plan to remove the 30 year old paint from my mast and leave it back to the bare aluminium any ideas for removing the paint. Soda blast, paint stripper? There are lots of paint strippers but which one actually works, and has anyone soda blaster. Any help would be great.
Cheers
7" sander/polisher with paint remover disk is the fastest and least messy option, imo. it also tends to scuff the surface making it better for paint adhesion.
OK thanks I don't really want to repaint so don't want a scuffed surfaced but would that polish out?
The scuffing is very light but the disks do something no paint stripper can do. They will buff off the clumps of oxide. I'd recommend repainting. An un-anodised mast will take on a splotchy appearance as it forms it's own oxide layer and will be very susceptible to galvanic corrosion wherever it abuts stainless steel. Having said that, I was shown this neat trick of painting raw aluminium with a few coats of penetrol - the stuff you mix with paint. The guy in the yard that passed this on painted his entire mast with the stuff. You just slap it on with a brush. I repainted my mast with epoxy undercoat and 2K LPU topcoat (and after five years it still looks great) but at the same time cleaned up all the cast components and painted them with penetrol from an ancient can I found in my shed and they are also holding up great. I initially thought the penetrol thing was BS, but it seems to work. It's clear and looks almost like a laquer when applied. Might be worth a shot as an alternative to painting.
The other suggestion (from the same guy) is to prep aluminium immediately prior to applying any coating using an aluminium cleaner that contains hydroflouric acid as an ingredient. This acid is the stuff they used to warn you about in school that will eat through flesh and bone so a lot of aluminium cleaners don't actually use it, but there are exceptions and (I think) Septone AluBrite is one. Use it pretty much full strength (taking adequate precautions!).
I have rebuilt and refurbished 2 masts (for Farr727 and Santana 22 - the latter putting a cut down Etchells mast into it with higher fractional rig and long boom big mainsail so as to cure the lee helm original design problem) and had excellent results from the below Norglass products - I don't know why they call this product norust though, when it is suitable for aluminium as well as the other metals noted.
www.norglass.com.au/products/norust-all-surface-primer
Then 2 coats of this;
www.norglass.com.au/products/northane-gloss
Also don't know why the photo there shows 1.33l hardener and 4l base and the tech data sheet has 2:1 ratio and the correct photo showing 2:1. I am probably missing something.
Anyway Norglass technical advice is 2nd to none and they will sort it out for you. A great Australian company.
I can't imagine re-rigging a mast and not re-painting it with the above system. Of course use Tefgel between stainless rivets and the alum mast to avoid galvanic corrosion. If you have stainless spreader bands suggest completely remove these and check that the galvanic corrosion barrier under them is still intact - else your mast will be eaten away like I found mine on the 24 footer in 2007. Lucky I had a section of mast to sleeve externally over the top of the single spreaders location with epoxy glue and rivets. Then rivetted the ss spreader band back on. It is still stronger than ever now. I used Duralac back then between the monel rivets and mast - apparently Tefgel is better now but I would assess both. Be aware that 3/16 monel or ss rivets take a large grip force to clench using a standard rivet gun from your local green shed. The external mast band at the spreaders will reduce your spreader angle a bit.
www.bunnings.com.au/our-range/tools/hand-tools/staples-rivet-guns/rivet-guns?gclid=EAIaIQobChMIktaS3sDg6gIVjHwrCh3uyQ8oEAAYASAAEgJlCPD_BwE&gclsrc=aw.ds
Some people rave about Nyalic - have never used it but it could be the go...........
www.nyalic.com.au/nyalic.com.au/MARINE.html
i used a stainless steel wire brush on a 125mm angle grinder. the brush was soft and radial , not axial/cup and aggressive. I washed the mast
with the Septone AluBrite as Reefmagnet said before I painted it.
I've been using the polystipper disc on the 5" grinder recently they seem to have the ability to move the paint fast but not so much the metal,
I stripped my Cav 32 mast about 6 years ago,using angle grinder.
slow noisy and environmentally unfriendly.
then nyalic, great stuff and easy to apply,flows like water.
I am very happy with the result, it looks good six years later still fine. I would never do it again that way, I think I would use a paint stripper, chemical,of some kind.
Hi scaramouche
I am very happy with the result, it looks good six years later still fine.
Is that unpainted?
gary
I bought a lt of nyalic to paint a raw aluminium mast be but couldn't do it in the end. I figured 40 years for the first paint job so a pretty mast it will be.
I took the paint off my Martzcraft 35 mast 6 years ago and its fine. It was looking scrappy and I asked my rigger for a quote. to strip it and repaint it. He recommended blasting off the paint ad leaving it bare. 6 years later its still perfect.
Mate stripped the paint off his Cole aluminum 42 footer, hull and mast. The mast he polished and coated with a clear finish the WA crayboats use on their bare aluminum boats. It's been more than 5 years and still looks brilliant. He did have to do some welding though. Paint covers all sins.
Its kind of logical to leave it unpainted but I never thought about it until Colin Beashel my shipwright suggested it. In my workshop I have a pile of aluminium offcuts and some of them have been there more 10 years and are same as they always were