de greasing before painting

[alan66]

I have just finished making the frames for a sweet pea and am ready to paint them, can anyone answer the two questions below ?

1. assemble the frames first then paint them or paint all components etc first then assemble ?

2. some of the steel has been oiled to stop it rusting, and I also used cutting oil whilst doing some of the drilling. whats the best stuff to use to clean the oil off with prior to painting ?

[chris vine]

Hi Alan,

I am sure the best way is to finish the loco and test it before painting. There are always teething problems and a bit of stripping down and reassembly which will almost inevitably damage the paint.

As for degreasing, White spirit is quite good. The trouble with cellulose thinners at similar flashy solvents is that they evaporate so quickly that the oil congeals again before you manage to wipe it off.

Watch out for solvent getting in gaps and joins etc. It will seep out again and mess up the painting.....

Have fun,
Chris.

[ukjimoo]

Hi all

When i finished my traction engine wheels 2 years ago, i primed them with red oxide to stop them rusting.

Now i am ready to paint them and the primer is covered in grease from handling. Im wondering now if priming them was a mistake because any efforts to degrease them will surely lift the primer in places and rubbing down is almost impossible because of all the spokes, rivets etc.

Any ideas?

[baggo]

I use a product called Marine clean for final cleaning and degreasing available from Frost Auto Restoration Techniques:

www.frost.co.uk

I've no connection with the firm but discovered them when restoring one of my motorbikes. They sell a lot of items useful to the model engineer.

Marine clean is an industrial strength cleaner/degreaser which is diluted with water (preferably hot) and used to scrub the components which are then rinsed in clean water. It can be used on any surface including paint.

Steel surfaces thus cleaned will rust before your very eyes so I use another product called Metal-Ready on these. It's basically a rust treatment but is also used as a primer before painting and prevents the surface oxidising.

Before using the Marine Clean you can use a solvent such as white spirit to get the worst off but I tend to use good old fashioned washing up liquid!

With regard to painting the chassis - I would tend to paint the chassis as a complete assembly rather than dismantle it and paint each component seperately. If you paint the stretchers, frame plates etc seperately you may find that on assembly the frames will finish up wider than they should be due to the extra thickness of the paint. This may cause clearance problems between wheel bosses and axle boxes etc. Perhaps not such a problem with the larger locos but definitely a problem in the smaller gauges! If you are worried about water getting in between the stretchers and frames, just give them a thin coat of primer before assembly although the final painting should seal any slight gaps and prevnt water ingress.

John

[Jo]

Degreasing: For those of you who have a dishwasher (and warning: don't get caught by her indoors) it's a great way of cleaning prior to painting. You may think that it will rust with all the water in there but that only occurs when you open the door! Which is the same problem you get when you get something sand blasted.

If your are worried about the rust then try something else in there next time you run the machine.....

[baggo]

Hmmm, that seems like a very good excuse to go out and buy one ! ;D

[ron]

I'll second the dishwasher idea with the same caveat------don't get caught

Ron

[chris vine]

HI Again,

Watch out for the washing up liquid and the dishwasher, I am sure they both work but there is a concern about the chemicals in them.

The problem is the "so clean it sparkles" thing. Most leave something behind on the surface.

Chris.

[alan66]

thanks for the help guys, I think i might give the dishwasher a try, ( less hard work ! ) but with a bit of scrap first to see how it go's. Its either that or the "marine clean" but they're out of stock at the moment.

good point about painting the components first increasing the distance betwwen the frames, hadn't thought of that.

[Phil Sutton]

I have read somewhere,think it was in "The finishing touch" by Robert G.Shephard,that washing up liquid has surfectants in it which leave a deposit behind that paint doesn't stick to very well.His advice was to use thinners and wipe off with clean cloths until the cloth remains clean after wiping.Then prime and when the primer has dried,get some top coat on,because primer tends to be porous,and lets moisture in,leading to rust.......

Best of luck

Phil

[GeorgeRay]

Not sure about steel but Bob Shepherd was adamant that for brass, washing up liquid would prevent the etch primer working. He also advocated cellulose thinners to be used immediately prior to painting, again only for brass because of the need to use the etch primer.

[steammadman]

get a box of "finnish" dish washer additive ,give your parts,(model parts , that is), giive them a good soak, dry them off, thougharally, i use a hairdryer, (borrow the wifes), the give the parts a good coat of primer.
you should find this works like a charm.
well it does for me anyhow

[steammadman]

sorry about the spelling mistakes above , my fingers got carried away.

well that's my excuse , anyway ! ! ! !

[Phil Sutton]

Aha you've got dyslexic fingers too!!! ;D ;D

Phil

[ron]

Something I'd forgotten about, you can buy stuff from automotive paint factors called 'Panel Wipe' it's used for degreasing car panels before spraying, it's excellent, even removes silicone traces which are a menace in a sprayshop, they also sell tack rags which are excellent for removing dust etc just before painting and between each coat.
Ron

[chris vine]

The version of panel wipe I used was called "Pre-Paint". Excellent stuff. I think I would prefer to use something made for the job rather than something which might leave something behind. All the hard work of painting will be for nought if the initial bond with the metal is suspect.

Chris.

[ron]

If you are painting onto bare steel it's also worth investigating etch primer, I've only ever used 2 pack in a spraygun on car panels, but people like Frost Restorations sell it in aerosols, it sticks like the proverbial, actually bonds into the steel and provides a very good basis for further coats.
Ron