AWGB Woodturning Forum
General Category => Websites, Videos & other sources of interest => Topic started by: Bryan Milham on May 10, 2015, 10:31:58 PM
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I've always said that woodturners don't use enough abrasive and are therefore are not important enough to have an abrasive designed for them.
Normal abrasives cannot handle the high speeds we subject them to, causing the facets of the grit break down too fast and in effect wear it out.
Having a search though the tinternet I've come across these, they actual;ly say they are designed for woodturners. I've not tried them, they may be just ordinary abrasive mounted on a foam backing, but at the very least, someone, somewhere has identified that woodturners need something different.
http://www.abrasivesplus.com/buy/grip-a-disc-50mm-sanding-disc_86.htm (http://www.abrasivesplus.com/buy/grip-a-disc-50mm-sanding-disc_86.htm)
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Bryan Simon Hope supplies a soft backing pad now for his Pro-Sanders
Ed
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Ed, I know. I have both his inertia sander and the deep reach bar.
But they till use standard abrasive.
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So, what is it that would be needed, a different abrasive substance or a different glue sticking it to the 'paper' ?
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The best system is the Simon Hope Pro Sander and the best abrasive bar none is Rhynogrip all obtainable from Simon hope.
For hand sanding Abrenet
Regards George
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Most of the abrasives we use are aluminium oxide based but I agree there are some which appear better than others.
The best way to avoid the overheating issue is to slow down! Run the lathe a little slower when sanding and if you are using powered sanders, slow that down too.
If you want even harder abrasives there are the ceramic discs from Norton https://thesandingglove.com/Norton-Dry-Ice-Ceramic-Discs.asp (https://thesandingglove.com/Norton-Dry-Ice-Ceramic-Discs.asp)
There are also zirconia and diamond discs too but that's probably overkill! ;-)
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Hi Bryan I can't see what is different with this sand paper/cloth sanding surface is it more flexible than the Rhynogrip supplied by Simon? Have you used them???
Ed
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Ed,
no, in my original post I said I'd not tried them, I also said 'they may be just ordinary abrasive mounted on a foam backing'. Though I couldn't specify what ordinary means as there are so many loop backed abrasives on the market.
What was interesting on the website was the fact that it said 'This sanding system was developed after years of careful thought and development, primarily for woodturners.'
It's the first time I've ever see abrasive advertised 'AT' woodturners, hence the comment 'at the very least, someone, somewhere has identified that woodturners need something different'
I've no idea if it's better than Rhynogrip, except it says it's designed not to fly off your inertia sander, which means your operating it too fast anyway.
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I think the bit they are referring to as designed for woodturners is the foam backing.
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Having taken a closer look at this I agree Paul, I'm intrigued I think that I will give them a call tomorrow
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Well I phoned them the sanding cloth face is standard aluminium oxide there 1/4" softish foam backing (their words not mine) this has a velcro back.
I think that they are just claiming they would be good for woodturners, the guy did not know what an inertia sanding system was.
Ed
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Ed, thanks for the follow-up.
Shame, I honestly thought someone might have finally made an abrasive for us.
Oh well, never mind. Maybe on day.
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So Bryan. What is it that is wrong with the current range of abrasives that is not suitable for woodturners? I have to admit that I use a stock of 3M abrasives that I acquired when I worked for them before retirement. I use various types and some are better than others. I am still in touch with those in that business, and I can talk to the technical people and see what their reaction is if I know what to put to them. Let me know what you think. Malcolm.
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Malcy,
There is nothing wrong with modern abrasives, they do their job well for what they are designed for, and the latest developments like Abronet (designed for the aircraft manufacturing industry) are even better. I've not tried the new ceramic or diamond ones (I'm not that rich).
The problem is not the abrasive, it's how we use it, we put it against timber that is rotating too fast, cause the facets of the grit to break, blunting them, overheating the paper (or cloth) causing it to breakdown the adhesive that holds the grit on, or the loop backing.
That's the problem, Us, abrasives don't like heat and high speed.
Don't say it, we should sand/abrade at under 500 RPM, I know that, but how many of us do it religiously?
And lets do some sums, were sanding a 12" platter with a 2" disc, the lathe is rotating at 500 RPM;
So for each rotation of the platter the disc (at the extreme edge) is rotating up to 6 times, multiply by the lathe speed, that's 3000 RPM. Are you really sanding at 500 RPM?
Result, grit breaks down, glue breaks down, disk flies off, okay not always and normally we don't sand as low as 500 RPM but at 1000 RPM the abrasive disk is doing 6000 RPM etc..
George,
Yes Rhynogrip is great stuff, it sticks to the hooks on the inertia sander very well, it's got a good abrasive coating, but J weight abrasive is still the lowest grade of cloth backed abrasive available. There are better ones.
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Malcy,
George,
Yes Rhynogrip is great stuff, it sticks to the hooks on the inertia sander very well, it's got a good abrasive coating, but J weight abrasive is still the lowest grade of cloth backed abrasive available. There are better ones.
You have lost me Bryan I don't know what J weight abrasive is.I use Rynogrip and Abranet and I probably use more than most turners but if you can tell me another one that is better and more economical I am always willing to learn
Regards George
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Most of Ax's first available sandpaper was then heavy blue J Weight then 2" wide-ish .. first I'd had having started 20yrs ago, still have some, as others have come alone as mentioned, over time which now use, as with Simons' they are good .. now today an J weight ... http://www.axminster.co.uk/axminster-abrasive-strip-kit (http://www.axminster.co.uk/axminster-abrasive-strip-kit) ...
Cheers
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George,
Sorry, I missed a whole bit out of my last post. To post the comment fully...
Yes Rhynogrip is great stuff, it sticks to the hooks on the inertia sander very well, it's got a good abrasive coating, but it's paper backed. A strong paper grade but still paper.
Cloth backed abrasives are far better for what we do, they are more flexible, J weight abrasive is still a low grade of cloth backed abrasive available. There are better ones.
As David says, the packs of abrasive strip from Axi are cloth and there was a cloth abrasive very popular before Rhynogrip (and inertia sanders) arrived, I seem to remember it to be Hermes or something like that, but I've never seen a cloth backed abrasive with a looped backing (prepared to be proved wrong on this of course).
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I never hand sand and find the Rhinogrip always works well on the Hope pro sander and I don't think cloth backed would work any better.
For most students because I want them to get the feel of the wood I mostly have them hand sanding with Abrenet which works fine.
Some students I have them both hand sanding and using the Hope pro sander.
Regards George
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I have tried many of the abrasives available from the main suppliers over the years and have always gone back to Rynogrip Red. It may be paper backed with cloth stuck to it, but it is perfectly flexible for my needs and more than this it cuts very efficiently, last longer than most I have tried and for the price I have found it to be the most cost effective and efficient. Like I say tried many and I always go back to it, as with all things though some will prefer a different brand.
For me it is important to learn to use the tools efficiently so finishing with abrasive is as minimal as possible, once this is achieve then a couple passed with each grit is all that should be needed (on sound wood). :)
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I've always said that woodturners don't use enough abrasive and are therefore are not important enough to have an abrasive designed for them.
Normal abrasives cannot handle the high speeds we subject them to, causing the facets of the grit break down too fast and in effect wear it out.
Having a search though the tinternet I've come across these, they actual;ly say they are designed for woodturners. I've not tried them, they may be just ordinary abrasive mounted on a foam backing, but at the very least, someone, somewhere has identified that woodturners need something different.
http://www.abrasivesplus.com/buy/grip-a-disc-50mm-sanding-disc_86.htm (http://www.abrasivesplus.com/buy/grip-a-disc-50mm-sanding-disc_86.htm)
Grip-a- disc have been around for many years. I believe they were originally designed and produced by Len Piers and later sold by his wife Jill after Len died. I use them on Simon's soft pad mainly for the inside of bowls because the soft foam backing allows them to mould easily to the surface.
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Hi
I have found the Rhynogrip to be the best abrasive available, although my preference is for the 'Plusline' which is white, rather than the 'Redline' which is red (obviously!) The Plusline is available 80-400grit and is a lot more flexible than the Redline. It doesn't last quire as long as the Redline, but is around 40% cheaper, and doesn't last 40% less long, so is better value to my mind. The Plusline is available from myself by the way ;)
Regarding the RPM of a bowl, no matter the size it is still doing the same REVOLUTIONS PER MINUTE, but it is going faster the further out, but I guess this would be measuered in feet/metres per second/minute.
Cheers
Richard