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MG Midget and Sprite Technical - Sanding blocks

When skimming and sanding filler on my dash recently, I realised I could do with one of those long board sanding blocks. When I wanted a long sander before I have used a 16" block of wood, but I may buy something more purpose made.

A quick look illustrates choices between rigid (photo)and flexible ones and also some use a velcro type system.

Any experience as to what sort is best for shaping flat and slightly convex surfaces on larger panels?

GuyW

Have a look at Perma-Grit tools
https://www.permagrit.com/

I have a couple of their sanding blocks and they are really good for all sorts of jobs. They might have something suitable...

C MADGE

I have one of those yellow ones with velcro fastening. 18" I think, which is a manageable size. You cannot do decent bodywork without one.

To do convex surfaces like wings/doors etc. sand in a criss-cross pattern 90 degrees to the curve.

Surprisingly useful in loads of other sanding situations too.

Cheers,
Malc.
Malcolm Le Chevalier

Does the velcro fastening system last well Rob?

For years I have made do with a length of wood and fastened the abraisive paper with drawing pins at either end. I mainly use a 4" block as well, but you definately need a long block sander to get the overall shape right first as smaller blocks just follow whatever contour your filler happens to have set at!

Those Permagrit abraisives look good for a more engineering approach but I couldn't see any equivalent long block ones on their site. I presume the abraisive isn't replaceble so I wonder how long they will last without clogging up when used on filler.
GuyW

I have the long sander...for what little I've used it it does well, but mine has clips at other end to hold what ever full sheet of sand paper I'm needing so no expensive Velcro coated paper

I'm one thst believes in wasting sand paper, ignition stops cutting I toss it for fresh, the thing I hate about sanding is the manoutny and the energenergy it consumes, so I'd rather waste 50 cents worth of paper then an extra 10 minutes of sanding

Prop
1 Paper

I have a version of what you have shown in your pic OP. And they certainly work well for flat surfaces.
For curved i use my DA sander, with a foam pad beneath the 150mm sanding disc you can with care sand into shallow curves.
As others have said, if you alternate you action through 90 degrees or so every couple of minutes you should be able to achieve pretty good results.
let the abrasive do the work !
P Bentley

C Madge,

Is the permagrit stuff like the old Cintride products which were IIRC tungsten carbide metal bonded onto a steel backing sheet. I had a few and they worked well but the company is now defunct AFAIK.
David Billington

I never thought about longboarding on cars but it makes perfect sense. Working on wooden boats longboarding is de rigeur for fairing hulls, in fact essential.
We generally made them as required, up to 3 or 4 feet long from cheap plywood with strips of paper from a roll with the the ends turned over the end of the board and fixed with a few staples. A few dabs of wood glue would keep it stable on the board, but it was still easy to remove with a few strokes of a sharp chisel.
A board as long as that is a two man job, but a couple of feet can be used solo and the ply is flexible enough to follow a gentle curve. Just needs a couple of bits of scrap batten for handles.

It's a cheap and cheerful thing if you don't want to buy one and it works.
Greybeard

A selection of these are what I've settled on

https://www.mirka.com/uk/uk/UK_TOOLS/UK_For-Hand-Sanding/

Connect to a Henry type vacuum for almost dust free sanding in confined spaces without the need for a face mask. Add a "disposable interface pad" to protect the Velcro and it will last way longer than I'll be around ;0)

I buy most of mine from the bay of e but scout for awhile to get a "bargain"

best of...
MGmike
M McAndrew

The Perma Grit sanding blocks have Tungsten Carbide sheets bonded to an aluminium block.

The longest block is 560mm which I have. Its really useful at times. The sides are at 90 degrees so it works well if you need to sand perpendicular to another surface.

They last well. Mine is at least ten years old and the grit has worn down a grade or two. They do get clogged up just like any other sander but can be easily unblocked with tap on a hard surface and a wire brush.


I haven't tried it on body work though.
C MADGE

I ordered one last night, similar to the one Mike later posted the link to, so I think I am on the right track! Though a different brand, it also has a dust extractor connector.
Havent worked out what a "disposable interface pad " is though! Double side velcro strip?
GuyW

Guy, 100% right, both parts of a Velcro strip back to back. If the loops wear out with changing sheets, rip the interface pad off and replace. A few quid extends the life of your sanding block immeasurably.

Best of....
MGmike
M McAndrew

Seeing as I have a council tax free month, I think I can afford that electric DA sander I have been promising myself. Any recommendations welcome!
GuyW

I'm interested too Guy but the ones I can find seem quite expensive! I'm not sure if a "random orbital" sander is the same thing?
Bill Bretherton

I am told that these "Dodo Juice" machines have a good reputation amongst car detailing fanatics. But I am just not sure if they would work equally well for bodywork sanding. Anyone know how good they would be?

http://tinyurl.com/ycys479q
GuyW

C Madge,

I noted that from their information but do you know what the tungsten carbide is bonded to before that is fixed to the aluminium. In the old Cintride sanding sheets it was a thin steel sheet IIRC.

Having a quick look I think I've answered my own question, see http://www.permagrit.com/swop-block-sheet-coarse-180-grit/ , so looks like the same type of product as the old Cintride so will have to bear it in mind.
David Billington

If you have an hour or so free it would be worth watching the tools and techniques this guy uses. It echoes quite closely how we put clay models together in the design studio with control surfaces and using slicks - or blades as he calls them, to model a surface quickly that requires very little cleaning up prior to paint. Here you can see the DA sander is only used for lightly denibbing the polyester filler - the final surface is created almost exclusively with blades and long sanders.

https://www.youtube.com/watch?v=-l_8lgsSTtQ
f pollock

This thread was discussed between 08/03/2018 and 10/03/2018

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