit more than just a flap wheel job
Edited By JasonB on 13/04/2019 20:30:20
|Andrew Tinsley||13/04/2019 20:49:26|
|890 forum posts|
I like to keep my machines looking as good as possible. It gives me an incentive to clean them down after use. Otherwise they just get covered in dirt oil and swarf which doesn't do them a lot of good.
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