Finishing regimes seem to be an extremely emotive subject in the woodturning fraternity, and fuelled by a couple of points in recent posts I did a bit of research.
I never knew the relationship between micromesh and sandpaper grits, in fact I used to sand to 600 wet and dry and then continue with 800, 1000, 1200 and then swop over to 1500 Micromesh on Acrylics. Well apparently I was wasting my time.
I used to get really fed up with the “silly” little squares of micromesh with the foam in between that were colour coded and the colour always used to come off. Was there any other product using micromesh? I have used the 3 x 6 sheets for a while and much prefer them – its easier to judge the pressure and I don’t get the burn marks – but that was probably because a few years back I used to try and sand far to quickly with Micromesh)
What finally spurred me into finding out was the debate about the abrasive quality of burnishing cream and what the grit rating of it was.
Couldn’t sleep last night and laid in bed at 3am and found this lot out.
Micromesh is made by a company based in Iowa trading as Micro-Surface. If you want to read about them they’re here:
MICRO-SURFACE FINISHING PRODUCTS, INC. The product range comprises (of particular interest to us) Micro mesh sheets, 3 x 6 inches, 6 x 12 inches and 12 x 12 inches. Micro mesh is available in three “strengths”, Regular , Mx, and AO, the letter standing for Aluminium Oxide which is marketed as a polishing medium for aluminium finishing. Don’t know what Mx stands for but it is for polishing harder metals (there is actually a fourth called MXD but I think it is even more specialised).
Soft Touch Pads, those with the coloured coding are available in 2 x 2 inch squares and also 3 x 4inch squares, again, available in all three grades. An interesting point here is that they are marketed by micro surface as being applicable for softer woods, implying that another grade is suitable for the harder woods, and the next up the scale is the AO type. You can also get rolls up to fifty foot long! (that’s a lot of pens!) You can also buy three to eight inch discs with either an adhesive or loop backing.
That’s the précis of the relevant micro mesh products, but there are more so take a look. One more that is relevant to the issue of grit labelling of burnishing cream is that they also sell fluids (aka abrasive slurries) and polishes. Micro finish liquid abrasive and Micro gloss are the two products that appear to be relevant to our hobby. Micro Gloss Liquid abrasive will remove a 9 micron scratch (?? See later on grit comparisons) whereas their standard finish is described as 1 micron Micro Gloss. It doesn’t say so but I assume therefore that the supposition is that it will remove a one micron scratch (?) and is therefore a superior product. This rates the abrasive qualities of the liquid abrasive at Micromesh grit 3200. The Micro gloss at the 1 micron level would appear to be at least, if not better than, 12000 (see the grit comparison table).
Just had a break for coffee and saw Pete’s post about Micromesh labelling, they are very open about it and there is a section on their website labelled “Private Labelling” so you can get this stuff under other names but I guess they wont let it go at lower prices.
Micromesh Grit Comparison chart:
Micromesh Regular USA Grit UK Grit Micron
P120 125
120
P150 100
180 P180 80
200 P220 65
P240 60
P320 52
240 50
280 P360 45
320
P400 42
P500
360
P600 40
1500 400 30
P800
500 P1000 20
P1200
1800 600 15
800 P1500 13
2400
P2000 10
1000
P2500 9
3200 1200
3600 1350 8
4000 1500 5
6000 4
8000 3
12000 ????
The USA Grit system is different from ours, so be warned as you can slip up! If you have insomnia you can check out the definitions of the two systems at
sandpaper , where you can find out about CAMI, ANSI, FEPA, and SNORE, the latter of which is the end result. But seriously there is some interesting stuff about stearated and non clog papers.
So, thought I would check out the uk distributors and there are several, some that specialise in the aerospace industry and since I don’t want to polish the hubble telescope, I moved on and found this company which specialises in the model making sector. Interesting, especially following Woodys post regarding Plasticard, as this company sell all sorts of colours and thicknesses, so here’s the next comp Jim, segmented plasticard! There are also cutters to make life easier and other things designed to empty our pockets!
Sylmasta Ltd is the web address, and they are based in Sussex.
Well no nearer finding out the grit comparison for Burnishing cream and cant find out any details as to the micron depth of scratch that any manufacturer will achieve. However found out that Fiddes burnishing cream is the same as Liberon, their websites use exactly the same wording to describe the product and its capability, but I suspect that someone will tell me that one is the holding company of the other?
On the other issue of finishing corian, and a post regarding the coating of a t cut paint finish on a car, the following may be relevant. Finishing a paint in an environment where prolonged exposure to UV is likely is necessary as the UV will, in the case of a polyester and polyurethane paint (and may be others I don’t know) create a situation that was known to the European Coil Coating Association as white paint flake migration. Paint appears solid but under prolonged exposure to UV light the paint can cause electro statically unattached flakes to migrate to the surface of the material making it appear as if the surface has been sprayed with sea water and the water allowed to evaporate, leaving a salt like deposit. This is both unsightly and causes degradation of the paint finish, ultimately leading to its collapse as a cosmetic and anti corrosion layer. My own opinion after working with metal coatings for over twenty years is that there is no need to coat acrylics after sanding, it wont degrade and the surface is sufficiently dense that additional coatings provide no real purpose as it will not have any prolonged (years) exposure to UV, but that is my opinion. My company used to overcoat the aluminium cladding panels that were coated with a polyester paint and sometimes, (alloy dependent) a polyurethane paint with a polyamide finish to stop the white paint flake migration that dulled the paint finish and left the residue.
The Penmakers guild have an article by Kurt Hertzog entitled working with Corian (
www.penmakersguild.com/articles/workingwithcorian.pdf) , that some of you may already have read. The salient points are that he uses 5 minute epoxy to bond corian to wood and ca to bond it to itself having sanded the surfaces to be bonded with 400 wet and dry, sorry don’t know if that is the American 400 or P400 UK grit!! On the subject of finishing Corian, Kurt Hertzog states “Do not use the Novus Polishes after Micro Mesh sanding as you’ll be going backwards.” I cant find any statistics to the abrasive qualities of the Novus polishes so this in itself isn’t much help. He does state though that if you want to take the finishing even further than basic sanding, you should sand to P400 and then use micromesh through to 12000. He doesn’t say don’t use any other polish, just “When you’ve finished the series (Grits) you’ll be amazed at the results.” He doesn’t then say, put this or that on top. As Corian is an acrylic I think it fair to assume that this advice would be the same for other turning acrylics.
On a finishing note, this isn’t my opinion except where stated and assumptions I have made, similarly, where stated. I am not telling anyone this is the way to do it, this was what I found out when I researched it and with a bit of other supplementary information thrown in that might be useful. I haven’t found out the micron scratch removal capabilities or the grit equivalent of burnishing cream but I am starting to get the feeling that the use of burnishing cream after micromesh could be a waste of time, technically at least, but I’ll continue to use it because it feels right to me (no logic in that at all!)