Welding on a metal boat with insulation

[fuss]

I just wondered if anyone has experience of welding (aluminium in this case) when a boat is full of sprayed insulation.
It seems that it is almost impossible to me which means that the moment you spray the insulation, any further mods involving welding are no longer possible because of fire risk etc.
Anyone with any experience to offer?
thanks John

 

[PeteE]

I have on a number of occasions welded my old ('77) Merc van which has sprayed-on insulation. Its a 2 man job - me outside welding and an expendable assistant inside with a water spray (and welding mask! + Fire Extinguisher).

Using MIG keeps v hot areas to a minimum, and all insulation is removed in the near vicinity before starting.

It works - but as you acknowledge, high risk (even higher on a boat). Elf'nSafti probably wouldn't approve.

 

[noelex]

It is reasonably easy to remove the insulation from the area to be welded and then replace it
One of the principals of good metal boat construction is that it should be possible (particularly for a steel boat) to remove the interior to access the hull or deck.
This is also often essential for repairs in a fiberglass yacht, but few GRP boats make any allowance for accessing all of the hull from the interior. Unfortunately in many fiberglass boats the interior is fitted before the deck is put on making removal impossible.
At least with a metal boat the interior has been installed with the deck welded on (in most cases) so it can be dismantled if necessary.

 

[Gumpy]

We cut our spray foamed barge in half and extended her!
Most sprayfoam doesnt burn these days (fire proof) it just melts back, however I would always recomend someone on the inside with a CO2 extinguiser as a backup.

Foam needs to be mqde good afterwards that about it.