grp machine polishing - help

[alteredoutlook]

Hi,

I have a grp boat that is in need of a good compound, polish and shine.

I have acquired an electric polisher (M14 thread) complete with a 7 inch 'velcro' backing pad and wool bonnet.

I think I need some additional polishing pads. But what type?

A quick google shows there are a myriad of pad's and of varying sizes. Macquire seems to be a well known (expensive?) make used in the automotive industry. Do their pads 'velcro' on to mine or do I have to have a special backing pads.

Alot of the american companies refer to 5/8 inch thread backing plates - now 5/8 is approx 14mm - but are they directly compatible? (a rant here - just when are our american cousins going to go decimal and join the rest of the world?)

Perhaps could anyone recommend a UK company to deal with?

thanks in advance

 

[samwise]

These guys are really excellent and can give you some really expert advice:

CleanyourCar

sales@cleanyourcar.co.uk

Call: 01484 841444

 

[GrumpyOldGit]

Use a gel coat polish about 2000 grade with the lambswool bonnet, NOTHING ELSE ! Dont be tempted to use a sponge pad as it will leave swirls in the gel. also use a mist of water while polishing and keep the surface damp . once polish has removed bloom on surface, wash off ( about 1m2 at a time ) and repeat till one side is done.
Immediately use a good quality CAR polish ie. Autoglym and seal the surface. repeat on the other side and stand back in amazement. will keep her beautiful for at least one season .

 

[VicS]

I use a foam compounding mop, kept moist with a water spray, and a traditional compouding paste ( currently Starbrite).
Places like Screwfix or Toolstation have the mops in various grades with a standard M14 fitting
I find about 900 rpm or so, which is appreciably lower than the max specified, a comfortable speed.

There are liquids .. Farecla do one.. which can be used with direct with a lambs wool bonnet without any water misting ... not tried it yet though.

 

[Sneaky Pete]

There was a good thread on here a couple of weeks ago.

http://www.ybw.com/forums/showthread.php?t=300501

There was some good links, it may give you some additional help and advise.

 

[Marine Reflections]

Hi,

I have a grp boat that is in need of a good compound, polish and shine.

I have acquired an electric polisher (M14 thread) complete with a 7 inch 'velcro' backing pad and wool bonnet.

I think I need some additional polishing pads. But what type?

A quick google shows there are a myriad of pad's and of varying sizes. Macquire seems to be a well known (expensive?) make used in the automotive industry. Do their pads 'velcro' on to mine or do I have to have a special backing pads.

Alot of the american companies refer to 5/8 inch thread backing plates - now 5/8 is approx 14mm - but are they directly compatible? (a rant here - just when are our american cousins going to go decimal and join the rest of the world?)

Perhaps could anyone recommend a UK company to deal with?

thanks in advance

Hi,
14mm & 5/8 won't be compatible with each other. If the thread on your polisher is 14mm then only buy 14mm backing pads.

You probably will need some more pads and even a new backing plate as the ones that come 'free' with most polishers are not that great.

The lambswool is probably as you say just a bonnet that is tied around the backing plate?
If so bin it! not worth the hassle, give it to the cat as a warm jacket.

I have found 3m to offer the best backing pads & polishing heads.

If you want to buy something to just get you through the one job.
They are nowhere near the quality, however Farecla do a 'G-mop' which has a fairly firm sponge head, with the 14mm thread and backing plate attached, they are around £5 and may last you through the whole job provided you do not apply too much pressure.

Most compounding & polishing liquids/pastes have enough lubricant in them to not need any water misting these days, in fact water misting will clog a decent pad.

Sponge polishing & compounding heads will not cause swirl marks, poor preparation and poor techniques will, but not sponge pads.

 

[Sans Bateau]

For boat polishing, here is some useful information:

http://www.anything-sailing.com/showthread.php/4538-Tips-For-Buffing-amp-Waxing-Gelcoat?p=55686

 

[Ex-SolentBoy]

I have just spent a day polishing a 40 year old hull (original gelcoat) that was a very very dull oxidised dark blue.

We used G3 compound and a polisher with a foam pad running at 900rpm. Sprayed water with a squirty bottle and medium pressure.

Finished off with a hand buff using Mer.

It looks like new.

 

[vikinglish]

I have just spent a day polishing a 40 year old hull (original gelcoat) that was a very very dull oxidised dark blue.

We used G3 compound and a polisher with a foam pad running at 900rpm. Sprayed water with a squirty bottle and medium pressure.

Finished off with a hand buff using Mer.

It looks like new.

+1. g3 and mer are hard to beat! Finish like glass if done with care

 

[nigelmercier]

Use a gel coat polish about 2000 grade with the lambswool bonnet, NOTHING ELSE ! Dont be tempted to use a sponge pad as it will leave swirls in the gel. ...

The lambswool bonnet is for polishing off, not polishing. You won't get swirls if you keep the revs low (1 or 2 on the dial).

 

[Marine Reflections]

Just to mention IMO that you will not avoid swirls just by keeping the revs of the polisher low.

Swirl marks, ghost tails, holograms and micro scratches are caused by two main reasons when performing the polishing process.

Firstly, not completely removing grit from the surface and allowing that grit to get caught up in the polishing head.
It is not just the above surface grit that needs to be removed, but also the tiny contaminates that have bonded, or baked on to & into the surface that need to be removed also.

If you place your hand inside a freezer zip bag and run your hands over the surface, you will feel little tiny bumps. These are the bits that need removing.

The second most common reason, is that compounds and polishes have 'diminishing particles' within them.
As the product is worked the particles reduce in size, if you do not work the product for long enough then the particles will not have reduced in size enough, leaving the surface swirled as it is in mid stage.

Running the polisher too fast, clears the worked area of polish before it has had a chance to work properly, it is for this reason some feel that dialing it too fast will create swirls.

So, as Nigel states, you will be helping a great deal by keeping the polishing at a slowish speed, 1-2 (900-1200) rpm on the dial of most rotary polishers, to give the product time to be worked.

Of course there are many other ways to swirl it, in cleaning being the biggest where the grit again is not removed before agitation.


Just to add:
If a surface has very, very bad oxidation the likes of G3 will not be anywhere near enough to remove all the oxidation. Mild, light oxidation yes.

If I had a pound every time I have seen people try compounding a build up of water deposits on top of a lightly oxidised gel coat, I would have... well probably only about 15 quid
but, you see that very severe oxidation takes much more than polishing to completely remove it back down to decent gel.

You can bring back a shine to the most severe oxidation by adding a shine on top, just like I can spill a drink on the carpet and make it 'shiny' but it will last as long as the product takes to dry out.

Trapping oxygen against gel coat with a false shine is also not good for the surface as there is no protection to the actual surface, in fact it will continue to oxidise 'behind the scenes'.

Tony

 

[Bosun Higgs]

Just to mention IMO that you will not avoid swirls just by keeping the revs of the polisher low.

Swirl marks, ghost tails, holograms and micro scratches are caused by two main reasons when performing the polishing process.

Firstly, not completely removing grit from the surface and allowing that grit to get caught up in the polishing head.
It is not just the above surface grit that needs to be removed, but also the tiny contaminates that have bonded, or baked on to & into the surface that need to be removed also.

If you place your hand inside a freezer zip bag and run your hands over the surface, you will feel little tiny bumps. These are the bits that need removing.

The second most common reason, is that compounds and polishes have 'diminishing particles' within them.
As the product is worked the particles reduce in size, if you do not work the product for long enough then the particles will not have reduced in size enough, leaving the surface swirled as it is in mid stage.

Running the polisher too fast, clears the worked area of polish before it has had a chance to work properly, it is for this reason some feel that dialing it too fast will create swirls.

So, as Nigel states, you will be helping a great deal by keeping the polishing at a slowish speed, 1-2 (900-1200) rpm on the dial of most rotary polishers, to give the product time to be worked.

Of course there are many other ways to swirl it, in cleaning being the biggest where the grit again is not removed before agitation.


Just to add:
If a surface has very, very bad oxidation the likes of G3 will not be anywhere near enough to remove all the oxidation. Mild, light oxidation yes.

If I had a pound every time I have seen people try compounding a build up of water deposits on top of a lightly oxidised gel coat, I would have... well probably only about 15 quid
but, you see that very severe oxidation takes much more than polishing to completely remove it back down to decent gel.

You can bring back a shine to the most severe oxidation by adding a shine on top, just like I can spill a drink on the carpet and make it 'shiny' but it will last as long as the product takes to dry out.

Trapping oxygen against gel coat with a false shine is also not good for the surface as there is no protection to the actual surface, in fact it will continue to oxidise 'behind the scenes'.

Tony

Interesting but thats mostly telling us what not to do. How about what we should do to get the shine back on a typical 10 to 15 year old white AWB?

Presumably the first step is a wash. Then remove the water line stain with Y10 or oxalic|? Then how do we get rifd of the bonded in bits of grit?

 

[Sans Bateau]

Have a look at the link in my post

 

[Marine Reflections]

Interesting but thats mostly telling us what not to do. How about what we should do to get the shine back on a typical 10 to 15 year old white AWB?

Presumably the first step is a wash. Then remove the water line stain with Y10 or oxalic|? Then how do we get rifd of the bonded in bits of grit?

Yes the first stage is a wash, but there are stages within the wash.

There have been quite a few decent links put up recently regarding the 'how to' here is a decent video from 3M regarding the polishing stages.

galadriel has put up a link that seems top be popping up a lot, worth a read.


On the subject of how to remove the bonded bits from the surface, there are a few to choose from:

Melamine foam is a little more aggressive foam than a normal sponge on the wash stage, these work very well as they are much more dense than a normal sponge and work much closer to the surface.

Clay bars, a malleable lump of clay that is rubbed over the surface and pulls out grit and dried on contaminates.

Acetone also is great for preparing/de-greasing the surface, harmless on gel coat and removes all traces of wax build up before polishing.

Different standards of finish are usually determined by decent prep.


Tony

 

[nigelmercier]

Just to mention IMO that you will not avoid swirls just by keeping the revs of the polisher low...

Indeed, but it helps. The best way is to use a dual-action polisher, like a DAS-6, Meguiars G220, or Dodo Juice.

 

[Marine Reflections]

Indeed, but it helps. The best way is to use a dual-action polisher, like a DAS-6, Meguiars G220, or Dodo Juice.

Sorry Nigel, I am stuck with between agreeing with you and disagreeing at the same time.

Again just in my opinion...
The dual action polishers are not the best way to avoiding swirls, but for the new user or one who may not bother with the same degree of prep, they will help, but still create problem swirls, even though in an oscillated / vibrated pattern, should the prep stages not be used, or when using a large diminishing particle compound.

There is simply not enough rotation going on to reduce the particle size when passing.

If I could replace the techniques used in preparation, along with pad and product compatibility and technique by using a Megs G220, or a DAS-6 then I would, but the truth is they can't possibly.

The only reason I use a dual action is for fine sanding, for this I use the Mirca Ceros, as they tend to vibrate far less, the rotation is not hindered by applying pressure, you have a choice of orbit, is near silent and is very, very light.

Should you be able to handle the vibration of a porter cable for long periods, they are one of the safest options for the new user, or when the polish being applied is very fine with very small diminishing particles.

My daughter (age 10) has the Megs G220, but prefers using a rotary for the very same reason I do, she does not create swirls as she understands what causes them.

 

[BlueSkyNick]

For boat polishing, here is some useful information:

http://www.anything-sailing.com/showthread.php/4538-Tips-For-Buffing-amp-Waxing-Gelcoat?p=55686

If somebody were to right an English version of that, with product recommendations to suit, it would be extremely helpful !

 

[Stork_III]

If somebody were to right an English version of that, with product recommendations to suit, it would be extremely helpful !

Try Boatsheen

 

[CharlesSwallow]

I've had five boats over the last 42 years and sold each one with a finish as good as the day I bought it.

I would not let a ROTARY polisher of ANY sort near my gelcoat. Instead I use a combination of a RANDOM ORBITAL polisher and pure elbow grease.

Parked next to mine in the yard at Gouvia Marina is a Moody which looks really clean in daylight (as mine does) but when the sodium lights come on, his hull is just a mass of swirls. Why? He lets a contractor polish it with a rotary finishing machine intended to be used or car body repairs for flatting down. Contrary to some of the ill-informed opinions posted here in the past, these machines are NOT used in the quality motor repair business for polishing the finished repair. Visit the Rolls-Royce dealership in Park Lane and you will find an ORBITAL being used for the early morning buff-up and certainly NOT a rotary.

One particularly good product which has come to the market in recent years is the 3M product shown:-

Chas

 

[nigelmercier]

...The dual action polishers are not the best way to avoiding swirls, but for the new user or one who may not bother with the same degree of prep, they will help...

Should you be able to handle the vibration of a porter cable for long periods, they are one of the safest options for the new user...

I agree totally, the prep is still important.

I've got a PC, but I can't face having to lug the 110V transformer with me.