Paint Stripping Advice

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Hofty
Posts: 1
Joined: Mon Aug 17, 2020 3:03 pm

Paint Stripping Advice

#1

Post by Hofty »

Hey Folks,

In need of some advice. I have bought a 12ft aluminium boat which has definitely seen some wear/tare on the paint job. Stripping it has become rather cumbersome and wondering if anyone wants to chime in for some advice or how to speed up the process?

So far I have tried on some spots to use: Paint stripper (Spray), orbital sander, belt sander and then a drill with wire cup attachment. The stripper seems to work but not really peeling the paint off in one attempt.

See pictures. What I am hoping to do is find a paint stripper that will take off all the paint in one attempt and if not "is it possible to use an angle grinder with a polycarbonate stripping disk?" 3M™ Scotch-Brite™ discs?
Attachments
Use of drill + wire cup
Use of drill + wire cup
b1.jpg (72.16 KiB) Viewed 1099 times
Peeling Paint
Peeling Paint
b2.jpg (97.54 KiB) Viewed 1099 times
Front + Peeling paint
Front + Peeling paint
b3.jpg (53.88 KiB) Viewed 1099 times
Paint Stripper peels off 1 layer at a time
Paint Stripper peels off 1 layer at a time
b4.jpg (103.89 KiB) Viewed 1099 times
2-3 coats of paint remover to bare aluminium
2-3 coats of paint remover to bare aluminium
b5.jpg (107.32 KiB) Viewed 1099 times
kmorin
Donator 08, 09, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21
Posts: 1589
Joined: Mon Aug 18, 2008 1:37 am
Location: Kenai, Alaska

Re: Paint Stripping Advice

#2

Post by kmorin »

hofty,
welcome to the AAB.com Forum, and I hope our resident paint and films expert will stop by the post and give you a definitive answer. In the meantime I'll share some paint stripping experience with you for what its worth?

First, any stripper that doesn't have the highly noxious, eye watering, and breath compromising fumes (that evaporate) isn't worth the chemicals its made of... (IMO) "If it ain't highly toxic- its not worth buying."

I had been left with a 206 by a friend who's "painting-the-plane-support-crew" left him high and dry; to mix a few metaphors. The plane was in a hangar that had no running water and here's what I learned about painting stripping.

I put the paint stripper into an electric open roaster with warm, water bath, and the lids to the can's cracked. I was wearing a North Half Face air purifying respirator and organic vapor filters (black activated charcoal) and safety glasses the entire time - I was in a hangar.

I found the paint stripper worked 5x as well if it was hot/warm when it was spread on. I used rubber/plastic painter's trowels and then a big win: pulled painter's thin visqueen over the paint stripper while wet and let it sit for 15-20 minutes without drying out or losing much the vapors so it was still "active".

I did the stripping in patches of about 5-6' from leading edge to trailing - which would be like the bottom of your skiff shown.

After the stripper had time to work- without losing its active ingredients to evaporation- I peeled the stripper, paint, and painter's visqueen into a bundle by rolling it up and catching it in a trash can/barrel. at this point 90% of the paint was gone and the easy part was over. I use rubber squeegee's to slop the wet paint and stripper mixture from one end to the other of any given area, keeping the thin visqueen with it and making a fairly compact package of each messy area.

Now, remaining around 30% of the rivets were rings of paint and here is what I did to get them cleaned. I used angle head drills, they turn MUCH slower than a 4" grinder even with a speed controller, and a hook and loop 2" and 4" by 1/4" shank sanding pad.

Scotchbrite (tm) pads or any version of them will stick to hook and loop sanding pads. I cut discs of SBrite marooon, and put them on the sanding pad mounted to a drill. Then I took a small paint brush and put a 'dab' of fresh stripper on the rivets with paint rings or any areas where the stripper hadn't left clean metal.

At each point I put a tablespoon or two of dry saw dust over the 'dab' or stripper and put the drill on that mixture and ran the drill for a few seconds, in 90% of cases this scouring by the sawdust mixed with stripper scoured the rivet head and surrounding aluminum clean.

I could strip a wing side (four sides!) and detail the flap pockets and other control surfaces recesses in two day's work. There are lots of rivets and they're of several types on an air frame surface.

The saw dust keeps a scouring action with little net abrasion of the metal while still cleaning the rivet rim and sheet material interface ( I was told by the painter this was a very big deal to avoid blistering, bubbling and solvent action by the new top coat)

So, take some painter's drop cloth thin visqueen and put it over warmed up stripper and let is sit for much longer than you think is wise. Avoid the fumes and see just how much of the paint can be lifted by chemicals?

Also I used nylon tooth brushes to help excavate rivet rings of paint not fully dissolved by stripper but mainly softened and this was in cooperation with the sanding pads running SBrite.

Incidentally, we found buying maroon square SBrite pads was WAY cheaper than the prepared hook and loop pads - 10x or something... so that is why we used the more inexpensive combination to 'buff' the aluminum wings.

Not sure this will come across in text, but this is how we stripped this airplane of its decades old paint. Mechanic/painter/plane builder who was to put on the new paint accepted the results of this rivet surface stripping and the paint job turned out not to have even one single 'blister' or rivet ring rupture due to left over paint- that includes the sheet overlaps and control surface pockets on the trailing edge.

While a light soda/sand blast would probably be the really best way to clean and prep your skiff for a new paint job: this method will work- its just not all that fast!!

Cheers,
Kevin Morin
Kenai, AK
kmorin
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