Fillers & Paint ?

I am at the point of tidying up the beam engine I have been making for some time. Prior to painting there are a lot of scratches, dents etc. which need covering. I have been using “Holt’s Cataloy knifing putty” but am not too impressed with it. I didn’t really want to use an epoxy or two part filler. The imperfections are very small and I feel that a very thin brushable filler or primer would be sufficient. I would be grateful of any suggestions you fellows might have?

Automotive spot putty is good for filling small holes and is applied with a flat metal or plastic blade. Depending on thickness, can be sanded in less than 1 hour. For larger areas, use a can of spray putty. Available from automotive paint and accessory suppliers.

Paul.

Knifing Putty is not much more than thick paint suitable for filling stone chips and the like, its hardening time is dependant on the thickness applied and much more than a sixteenth of an inch can take days to go off. P38 Isopon hardens all through in about 20 minutes and sands well, if the imperfections are that small filler primer in multiple thin coats is probably the best option.

2K filler primer can be mixed up thick and brushed on, being that it goes off by chemical reaction, it's much better than cellulose paint, it dries nice and hard, and when sanding it's almost 'chalky' but be warned, it will leave visible brush marks where you don't sand, I have a feeling the putty you used started falling out/peeling off when you sanded it?

Spray "high build filler/primer" will do a lot of small surface inperfections. Put that on and it will show up larger problems which can be knifed and then rub it right down before using grey/red primer. Something like U-Pol's "High-5" is what I use.

More detail of how I prep and paint castings in this thread You can also see how thin the 2k body filler can be rubbed down to.

Edited By JasonB on 26/04/2019 07:09:51

Plus 1 for filler primer, as Jason says it does lose a lot of small imperfections and leaves just the larger dents and scratches, I,ve used it for years and its the first thing I apply before reaching for the filler.

Ron

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Many thanks for the filler suggestions etc. this has certainly given me plenty of info. Now I have the basic idea I will have a shop around. Once again, thanks to all.
Malc.