Any tips on striping my hull with a heat gun???

[djn]

Hi All, I will be starting the striping process this weekend. Thirty years ago the hull was covered with two coats of west system (no cloth) then painted. I have an industrial heat gun. Any tips on how the speed the process or how to avoid damage? Cheers.

[Dan McCosh]

Why do you want to strip the hull?

[Peter Malcolm Jardine]

Epoxy doesn't like heat... I don't envy your job. I wouldn't want to own a boat that had been covered in epoxy in the first place.

[mcdenny]

I'd be wary of damaging the epoxy with heat. Over about 150 F it starts to break down.

[djn]

Hi Dan, we bought the boat this summer and it was on the hard for five years. The planks were dried out and I had to use 3M 5200 on the cracks just to sail it back down to lake St. Clair without sinking. It has been thirty years since the hull was last taken down and refinished and I just figured it would be a good time to take it down again to see what I have. Any sage advise is welcomed. Cheers.

[Dan McCosh]

In general, paint, unlike varnish, does not deteriorate much over time. It does build up. Sanding usually takes off the surplus, and leaves a good undercoat for new paint, but stripping means filling in with primer, etc. , aside from the effort in doing the stripping. Even bare spots are easy to fill and sand flush with the rest of the suface. Significant peeling usually indicates other problems than the paint itself. I think our hull was stripped some 30 years ago--not sure why. I wouldn't do it again.

[Dick Wynne]

If bent on stripping it I would use Nitromors (http://www.makingdiyeasier.co.uk/nitromors/pvremovers.html) paint remover, I have found it removes the paint and leaves the epoxy unaffected. Also allegedly kind to wood. Never had any problems with it. Have uesed heat on same boat, but laborious and results inconsistent. Chemicals may not be so un-green as the kW-hours you will get through with heat...

[RonW]

If you want to strip the epoxy, get a product called soy gel , it is non toxic, totally enviormentally friendly, and it will easily strip the epoxy. It is used on concrete to strip epoxy coatings. About $60 a gallon.

www.franmar.com

[Brian Palmer]

I used a heat gun to strip some weathered cedar floor boards and seats that seem to have had epoxy and varnish, but not a uniform coat of epoxy. The result was that there was still some epoxy left after the varnish was stripped. The varnish bubbled right up, but the epoxy just got soft and gooey, then started to smoke and burn, so I left it if it was still solid.

The epoxy being harder than the wood, it did not come off as quickly when sanding, so the epoxy areas were left higher than the surrounding wood. If this were a hull, it would look really bad.

Just something to think about. Sanding down to solid paint may be better than trying to heat strip with the epoxy underneath.

--Brian

[djn]

OK, here is the new question.....Do I have to strip the hull??? After reading so of these post, I get the sense that if it ain't broke don't fix it. The only reason I was thinking about stripping the hull is to truely see what I have. You know, are the planks sound, is there rot starting up anywhere?? Can I get an accurate check on all that without stripping? I know the dead wood is getting mushy and the keel is rusting up and there are plank cracks showing, and there is a little bit of paint peel down to the bare wood. So what do you think? Thank, as always, for your help.

[keelbolts]

If the finish is well adhered, leave it. If you want to remove it, get a Pro-Prep scraper and keep it sharp. They work better than most scrapers I've used. I don't know about other brands, but West epoxy seems to crystalize and come off as a powder. Poly varnishes tend to turn into the melted plastic they are, creating a mess on your scraper. Epoxy is not hard to remove w/ heat and a scraper.

[Wild Wassa]

I presume you are only writing about oil based paint over epoxy ... too easy if that is all you are removing. Spend time calibrating the gun temperature to the time you will exposed the paint to heat. The time you take now to find the best time/temp combination can save much work ... once you get it sorted.

A tungsten carbide scraper and a heat gun will knock the job over very quickly. I don't understand the drama about removing epoxy, epoxy comes of easily with heat. I change/rotate tungsten carbide blades often when stripping. Don't skimp on blades, sharp blades makes the stripping easier.

I'm not shy to wood everything I paint. Many times I wouldn't find problems if I balked at removing paint and epoxy. Painting is 98% prep, the other 2% the actual painting part, is the easy bit.

I strip paint quickly, but then I do strip a lot. I like to use a grinder with a polyfan disk if the job is not suitable for a heat gun. Polyfans don't suit everyone of course, they require the painter to stay well focussed when used on wood. With polyfan disks #180-220 grit makes short work of any paint.

When it comes to using chemical strippers I find Selleys 'Polystrippa', is excellent, when used twice. Metho breaks down the residues from the stipper well, I like to use metho. Polystrippa residues can also be neutralized with water.

Warren.

[Bob Cleek]

A heat gun is great for small scale work, but for stripping a hull, it just doesn't have the power you want. What you need is a propane torch. It has about twice the heat power of a heat gun and won't burn out like a heat gun will if run too long.

http://www.gap-group.co.uk/upload/products/pics/pic213.jpg

I prefer a torch with a fan tip, or a number of holes, like a gas stove burner and with a much shorter wand than the one pictured. (Which I've always been able to borrow from the yard on the rare occasions I've needed it, fortunately.) Also, for hulls, where you will be working on inverted surfaces, invest in a welder's jacket, or at least welder's long gloves. The bits of hot molten paint will fall on your exposed forearms, stick and burn like napalm. (I've go the scars to confirm this!) Use a scraper and keep it sharp. Work from the bottom up, so the rising heat will preheat the area you will be scraping next. With the torch in one hand and the scraper in the other, you can get a rythm down and make fairly quick work of it. You have to KEEP MOVING. If you dally too long in one spot, you will scorch the wood. This is so with either a heat gun or a torch, but moreso with the hotter torch.

IMPORTANT CAUTION!!!

It is extremely likely that you will be working with lead based paint, or scraping on a lead keel, and so on. The fumes from heated paint, whether created by heat gun or torch, are most certainly toxic. Minimal exposure outside when doing a relatively small job isn't that big of a deal, but working all day long under a hull IS. Lead oxide should not be inhaled. If you don't have a separate air-pac breathing system when doing this job, you should rig up the biggest fan you can find and have it directed to blow the smoke and fumes away from you towards the guy hauled out next to you!

Have fun... one of the nastier jobs of boat ownership, but sometimes necessary.

[gaffman]

Bob Cleek's last note is right on. The only thing I would like to add is that you may consider sharpening a garden hoe real well, and dragging the molten epoxy off with that.

[djn]

Hi Bob and Gaffman, using that much heat really scares me. I guess I would just have to go very slow at first. Cheers.

[Woxbox]

Seems like a lot of work just to have a look at the wood underneath. The standard surveyer technique of tapping the hull with a hammer will locate bad spots very quickly. There's no mistaking the difference between sound and rotted wood.

If it has to be stripped, I've tried all the techniques and prefer a foam-backed 8" disk on a variable speed sander/grinder.

[Brian Palmer]

DJN,

I would not be intimidated by using a propane torch to remove paint. When I was 17, I was actually entrusted with a propane burner like that to remove the paint from a very nice cedar planked Maine pea pod. The owner was even gone the whole time I did it. It came out fine.

--Brian

[djn]

Here is another question; my keel is rusted fail bad in places, what should I paint it with after it is cleaned up?

[Jay Greer]

Absolutely the most effective protective primer for ferrous metals is a product developed for the US Navy during the Korean war. This primer called "Devcon Z" is 95% pure zink. Only hot dip galvanizing is more effective. http://www.jmindsupply.com/Devcon%20Items/devcon-z%20cold%20galvanizing.htm
Jay

[Bob Cleek]

If you use a torch vs a heat gun, you don't want to go slow, you want to go FAST! Which is the point. With the heat gun, once you get the hang of heating the area ahead of your scraper with one hand while you scrape with the other (sort of like chewing gum and walking at the same time), you'll find the heat gun is way too slow for you. The lower heat of a heat gun is fine for thin coats of paint and varnish on finish areas, but it will take you forever and a day to get through a build up of thick bottom paint.

What you are looking for is enough heat to just raise a bubble and make the finish soft enough that you take it all off right down to the wood in one swipe with a sharp scraper. Since properly stripping with a sharp scraper is going to take very little time, you want a heat source that will heat the same area you scrape about as fast as you can scrape it. You don't want to be heating, then pulling the heat away and scraping, while the area around the work cools, then starting up heating again, then pulling away the heat source and trying to scrape it before it cools, then... you get it, I hope.