sanding down fibre glass coated sheets with a floor sander

[AstonHill]

Dont know if this should be posted in the "floors stairs and lofts" section; but any road. I stared a thead in this section not so long ago about sanding down a very dirty and oily floor. I was adviced to hire a floor stander from HCS.

Anyway; in that time I have had some scrap/ second hard plywood delivered. Its sheets of plywood from a scrapped box trailer. Its about 1" thick and they sprayed both sides with fibre glass in the factory. Anyway I see that HCS hire out wall sander too! for which I want to sand down the fibre glass walls of my dirty box trailer (along with the oily greasy wodern floors as well)

I was going to leave hiring the floor sander until a little while and other stuff arrived and stuff. Anyway I am thinking of using the floor sander to sand down the scrap/ used trailer panels with the floor sander. As I intend to make walls out of these.

But my question is, is the floor sander suitable for sanding down fiber glass or not?

Cheers
AH

 

[Deleted member 174758]

Is this a smooth fibber gloss surface, or one with all the fibbers visible? If it is smooth, the surface has possibly been finished with a gel coat, in which case it can be sanded and a new gel coat applied. On cars, etc this is normally done with a random orbit sander

 

[AstonHill]

The inside walls are defo smooth! (not sure about the out side though)
But HSS do a wall sanding machine as well as a floor snader. Should I hire this or not?

As on my other thread when I asked about sanding down the wooden floor or my trailer, I was told not to waste my time with an angle grinder and a wood sanding pad for it, and to get a proper machine for the job considering the size of the area. For the smooth fiber glass walls I want to sand down hear; what do you think I should get? Bear in mind its a 45' long 8' tall 8' wide box

Angle grinder with right pad or hire a wall sanding machine ?

Cheers

 

[Deleted member 174758]

Wall sanding machines are designed for plaster, a much softer material, so they probably don't have the power needed for the job

I still don't think a small angle grinder is the tool for the job - maybe a 9in one would be appropriate due to the surface area you will be covering, but personally, I'd use a 4in/100mm belt sander if I was doing any large amount of panels (easy to say because I own one)

I presume all you want to do is take a light pass off the surface with the intention of cleaning it and providing a mechanical key for any subsequent (paInted) finish.

 

[AstonHill]

Wall sanding machines are designed for plaster, a much softer material, so they probably don't have the power needed for the job

OK lets forget that one then

I still don't think a small angle grinder is the tool for the job - maybe a 9in one would be appropriate due to the surface area you will be covering, but personally, I'd use a 4in/100mm belt sander if I was doing any large amount of panels (easy to say because I own one)

Do you go though a lot of belts when using it?

I presume all you want to do is take a light pass off the surface with the intention of cleaning it and providing a mechanical key for any subsequent (paInted) finish.

Yes all it is, is to clean it up from many years of dirt. Not looking to do much cutting al all, more like T-cutting a car thing

 

[Deleted member 174758]

Do you go though a lot of belts when using it?

You will use whatever it takes. TBH until you try doing the job you won't know how many flys (or discs) you will end up using). One thing is for certain, though, you willneed some way to deal with the extremely fine dust that comes off fibreglass resin - so a tool connected to an M-class vacuum is a must. As is a decent face-fitted P3 dust mask (been there, etc). Don't be tempted to cheap out and use a Henry - they simply aren't up to the job

Incidentally, the life of belts an be extended by periodic cleaning with a crepe belt cleaner (you clamp the cleaner block in a vice and run the sander against it for a few minutes)

Belt sanders cut very quickly and need to be kept in (side to side) motion at all times, but they are very effective and if needs be can be hired (along with the extractors)

 

[AstonHill]

You will use whatever it takes. TBH until you try doing the job you won't know how many flys (or discs) you will end up using). One thing is for certain, though, you willneed some way to deal with the extremely fine dust that comes off fibreglass resin - so a tool connected to an M-class vacuum is a must. As is a decent face-fitted P3 dust mask (been there, etc). Don't be tempted to cheap out and use a Henry - they simply aren't up to the job

Yer I know about the fibre glass **** thing! it creates **** on the paws of the arms and hands, so in the lungs I guess it could be life threatening! Best use a proper dusk mask I guess (and no, not those childish mary poppins things called face nappies to protect you from the the emperor's new clothes dressed up as covid)

Incidentally, the life of belts an be extended by periodic cleaning with a crepe belt cleaner (you clamp the cleaner block in a vice and run the sander against it for a few minutes)

Dose the **** stick to the belt or end up in the vacume bag?

Belt sanders cut very quickly and need to be kept in (side to side) motion at all times, but they are very effective and if needs be can be hired (along with the extractors)

So should most of the **** go into the extractor bag and not stick to the belt then?

Should a decent machine keep the belts top dead centre and thus stop the belts from ripping?

 

[Deleted member 174758]

Dose the **** stick to the belt or end up in the vacume bag?...

So should most of the **** go into the extractor bag and not stick to the belt then?

With a decent extractor a goodly percentage ends up in the vacuum, however you will always get a percentage sticking to the belt which can cause clogging or worse still glazing of the abrasives. Initially you would need to watch for this and use a crepe cleaning "stick" to unclog the belt before it gets to the point of being glazed. It is also important to work up through the grits and not just assume you can start with a fine grit

Should a decent machine keep the belts top dead centre and thus stop the belts from ripping?

AFAIK belt sanders all have manual tracking adjustment on the front roller. I've had a few in both 3in and 4in sizes over the years (Makita/Wolf, Bosch, Holz-Her, Elu) and they all had tracking adjustment. Once your belt is tracking correctly (a few seconds work), then that's it for thecsession.

 

[AstonHill]

With a decent extractor a goodly percentage ends up in the vacuum, however you will always get a percentage sticking to the belt which can cause clogging or worse still glazing of the abrasives.

Any idea how many bets I would need for a 45'x8' floor? bearing in mind it quite bad, (45 foot trailer)

Initially you would need to watch for this and use a crepe cleaning "stick" to unclog the belt before it gets to the point of being glazed.

Crepe cling stick?

It is also important to work up through the grits and not just assume you can start with a fine grit

Sure! as its a bad floor I intend to go with the most coarse grinding pads Travis Perkins have. Maybe when the belt have worn out then I can use the same belts for the fine finish

 

[Deleted member 174758]

Any idea how many bets I would need for a 45'x8' floor? bearing in mind it quite bad, (45 foot trailer)

That is simply impossible to say

Crepe cling stick?

Crepe belt cleaner. Even Amazon sell them

...as its a bad floor I intend to go with the most coarse grinding pads Travis Perkins have. Maybe when the belt have worn out then I can use the same belts for the fine finish

That isn't how aluminium oxide abrasives work. As the belt wears down you'll simply find that it cuts less effectively with variable results (i.e. some part of the belt will be a lot coarser than others)

 

[AstonHill]

That isn't how aluminium oxide abrasives work. As the belt wears down you'll simply find that it cuts less effectively with variable results (i.e. some part of the belt will be a lot coarser than others)

But should it still be OK for sanding/ dusting down?

Also what do you think of the wall sander? OK for wood/ fiber glass or only good for light plaster board ?

Cheers

 

[Deleted member 174758]

...what do you think of the wall sander? OK for wood/ fiber glass or only good for light plaster board ?

This has already been covered

Wall sanding machines are designed for plaster, a much softer material, so they probably don't have the power needed for the job.

No matter how many times you ask a question, the answer won't change

But should it still be OK for sanding/ dusting down?

I refer you to my earlier response

Suck it and see

 

[AstonHill]

This has already been covered

OK wont ask stupid question again