Steel hull repair

[Jason Crum]

I would like to know if anyone has ever heard of spraying fiberglass over a steel hull?? I pulled our 1974 Stardust houseboat to paint. I had it sandblasted and discovred pinholes on the bottom. I dont want to plate it. I would like to have fiberglass sprayed on it.Is this possible?? Thanks Jason

[georgelewisray]

You can coat the steel with glass but you need to provide some corosion protection for the steel (?epoxy over blasted steel?) and a good bonding surface for the glass. Are you planning on using the vessel until it is time to throw it away or are you hoping for resale value?

[Jason Crum]

I want to use the boat, Hopfully for a long time. Please let me give you some more info on this. The man here who does this puts 3/4 inch vyinlester resin on with a chopper gun all the way up to the cats walks.then he gel coats the glass and the paints it. The boat lives in fresh water and top speed is 8 knts. What do you think?? Thanks for your input,Jason

[Thunderhead19]

Well, the thing is that the rust boogeyman already got ya. You definitely need to clean up every last bit of it before going at it. And if the metal is so thin that you have holes, you probably should attend to the thin spots because they can flex and strech alot and de-bond from the glass. Thin spots, believe it of not, promote further corrosion and so do pin holes (I'm sure they're just patches here and there). I don't know the man who sprays the boats, so I can only guess he knows what he's doing. Is he doing 3/4" inside and 3/4" outside? What are the dimensions of your hull?

[Jason Crum]

The hull measures 16 x 58 and he is putting 3/4 on the outside of the sandblasted hull.the pin holes are sparatic to say the least. We ae also using a mechnical bond in the form of 1/8 inch wire mess with 2 inch squares welded to the hull the sprayed over.Thanks so much for the reply and your opinon is really valued, Jason.

[MikeJohns]

Allready replied to your post in the open discussion so I will copy it here too...

I wouldn't do it.
This doesn't sound like a recipe for a long term reliable fix. Expansion coefficients are different for a start so don't expect the GRP to remain adhered to the steel then youll end up ( a few years down the track) with acidic fluid pockets finishing the corrosion job in short order.

You will end up with a rusting mould inaccessible for repair. Far better to actually patch the hull. In most instances the corroded through parts will not be as extensive as you think, steel is also the most easily repaired hull material so use the advantage you have.

Incidentally old steel hulls beyond repair have been ferro-cementeed over with great success and this is a much better solutiuon since the expansion coefficients match and the alkaline environment is protective to the steel.

Cheers

[Jason Crum]

Thanks alot for the input. I had not thought about acid pockets.That a very good point.

Jason

[Thunderhead19]

I would recommend ferro-cement too. It's an excellent solution, and not too expensive. There is a bit of skill involved, you'll probably have to find someone experienced with ferro hulls.

[Jason Crum]

I am in the process of putting a new steel bottom on. After a lot of input and thought I took the plunge and hired a welding company to replace the steel. Thanks to all for your help in this decision. Jason