Okay, What's the Trick - Rubbing Back Plastic.

[mx250]

Okay, what's the trick to rubbing back plastic - '74 Yamaha OEM guards.

I'm currently using P120 sand paper. Rub too hard (hand rubbing) and it seems to burn the plastic and mark it. Light rubbing will get rid of oxidizing but doesn't seem to get out imperfection.

(I'm sure with experimentation I might 'get there' but I thought I would cut corners and draw on the collective wisdom.)

[Graeme M]

There's an article in an earlier VMX magazine that gives the lowdown I think. I did my IT175 tank and guards that were very chalky and got them to a perfect high gloss finish - took ages. I started by scraping back with a sharp blade to get the chalky layer off. Then used wet and dry paper, starting at about 240 using warm water with a dash of dishwashing liquid. Moved onto 320, 400, 600, 800 and 1200. Finally a light polish back with a cutting cream and then a buff with a lambswool buff. That was tricky cos it needed just the right speed, pressure and movement. Took a long time, and wore my fingers to the bone... The hardest part was the wet and dry, the coarse paper actually digs quite deep so you need to be very gentle at that stage to just dress up the lager imperfections. The finer grades are where you start to put in the muscle to clean up the surface and get the right curve etc. The buff is where the high gloss finish appears.

Maybe there's an easier way, but that's how I did it.

My recommendation? Buy NOS...

[mx250]

My recommendation? Buy NOS...

I was expecting the NOS comments . Which probably the best most economical advice.

But hey, this is s hobby - waste not, want not .

I wasn't going to take them back to OEM (they were painted from factory (MX250)), I was just getting them ready to spray. I try the water and detergent trick.

Thanks Graeme.

[Nathan S]

Scrape 'em. Sand 'em. Paint 'em.
 If you're going to paint them, then the sanding part can take a lot less time than it usually would.
A non ride bike might get away with high fill primer but its a crappy solution when the good solution is only an hour of extra work.

[mainline]

if you're going to paint them, then make sure you use a plastic specific primer beforehand. Supercheap and the rest sell it.

[steve7406]

Mx250 get hold of vmx#14 it has a great article on how to restore plastic tanks i followed it to the letter when restoring the tank for my rm250 it now looks fantasic it took a lot of work but.

[steve7406]

Sorry mx250 my mistake vmx#33 will help you with your restoration.

[maicoman]

There's an article in an earlier VMX magazine that gives the lowdown I think. I did my IT175 tank and guards that were very chalky and got them to a perfect high gloss finish - took ages. I started by scraping back with a sharp blade to get the chalky layer off. Then used wet and dry paper, starting at about 240 using warm water with a dash of dishwashing liquid. Moved onto 320, 400, 600, 800 and 1200. Finally a light polish back with a cutting cream and then a buff with a lambswool buff. That was tricky cos it needed just the right speed, pressure and movement. Took a long time, and wore my fingers to the bone... The hardest part was the wet and dry, the coarse paper actually digs quite deep so you need to be very gentle at that stage to just dress up the lager imperfections. The finer grades are where you start to put in the muscle to clean up the surface and get the right curve etc. The buff is where the high gloss finish appears.

Maybe there's an easier way, but that's how I did it.

My recommendation? Buy NOS...

I pretty much follow the same procedure as Graeme but from 1200 wet & dry I go to 1500 and then 2000. Generally the plastic looks dead flat. I then buff it with the lambs wool pad using Meguires wet look polish. I've done my PE tank and it came up like glass. I'm also doing forum member Adam N's RM 465 plastics at the moment. The tank came up well and I was doing the guards last night while the GP was on. Forget polishing by hand as you will never get the finish that a machine can get.
    Also before you start, as a rule check the colour of the plastic on the underside. If there is a rich pigment of colour left in the plastic chances are the plastic will only need a scrape or sand. If it is faded underneath and there is very little pigment left forget it. No amount of sanding or scraping will bring it back again. The gloss on the plastic is achieved as the guard comes off mould in the moulding process.
 Happy sanding MX250

[maicoman]

Also try Meguires Canuba Wax. I apply during the final buff and it gives that mirror finish. It is absorbed into the tank and hold s it's shine for quite some time before it needs rebuffing.

[crash n bern]

If it's chalky you can sandblast it. Or you can hit it with a heat gun and the chalky stuff melts to a shiny smooth surface.  Bit tricky to get uniform so I would experiment on some throw out parts before you did it.

Or you can sandblast the chalk off then use the heat gun to smooth and shine it up.  Or sandblast then sanding and polishing which will give you more control over the end finish. The heat gun can be hit and miss as you can get hot spots or melt bits if your not accurate.

[Rhodesy]

Another thing you can use first off is stainless steel wool the cunky stuff! Then buff with some jiff.

[mx250]

Thanks Brains Trust. Lots of good info there. I'll start with Graeme's advice and use water and detergent - I should have done this in summer .

[PCMAX]

You could always use a product called Plastic Renew by PC Racing (Ballards sell it). You still need to do the rubbing wih progressivly finer grades of wet & dry though but it brings the gloss back like new.It comes with all the instructions and even some wet & dry & fine steel wool for polishing.

[Mike52]

Back of an old hacksaw blade works great on the chalky stuff.
The sandpapering takes a lot of patience .
My tank is not finished yet because of the patience bit.

[mx250]

Back of an old hacksaw blade works great on the chalky stuff.

I've been using the blade of a Stanley knife held at 90 degrees - works great . Very quick and very controllable. You have to be careful with the pressure which is good and bad. The good is you can quickly shave off scratches. The bad is you can change the shape and profile if you are not careful.

Now to the finishing off process. I'll probably 'rattle can' them.