Removing "great stuff" foam sealant from inside the mast

Jul 26, 2023
24
TBD TBD NY
Ok, so this was an interesting one to me... I'm looking at a nice deal on a (mostly) well-kept Catalina 25. Overall the boat just needs some cosmetic work however, the current owner injected some "great stuff" foam sealant into the mast. They own the boat as a home and mostly used it just to sleep on, not sail. The sound of the wires inside the mast clanking around at night was annoying, so their solution was to squirt some of this stuff in there. It looks like this is a solution that was discussed here before however, I've never heard of such a thing.

I'd want to remove this for potential performance reasons and to regain the ability to step/unstep the mast. Has anyone had experience removing this stuff from inside the mast? Is this easy or would I be walking into a hairy problem?

Thanks!
 
Jan 19, 2010
12,553
Hobie 16 & Rhodes 22 Skeeter Charleston
Do you need to get it all out? Or just enough to run wires up the mast?
 
Mar 20, 2015
3,212
C&C 30 Mk1 Winnipeg
Has anyone had experience removing this stuff from inside the mast? Is this easy or would I be walking into a hairy problem?
Our boat had 7 feet of it in the bottom of our keel stepped mast. (Presumably in a misguided attempt to prevent water getting down the mast, into the bilge)

Horribly implemented idea. It prevented running new wires, and trapped water so that it would have damaged the mast extrusion if it froze while the mast was stepped.

I removed it with 3 different diameters of abs plastic pipe, with the end cut into hole saw type teeth . I then rotated the pipe to cut sections out.

I also used the pipe as a scraper for the inside wall of mast,.once most of the foam was removed.

If needed, you could make the longer than 10 feet by using plastic pipe couplers.

Unfortunately,.dispute my best efforts, this method resulted in damaged wiring, but since I was redoing part of the wiring anyhow, it wasnt a big deal.

I then installed plastic conduit into the mast and riveted it in place. The conduit stopped the noise while still making it easy to run new wiring in the future.
 
Last edited:
Mar 20, 2015
3,212
C&C 30 Mk1 Winnipeg
Many foams will dissolve with gasoline or acetone.
I was told the same thing.... unfortunately great stuff type spray foam only dissolves with acetone when UNCURED.

Had it worked, I wondered how I would get the dissolved goo out.
 
Mar 20, 2015
3,212
C&C 30 Mk1 Winnipeg
“Potato Gun” comes to mind.
Being someone who likes potato cannons...That I'd like to see. :biggrin:

Unfortunately even if it was dissolved to goo, the wiring and mast hardware would make that impossible to do a good job cleaning it out with air pressure or a plunger.
 
Last edited:
Mar 20, 2015
3,212
C&C 30 Mk1 Winnipeg
FWIW, I have often seen people suggest using solvent on polyurethane based spray foam.

Here is a quote directly from the company that makes "great stuff" brand spray foam, but it applies to the other brands.

"There is no solvent that will remove cured insulating foam.

For cured foam, remove as much as possible with a dull scraper or a hacksaw blade and then try scrubbing the remaining film with a non-abrasive cleaner. If that does not work, gradually move up to more aggressive means including sanding, sandblasting, and repainting."
 
Last edited:
Mar 20, 2015
3,212
C&C 30 Mk1 Winnipeg
@Anchored87
I should mention that when I was using homemade abs pipe "saws" to get spray foam out of our mast, removing any mounting hardware that instruded into the mast made it much easier.

I initially tried using smaller abs pipe so that I could try avoid the hardware fasteners, and mast wiring, but it was a tiring and time wasting effort.
 
  • Like
Likes: Timm R Oday25
Jan 19, 2010
12,553
Hobie 16 & Rhodes 22 Skeeter Charleston
Being someone who likes potato cannons...That I'd like to see. :biggrin:

Unfortunately even if it was dissolved to goo, the wiring and mast hardware would make that impossible to do a good job cleaning it out with air pressure or a plunger.
I think what @Ward H was suggesting is to spray to hairspray (or ignition fluid) into the mast behind the foam, then LIGHT IT UP and shoot the foam out... the foam would be the "potato".:yikes:

Sounds fun... probably earn you a spot on this year's Darwin awards... and if you decide to try it, please film it..(just kidding... don't do it):thumbsdown:
 
Mar 20, 2015
3,212
C&C 30 Mk1 Winnipeg
Sounds fun... probably earn you a spot on this year's Darwin awards... and if you decide to try it, please film it..(just kidding... don't do it):thumbsdown:
Yup. Would be fun. From long distance away. Moreso if it was a fail video on YouTube which lacked involvement of my loved ones.

Of course this is coming from someone who wants to mount air cannons that fire balloons, on the club boats so we can have sea battles.

Did I mention I did pyrotechnics professionally in a past life ?
 
Last edited:
Mar 20, 2015
3,212
C&C 30 Mk1 Winnipeg
When and where? I definitely want to watch this one!

I miss read perhaps - I was thinking firing balloons that are on fire...
I envision 3 water balloon launchers on one side.
Not sure how judging/scoring would work.
Sure as heck don't want to use balloons that would hurt anyone or stain their boat.

Just got back from 2 weeks on the water and great ideas occur when you are bored while motoring in calms.

Me: racing a keelboat with a hullspeed of 6.6 knots is, Meh.
Him: don't you have a kids toy cannon ? What if we had a bunch of them ?

No.. no fire, either propellant or projectile, would be involved.. ... even if it is compelling.



 
Jul 26, 2023
24
TBD TBD NY
@Leeward Rail @rgranger Thanks for the tips. I think the pvc "saw" may be the best route but my main issue is that I'd have to sail this from the current owner's location to my location. They don't sail this boat so I'm nervous whether or not I'd even be able to raise the main (halyards run through the mast on this boat I think). If I can't make it through the rest of this season without addressing the issue I may pass on this one.

Otherwise, it seems like the PVC idea is the best solve. How much wiring did this destroy and should I expect to have to replace it afterwards? I'm trying to understand how much I should factor this cost into my offer.
 
  • Like
Likes: Leeward Rail
Apr 5, 2009
3,098
Catalina '88 C30 tr/bs Oak Harbor, WA
One word. Slingshot!
build ones that will mount into the winch socket to launch small to medium sized water balloons.
 
Mar 20, 2015
3,212
C&C 30 Mk1 Winnipeg
How much wiring did this destroy and should I expect to have to replace it afterwards? I'm trying to understand how much I should factor this cost into my offer.
The problem is the existing wiring wasn't in a linear location. So even though it looked like I wouldn't hit the wiring.. partway into the foam, I did.
My mistaken assumption was that the wire insulation/sheath would stand up to the plastic "saw" teeth. It didn't. I ended up replacing all the wiring. Coax for VHF included.

That said, my foam was 7 feet long. .if the foam in the boat your are looking at is only a small section, you may get away without damaging any wiring. Obviously no guarantees, so I would assume you end up replacing it all and factor that into price.

So the halyards are also foamed into place ? just like the wiring... if the foam isn't thick, you may get lucky.. but I would assume halyard replacement would be needed.
 
Last edited:
Mar 20, 2015
3,212
C&C 30 Mk1 Winnipeg
One word. Slingshot!
build ones that will mount into the winch socket to launch small to medium sized water balloons.
Not enough for a true broadside (unless you have multiple crew on the rail), and boring since there is no noise.
 
Last edited:
Mar 20, 2015
3,212
C&C 30 Mk1 Winnipeg
halyards run through the mast on this boat I think
The Catalina 25 has halyards in the mast.
Depending on age, it may have wire to rope halyards. I would inspect the halyards and shelves, and if needed, replace them with all rope halyards and new sheaves.

Easy peezy when the mast is down. Especially so since a Catalina 25 is trailerable and therefore "easy" to drop the mast. And you would need to drop the mast to remove the foam.

Hmm.. I wonder if the foam area is small enough that the halyards can be yanked loose ?
 
Last edited:
Jul 26, 2023
24
TBD TBD NY
Hmm.. I wonder if the foam area is small enough that the halyards can be yanked loose ?
I'm hoping this is the case. Worst case scenario, what is a typical price in the NE US to purchase new halyard / wiring? Though this is kind of a moot point b/c if I can't sail the boat away I can't buy it...
 
Mar 20, 2015
3,212
C&C 30 Mk1 Winnipeg
what is a typical price in the NE US to purchase new halyard / wiring
Wiring would depend on what is on the mast and length of cables

VHF antenna, Masthead light and combo steaming/decklight is what my Catalina 22 had If the boat has instruments on the masthead that would complicate things.

I am in Canada but a halyard kit is listed online for $300 USD including sheaves.

Is there a local chandler near you or the boat ? I prefer buying locally.

I would definitely contact the SBO store.
They are great to work with and could likely help you with wire and halyard pricing and availability
 
Last edited:
  • Helpful
Likes: JamesG161