AWGB Woodturning Forum

General Category => General Discussion => Topic started by: davej on July 22, 2018, 03:36:51 PM

Title: Sanding speed
Post by: davej on July 22, 2018, 03:36:51 PM

Hi. I use Hope sanding arbour and pads to sand my work, I have been having a few problems with the foam ?on the arbours melting and losing the velcro holding the pads on. Am I sanding to fast.
Thanks
Dave

Title: Re: Sanding speed
Post by: Lazurus on July 22, 2018, 03:47:01 PM

Certainly sounds that way, perhaps too much pressure to. I use an air sander as well as the usual electric and yet to loose any foam or Velcro. I am sure others will be able to offer better advice as I do not use the HOPE system myself.

Title: Re: Sanding speed
Post by: Les Symonds on July 22, 2018, 03:56:58 PM

The Hope system is very free-running, unlike some woodturner's sanding systems which don't have bearings, so if you're melting/mashing the foam backings, you must be sanding at much too high a speed. A couple of hundred RPM should be loads.
Les

Title: Re: Sanding speed
Post by: APH on July 22, 2018, 04:05:03 PM

I would suspect that speed isn't the main issue here, but how much pressure you're using.
You need a certain amount of pressure and correct presentation to get the Hope arbor spinning, but it's then a careful balancing act to keep the pressure as low as possible. You want to allow the abrasive to cut well without overheating it, which would cause your velcro & arbor to melt. Also too much pressure will make it harder for the saw dust to escape the abrasive grit which in turn will further reduce the cutting ability of the abrasive and lead to further heat build up.

Title: Re: Sanding speed
Post by: Derek on July 22, 2018, 06:59:20 PM

Sounds like the question has been answered and I agree with the above comments about to fast and to much pressure

Title: Re: Sanding speed
Post by: Bryan Milham on July 22, 2018, 08:06:29 PM

As said above, slow the speed down but even that will not solve everything. If you only have the one sanding head, it will get hot being used for all the grits.

The trick is to buy spare sanding heads (I suggest 2 more) and use them in turn with each finer grit, to give them time to cool down.

Title: Re: Sanding speed
Post by: bodrighywood on July 22, 2018, 08:25:26 PM

I have had the same problem with the last lot I bought. Within a month every one has seperated. Not convince it is speed related as I am sanding at about 800rpm. usually.

pete

Title: Re: Sanding speed
Post by: Bryan Milham on July 22, 2018, 10:15:58 PM

Okay, admission time. I love the Hope sander, I hate his sanding arbours, they are useless as noted by all above.

I make my own...

2" Sanding Arbour - https://www.ebay.co.uk/itm/Sanding-Backing-Pad-2-50-mm-Hook-and-Loop/231886518984?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 (https://www.ebay.co.uk/itm/Sanding-Backing-Pad-2-50-mm-Hook-and-Loop/231886518984?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649)

3" Sanding Arbour - https://www.ebay.co.uk/itm/Sanding-Backing-Pad-Hook-and-Loop-3-75mm-with-6mm-Thread-Spindle/231886552678?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 (https://www.ebay.co.uk/itm/Sanding-Backing-Pad-Hook-and-Loop-3-75mm-with-6mm-Thread-Spindle/231886552678?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649)

50mm Hook & Loop - https://www.ebay.co.uk/itm/Sew-On-Rolls-Hook-and-Loop-Tape-Black-or-White-16mm-20mm-25mm-38mm-50mm-100mm/361496429819?hash=item542addc4fb:m:mZMQygdqMJ5_8P3xyPnZ65g (https://www.ebay.co.uk/itm/Sew-On-Rolls-Hook-and-Loop-Tape-Black-or-White-16mm-20mm-25mm-38mm-50mm-100mm/361496429819?hash=item542addc4fb:m:mZMQygdqMJ5_8P3xyPnZ65g)

8mm or 10mm Neoprene Foam - https://www.ebay.co.uk/itm/ADHESIVE-BACKED-BLACK-NEOPRENE-SPONGE-FOAM-RUBBER-SHEET-2mm-15mm-THICK/262636002057?hash=item3d26535b09:m:m8fgFlTknXM-dbE1dG5tnzQ (https://www.ebay.co.uk/itm/ADHESIVE-BACKED-BLACK-NEOPRENE-SPONGE-FOAM-RUBBER-SHEET-2mm-15mm-THICK/262636002057?hash=item3d26535b09:m:m8fgFlTknXM-dbE1dG5tnzQ)

Use Evostick or a contact adhesive on the on foam side without the sticky and on the Hook & Loop.

I've gone through several interface pads but only ever had one arbour fail and that was the threaded insert, I guess I did get one 'too hot'

I have a set of 2" and 3" for all grit sizes, saves keep swooping abrasive discs over, just a quick change of arbour.

Title: Re: Sanding speed
Post by: davej on July 23, 2018, 03:08:08 PM

Thanks for the input, will slow down and ease off.
Dave

Title: Re: Sanding speed
Post by: Wood spinner on July 25, 2018, 03:24:11 PM

Sanding ,

The faster you sand the hotter things get

Do you need speed = No

If you obtaing a good Finnish straight from your tool then you only need a short period of time with each grade of paper .
I us a home made sanding pad , made from a old mouse mat , cut strips of sand paper , as you are sanding you can feel the heat starting to build up , Heat also causes micro cracking on some timbers , Slow speed and cautios aproch is the winner her , For me anyway  ;)
If it gets hot you have sanded for to long ( My opinion , others will disagree )