Soda blasting paint from GRP

[Shox Dr]

Has anyone removed paint from fibre glass using Soda.

 

[Keith 66]

A local boatyard used to remove antifoul using some kind of plastic blasting media, they stopped due to complaints from other boat owners, the stuff went everywhere. I have heard of dry ice blasting being used for similar, that just leaves the paint residue behind.

 

[W.olly]

Has anyone removed paint from fibre glass using Soda.

I was for the boat but went with paving sand in the end. After buying a soda blaster aswell lol. Only due to the price difference.

Glad i did aswell as the snad did a good job but as soda is finer/softer i dont think the compressors wouldnt of done the job.

 

[Shox Dr]

The paint's on an aircraft. So it's with soda or walnuts. They are wanting to scrape it off. I've suggested blasting.

 

[Wallace]

Aircraft paint stripper?

 

[grim_d]

Aircraft paint stripper?

You can't use burn your skin off (DCM) stripper on fibreglass.

Many marine based strippers are specifically designed for things like grp.

I don't know for sure what goes on in the composite workshop at work but I think they sand paint off to do repairs on composite materials. aluminium is paint stripped.

I know there is a blasting cabinet but I think it may be for peening rather than actual blasting.

 

[ajlelectronics]

I have tried all sorts on GRP and the only reliable method is sanding. If strippers were any good, they would eat the resin. Blasting damages the surface if powerful enough to remove the paint. The only other option is that 1K paints are attacked by Acetone which is safe, but it leaves a mess behind.

 

[graffian]

Aircraft Stripper is what people used to use bare metal[you know what i mean] vettes.

 

[henry Kadzielski]

Has anyone removed paint from fibre glass using Soda.

The first question that needs to be asked is what paint. If it is the antifoul then you can pressure blast with walnut husk. You still need to be careful but it works. There is an alternative which is plastic abrasive. This is small hard and sharp chips of plastic as the media. I use this plastic abrasive in one of my cabinets to blast airless paint pumps prior to dismantling and to blast clean all the internal components prior to assembly. The plastic is more expensive than the walnut, but it gets reused. The problem with the plastic is that it is light and goes along way in the wind. People around you will complain. Soda is VERY SLOW AND VERY MESSY. Did I say it was slow and messy, oh yes I did.
Many years ago one of the big trawlers here was to go on the slip and it was suggested to 'soda blast' the outside to bare timber and repaint, sounded good. The shiprights that I know had a soda setup (big money) so they want some use. Anyway I said that it wouldn't work , but they pressed on. Two weeks later they ended up burning the paint, scraping and finally sanding, what do I know
Soda works, has its uses and applications, but is not for all.
If the paint is on the gelcote that changes everything, is it single or two pack. If it is two pack please refer to

I have tried all sorts on GRP and the only reliable method is sanding. If strippers were any good, they would eat the resin. Blasting damages the surface if powerful enough to remove the paint. The only other option is that 1K paints are attacked by Acetone which is safe, but it leaves a mess behind.

I can second the post above, having done a few and still in the process of one now. A good randon orbital sander will be your best friend.
Anyway my thoughts only (if I was smart I would be doing something else)

 

[Shox Dr]

To reiterate it's an aircraft. Not sure on paint type. It is flaking off with a metal scraper, but is taking sooooo long. [thankfully I'm not the poor sod trying to remove it, just trying to find a better solution]

Cant use chemicals or abrasives. Period.

 

[ajlelectronics]

Well then you are down to using scrapers and that will leave plenty of gelcoat damage in its wake.

 

[Shox Dr]

Well then you are down to using scrapers and that will leave plenty of gelcoat damage in its wake.

Agreed, however I have cleared about 3sq/ft without nicking the gelcoat, but it's taking too long IMO.

 

[brightspark]

anything that removes paint by blasting with anything is abrasive if it removes paint and it wont distinguish between paint and gel coat unless the gel coat is harder than the paint . keep scraping

 

[Keith 66]

Out of interest the plastic blasting media that i saw used at the local boatyard left the gelcoat surface perfectly clean & smooth almost shiny. There was no pitting & no damage as with sand blasting. But the mess!

 

[ajlelectronics]

One other possibility is to use a compressed air jet. I have found that effective where the paint is already flaking away.

 

[Shox Dr]

I'll get them to order some, and try it out. If it doesnt work then there's always EHP

 

[mpats]

Odd, everything I've every done or known about has been appropriate chemical stripper on metal and abrasive on composite. Standard practices and everything you learn doing your license and working in industry tells you to never use a metallic scraper on aircraft, and not to use chemical (for paint stripping) but rather use mechanical means on composite.

For example, when re-painting several aircraft all composite sections were done using a combination of machine and hand rubbing down.

If soda blasting is being used on parts it's done with a plastic media in the blast cabinet.

 

[ajlelectronics]

It does seem strange not to allow abrasives, how is it prepped for paint without?

 

[Shox Dr]

I've just run 22kg of machine mart soda through one of their pots. I had a go and removed 10sq" back to gelcoat in about a minute. Left it another, and came back to 4sqft no soda and 1 1/4hrs work. I know he knows how to blast he has his own, I suspect he doesnt want the job, so is laming it

I'm looking for 1t quotes if there's any suppliers reading this (pm me)


To be continued

 

[RichardM]

From experience removing paint from motorbike fibreglass, don't use stripper as it will swell the gelcoat. Never tried blasting, resorted to rubbing down for best re-spray results