Removing polyurethane sealant?

[KompetentKrew]

I imagine water ingress to be particularly undesirable in a woodcore epoxy yacht, so perhaps the love of polyurethane sealant held by the previous owner of my boat is understandable.

He used Bison PolyMax, but I guess all polyurethane sealant is basically similar to Sikafix?

Any tips on removing the stuff, please?

Below is a photo of the mounting base for a Garmin GPS 72H which I'd like to remove - as well as being screwed down, copious amounts of sealant has been applied.

I thought I'd ask here because it feels extremely well bonded. I managed to get a flat-bladed screwdriver under the edge, but prying felt like I might break something.

Is there no solvent which releases this kind of sealant? Do I just have to chisel the b#@!*☠︎ off?

Thanks in advance for any suggestions.

 

[Poignard]

You could try tapping a thin stripping knife or scrapper under it with a mallet

This sort of thing :

https://www.toolstation.com/prep-pr...MI78itmNWW4wIVz7ftCh2UqQd9EAQYCyABEgJ3dPD_BwE

CT1 Multisolve might dissolve it but the trouble is you can only get at the edge

https://www.ct1.com/our-products/multisolve/

 

[Yngmar]

A putty knife shoved under all around usually separates it. Then you can scrap the rest out.

 

[FlyingGoose]

You could try tapping a thin scraper under it

Agreed a thin quality scrapper and a hammer will cut through it , did this when removing all hatches when stuck down

 

[KompetentKrew]

You could try tapping a thin stripping knife or scrapper under it with a mallet

This sort of thing :

https://www.toolstation.com/prep-premier-stripping-knife/p21904

Thanks! That looks just the job!

 

[Akestor]

A wide and very thin putty knife. The one above is narrow and thick and might damage the gelcoat.. You should keep it as much parallel to the deck as possible to not dig into the gelcoat. Tap at the full perimeter not in one spot only and it ill pop out!

 

[GrahamHR]

Is there no solvent which releases this kind of sealant? Do I just have to chisel the b#@!*☠︎ off?

Thanks in advance for any suggestions.

DMF, dimethyl formamide. Used in the printing industry; It converts polyurethanes into a weak gel. Not that I'd recommend amateur use even if you can find it for sale.

 

[thinwater]

De-Bond Marine Formula. Follow the instructions and it works a treat. Should peal right off, no scratching around.

Tested, Practical Sailor Magazine.

 

[robertj]

Wd40?

 

[eilerts]

Use hot air gun gently until it reaches 60C. Be careful not to inhale any fumes from the polyurethane. Protect the surrounding gelcoat with a mask.
When the base is gone, skrape of most of the remaining sealant and wash/rub off the remaining film with acetone.