Sanding the long panels so they're flat... Help!

Well, the title gives you a clue-

I've got a 73 bay that's been in limbo for a fairly long time, been cracking on with it the past couple of weeks.

It's had a full side panel opposite the sliding door and it's like a rollercoaster! It's the biggest flat area I've ever had to prep, I'm fairly useful with filler when I need to be but this is doing my tree in! Is it best to use a large flat bed sander and just keep at it? i'm struggling to keep it anywhere near flat and I really don't want to spend too much time on it... It doesn't have to be perfect, it's not a show pony it's going to be my summer cruiser, but I don't want it to look a dog either!

Any tips?

 

had the same pob mate
used a good long block i used a 500mm piece of 4x2 pse and used a ruff paper like a 120 grit until the whole panel was flat
then proceed up grades of paper until alls smooth and flat takes ages )

 

Get a can of black spray paint and put a mist coat over your panel then when you block sand it you will see the low spot still have black paint on them so you can add filler there then block again
Mine side panel aren't arrow strait but look good took me a while to be fair .
Good luck

 

Cheers gents, the local paintshop sells the long sanding blocks- What paper do I use with them? I usually just use P80 sheets for sanding but they won't be big enough...

 

i use 80 or 120 glass or oxcide paper for shaping filler its on a roll about 100mmm wide just rite for a long block

 

I used one of these after I saw it in the local builders yard. It is made by Rolson and is a dry lining sanding tool (about 1200mm long and 100mm wide) I used it with the standard rool glass paper which I secured with the handles.
It was fantastic at getting the big panels flat (use a spray guide coat too)
Can't recall how much I paid for it though... but it was quite cheap I think.

 

Cheers everyone, will crack on today.

Might buy one of those big dry lining jobbers, they looks spot on!

 

£7 from Machine Mart in the sale! Bargain! Just trying to find the paper for it now- How did you get on with yours? It looks like how it's fastened it'd rip really easy? Was hoping to find some with a sticky back that won't budge!

 

i used a Mirka long block. About 40 quid, but well worth it. it ploughs through tacky filler and smooths dry filler like its butter. And you can use an extractor.

Well in.

PSG

 

Just had a look at those, I've used their Net sanding stuff before but they stopped selling it round here so I went back to P80 for all my filler jobs! Will try track some down though, forgot how good it was!

 

Hi Georgey,
£7s a bargain! (Wasn't sure where I'd bought it) No problem with the paper ripping, I just made a 8mm hole for the handle bolt and tightened the paper under the handle, then pulled it to the other end, folded it around and again secured it under the handle.
The good thing was that the aluminium base was flexible enough along the length to shape to the slight curvature of the panel I you wanted it to. Very light to use, vertically or horizontally.
It proved to be quite a good cheap fix for me. Shame you're not near, you would be welcome to borrow mine!
Good luck!!

 

all said and done its a fine art and hard work but its just experience and learning from your mistakes oh and the rite tools
must admit mine are' nt arrow straight but i aint finished yet :-
one day eh!

 

Haven't dared to tackle it yet!

Will get some pics up next week when I've done it and you can see my poor effort! haha

 

Depending how much filler is on there, If alot crack out the 40 grit paper,

Use a long block (420mm), velcro or stick on to flat it back properly, machine mart do air powered ones for about £80, maybe sell it on afterwards.

If you're serious and dont mind spending some cash, 3M purple paper is the daddy of abrasive papers, doesnt clog, lasts about 4 times longer than any other, and is only about double price of other mid range papers. (about £1 pr long sheet)

Theres no real shortcuts though, as its time consuming, tedious and dirty work, it can be made more bearable by wearing a mask ;D

 

And don't do it in your garage, otherwise EVERYTHING will get covered in dust.

Guess how I know that one?

 

I am at this stage on my nearside rear panel. I have previously welded in a new rear arch but left the top part in paint until now. I obviously had some distortion from the welding which I tried to keep to a minimum. This was on top of accident damage I uncovered when stripping the top half.
Once I had stripped off the paint & filler I had the old 'oil canning' problem. (where areas of the panel pop in & out when pressed). This is where the panel is to large and so needs shrinking to tighten it up. The only way I could achieve this was to weld at the centre of the loose/baggy areas. As you weld the panel expands but then shrinks as it cools tightening the panel.

Then its a case of filling the complete panel & working on it as others have said. it is a long & laborious task but satisfying when you get a good result.

I remember I spent a good 4 days on the offside of my bus last year getting it flat & it's still not arrow straight but acceptable to me.

I use a large piece of polystyrene as a sanding block about 6-700mm long with rolls of 60 grit paper. Being polystyrene its easy to fix the abrasive paper. I just fold it over the ends and use large copper tacks (like plaster board nails), which easily push into the block. Here's the block:




I also have a mirka long block but prefer the polystyrene block as it has a slight bit of give in it. This helps when trying to get the slight radius of the panels in the vertical direction.

I expect to be spending most of the long weekend trying to get the rear panel straight.

Good luck with yours georgeyv and post up some pic's of your progress.

 

I hate getting bus panels proper flat

Every time ive got one proper flat im proud but feel a little bit of my soul disolve

I think ive spent a week of my life on one panel and ill never get that week back but its a good job


Paul weedings prepping and painting my bus so i may not end up in rehab this year but paul may if he hasent heard about my picky eye by now

:laugh2: :laugh2: :laugh2: :laugh2:

 

Thing is when your sanding or prepping with your eye so close to the body you see every little imperfection. When you stand back and look at the whole thing you can't see most of it.

Sometimes its better to know when to call it quits, also these buses were never arrow straight anyway and unless your going for show standard if you don't do it right then the paint will make it look worse.