Hot air gun ok on GRP?

Little Rascal

Little Rascal

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I need to remove flaking and peeling paint from the interior glassfibre of my Hunter Europa.

I'm reluctant to start playing with chemical strippers ...

Will a hot air gun do any damage to the GRP?
 
I would try and scrape and abrade the paint off before using a hit air gun. It is common to use a hair dryer to remove old boat names and I tried with a Black and Decker hot air gun.

It was very difficult to control the heat by keeping the nozzle at a certain distance, too far and not hot enough and too close the heat was very hot. The difference between too far and too close was not a lot, at least as far as my shaky hands were concerned.

I also scorched some teak gunwhale. Considering that a method to loosen fasteners embedded in GRP is heat, I would recommend that you do not use a hot air gun.

I have used sanding pads with coarse sandpaper, 80 grit, to clean up saloon berth lockers where one side is the inside GRP of the hull. It worked well but have a vacuum handy to frequently clear up the dust.
 
Thanks for the input.

The Europa doesnt have an interior moulding so it's not painted gelcoat but just the rough inside of the lay up. I was a little concerned that I would start to cut into the glass if I scrape or sand too hard.

I plan to paint /headline with vinyl again so I suppose I just need to provide a suitably clean and smooth surface to paint on/glue to.
 
Little Rascal said:
The Europa doesnt have an interior moulding so it's not painted gelcoat but just the rough inside of the lay up. I was a little concerned that I would start to cut into the glass if I scrape or sand too hard.
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Angle grinder. Rotary wire brush. Gentle hand. PROTECTIVE CLOTHING.

Been there, done that - Hunter 490.
 
I had to remove years of paint recently - I did use a hot air gun but very carefully. I found that home made scrapers were the best tool to use with the hot air gun. I used steel from a 22" panel saw, the type which has induction hardened teeth. I used a grinder with a cutting wheel for stainless steel (about a quid each) to cut and shape the blades, them sandwiched them between bits of offcut mahogany (from a front door) for handles. They sharpened up nicely and held an edge for quite a while between sharpening.

Make a few of different shapes, and several of the same shape to sharpen all at once. A broad blade with a narrowish point (like a pear with a truncated end) was best for use with the hot air gun - it deflected the heat and also heated up the blade to slice through the paint. Scrapers which PULL to cut are much easier to use than those you PUSH. I got one of those proper scrapers with a handle but it was no better than the home made ones - in fact the pointy edges of the triangle were a liability.

I also used an angle grinder but with a flap disc - actually quite a few flap discs - but it needs a steady hand.

The dust is a killer, do use face mask / eye protection!

Chemicals just made a horrible mess, washing them off just spread the gunge even further.

Personally I wouldn't take a wire brush on a grinder anywhere near GRP; if it goes wrong it will go very wrong!
 
I'd try the hot air gun on half setting . I've done mahogany and ply in dinghies that way.
Just keep passing your scraper hand under the hot air. You'll soon get to judge how hot you are making things.
You'd be amazed hot hot you need to get grp to scorch and then burn. We tried some to destruction with a gas blowtorch. It took about 15 seconds to suddenly turn black and start burning. It does it very suddenly though.
 
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