Poly Abrasive, flap disc, etc on raised bolts and corners

[paulgt]

Hi All,

I need to prep some walls and ceiling of an old steel barge. The area in question will be covered with sprayfoam insulation once cleaned. There are ribs with rivet and bolt heads exposed on the interior that need paint and rust removing. There are about 15 ribs (5m wide barge, spaced .5m) and I am not too worried about the flat areas but wonder if anyone has any recommendations for cleaning the raised areas with ribs/rivet heads and corners.

I realise that I have a lot of these and consumables are going to cost me. I've heard some horror stories from people who have done similar jobs with wire cups/grinders and been picking steel out of their knees a year later.

I've got decent welding/grinding safety kit - mask with grinder mode, gauntlets, leather jacket, clear, goggles - the only thing I don't have is thick leather trousers.

I'd rather pay the extra for consumables that will make the job easier. Poly abrasive look a good solution to my amateur eye or are they more suited to flat surfaces.

I'd appreciate any advice - either on the protection or consumable front to make this a less painful task.

Many thanks,

Paul

 

[Keith 66]

Back in 83 i had the unfortunate task of cleaning a 35ft steel trawler inside & out at Mikes boatyard Leigh on sea, there were 3 of us with grinders & cup brushes etc. It was the filthiest poxiest job i ever had & took us nearly a month. It would have been cheaper for the boss to pay the money & have it blasted properly but he got a **** job & deserved it. I wish you luck.

Mod: language edit

 

[paulgt]

Hi Keith,

I feel like humming "always look on the bright side of life...". If you are still traumatised from 83, it must have been terrible! Right now it doesn't help that it is freezing in the mornings and condensation is a pain too.

There are some random environmental restrictions on this particular site that make blasting a non-starter so sadly, it is what it is.

I realise it is a **** job but would appreciate some advice on which technique/consumables might be the least painful.

Cheers,

Paul

 

[Dormeister]

In my experience poly abrasives will be perfect for the areas around the bolts and rivets. But if you.get anywhere near them it will just shred the disc peices.

If I were doing the job (and Ive done similar in the past), i would go over all the nuts & rivets with a wire wheel - knotted preferabley and about 25mm around. Then do the rest with a poly.

 

[DanielW]

To stop you getting wire needles in your knees? then wear protective knee pads,flap wheels/disc will just shred on raised surfaces like bolts and stuff and I would myself use wire wheels either in a drill or grinder.

 

[rtbcomp]

Would spot-blasting with a decent syphon gun raise the same environmental issues? It wouldn't generate clouds of dust like using an industrial setup.

 

[paulgt]

Thanks for the tips guys. rtbcomp - what compressor do syphon guns need? Mine is only 15cfm.

Cheers,

Paul

 

[brightspark]

using a syphon gun even at 90psi pressure would take forever on rusted steel .to get anywhere reasonable u would need a presurised pot with 3mm jet running a 22cfm compressor minimum

 

[rtbcomp]

Thanks for the tips guys. rtbcomp - what compressor do syphon guns need? Mine is only 15cfm.

Cheers,

Paul

You should be OK if you're most just giving it short bursts on the bolt heads rather than a continuous blast. Anglo-Abrasives do one that gives a choice of air nozzles, go for the smallest. Use a sharp grit such as crushed glass.

If you do run out of air then just do some flat bits with a polydisc &c whilst the compressor catches up.